Research ArticleParametric Investigation and ThermoeconomicOptimization of a Combined Cycle for Recoveringthe Waste Heat from Nuclear Closed Brayton Cycle

Lihuang Luo Hong Gao Chao Liu and Xiaoxiao Xu

Key Laboratory of Low-Grade Energy Utilization Technologies and Systems of Ministry of EducationCollege of Power Engineering Chongqing University Chongqing 400030 China

Correspondence should be addressed to Hong Gao gaohongcqueducn

Received 19 April 2016 Accepted 22 June 2016

Academic Editor Xiangdong Li

Copyright copy 2016 Lihuang Luo et al This is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

A combined cycle that combines AWM cycle with a nuclear closed Brayton cycle is proposed to recover the waste heat rejectedfrom the precooler of a nuclear closed Brayton cycle in this paper The detailed thermodynamic and economic analyses are carriedout for the combined cycle The effects of several important parameters such as the absorber pressure the turbine inlet pressurethe turbine inlet temperature the ammonia mass fraction and the ambient temperature are investigated The combined cycleperformance is also optimized based on a multiobjective function Compared with the closed Brayton cycle the optimized poweroutput and overall efficiency of the combined cycle are higher by 241 and 243 respectivelyThe optimized LEC of the combinedcycle is 073 lower than that of the closed Brayton cycle

1 Introduction

With the development of the world economy the totalenergy consumption increases steadily The consumption ofthe energy especially fossil energy resources causes andaccelerates the occurrence of many environmental problemsNuclear energy is an efficient energy source that plays animportant role in current energy demand Because of itsinherent safety the high temperature gas-cooled reactor(HTGR) has attracted many attentions of the researchers Toensure the high efficiency of nuclear power plant reasonablethermodynamic cycle should be used Despite the higher effi-ciency of HTGR a large amount of waste heat is dischargedfrom the precooler of the nuclear closed Brayton cycle Thusresearch topics focus on recovery and utilization of this lowgrade thermal energy

At present the waste heat of the closed Brayton cyclecan be recovered by several ways as follows desalinationOrganic Rankine Cycle (ORC) Kalina cycle and ammonia-water combined powercooling cycle Soroureddin et al[1] proposed the utilization of this waste heat for powerproduction by using ORC Dardour et al [2] proposed

and analyzed the utilization of waste heat fromGT-MHR andPBMR reactors for nuclear desalination of sea water SinceKalina [3] introduced the Kalina cycle with the ammonia-water mixture as the working fluid at least 30 new cyclesbased on the Kalina cycle have been presented Goswami[4] also put forward a combined powercooling cogenerationcycle with ammonia-water mixture as working fluid Fora turbine inlet temperature and pressure of 410 K and 30bar the first law efficiency is 2354 such value is muchbetter than ORC or Kalina cycle [5] Padilla et al [6] andLu and Goswami [7] modified the combined powercoolingcogeneration cycle and studied the effect of key parameterson cycle performance Pouraghaie et al [8] revealed that theefficiency of the combined powercooling cogeneration cycleis much higher than that of a conventional steam Rankinecycle Demirkaya et al [9] also found that the combinedpowercooling cogeneration cycle has a promising prospectfor effective utilization ofwaste heat because of the reasonablygood matching between the temperature profiles of heliumand ammonia-water mixture in the boiler

Meanwhile many investigations focused on the designand optimization of waste heat recovery system Some studies

Hindawi Publishing CorporationScience and Technology of Nuclear InstallationsVolume 2016 Article ID 6790576 12 pageshttpdxdoiorg10115520166790576

2 Science and Technology of Nuclear Installations

24 25

6

5

2

2

1

3

4

Reactor coreRecuperator

6

HeliumAmmonia-water mixtureWater

Precooler

15

13

Rectifier

Turbine

Boiler

8

9

10

11

12

14

1516

17

18

19

20 21 22 23

Absorber

Pump

HT recuperator

Cooler

7

Turbine

Compressor

5

11998400

Figure 1 Schematic diagram of the combined cycle

optimized the system according to the net power outputcooling output first law efficiency and second law efficiency[8ndash10] Shengjun et al [11] used five indicators thermalefficiency exergy efficiency recovery efficiency and so on tooptimize the subcritical ORC system and transcritical cycleGuo et al [12] used the net power output per unit mass flowrate of hot source ratio of total heat transfer area to net poweroutput and electricity production cost to screen workingfluids Coskun et al [13] proposed four cycles to utilize thegeothermal energy and selected one cycle to optimize forthe turbine inlet pressure that would generate maximumpower output energy and exergy efficiencies Zare et al[14] carried out an exergoeconomic analysis for a combinedGT-MHRKalina cycle and compared the performance withthe Gas Turbine-Modular Helium Reactor (GT-MHR) plantBahlouli et al [15] perform a parametric study and multiob-jective optimization for a bottoming cycle of a trigenerationsystem with HCCI engine as prime mover Feng et al [16]conducted a sensitivity analysis for low temperature ORCs(Organic Rankine Cycles) as well as the thermos-economiccomparison between the basic ORC and regenerative ORC

According to the studies proposed in the public liter-atures few investigations focused on the system economicanalysis of the combined cycle especially the evaluation of thelevelized energy cost (LEC) In this paper a combined cyclein which a powercooling cogeneration cycle is integratedinto the nuclear closed Brayton cycle is proposed to recoverand utilize the waste heat rejected from the precooler ofthe closed Brayton cycle Based on a detailed parametric

analysis a multiobjective function 119865(119883) integrating theoverall efficiency and the system cost is used to optimize thethermodynamic and the economic performances of the com-bined cycle So the main contributions of the paper are thecombined system analysis and multiobjective optimizationaccording to several important parameters

2 System Description and Assumptions

A schematic diagram of the proposed combined cycle isshown in Figure 1 The nuclear core of HTGR is the heatsource of the closed Brayton cycle High pressure heliumas the coolant and the working fluid [2] is heated in thereactor and then enters the gas turbine (state 1) for expansionto convert thermal energy into shaft power thereby drivingthe compressors and the electric generator on a single shaftSince the temperature of the exhaust gas from the turbine(state 2) is still high a recuperator is equipped to utilize theenergy of the exhaust gas from the gas turbine in which thecold helium from the compressor (state 6) is preheated bythe turbine exhaust gas Then the exhaust gas flows throughthe precooler to be cooled (state 5) The cooled helium haslow pressure and low temperature after the precooler (state 5)and is compressed by the compressor (state 6) Helium withhigh pressure and low temperature enters the other side ofthe recuperator mentioned above to be preheated (state 7)before finally flowing into the reactor core to be heated againto repeat the thermodynamic cycle

Science and Technology of Nuclear Installations 3

Table 1 Energy relations for the equipment of closed Brayton cycle and AWM cycle

Cycle Equipment Energy equations

Closed Brayton cycle

Reactor core 119876core = 1198981(ℎ1minus ℎ7)

Turbine 119882119879= 1198981(ℎ1minus ℎ2119904) 120578119904119879

Recuperator (ℎ2minus ℎ3) = (ℎ

7minus ℎ6)

Precooler 119876precooler = 1198981(ℎ4minus ℎ5)

Compressor 119882119862=1198981(ℎ6119904minus ℎ5)

120578119904119862

AWM cycle

Boiler 1198981(ℎ3minus ℎ4) = 119898

12ℎ12+ 11989817ℎ17minus 11989811ℎ11minus 11989813ℎ13

Rectifier 11989814ℎ14+ 11989813ℎ13+ 119898111015840 (ℎ111015840 minus ℎ9) = 119898

12ℎ12

HT recuperator 11989817(ℎ17minus ℎ18) = 119898

10(ℎ10minus ℎ9)

Absorber 119876absorber = 11989819ℎ19+ 11989816ℎ16minus 1198988ℎ8

Turbine 119882119879= 11989814(ℎ14minus ℎ15119904) 120578119904119879

Cooler 119876cool = 11989815(ℎ16minus ℎ15)

Pump 119882119875=1198988(ℎ9119904minus ℎ8)

120578119904119875

Throttle valve ℎ19= ℎ18

120578119904119879 120578119904119862 and 120578119904119875 represent the isentropic efficiency of the turbine the compressor and the pump respectively

The helium flowing out from the gas turbine flowsinto the hot side of the recuperator where the helium iscooled to about 400K To reduce the compressor powerconsumption the helium should be cooled to about 300Kbefore flowing into the compressorThus the ammonia-waterpowercooling cycle (AWM) proposed by Goswami [17] in2000 is coupled into this closed Brayton cycle to utilize thewaste heat rejected from the precooler In this situation theheliumflowing out from the hot side of the recuperator entersa boiler before entering the precoolerTheheat released by thehelium passing through the boiler is the heat resource of theAWMcycleThen a part of theHTGRwaste heat is recoveredfor the AWM cycle to produce power The AWM cycle useshigh concentration of ammonia as the working fluid whichcan be expanded to a very low temperature in the turbineThe very low temperature ammonia-water mixture providesrefrigerationThenet effects are the production of both powerand refrigeration

An ammonia-water mixture (state 8) is pumped to a highpressure (state 9) and heated to boil off ammonia (state 12)The vapor is enriched in ammonia by condensing a part ofthe vapor in a rectifier (state 14) The condensate is richerin water and returned to the boiler (state 13) The ammoniavapor which is almost pure ammonia can be expanded ina turbine to exit at a very low temperature (state 15) Afterexpansion in the turbine to generate power low temperatureammonia first provides cooling capacity in the cooler (state16) and is absorbed by low concentration solution from theboiler in an absorber to form the basic ammonia-water liquidsolution to complete the cycle (state 8) [17]

The following assumptions are used in this work

(1) The system operates in a steady state condition(2) Changes in kinetic and potential energies are

neglected(3) The pressure loss due to the frictional effects is

neglected

(4) The turbine and the pump in the combined cycle haveisentropic efficiencies [15]

(5) The ammonia-water solution leaving the absorber(state 8) is a saturated liquid at low pressure

3 System Modeling

31 Thermodynamic Modeling A MATLAB code has beendeveloped to carry out the numerical simulations for thiscombined cycle The thermodynamic properties of the statesin the closed Brayton cycle are evaluated by REFPROP 90The thermodynamic properties of the states of the bottomcycle (AWM cycle) are evaluated by the method proposedby Xu and Goswami [18] For thermodynamic analysisthe principles of mass and energy conservations as wellas the second law of thermodynamics are applied to eachcomponent

To simplify the calculation just one operation conditionof the closed Brayton cycle is selected according to theliterature [19] and the parameters are listed in Table 5

The energy relations for the equipment of combined cycleare listed in Table 1

For the combined cycle the net power output can bedefined as follows

119882netCombinedcycle = 119882net119861 +119882netAWM

= (119882119879minus119882119862)119861+ (119882119879minus119882119875)AWM

(1)

The overall efficiency of the combined cycle is defined asfollows

120578overallCombinedcycle =119882net119861 +119882netAWM +119882cool

119876core (2)

4 Science and Technology of Nuclear Installations

Table 2 Comparison between the properties of the present work and those from the published literature [17]

State T (K) p (bar) h (kJkg) s (kJkg K) x119886lowast

119887lowast

119886lowast

119887lowast

119886lowast

119887lowast

8 2800 20 minus2141 minus2144 minus01060 minus01061 053 0539 2800 300 minus2114 minus2116 minus01083 minus01084 053 05311 3781 300 2463 2467 12907 12924 053 05312 4000 300 15472 15498 46102 46223 09432 0945113 3600 300 2058 2061 11185 11201 06763 0676014 3600 300 13732 13741 41520 41546 09921 0993815 2570 20 11489 11776 45558 46702 09921 0993816 2800 20 12787 12846 50461 50734 09921 0993817 4000 300 3482 3479 15544 15563 04147 0426918 3000 300 minus1190 minus1207 02125 02105 04147 04269119886lowast the thermodynamic properties presented in literature [17]119887lowast the thermodynamic properties calculated in this work

The cooling capacity is converted to equivalent power and canbe expressed as

119882cool =119876coolcop

(3)

where cop is the coefficient of performance and set as 4 [20]

311 Verification of Ammonia-Water Thermodynamic Prop-erties To verify the developed thermodynamic models forAWM cycle the available data in the literature are usedThe comparisons between the simulation results and thosereported in the published literature are presented in Table 2For AWM cycle the data in Table 2 indicate a very goodagreement between simulation results of this paper and thosein published literature [17] and the maximum deviation isonly 25

32 Economic Modeling To evaluate the thermoeconomicperformance of the combined cycle levelized energy cost(LEC) is analyzed in this paper Because the aim of this paperis to evaluate the effect of AWM cycle on the thermodynamicand economic performances of the combined cycle theHTGRplant (closed Brayton cycle) specific cost is assumed tobe 1073$kW [21] A cost of 8$MWh is assumed for nuclearfuel [22]

Then the capital investment of AWM cycle is calculatedAccording to the literature [23] the heat exchangers pumpand turbine contribute largely to the total cost We assumethat all of the heat exchangers in AWM system are shell-and-tube heat exchanger [24 25]

The heat exchanger area can be expressed as follows

119860 =119876

(119880Δ119879119898)

Δ119879119898=

(Δ119879max minus Δ119879min)

ln (Δ119879maxΔ119879min)

(4)

where 119876 represents the heat exchanger heat load 119880 standsfor the overall heat transfer coefficient and Δ119879

119898is the log-

arithmic mean temperature difference The heat transfer

Table 3 Heat transfer coefficients for heat exchangers [33]

Component Heat transfer coefficient (Wm2K)Absorber 800Separator 900Cooler 1000Recuperator 800

coefficients of some heat exchangers inAWMcycle are shownin Table 3

The overall heat transfer coefficient of the boiler can becalculated as follows [26]

1

119880=

1

ℎHe+120575

119896+

1

ℎaw+ 119877 (5)

where ℎHe is the heat transfer coefficient of the heliumℎaw is the ammonia-water heat transfer coefficient and is2000W(m2K) [27] according to the characteristic of thecycle 120575 is the thickness of the heat exchanger tube 119896 is theheat conductivity of the tube 119877 is the heat resistance of thetube

The heat transfer coefficient of the helium in the shell iscalculated by the following equations

NuHe = 0023Re08HePr065

He (119879119908

119879119887

)

minus119888

119888 = 057 minus (159

119897119889)

ℎHe =Nu 120582119889

(6)

For the above equations Re and Pr are Reynolds numberand Prandtl number respectively 119879

119908and 119879

119887are the temper-

atures of the shell and tube respectively 120582 is the thermalconductivity coefficient 119889 is the diameter or equivalenthydraulic diameter of the heat exchanger 119897 is the length ofthe tube

Science and Technology of Nuclear Installations 5

Table 4 Coefficients required for the cost evaluation for each component [26]

Components 1198701

1198702

1198703

1198621

1198622

1198623

1198611

1198612

119865119898

119865119887119898

Turbine 315140 05890 0 0 0 0 0 0 0 350Pump 35790 03210 00290 01680 03480 04840 180 151 180 Equation (9)Heat exchanger 32138 02688 007961 minus0064991 005025 001474 180 150 125 Equation (9)

Table 5 Specifications of the combined cycle [19]

Parameters Valuem1(kgs) 3588

120578119904119875

085T1(K) 11791

T5(K) 301

p1(bar) 676

120578119904119879

085120578119904119862

085T3(K) 3988

T7(K) 8554

p2(bar) 310

The capital costs of the AWM system consist of the heatexchanger pump and turbine costs and are expressed asfollows [26 28]

lg119862119887= 1198701+ 1198702lg119885 + 119870

3(lg119885)2 (7)

where 119862119887is the estimated component cost based on US

dollars in the year of 1996 119885 is a parameter related to cyclecomponents For the heat exchanger 119885 refers to the areaof heat exchanger 119860 For the pump 119885 means the powerconsumption in pump119882

119901 For the turbine 119885 represents the

power output 119882out The coefficients of 1198701 1198702 and 119870

3are

listed in Table 4The capital cost 119862 which is corrected according to the

component materials and the pressure is determined by (8)as follows

119862 = 119862119887119865119887119898 (8)

where the coefficient 119865119887119898

is 35 for the turbine and thecoefficients 119865

119887119898for other components are calculated by (9)

[29] as follows

119865119887119898

= 1198611+ 1198612119865119898119865119901 (9)

where 1198611and 119861

2are the coefficients of different types of

the components and 119865119898

is the correction coefficient forthe component materials The values of 119861

1 1198612 and 119865

119898are

presented in Table 4119865119901represents the pressure correction coefficient and is

calculated by

lg119865119901= 1198621+ 1198622times lg119901 + 119862

3times (lg119901)2 (10)

The coefficients of 1198621 1198622 and 119862

3are also shown in

Table 4

Thus the cost of the AWM system in the year 1996119862AWM1996 can be evaluated as follows

119862AWM1996 = 119862119867+ 119862119864+ 119862119901 (11)

According to the time value of money the cost of closedBrayton system in the year of 2006 and the AWM system inthe year of 1996 are converted into the capital costs in the yearof 2015 respectively and the total cost of the combined cycle(1198622015

) is their sum as follows

1198622015

= 1198621198612006

CEPCI2015

CEPCI2006

+ 119862AWM1996CEPCI

2015

CEPCI1996

(12)

where CEPCI1996

CEPCI2006

and CEPCI2015

are the chemi-cal plant cost indexes in the years 1996 2006 and 2015 andthe values are 382 510 and 592 respectively [30]

The capital recovery factor (CRF) is defined as follows

CRF = 119894 (1 + 119894)119879119904

(1 + 119894)119879119904 minus 1

(13)

In this equation 119894 is the discount rate and is 5 with inflationrate zero [21] The economic life of the combined system (119879

119904)

is 40 yearsFor each year the operation hour of the system is

calculated as follows

OP119904= 365 times 24 times 119871

119891 (14)

In the combined system the levelized energy cost (LEC)can be calculated by (14) One has

LEC =CRF times 119862

2015+ COM

119904

(119882net +119882cool) timesOP119904

(15)

where COM119904is the system operation and maintenance cost

and is 15 of 1198622015

The load factor 119871119891is taken as 075 [31]

33 Optimization Model A simple thermodynamic opti-mization or economical optimization might draw differ-ent results because it is difficult to ensure a global cost-effective cycle design Thus the optimizations on both thethermodynamics and economics are simultaneously neededin the assessment of the combined cycle Regarding thisoverall efficiency 120578overallCombinedcycle and levelized energy cost(LEC) are selected to build a multiobjective function asthe performance indicator in this paper The multiobjectiveoptimization model is constructed as follows

The first objective function 1198651(119883) is expressed by the

following

min 1198651(119883) =

1

120578overallCombinedcycle (16)

6 Science and Technology of Nuclear Installations

34 36 38 40 42 44280

281

282

283

284

285

Pow

er o

utpu

t (M

W)

Absorber pressure (bar)

x8 = 0555

x8 = 0530

x8 = 0480

p14 = 17bar

Ta = 288KΔTpinch = 5K

T14 = 352K

Figure 2 Variation of power output of combined cycle withabsorber pressure

The second objective function 1198652(119883) is expressed by the

following

min 1198652(119883) = LEC (17)

The first objective function 1198651(119883) represents system

thermodynamic property and the second objective function1198652(119883) is the thermoeconomic propertyIn this paper the method of linear weighted evaluation

function is adopted to solve the objective function optimiza-tion model [28] which contains more than two performanceindicators The multiobjective function 119865(119883) is given by thefollowing

119865 (119883) = 1205721198651(119883) + 120573119865

2(119883) (18)

where120572 and120573 are theweight coefficients of objective functionand amethod proposed byP1aSAkK5 is applied to solve thesetwo weight coefficients [32]

120572 =

(1198651

2minus 1198652

2)

[(1198652

1minus 1198651

1) + (119865

1

2minus 1198652

2)]

120573 =

(1198652

1minus 1198651

1)

[(1198652

1minus 1198651

1) + (119865

1

2minus 1198652

2)]

(19)

4 Results and Discussion

41 Effect of Absorber Pressure The absorber pressure is theoutlet pressure of ammonia-water turbine If the absorberpressure is high the working fluid cannot expand fully inthe turbine and both the power output and overall efficiencydecrease in turn (Figures 2 and 3) Figure 4 shows that LECincreases with increasing absorber pressure The reason is

34 36 38 40 42 44472

473

474

475

476

477

478

479

480

Absorber pressure (bar)

120578ov

eral

lcom

bine

dcyc

le(

)

x8 = 0555

x8 = 0530

x8 = 0480

p14 = 17barT14 = 352K

ΔTpinch = 5KTa = 288K

Figure 3 Variation of overall efficiency of combined cycle withabsorber pressure

34 36 38 40 42 440070

0071

0072

0073

0074

0075

Absorber pressure (bar)

LEC C

ombi

nedc

ycle(U

SDk

Wh)

x8 = 0555

x8 = 0530

x8 = 0480

p14 = 17bar

T14 = 352K

ΔTpinch = 5KTa = 288K

Figure 4 Variation of LEC of combined cycle with absorberpressure

that the higher absorber pressure leads to less power outputwhich causes the increase in LEC However if absorberpressure is far less than 35 bar the working fluid at the outletof the absorber will change into vapor-liquid mixture Thisincreases the pump power consumption greatlyThe relation-ships of 119865(119883) with the absorber pressure are demonstratedin Figure 5 119865(119883) increases monotonically with increasingabsorber pressure Because the lowest 119865(119883) means the bestperformance the lower absorber pressure is beneficial for thethermodynamic and economic performances

Science and Technology of Nuclear Installations 7

34 36 38 40 42 44002160

002165

002170

002175

002180

002185

002190

F(X

)

Absorber pressure (bar)

x8 = 0555

x8 = 0530

x8 = 0480

p14 = 17bar

T14 = 352K

ΔTpinch = 5KTa = 288K

Figure 5 Variation of 119865(119883) of combined cycle with absorberpressure

15 20 25 30 35276

278

280

282

284

Pow

er o

utpu

t (M

W)

Turbine inlet pressure (bar)

x8 = 0555x8 = 0530

x8 = 0480

T14 = 352K

ΔTpinch = 5KTa = 288K

p8 = 35bar

Figure 6 Variation of power output of combined cycle with turbineinlet pressure

42 Effect of Turbine Inlet Pressure As shown in Figures 6 and7 the variations of the power output and overall efficiencywith the turbine inlet pressure are presented The enthalpydrop across the turbine increases as the turbine inlet pressureincreases However the enthalpy gains because of increasingturbine inlet pressure cannot compensate for the drop in thevapor flow rate Thus the turbine work output decreasesOwing to the decrease of vapor flow rate both the coolingcapacity and the equivalent work of cooling capacity (119882cool)increase first and then decrease However the equivalentwork of cooling capacity is too little comparedwith the poweroutput of the combined cycle Hence the power output andoverall efficiency decrease with the increasing turbine inlettemperature

15 20 25 30 35

466

468

470

472

474

476

478

480

Turbine inlet pressure (bar)

x8 = 0555x8 = 0530

x8 = 0480

T14 = 352K

ΔTpinch = 5KTa = 288K

p8 = 35bar120578ov

eral

lcom

bine

dcyc

le(

)

Figure 7 Variation of overall efficiency of combined cycle withturbine inlet pressure

15 20 25 30 3500710

00715

00720

00725

00730

00735

00740

Turbine inlet pressure (bar)

LEC C

ombi

nedc

ycle(U

SDk

Wh)

x8 = 0555x8 = 0530

x8 = 0480

T14 = 352K

ΔTpinch = 5KTa = 288K

p8 = 35bar

Figure 8 Variation of LEC of combined cycle with turbine inletpressure

As shown in Figure 8 LEC decreases at first and thenincreases with increasing turbine inlet pressure When theammonia mass fraction is 0555 LEC reaches the minimumof 00712USD(kWh) with the turbine inlet pressure of 305bar Figure 9 shows that 119865(119883) decreases first and increaseswith the increasing turbine inlet pressure when the ammoniamass fraction is 053 or 0555 Thus an optimal turbine inletpressure is present and the optimal turbine inlet pressurevalue is changing with the ammonia mass fraction

43 Effect of Turbine Inlet Temperature Figure 10 showsthat the power output increases with increasing turbine

8 Science and Technology of Nuclear Installations

15 20 25 30 3500216

00217

00218

00219

00220

00221

00222

F(X

)

Turbine inlet pressure (bar)

x8 = 0555x8 = 0530

x8 = 0480

T14 = 352K

ΔTpinch = 5KTa = 288K

p8 = 35bar

Figure 9 Variation of 119865(119883) of combined cycle with turbine inletpressure

345 348 351 354 357 360280

281

282

283

284

285

Turbine inlet temperature (K)

Pow

er o

utpu

t (M

W)

x8 = 0555x8 = 0530

x8 = 0480

ΔTpinch = 5KTa = 288K

p8 = 35barp14 = 17bar

Figure 10 Variation of power output of combined cyclewith turbineinlet temperature

inlet temperature With fixed pressure ratio increase in inlettemperature leads to higher inlet enthalpy of working fluidThe exit enthalpy of working fluid also increases at thesame time because of high exit temperature But the increasein enthalpy caused by the increase in inlet temperature ismore than that because of the increase in exit temperatureHence the turbine work output rises up as the turbine inlettemperature increases

Because the increasing turbine inlet temperatureincreases cooler inlet temperature the equivalent work ofcooling capacity (119882cool) declines However the increase ofpower output compensates for the drop in the equivalent

345 348 351 354 357 360

472

474

476

478

480

Turbine inlet temperature (K)

x8 = 0555x8 = 0530

x8 = 0480

ΔTpinch = 5KTa = 288K

p8 = 35barp14 = 17bar

120578ov

eral

lcom

bine

dcyc

le(

)

Figure 11 Variation of overall efficiency of combined cycle withturbine inlet temperature

345 348 351 354 357 3600070

0071

0072

0073

0074

0075

Turbine inlet temperature (K)

x8 = 0555x8 = 0530

x8 = 0480

ΔTpinch = 5KTa = 288K

p8 = 35barp14 = 17bar

LEC C

ombi

nedc

ycle(U

SDk

Wh)

Figure 12 Variation of LEC of combined cycle with turbine inlettemperature

work of cooling capacity This fact results in the slightincrease of overall efficiency (Figure 11)

As shown in Figure 12 LEC increases with increasingturbine inlet temperature monotonously This fact impliesthat the lower inlet temperature results in better economicperformance Figure 13 shows that 119865(119883) changes very slightlywhen the turbine inlet temperature is lower than 253K

44 Effect of AmmoniaMass Fraction Figures 14 and 15 revealthat the power output and overall efficiency will benefit fromincreased ammonia mass fraction Increasing the ammoniamass fraction will improve the thermodynamic performanceof the combined cycle because the higher the ammonia

Science and Technology of Nuclear Installations 9

345 348 351 354 357 360

002156

002163

002170

002177

002184

F(X

)

Turbine inlet temperature (K)

x8 = 0555x8 = 0530

x8 = 0480

ΔTpinch = 5KTa = 288K

p8 = 35barp14 = 17bar

Figure 13 Variation of 119865(119883) of combined cycle with turbine inlettemperature

035 040 045 050 055274

276

278

280

282

284

Pow

er o

utpu

t (M

W)

Ammonia mass fraction

p14 = 17barp14 = 23barp14 = 28bar

p8 = 35barT14 = 352K

ΔTpinch = 5KTa = 288K

Figure 14 Variation of power output of combined cycle withammonia mass fraction

concentration the greater the ammonia vapor flow rateexpanding in the turbine However if the ammonia massfraction is too high the pump power consumption willincrease greatly because the ammonia liquid mixture at theoutlet of the absorber (state 8) will change into the vapor-liquid mixture

Figure 16 shows the effect of ammonia mass fractionon LEC With the increase of ammonia mass fraction LECdecreases initially and then increases The higher the turbineinlet pressure the smaller the optimal ammonia mass frac-tion When the turbine inlet pressure is 17 bar LEC reachesthe minimum of 00716USD(kWh) with an ammonia massfraction of 0405 When the turbine inlet pressure is 17bar LEC reaches the minimum of 00713USD(kWh) with

035 040 045 050 055

465

468

471

474

477

480

Ammonia mass fraction

120578ov

eral

lcom

bine

dcyc

le(

)

p14 = 17barp14 = 23barp14 = 28bar

p8 = 35barT14 = 352K

ΔTpinch = 5KTa = 288K

Figure 15 Variation of overall efficiency of combined cycle withammonia mass fraction

035 040 045 050 055

0071

0072

0073

0074

0075

Ammonia mass fraction

p14 = 17barp14 = 23barp14 = 28bar

p8 = 35barT14 = 352K

ΔTpinch = 5KTa = 288K

LEC C

ombi

nedc

ycle(U

SDk

Wh)

Figure 16 Variation of LEC of combined cycle with ammonia massfraction

an ammonia mass fraction of 0545 Figure 17 presentsthe variations of 119865(119883) with ammonia mass fraction 119865(119883)decreases rapidly with increasing ammonia mass fraction

45 System Optimization In this work SA (SimulatedAnnealing) is employed to obtain the optimum combinationof the key parameters For the optimization the constraintsare simplified as follows

Subject to

170 ⩽ 11990114(bar) ⩽ 340

345 ⩽ 11987914(K) ⩽ 375

036 ⩽ 1199098⩽ 0555

10 Science and Technology of Nuclear Installations

035 040 045 050 05500216

00218

00220

00222

00224

00226

F(X

)

Ammonia mass fraction

p14 = 17barp14 = 23barp14 = 28bar

p8 = 35barT14 = 352K

ΔTpinch = 5KTa = 288K

Figure 17 Variation of F(X) of combined cycle with ammonia massfraction

288 ⩽ 119879119886(K) ⩽ 300

0 ⩽11989810

1198989

⩽ 1

0 ⩽11989812

1198981

⩽ 1

(11987917minus 11987910) ⩾ 5K

(1198794minus 11987911) ⩾ 5K

(1198793minus 119879Boiler) ⩾ 5K

119879Boiler ⩾ 119879Rectifier

119876cool gt 0

11990114⩾ 1199018

(20)

The selection of the above-mentioned parameters for thisoptimization is according to the literatures [6 9 13]

Table 6 shows some results of the closed Brayton cycle Tocompare the thermodynamic and economic performances ofthe combined cycle with those of the closed Brayton cyclethree parameters are defined as follows

RV119882net

=

(119882netCombinedcycle minus119882netBrayton)

119882netBrayton

RV120578overall

=

(120578overallCombinedcycle minus 120578overallBrayton)

120578overallBrayton

RVLEC =

(LECCombinedcycle minus LECBrayton)

LECBrayton

(21)

Table 6 Results of the closed Brayton cycle

Parameters Value119876core (MW) 59364120578overall119861 466119882net119861 (MW) 27690LEC119861(USD(kWh)) 00711

Table 7 Optimization results

Parameters Optimization results

Δ119879pinch = 5K 1199018= 35 bar

11990114= 181 bar 119879

14= 345K

1199098= 0555

F(X) = 002164119882netCombinedcycle = 28356MWRV119882net

= 241120578overallCombinedcycle = 4791RV

120578overall= 243LECCombinedcycle =00706USD(kWh) RVLEC =minus073

Table 7 lists the result of the parameters for the optimiza-tion The optimized power output and overall efficiency forthe combined cycle are 28356MW and 4791 respectivelyThese values are 241 and 243 higher than those of theclosedBrayton cycle respectively Both the lower average heataddition temperature and the higher back pressure of turbinein AWM cycle result in less power output and lower overallefficiency of the combined cycle

Comparingwith closedBrayton cycle the combined cyclereduces the LEC slightly The optimized LEC of combinedcycle is 073 lower than that of the closed Brayton cycleThereason is that the AWM utilizes the waste heat and adds thepower output and the cooling capacity to the closed Braytoncycle However the total capital investment increases due tothe combined AWM system

5 Conclusions

In this paper a combined cycle which combines AWM cycleand a nuclear closed Brayton cycle to recover the wasteheat rejected from the precooler is proposed A detailedparametric study and optimization are carried out for thiscombined cycle according to the thermodynamics and eco-nomics performances The combined cycle can potentiallybe used to improve the power output and overall efficiencyThe power output and overall efficiency of the combinedcycle increase with increasing turbine inlet temperature andammonia mass fraction but the turbine inlet temperatureand the ammonia mass fraction are limited by the heatsource temperature and the absorb pressure respectivelyCompared with the closed Brayton cycle the optimizedpower output and overall efficiency increase by 241 and243 respectively LEC increases with decreasing absorberpressure and turbine inlet temperature The optimized LECof the combined cycle is 00706USD(kWh) which is 073lower than those of the closed Brayton cycle

Science and Technology of Nuclear Installations 11

Competing Interests

The authors declare that there are no competing interestsregarding the publication of this paper and regarding thefunding that they have received

Acknowledgments

This present research was supported by the Chinese NaturalScience Fund (Project no 51306216) and the FundamentalResearch Funds for the Central University (Project noCDJ2R13140016)

References

[1] A Soroureddin A S Mehr S M S Mahmoudi and M YarildquoThermodynamic analysis of employing ejector and organicRankine cycles for GT-MHR waste heat utilization A Compar-ative Studyrdquo Energy Conversion and Management vol 67 pp125ndash137 2013

[2] S Dardour S Nisan and F Charbit ldquoUtilisation of waste heatfrom GT-MHR and PBMR reactors for nuclear desalinationrdquoDesalination vol 205 no 1ndash3 pp 254ndash268 2007

[3] A I Kalina ldquoCombined-cycle system with novel bottomingcyclerdquo Journal of Engineering for Gas Turbines and Power vol106 no 4 pp 737ndash742 1984

[4] D Y Goswami ldquoSolar thermal power technology present statusand ideas for the futurerdquo Energy Sources vol 20 no 2 pp 137ndash145 1998

[5] D S Ayou J C Bruno R Saravanan and A Coronas ldquoAnoverview of combined absorption power and cooling cyclesrdquoRenewable and Sustainable Energy Reviews vol 21 pp 728ndash7482013

[6] R V Padilla G Demirkaya D Y Goswami E Stefanakos andM M Rahman ldquoAnalysis of power and cooling cogenerationusing ammonia-water mixturerdquo Energy vol 35 no 12 pp4649ndash4657 2010

[7] S Lu and D Y Goswami ldquoOptimization of a novel combinedpowerrefrigeration thermodynamic cyclerdquo Journal of SolarEnergy Engineering vol 125 no 2 pp 212ndash217 2003

[8] M Pouraghaie K Atashkari S M Besarati and N Nariman-zadeh ldquoThermodynamic performance optimization of a com-bined powercooling cyclerdquo Energy Conversion and Manage-ment vol 51 no 1 pp 204ndash211 2010

[9] G Demirkaya R Vasquez Padilla D Y Goswami E Ste-fanakos and M M Rahman ldquoAnalysis of a combined powerand cooling cycle for low-grade heat sourcesrdquo InternationalJournal of Energy Research vol 35 no 13 pp 1145ndash1157 2011

[10] L S Vieira J L Donatelli and M E Cruz ldquoExergoeconomicimprovement of a complex cogeneration system integratedwith a professional process simulatorrdquo Energy Conversion andManagement vol 50 no 8 pp 1955ndash1967 2009

[11] Z ShengjunWHuaixin andG Tao ldquoPerformance comparisonand parametric optimization of subcritical Organic RankineCycle (ORC) and transcritical power cycle system for low-temperature geothermal power generationrdquoApplied Energy vol88 no 8 pp 2740ndash2754 2011

[12] T Guo H X Wang and S J Zhang ldquoFluids and parametersoptimization for a novel cogeneration system driven by low-temperature geothermal sourcesrdquo Energy vol 36 no 5 pp2639ndash2649 2011

[13] A Coskun A Bolatturk and M Kanoglu ldquoThermodynamicand economic analysis and optimization of power cycles for amedium temperature geothermal resourcerdquo Energy Conversionand Management vol 78 pp 39ndash49 2014

[14] V Zare S M S Mahmoudi and M Yari ldquoOn the exergoe-conomic assessment of employing Kalina cycle for GT-MHRwaste heat utilizationrdquoEnergy Conversion andManagement vol90 pp 364ndash374 2015

[15] K Bahlouli R Khoshbakhti Saray andN Sarabchi ldquoParametricinvestigation and thermo-economic multi-objective optimiza-tion of an ammonia-water powercooling cycle coupled withan HCCI (homogeneous charge compression ignition) enginerdquoEnergy vol 86 pp 672ndash684 2015

[16] Y Feng Y Zhang B Li J Yang and Y Shi ldquoSensitivity analysisand thermoeconomic comparison of ORCs (organicRankinecycles) for low temperature waste heat recoveryrdquo Energy vol82 pp 664ndash677 2015

[17] F Xu D Y Goswami and S S Bhagwat ldquoA combinedpowercooling cyclerdquo Energy vol 25 no 3 pp 233ndash246 2000

[18] F Xu and D Y Goswami ldquoThermodynamic properties ofammonia-watermixtures for power-cycle applicationsrdquo Energyvol 24 no 6 pp 525ndash536 1999

[19] M S El-Genk and J-M Tournier ldquoNoble gas binary mixturesfor gas-cooled reactor power plantsrdquo Nuclear Engineering andDesign vol 238 no 6 pp 1353ndash1372 2008

[20] F W Yu K T Chan R K Y Sit et al ldquoReview of standardsfor energy performance of chiller systems serving commercialbuildingsrdquo Energy Procedia vol 61 pp 2778ndash2782 2014

[21] S Nisan and S Dardour ldquoEconomic evaluation of nucleardesalination systemsrdquo Desalination vol 205 no 1ndash3 pp 231ndash242 2007

[22] L E Herranz J I Linares and B Y Moratilla ldquoPower cycleassessment of nuclear high temperature gas-cooled reactorsrdquoApplied Thermal Engineering vol 29 no 8-9 pp 1759ndash17652009

[23] HDMadhawaHettiarachchiMGolubovicWMWorek andY Ikegami ldquoOptimum design criteria for an Organic Rankinecycle using low-temperature geothermal heat sourcesrdquo Energyvol 32 no 9 pp 1698ndash1706 2007

[24] Y T Zhu W H Qu and P Y Yu Chemical Equipment DesignManual Chemical Industry Press 2005

[25] Q Songwen Heat Exchanger Design Handbook ChemicalIndustry Press 2002

[26] R Turton R C Bailie W B Whiting et al Analysis Synthesisand Design of Chemical Processes Prentice Hall Upper SaddleRiver NJ USA 1997

[27] F Taboas M Valles M Bourouis and A Coronas ldquoFlowboiling heat transfer of ammoniawater mixture in a plate heatexchangerrdquo International Journal of Refrigeration vol 33 no 4pp 695ndash705 2010

[28] L Xiao S-Y Wu T-T Yi C Liu and Y-R Li ldquoMulti-objectiveoptimization of evaporation and condensation temperatures forsubcritical organic Rankine cyclerdquo Energy vol 83 pp 723ndash7332015

[29] C E Campos Rodrıguez J C Escobar Palacio O J Venturiniet al ldquoExergetic and economic comparison of ORC and Kalinacycle for low temperature enhanced geothermal system inBrazilrdquo Applied Thermal Engineering vol 52 no 1 pp 109ndash1192013

[30] D Mignard ldquoCorrelating the chemical engineering plant costindex with macro-economic indicatorsrdquo Chemical EngineeringResearch and Design vol 92 no 2 pp 285ndash294 2014

12 Science and Technology of Nuclear Installations

[31] httpwwwneimagazinecomnewsnewsnuclear-reactor-per-formance-by-vendors-agrs-23

[32] H W Tang Practical Introduction to Mathematical Program-ming Dalian Institute of Technology Press 1986

[33] V Zare S M S Mahmoudi and M Yari ldquoAn exergoeconomicinvestigation of waste heat recovery from the Gas Turbine-Modular Helium Reactor (GT-MHR) employing an ammonia-water powercooling cyclerdquo Energy vol 61 pp 397ndash409 2013

TribologyAdvances in

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

International Journal of

AerospaceEngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

FuelsJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal ofPetroleum Engineering

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Industrial EngineeringJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Power ElectronicsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in

CombustionJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Renewable Energy

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

StructuresJournal of

International Journal of

RotatingMachinery

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

EnergyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporation httpwwwhindawicom

Journal ofEngineeringVolume 2014

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

International Journal ofPhotoenergy

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Nuclear InstallationsScience and Technology of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Solar EnergyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Wind EnergyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Nuclear EnergyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

High Energy PhysicsAdvances in

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

2 Science and Technology of Nuclear Installations

24 25

6

5

2

2

1

3

4

Reactor coreRecuperator

6

HeliumAmmonia-water mixtureWater

Precooler

15

13

Rectifier

Turbine

Boiler

8

9

10

11

12

14

1516

17

18

19

20 21 22 23

Absorber

Pump

HT recuperator

Cooler

7

Turbine

Compressor

5

11998400

Figure 1 Schematic diagram of the combined cycle

optimized the system according to the net power outputcooling output first law efficiency and second law efficiency[8ndash10] Shengjun et al [11] used five indicators thermalefficiency exergy efficiency recovery efficiency and so on tooptimize the subcritical ORC system and transcritical cycleGuo et al [12] used the net power output per unit mass flowrate of hot source ratio of total heat transfer area to net poweroutput and electricity production cost to screen workingfluids Coskun et al [13] proposed four cycles to utilize thegeothermal energy and selected one cycle to optimize forthe turbine inlet pressure that would generate maximumpower output energy and exergy efficiencies Zare et al[14] carried out an exergoeconomic analysis for a combinedGT-MHRKalina cycle and compared the performance withthe Gas Turbine-Modular Helium Reactor (GT-MHR) plantBahlouli et al [15] perform a parametric study and multiob-jective optimization for a bottoming cycle of a trigenerationsystem with HCCI engine as prime mover Feng et al [16]conducted a sensitivity analysis for low temperature ORCs(Organic Rankine Cycles) as well as the thermos-economiccomparison between the basic ORC and regenerative ORC

According to the studies proposed in the public liter-atures few investigations focused on the system economicanalysis of the combined cycle especially the evaluation of thelevelized energy cost (LEC) In this paper a combined cyclein which a powercooling cogeneration cycle is integratedinto the nuclear closed Brayton cycle is proposed to recoverand utilize the waste heat rejected from the precooler ofthe closed Brayton cycle Based on a detailed parametric

analysis a multiobjective function 119865(119883) integrating theoverall efficiency and the system cost is used to optimize thethermodynamic and the economic performances of the com-bined cycle So the main contributions of the paper are thecombined system analysis and multiobjective optimizationaccording to several important parameters

2 System Description and Assumptions

A schematic diagram of the proposed combined cycle isshown in Figure 1 The nuclear core of HTGR is the heatsource of the closed Brayton cycle High pressure heliumas the coolant and the working fluid [2] is heated in thereactor and then enters the gas turbine (state 1) for expansionto convert thermal energy into shaft power thereby drivingthe compressors and the electric generator on a single shaftSince the temperature of the exhaust gas from the turbine(state 2) is still high a recuperator is equipped to utilize theenergy of the exhaust gas from the gas turbine in which thecold helium from the compressor (state 6) is preheated bythe turbine exhaust gas Then the exhaust gas flows throughthe precooler to be cooled (state 5) The cooled helium haslow pressure and low temperature after the precooler (state 5)and is compressed by the compressor (state 6) Helium withhigh pressure and low temperature enters the other side ofthe recuperator mentioned above to be preheated (state 7)before finally flowing into the reactor core to be heated againto repeat the thermodynamic cycle

Science and Technology of Nuclear Installations 3

Table 1 Energy relations for the equipment of closed Brayton cycle and AWM cycle

Cycle Equipment Energy equations

Closed Brayton cycle

Reactor core 119876core = 1198981(ℎ1minus ℎ7)

Turbine 119882119879= 1198981(ℎ1minus ℎ2119904) 120578119904119879

Recuperator (ℎ2minus ℎ3) = (ℎ

7minus ℎ6)

Precooler 119876precooler = 1198981(ℎ4minus ℎ5)

Compressor 119882119862=1198981(ℎ6119904minus ℎ5)

120578119904119862

AWM cycle

Boiler 1198981(ℎ3minus ℎ4) = 119898

12ℎ12+ 11989817ℎ17minus 11989811ℎ11minus 11989813ℎ13

Rectifier 11989814ℎ14+ 11989813ℎ13+ 119898111015840 (ℎ111015840 minus ℎ9) = 119898

12ℎ12

HT recuperator 11989817(ℎ17minus ℎ18) = 119898

10(ℎ10minus ℎ9)

Absorber 119876absorber = 11989819ℎ19+ 11989816ℎ16minus 1198988ℎ8

Turbine 119882119879= 11989814(ℎ14minus ℎ15119904) 120578119904119879

Cooler 119876cool = 11989815(ℎ16minus ℎ15)

Pump 119882119875=1198988(ℎ9119904minus ℎ8)

120578119904119875

Throttle valve ℎ19= ℎ18

120578119904119879 120578119904119862 and 120578119904119875 represent the isentropic efficiency of the turbine the compressor and the pump respectively

The helium flowing out from the gas turbine flowsinto the hot side of the recuperator where the helium iscooled to about 400K To reduce the compressor powerconsumption the helium should be cooled to about 300Kbefore flowing into the compressorThus the ammonia-waterpowercooling cycle (AWM) proposed by Goswami [17] in2000 is coupled into this closed Brayton cycle to utilize thewaste heat rejected from the precooler In this situation theheliumflowing out from the hot side of the recuperator entersa boiler before entering the precoolerTheheat released by thehelium passing through the boiler is the heat resource of theAWMcycleThen a part of theHTGRwaste heat is recoveredfor the AWM cycle to produce power The AWM cycle useshigh concentration of ammonia as the working fluid whichcan be expanded to a very low temperature in the turbineThe very low temperature ammonia-water mixture providesrefrigerationThenet effects are the production of both powerand refrigeration

An ammonia-water mixture (state 8) is pumped to a highpressure (state 9) and heated to boil off ammonia (state 12)The vapor is enriched in ammonia by condensing a part ofthe vapor in a rectifier (state 14) The condensate is richerin water and returned to the boiler (state 13) The ammoniavapor which is almost pure ammonia can be expanded ina turbine to exit at a very low temperature (state 15) Afterexpansion in the turbine to generate power low temperatureammonia first provides cooling capacity in the cooler (state16) and is absorbed by low concentration solution from theboiler in an absorber to form the basic ammonia-water liquidsolution to complete the cycle (state 8) [17]

The following assumptions are used in this work

(1) The system operates in a steady state condition(2) Changes in kinetic and potential energies are

neglected(3) The pressure loss due to the frictional effects is

neglected

(4) The turbine and the pump in the combined cycle haveisentropic efficiencies [15]

(5) The ammonia-water solution leaving the absorber(state 8) is a saturated liquid at low pressure

3 System Modeling

31 Thermodynamic Modeling A MATLAB code has beendeveloped to carry out the numerical simulations for thiscombined cycle The thermodynamic properties of the statesin the closed Brayton cycle are evaluated by REFPROP 90The thermodynamic properties of the states of the bottomcycle (AWM cycle) are evaluated by the method proposedby Xu and Goswami [18] For thermodynamic analysisthe principles of mass and energy conservations as wellas the second law of thermodynamics are applied to eachcomponent

To simplify the calculation just one operation conditionof the closed Brayton cycle is selected according to theliterature [19] and the parameters are listed in Table 5

The energy relations for the equipment of combined cycleare listed in Table 1

For the combined cycle the net power output can bedefined as follows

119882netCombinedcycle = 119882net119861 +119882netAWM

= (119882119879minus119882119862)119861+ (119882119879minus119882119875)AWM

(1)

The overall efficiency of the combined cycle is defined asfollows

120578overallCombinedcycle =119882net119861 +119882netAWM +119882cool

119876core (2)

4 Science and Technology of Nuclear Installations

Table 2 Comparison between the properties of the present work and those from the published literature [17]

State T (K) p (bar) h (kJkg) s (kJkg K) x119886lowast

119887lowast

119886lowast

119887lowast

119886lowast

119887lowast

8 2800 20 minus2141 minus2144 minus01060 minus01061 053 0539 2800 300 minus2114 minus2116 minus01083 minus01084 053 05311 3781 300 2463 2467 12907 12924 053 05312 4000 300 15472 15498 46102 46223 09432 0945113 3600 300 2058 2061 11185 11201 06763 0676014 3600 300 13732 13741 41520 41546 09921 0993815 2570 20 11489 11776 45558 46702 09921 0993816 2800 20 12787 12846 50461 50734 09921 0993817 4000 300 3482 3479 15544 15563 04147 0426918 3000 300 minus1190 minus1207 02125 02105 04147 04269119886lowast the thermodynamic properties presented in literature [17]119887lowast the thermodynamic properties calculated in this work

The cooling capacity is converted to equivalent power and canbe expressed as

119882cool =119876coolcop

(3)

where cop is the coefficient of performance and set as 4 [20]

311 Verification of Ammonia-Water Thermodynamic Prop-erties To verify the developed thermodynamic models forAWM cycle the available data in the literature are usedThe comparisons between the simulation results and thosereported in the published literature are presented in Table 2For AWM cycle the data in Table 2 indicate a very goodagreement between simulation results of this paper and thosein published literature [17] and the maximum deviation isonly 25

32 Economic Modeling To evaluate the thermoeconomicperformance of the combined cycle levelized energy cost(LEC) is analyzed in this paper Because the aim of this paperis to evaluate the effect of AWM cycle on the thermodynamicand economic performances of the combined cycle theHTGRplant (closed Brayton cycle) specific cost is assumed tobe 1073$kW [21] A cost of 8$MWh is assumed for nuclearfuel [22]

Then the capital investment of AWM cycle is calculatedAccording to the literature [23] the heat exchangers pumpand turbine contribute largely to the total cost We assumethat all of the heat exchangers in AWM system are shell-and-tube heat exchanger [24 25]

The heat exchanger area can be expressed as follows

119860 =119876

(119880Δ119879119898)

Δ119879119898=

(Δ119879max minus Δ119879min)

ln (Δ119879maxΔ119879min)

(4)

where 119876 represents the heat exchanger heat load 119880 standsfor the overall heat transfer coefficient and Δ119879

119898is the log-

arithmic mean temperature difference The heat transfer

Table 3 Heat transfer coefficients for heat exchangers [33]

Component Heat transfer coefficient (Wm2K)Absorber 800Separator 900Cooler 1000Recuperator 800

coefficients of some heat exchangers inAWMcycle are shownin Table 3

The overall heat transfer coefficient of the boiler can becalculated as follows [26]

1

119880=

1

ℎHe+120575

119896+

1

ℎaw+ 119877 (5)

where ℎHe is the heat transfer coefficient of the heliumℎaw is the ammonia-water heat transfer coefficient and is2000W(m2K) [27] according to the characteristic of thecycle 120575 is the thickness of the heat exchanger tube 119896 is theheat conductivity of the tube 119877 is the heat resistance of thetube

The heat transfer coefficient of the helium in the shell iscalculated by the following equations

NuHe = 0023Re08HePr065

He (119879119908

119879119887

)

minus119888

119888 = 057 minus (159

119897119889)

ℎHe =Nu 120582119889

(6)

For the above equations Re and Pr are Reynolds numberand Prandtl number respectively 119879

119908and 119879

119887are the temper-

atures of the shell and tube respectively 120582 is the thermalconductivity coefficient 119889 is the diameter or equivalenthydraulic diameter of the heat exchanger 119897 is the length ofthe tube

Science and Technology of Nuclear Installations 5

Table 4 Coefficients required for the cost evaluation for each component [26]

Components 1198701

1198702

1198703

1198621

1198622

1198623

1198611

1198612

119865119898

119865119887119898

Turbine 315140 05890 0 0 0 0 0 0 0 350Pump 35790 03210 00290 01680 03480 04840 180 151 180 Equation (9)Heat exchanger 32138 02688 007961 minus0064991 005025 001474 180 150 125 Equation (9)

Table 5 Specifications of the combined cycle [19]

Parameters Valuem1(kgs) 3588

120578119904119875

085T1(K) 11791

T5(K) 301

p1(bar) 676

120578119904119879

085120578119904119862

085T3(K) 3988

T7(K) 8554

p2(bar) 310

The capital costs of the AWM system consist of the heatexchanger pump and turbine costs and are expressed asfollows [26 28]

lg119862119887= 1198701+ 1198702lg119885 + 119870

3(lg119885)2 (7)

where 119862119887is the estimated component cost based on US

dollars in the year of 1996 119885 is a parameter related to cyclecomponents For the heat exchanger 119885 refers to the areaof heat exchanger 119860 For the pump 119885 means the powerconsumption in pump119882

119901 For the turbine 119885 represents the

power output 119882out The coefficients of 1198701 1198702 and 119870

3are

listed in Table 4The capital cost 119862 which is corrected according to the

component materials and the pressure is determined by (8)as follows

119862 = 119862119887119865119887119898 (8)

where the coefficient 119865119887119898

is 35 for the turbine and thecoefficients 119865

119887119898for other components are calculated by (9)

[29] as follows

119865119887119898

= 1198611+ 1198612119865119898119865119901 (9)

where 1198611and 119861

2are the coefficients of different types of

the components and 119865119898

is the correction coefficient forthe component materials The values of 119861

1 1198612 and 119865

119898are

presented in Table 4119865119901represents the pressure correction coefficient and is

calculated by

lg119865119901= 1198621+ 1198622times lg119901 + 119862

3times (lg119901)2 (10)

The coefficients of 1198621 1198622 and 119862

3are also shown in

Table 4

Thus the cost of the AWM system in the year 1996119862AWM1996 can be evaluated as follows

119862AWM1996 = 119862119867+ 119862119864+ 119862119901 (11)

According to the time value of money the cost of closedBrayton system in the year of 2006 and the AWM system inthe year of 1996 are converted into the capital costs in the yearof 2015 respectively and the total cost of the combined cycle(1198622015

) is their sum as follows

1198622015

= 1198621198612006

CEPCI2015

CEPCI2006

+ 119862AWM1996CEPCI

2015

CEPCI1996

(12)

where CEPCI1996

CEPCI2006

and CEPCI2015

are the chemi-cal plant cost indexes in the years 1996 2006 and 2015 andthe values are 382 510 and 592 respectively [30]

The capital recovery factor (CRF) is defined as follows

CRF = 119894 (1 + 119894)119879119904

(1 + 119894)119879119904 minus 1

(13)

In this equation 119894 is the discount rate and is 5 with inflationrate zero [21] The economic life of the combined system (119879

119904)

is 40 yearsFor each year the operation hour of the system is

calculated as follows

OP119904= 365 times 24 times 119871

119891 (14)

In the combined system the levelized energy cost (LEC)can be calculated by (14) One has

LEC =CRF times 119862

2015+ COM

119904

(119882net +119882cool) timesOP119904

(15)

where COM119904is the system operation and maintenance cost

and is 15 of 1198622015

The load factor 119871119891is taken as 075 [31]

33 Optimization Model A simple thermodynamic opti-mization or economical optimization might draw differ-ent results because it is difficult to ensure a global cost-effective cycle design Thus the optimizations on both thethermodynamics and economics are simultaneously neededin the assessment of the combined cycle Regarding thisoverall efficiency 120578overallCombinedcycle and levelized energy cost(LEC) are selected to build a multiobjective function asthe performance indicator in this paper The multiobjectiveoptimization model is constructed as follows

The first objective function 1198651(119883) is expressed by the

following

min 1198651(119883) =

1

120578overallCombinedcycle (16)

6 Science and Technology of Nuclear Installations

34 36 38 40 42 44280

281

282

283

284

285

Pow

er o

utpu

t (M

W)

Absorber pressure (bar)

x8 = 0555

x8 = 0530

x8 = 0480

p14 = 17bar

Ta = 288KΔTpinch = 5K

T14 = 352K

Figure 2 Variation of power output of combined cycle withabsorber pressure

The second objective function 1198652(119883) is expressed by the

following

min 1198652(119883) = LEC (17)

The first objective function 1198651(119883) represents system

thermodynamic property and the second objective function1198652(119883) is the thermoeconomic propertyIn this paper the method of linear weighted evaluation

function is adopted to solve the objective function optimiza-tion model [28] which contains more than two performanceindicators The multiobjective function 119865(119883) is given by thefollowing

119865 (119883) = 1205721198651(119883) + 120573119865

2(119883) (18)

where120572 and120573 are theweight coefficients of objective functionand amethod proposed byP1aSAkK5 is applied to solve thesetwo weight coefficients [32]

120572 =

(1198651

2minus 1198652

2)

[(1198652

1minus 1198651

1) + (119865

1

2minus 1198652

2)]

120573 =

(1198652

1minus 1198651

1)

[(1198652

1minus 1198651

1) + (119865

1

2minus 1198652

2)]

(19)

4 Results and Discussion

41 Effect of Absorber Pressure The absorber pressure is theoutlet pressure of ammonia-water turbine If the absorberpressure is high the working fluid cannot expand fully inthe turbine and both the power output and overall efficiencydecrease in turn (Figures 2 and 3) Figure 4 shows that LECincreases with increasing absorber pressure The reason is

34 36 38 40 42 44472

473

474

475

476

477

478

479

480

Absorber pressure (bar)

120578ov

eral

lcom

bine

dcyc

le(

)

x8 = 0555

x8 = 0530

x8 = 0480

p14 = 17barT14 = 352K

ΔTpinch = 5KTa = 288K

Figure 3 Variation of overall efficiency of combined cycle withabsorber pressure

34 36 38 40 42 440070

0071

0072

0073

0074

0075

Absorber pressure (bar)

LEC C

ombi

nedc

ycle(U

SDk

Wh)

x8 = 0555

x8 = 0530

x8 = 0480

p14 = 17bar

T14 = 352K

ΔTpinch = 5KTa = 288K

Figure 4 Variation of LEC of combined cycle with absorberpressure

that the higher absorber pressure leads to less power outputwhich causes the increase in LEC However if absorberpressure is far less than 35 bar the working fluid at the outletof the absorber will change into vapor-liquid mixture Thisincreases the pump power consumption greatlyThe relation-ships of 119865(119883) with the absorber pressure are demonstratedin Figure 5 119865(119883) increases monotonically with increasingabsorber pressure Because the lowest 119865(119883) means the bestperformance the lower absorber pressure is beneficial for thethermodynamic and economic performances

Science and Technology of Nuclear Installations 7

34 36 38 40 42 44002160

002165

002170

002175

002180

002185

002190

F(X

)

Absorber pressure (bar)

x8 = 0555

x8 = 0530

x8 = 0480

p14 = 17bar

T14 = 352K

ΔTpinch = 5KTa = 288K

Figure 5 Variation of 119865(119883) of combined cycle with absorberpressure

15 20 25 30 35276

278

280

282

284

Pow

er o

utpu

t (M

W)

Turbine inlet pressure (bar)

x8 = 0555x8 = 0530

x8 = 0480

T14 = 352K

ΔTpinch = 5KTa = 288K

p8 = 35bar

Figure 6 Variation of power output of combined cycle with turbineinlet pressure

42 Effect of Turbine Inlet Pressure As shown in Figures 6 and7 the variations of the power output and overall efficiencywith the turbine inlet pressure are presented The enthalpydrop across the turbine increases as the turbine inlet pressureincreases However the enthalpy gains because of increasingturbine inlet pressure cannot compensate for the drop in thevapor flow rate Thus the turbine work output decreasesOwing to the decrease of vapor flow rate both the coolingcapacity and the equivalent work of cooling capacity (119882cool)increase first and then decrease However the equivalentwork of cooling capacity is too little comparedwith the poweroutput of the combined cycle Hence the power output andoverall efficiency decrease with the increasing turbine inlettemperature

15 20 25 30 35

466

468

470

472

474

476

478

480

Turbine inlet pressure (bar)

x8 = 0555x8 = 0530

x8 = 0480

T14 = 352K

ΔTpinch = 5KTa = 288K

p8 = 35bar120578ov

eral

lcom

bine

dcyc

le(

)

Figure 7 Variation of overall efficiency of combined cycle withturbine inlet pressure

15 20 25 30 3500710

00715

00720

00725

00730

00735

00740

Turbine inlet pressure (bar)

LEC C

ombi

nedc

ycle(U

SDk

Wh)

x8 = 0555x8 = 0530

x8 = 0480

T14 = 352K

ΔTpinch = 5KTa = 288K

p8 = 35bar

Figure 8 Variation of LEC of combined cycle with turbine inletpressure

As shown in Figure 8 LEC decreases at first and thenincreases with increasing turbine inlet pressure When theammonia mass fraction is 0555 LEC reaches the minimumof 00712USD(kWh) with the turbine inlet pressure of 305bar Figure 9 shows that 119865(119883) decreases first and increaseswith the increasing turbine inlet pressure when the ammoniamass fraction is 053 or 0555 Thus an optimal turbine inletpressure is present and the optimal turbine inlet pressurevalue is changing with the ammonia mass fraction

43 Effect of Turbine Inlet Temperature Figure 10 showsthat the power output increases with increasing turbine

8 Science and Technology of Nuclear Installations

15 20 25 30 3500216

00217

00218

00219

00220

00221

00222

F(X

)

Turbine inlet pressure (bar)

x8 = 0555x8 = 0530

x8 = 0480

T14 = 352K

ΔTpinch = 5KTa = 288K

p8 = 35bar

Figure 9 Variation of 119865(119883) of combined cycle with turbine inletpressure

345 348 351 354 357 360280

281

282

283

284

285

Turbine inlet temperature (K)

Pow

er o

utpu

t (M

W)

x8 = 0555x8 = 0530

x8 = 0480

ΔTpinch = 5KTa = 288K

p8 = 35barp14 = 17bar

Figure 10 Variation of power output of combined cyclewith turbineinlet temperature

inlet temperature With fixed pressure ratio increase in inlettemperature leads to higher inlet enthalpy of working fluidThe exit enthalpy of working fluid also increases at thesame time because of high exit temperature But the increasein enthalpy caused by the increase in inlet temperature ismore than that because of the increase in exit temperatureHence the turbine work output rises up as the turbine inlettemperature increases

Because the increasing turbine inlet temperatureincreases cooler inlet temperature the equivalent work ofcooling capacity (119882cool) declines However the increase ofpower output compensates for the drop in the equivalent

345 348 351 354 357 360

472

474

476

478

480

Turbine inlet temperature (K)

x8 = 0555x8 = 0530

x8 = 0480

ΔTpinch = 5KTa = 288K

p8 = 35barp14 = 17bar

120578ov

eral

lcom

bine

dcyc

le(

)

Figure 11 Variation of overall efficiency of combined cycle withturbine inlet temperature

345 348 351 354 357 3600070

0071

0072

0073

0074

0075

Turbine inlet temperature (K)

x8 = 0555x8 = 0530

x8 = 0480

ΔTpinch = 5KTa = 288K

p8 = 35barp14 = 17bar

LEC C

ombi

nedc

ycle(U

SDk

Wh)

Figure 12 Variation of LEC of combined cycle with turbine inlettemperature

work of cooling capacity This fact results in the slightincrease of overall efficiency (Figure 11)

As shown in Figure 12 LEC increases with increasingturbine inlet temperature monotonously This fact impliesthat the lower inlet temperature results in better economicperformance Figure 13 shows that 119865(119883) changes very slightlywhen the turbine inlet temperature is lower than 253K

44 Effect of AmmoniaMass Fraction Figures 14 and 15 revealthat the power output and overall efficiency will benefit fromincreased ammonia mass fraction Increasing the ammoniamass fraction will improve the thermodynamic performanceof the combined cycle because the higher the ammonia

Science and Technology of Nuclear Installations 9

345 348 351 354 357 360

002156

002163

002170

002177

002184

F(X

)

Turbine inlet temperature (K)

x8 = 0555x8 = 0530

x8 = 0480

ΔTpinch = 5KTa = 288K

p8 = 35barp14 = 17bar

Figure 13 Variation of 119865(119883) of combined cycle with turbine inlettemperature

035 040 045 050 055274

276

278

280

282

284

Pow

er o

utpu

t (M

W)

Ammonia mass fraction

p14 = 17barp14 = 23barp14 = 28bar

p8 = 35barT14 = 352K

ΔTpinch = 5KTa = 288K

Figure 14 Variation of power output of combined cycle withammonia mass fraction

concentration the greater the ammonia vapor flow rateexpanding in the turbine However if the ammonia massfraction is too high the pump power consumption willincrease greatly because the ammonia liquid mixture at theoutlet of the absorber (state 8) will change into the vapor-liquid mixture

Figure 16 shows the effect of ammonia mass fractionon LEC With the increase of ammonia mass fraction LECdecreases initially and then increases The higher the turbineinlet pressure the smaller the optimal ammonia mass frac-tion When the turbine inlet pressure is 17 bar LEC reachesthe minimum of 00716USD(kWh) with an ammonia massfraction of 0405 When the turbine inlet pressure is 17bar LEC reaches the minimum of 00713USD(kWh) with

035 040 045 050 055

465

468

471

474

477

480

Ammonia mass fraction

120578ov

eral

lcom

bine

dcyc

le(

)

p14 = 17barp14 = 23barp14 = 28bar

p8 = 35barT14 = 352K

ΔTpinch = 5KTa = 288K

Figure 15 Variation of overall efficiency of combined cycle withammonia mass fraction

035 040 045 050 055

0071

0072

0073

0074

0075

Ammonia mass fraction

p14 = 17barp14 = 23barp14 = 28bar

p8 = 35barT14 = 352K

ΔTpinch = 5KTa = 288K

LEC C

ombi

nedc

ycle(U

SDk

Wh)

Figure 16 Variation of LEC of combined cycle with ammonia massfraction

an ammonia mass fraction of 0545 Figure 17 presentsthe variations of 119865(119883) with ammonia mass fraction 119865(119883)decreases rapidly with increasing ammonia mass fraction

45 System Optimization In this work SA (SimulatedAnnealing) is employed to obtain the optimum combinationof the key parameters For the optimization the constraintsare simplified as follows

Subject to

170 ⩽ 11990114(bar) ⩽ 340

345 ⩽ 11987914(K) ⩽ 375

036 ⩽ 1199098⩽ 0555

10 Science and Technology of Nuclear Installations

035 040 045 050 05500216

00218

00220

00222

00224

00226

F(X

)

Ammonia mass fraction

p14 = 17barp14 = 23barp14 = 28bar

p8 = 35barT14 = 352K

ΔTpinch = 5KTa = 288K

Figure 17 Variation of F(X) of combined cycle with ammonia massfraction

288 ⩽ 119879119886(K) ⩽ 300

0 ⩽11989810

1198989

⩽ 1

0 ⩽11989812

1198981

⩽ 1

(11987917minus 11987910) ⩾ 5K

(1198794minus 11987911) ⩾ 5K

(1198793minus 119879Boiler) ⩾ 5K

119879Boiler ⩾ 119879Rectifier

119876cool gt 0

11990114⩾ 1199018

(20)

The selection of the above-mentioned parameters for thisoptimization is according to the literatures [6 9 13]

Table 6 shows some results of the closed Brayton cycle Tocompare the thermodynamic and economic performances ofthe combined cycle with those of the closed Brayton cyclethree parameters are defined as follows

RV119882net

=

(119882netCombinedcycle minus119882netBrayton)

119882netBrayton

RV120578overall

=

(120578overallCombinedcycle minus 120578overallBrayton)

120578overallBrayton

RVLEC =

(LECCombinedcycle minus LECBrayton)

LECBrayton

(21)

Table 6 Results of the closed Brayton cycle

Parameters Value119876core (MW) 59364120578overall119861 466119882net119861 (MW) 27690LEC119861(USD(kWh)) 00711

Table 7 Optimization results

Parameters Optimization results

Δ119879pinch = 5K 1199018= 35 bar

11990114= 181 bar 119879

14= 345K

1199098= 0555

F(X) = 002164119882netCombinedcycle = 28356MWRV119882net

= 241120578overallCombinedcycle = 4791RV

120578overall= 243LECCombinedcycle =00706USD(kWh) RVLEC =minus073

Table 7 lists the result of the parameters for the optimiza-tion The optimized power output and overall efficiency forthe combined cycle are 28356MW and 4791 respectivelyThese values are 241 and 243 higher than those of theclosedBrayton cycle respectively Both the lower average heataddition temperature and the higher back pressure of turbinein AWM cycle result in less power output and lower overallefficiency of the combined cycle

Comparingwith closedBrayton cycle the combined cyclereduces the LEC slightly The optimized LEC of combinedcycle is 073 lower than that of the closed Brayton cycleThereason is that the AWM utilizes the waste heat and adds thepower output and the cooling capacity to the closed Braytoncycle However the total capital investment increases due tothe combined AWM system

5 Conclusions

In this paper a combined cycle which combines AWM cycleand a nuclear closed Brayton cycle to recover the wasteheat rejected from the precooler is proposed A detailedparametric study and optimization are carried out for thiscombined cycle according to the thermodynamics and eco-nomics performances The combined cycle can potentiallybe used to improve the power output and overall efficiencyThe power output and overall efficiency of the combinedcycle increase with increasing turbine inlet temperature andammonia mass fraction but the turbine inlet temperatureand the ammonia mass fraction are limited by the heatsource temperature and the absorb pressure respectivelyCompared with the closed Brayton cycle the optimizedpower output and overall efficiency increase by 241 and243 respectively LEC increases with decreasing absorberpressure and turbine inlet temperature The optimized LECof the combined cycle is 00706USD(kWh) which is 073lower than those of the closed Brayton cycle

Science and Technology of Nuclear Installations 11

Competing Interests

The authors declare that there are no competing interestsregarding the publication of this paper and regarding thefunding that they have received

Acknowledgments

This present research was supported by the Chinese NaturalScience Fund (Project no 51306216) and the FundamentalResearch Funds for the Central University (Project noCDJ2R13140016)

References

[1] A Soroureddin A S Mehr S M S Mahmoudi and M YarildquoThermodynamic analysis of employing ejector and organicRankine cycles for GT-MHR waste heat utilization A Compar-ative Studyrdquo Energy Conversion and Management vol 67 pp125ndash137 2013

[2] S Dardour S Nisan and F Charbit ldquoUtilisation of waste heatfrom GT-MHR and PBMR reactors for nuclear desalinationrdquoDesalination vol 205 no 1ndash3 pp 254ndash268 2007

[3] A I Kalina ldquoCombined-cycle system with novel bottomingcyclerdquo Journal of Engineering for Gas Turbines and Power vol106 no 4 pp 737ndash742 1984

[4] D Y Goswami ldquoSolar thermal power technology present statusand ideas for the futurerdquo Energy Sources vol 20 no 2 pp 137ndash145 1998

[5] D S Ayou J C Bruno R Saravanan and A Coronas ldquoAnoverview of combined absorption power and cooling cyclesrdquoRenewable and Sustainable Energy Reviews vol 21 pp 728ndash7482013

[6] R V Padilla G Demirkaya D Y Goswami E Stefanakos andM M Rahman ldquoAnalysis of power and cooling cogenerationusing ammonia-water mixturerdquo Energy vol 35 no 12 pp4649ndash4657 2010

[7] S Lu and D Y Goswami ldquoOptimization of a novel combinedpowerrefrigeration thermodynamic cyclerdquo Journal of SolarEnergy Engineering vol 125 no 2 pp 212ndash217 2003

[8] M Pouraghaie K Atashkari S M Besarati and N Nariman-zadeh ldquoThermodynamic performance optimization of a com-bined powercooling cyclerdquo Energy Conversion and Manage-ment vol 51 no 1 pp 204ndash211 2010

[9] G Demirkaya R Vasquez Padilla D Y Goswami E Ste-fanakos and M M Rahman ldquoAnalysis of a combined powerand cooling cycle for low-grade heat sourcesrdquo InternationalJournal of Energy Research vol 35 no 13 pp 1145ndash1157 2011

[10] L S Vieira J L Donatelli and M E Cruz ldquoExergoeconomicimprovement of a complex cogeneration system integratedwith a professional process simulatorrdquo Energy Conversion andManagement vol 50 no 8 pp 1955ndash1967 2009

[11] Z ShengjunWHuaixin andG Tao ldquoPerformance comparisonand parametric optimization of subcritical Organic RankineCycle (ORC) and transcritical power cycle system for low-temperature geothermal power generationrdquoApplied Energy vol88 no 8 pp 2740ndash2754 2011

[12] T Guo H X Wang and S J Zhang ldquoFluids and parametersoptimization for a novel cogeneration system driven by low-temperature geothermal sourcesrdquo Energy vol 36 no 5 pp2639ndash2649 2011

[13] A Coskun A Bolatturk and M Kanoglu ldquoThermodynamicand economic analysis and optimization of power cycles for amedium temperature geothermal resourcerdquo Energy Conversionand Management vol 78 pp 39ndash49 2014

[14] V Zare S M S Mahmoudi and M Yari ldquoOn the exergoe-conomic assessment of employing Kalina cycle for GT-MHRwaste heat utilizationrdquoEnergy Conversion andManagement vol90 pp 364ndash374 2015

[15] K Bahlouli R Khoshbakhti Saray andN Sarabchi ldquoParametricinvestigation and thermo-economic multi-objective optimiza-tion of an ammonia-water powercooling cycle coupled withan HCCI (homogeneous charge compression ignition) enginerdquoEnergy vol 86 pp 672ndash684 2015

[16] Y Feng Y Zhang B Li J Yang and Y Shi ldquoSensitivity analysisand thermoeconomic comparison of ORCs (organicRankinecycles) for low temperature waste heat recoveryrdquo Energy vol82 pp 664ndash677 2015

[17] F Xu D Y Goswami and S S Bhagwat ldquoA combinedpowercooling cyclerdquo Energy vol 25 no 3 pp 233ndash246 2000

[18] F Xu and D Y Goswami ldquoThermodynamic properties ofammonia-watermixtures for power-cycle applicationsrdquo Energyvol 24 no 6 pp 525ndash536 1999

[19] M S El-Genk and J-M Tournier ldquoNoble gas binary mixturesfor gas-cooled reactor power plantsrdquo Nuclear Engineering andDesign vol 238 no 6 pp 1353ndash1372 2008

[20] F W Yu K T Chan R K Y Sit et al ldquoReview of standardsfor energy performance of chiller systems serving commercialbuildingsrdquo Energy Procedia vol 61 pp 2778ndash2782 2014

[21] S Nisan and S Dardour ldquoEconomic evaluation of nucleardesalination systemsrdquo Desalination vol 205 no 1ndash3 pp 231ndash242 2007

[22] L E Herranz J I Linares and B Y Moratilla ldquoPower cycleassessment of nuclear high temperature gas-cooled reactorsrdquoApplied Thermal Engineering vol 29 no 8-9 pp 1759ndash17652009

[23] HDMadhawaHettiarachchiMGolubovicWMWorek andY Ikegami ldquoOptimum design criteria for an Organic Rankinecycle using low-temperature geothermal heat sourcesrdquo Energyvol 32 no 9 pp 1698ndash1706 2007

[24] Y T Zhu W H Qu and P Y Yu Chemical Equipment DesignManual Chemical Industry Press 2005

[25] Q Songwen Heat Exchanger Design Handbook ChemicalIndustry Press 2002

[26] R Turton R C Bailie W B Whiting et al Analysis Synthesisand Design of Chemical Processes Prentice Hall Upper SaddleRiver NJ USA 1997

[27] F Taboas M Valles M Bourouis and A Coronas ldquoFlowboiling heat transfer of ammoniawater mixture in a plate heatexchangerrdquo International Journal of Refrigeration vol 33 no 4pp 695ndash705 2010

[28] L Xiao S-Y Wu T-T Yi C Liu and Y-R Li ldquoMulti-objectiveoptimization of evaporation and condensation temperatures forsubcritical organic Rankine cyclerdquo Energy vol 83 pp 723ndash7332015

[29] C E Campos Rodrıguez J C Escobar Palacio O J Venturiniet al ldquoExergetic and economic comparison of ORC and Kalinacycle for low temperature enhanced geothermal system inBrazilrdquo Applied Thermal Engineering vol 52 no 1 pp 109ndash1192013

[30] D Mignard ldquoCorrelating the chemical engineering plant costindex with macro-economic indicatorsrdquo Chemical EngineeringResearch and Design vol 92 no 2 pp 285ndash294 2014

12 Science and Technology of Nuclear Installations

[31] httpwwwneimagazinecomnewsnewsnuclear-reactor-per-formance-by-vendors-agrs-23

[32] H W Tang Practical Introduction to Mathematical Program-ming Dalian Institute of Technology Press 1986

[33] V Zare S M S Mahmoudi and M Yari ldquoAn exergoeconomicinvestigation of waste heat recovery from the Gas Turbine-Modular Helium Reactor (GT-MHR) employing an ammonia-water powercooling cyclerdquo Energy vol 61 pp 397ndash409 2013

TribologyAdvances in

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

International Journal of

AerospaceEngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

FuelsJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal ofPetroleum Engineering

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Industrial EngineeringJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Power ElectronicsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in

CombustionJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Renewable Energy

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

StructuresJournal of

International Journal of

RotatingMachinery

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

EnergyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporation httpwwwhindawicom

Journal ofEngineeringVolume 2014

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

International Journal ofPhotoenergy

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Nuclear InstallationsScience and Technology of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Solar EnergyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Wind EnergyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Nuclear EnergyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

High Energy PhysicsAdvances in

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Science and Technology of Nuclear Installations 3

Table 1 Energy relations for the equipment of closed Brayton cycle and AWM cycle

Cycle Equipment Energy equations

Closed Brayton cycle

Reactor core 119876core = 1198981(ℎ1minus ℎ7)

Turbine 119882119879= 1198981(ℎ1minus ℎ2119904) 120578119904119879

Recuperator (ℎ2minus ℎ3) = (ℎ

7minus ℎ6)

Precooler 119876precooler = 1198981(ℎ4minus ℎ5)

Compressor 119882119862=1198981(ℎ6119904minus ℎ5)

120578119904119862

AWM cycle

Boiler 1198981(ℎ3minus ℎ4) = 119898

12ℎ12+ 11989817ℎ17minus 11989811ℎ11minus 11989813ℎ13

Rectifier 11989814ℎ14+ 11989813ℎ13+ 119898111015840 (ℎ111015840 minus ℎ9) = 119898

12ℎ12

HT recuperator 11989817(ℎ17minus ℎ18) = 119898

10(ℎ10minus ℎ9)

Absorber 119876absorber = 11989819ℎ19+ 11989816ℎ16minus 1198988ℎ8

Turbine 119882119879= 11989814(ℎ14minus ℎ15119904) 120578119904119879

Cooler 119876cool = 11989815(ℎ16minus ℎ15)

Pump 119882119875=1198988(ℎ9119904minus ℎ8)

120578119904119875

Throttle valve ℎ19= ℎ18

120578119904119879 120578119904119862 and 120578119904119875 represent the isentropic efficiency of the turbine the compressor and the pump respectively

The helium flowing out from the gas turbine flowsinto the hot side of the recuperator where the helium iscooled to about 400K To reduce the compressor powerconsumption the helium should be cooled to about 300Kbefore flowing into the compressorThus the ammonia-waterpowercooling cycle (AWM) proposed by Goswami [17] in2000 is coupled into this closed Brayton cycle to utilize thewaste heat rejected from the precooler In this situation theheliumflowing out from the hot side of the recuperator entersa boiler before entering the precoolerTheheat released by thehelium passing through the boiler is the heat resource of theAWMcycleThen a part of theHTGRwaste heat is recoveredfor the AWM cycle to produce power The AWM cycle useshigh concentration of ammonia as the working fluid whichcan be expanded to a very low temperature in the turbineThe very low temperature ammonia-water mixture providesrefrigerationThenet effects are the production of both powerand refrigeration

An ammonia-water mixture (state 8) is pumped to a highpressure (state 9) and heated to boil off ammonia (state 12)The vapor is enriched in ammonia by condensing a part ofthe vapor in a rectifier (state 14) The condensate is richerin water and returned to the boiler (state 13) The ammoniavapor which is almost pure ammonia can be expanded ina turbine to exit at a very low temperature (state 15) Afterexpansion in the turbine to generate power low temperatureammonia first provides cooling capacity in the cooler (state16) and is absorbed by low concentration solution from theboiler in an absorber to form the basic ammonia-water liquidsolution to complete the cycle (state 8) [17]

The following assumptions are used in this work

(1) The system operates in a steady state condition(2) Changes in kinetic and potential energies are

neglected(3) The pressure loss due to the frictional effects is

neglected

(4) The turbine and the pump in the combined cycle haveisentropic efficiencies [15]

(5) The ammonia-water solution leaving the absorber(state 8) is a saturated liquid at low pressure

3 System Modeling

31 Thermodynamic Modeling A MATLAB code has beendeveloped to carry out the numerical simulations for thiscombined cycle The thermodynamic properties of the statesin the closed Brayton cycle are evaluated by REFPROP 90The thermodynamic properties of the states of the bottomcycle (AWM cycle) are evaluated by the method proposedby Xu and Goswami [18] For thermodynamic analysisthe principles of mass and energy conservations as wellas the second law of thermodynamics are applied to eachcomponent

To simplify the calculation just one operation conditionof the closed Brayton cycle is selected according to theliterature [19] and the parameters are listed in Table 5

The energy relations for the equipment of combined cycleare listed in Table 1

For the combined cycle the net power output can bedefined as follows

119882netCombinedcycle = 119882net119861 +119882netAWM

= (119882119879minus119882119862)119861+ (119882119879minus119882119875)AWM

(1)

The overall efficiency of the combined cycle is defined asfollows

120578overallCombinedcycle =119882net119861 +119882netAWM +119882cool

119876core (2)

4 Science and Technology of Nuclear Installations

Table 2 Comparison between the properties of the present work and those from the published literature [17]

State T (K) p (bar) h (kJkg) s (kJkg K) x119886lowast

119887lowast

119886lowast

119887lowast

119886lowast

119887lowast

8 2800 20 minus2141 minus2144 minus01060 minus01061 053 0539 2800 300 minus2114 minus2116 minus01083 minus01084 053 05311 3781 300 2463 2467 12907 12924 053 05312 4000 300 15472 15498 46102 46223 09432 0945113 3600 300 2058 2061 11185 11201 06763 0676014 3600 300 13732 13741 41520 41546 09921 0993815 2570 20 11489 11776 45558 46702 09921 0993816 2800 20 12787 12846 50461 50734 09921 0993817 4000 300 3482 3479 15544 15563 04147 0426918 3000 300 minus1190 minus1207 02125 02105 04147 04269119886lowast the thermodynamic properties presented in literature [17]119887lowast the thermodynamic properties calculated in this work

The cooling capacity is converted to equivalent power and canbe expressed as

119882cool =119876coolcop

(3)

where cop is the coefficient of performance and set as 4 [20]

311 Verification of Ammonia-Water Thermodynamic Prop-erties To verify the developed thermodynamic models forAWM cycle the available data in the literature are usedThe comparisons between the simulation results and thosereported in the published literature are presented in Table 2For AWM cycle the data in Table 2 indicate a very goodagreement between simulation results of this paper and thosein published literature [17] and the maximum deviation isonly 25

32 Economic Modeling To evaluate the thermoeconomicperformance of the combined cycle levelized energy cost(LEC) is analyzed in this paper Because the aim of this paperis to evaluate the effect of AWM cycle on the thermodynamicand economic performances of the combined cycle theHTGRplant (closed Brayton cycle) specific cost is assumed tobe 1073$kW [21] A cost of 8$MWh is assumed for nuclearfuel [22]

Then the capital investment of AWM cycle is calculatedAccording to the literature [23] the heat exchangers pumpand turbine contribute largely to the total cost We assumethat all of the heat exchangers in AWM system are shell-and-tube heat exchanger [24 25]

The heat exchanger area can be expressed as follows

119860 =119876

(119880Δ119879119898)

Δ119879119898=

(Δ119879max minus Δ119879min)

ln (Δ119879maxΔ119879min)

(4)

where 119876 represents the heat exchanger heat load 119880 standsfor the overall heat transfer coefficient and Δ119879

119898is the log-

arithmic mean temperature difference The heat transfer

Table 3 Heat transfer coefficients for heat exchangers [33]

Component Heat transfer coefficient (Wm2K)Absorber 800Separator 900Cooler 1000Recuperator 800

coefficients of some heat exchangers inAWMcycle are shownin Table 3

The overall heat transfer coefficient of the boiler can becalculated as follows [26]

1

119880=

1

ℎHe+120575

119896+

1

ℎaw+ 119877 (5)

where ℎHe is the heat transfer coefficient of the heliumℎaw is the ammonia-water heat transfer coefficient and is2000W(m2K) [27] according to the characteristic of thecycle 120575 is the thickness of the heat exchanger tube 119896 is theheat conductivity of the tube 119877 is the heat resistance of thetube

The heat transfer coefficient of the helium in the shell iscalculated by the following equations

NuHe = 0023Re08HePr065

He (119879119908

119879119887

)

minus119888

119888 = 057 minus (159

119897119889)

ℎHe =Nu 120582119889

(6)

For the above equations Re and Pr are Reynolds numberand Prandtl number respectively 119879

119908and 119879

119887are the temper-

atures of the shell and tube respectively 120582 is the thermalconductivity coefficient 119889 is the diameter or equivalenthydraulic diameter of the heat exchanger 119897 is the length ofthe tube

Science and Technology of Nuclear Installations 5

Table 4 Coefficients required for the cost evaluation for each component [26]

Components 1198701

1198702

1198703

1198621

1198622

1198623

1198611

1198612

119865119898

119865119887119898

Turbine 315140 05890 0 0 0 0 0 0 0 350Pump 35790 03210 00290 01680 03480 04840 180 151 180 Equation (9)Heat exchanger 32138 02688 007961 minus0064991 005025 001474 180 150 125 Equation (9)

Table 5 Specifications of the combined cycle [19]

Parameters Valuem1(kgs) 3588

120578119904119875

085T1(K) 11791

T5(K) 301

p1(bar) 676

120578119904119879

085120578119904119862

085T3(K) 3988

T7(K) 8554

p2(bar) 310

The capital costs of the AWM system consist of the heatexchanger pump and turbine costs and are expressed asfollows [26 28]

lg119862119887= 1198701+ 1198702lg119885 + 119870

3(lg119885)2 (7)

where 119862119887is the estimated component cost based on US

dollars in the year of 1996 119885 is a parameter related to cyclecomponents For the heat exchanger 119885 refers to the areaof heat exchanger 119860 For the pump 119885 means the powerconsumption in pump119882

119901 For the turbine 119885 represents the

power output 119882out The coefficients of 1198701 1198702 and 119870

3are

listed in Table 4The capital cost 119862 which is corrected according to the

component materials and the pressure is determined by (8)as follows

119862 = 119862119887119865119887119898 (8)

where the coefficient 119865119887119898

is 35 for the turbine and thecoefficients 119865

119887119898for other components are calculated by (9)

[29] as follows

119865119887119898

= 1198611+ 1198612119865119898119865119901 (9)

where 1198611and 119861

2are the coefficients of different types of

the components and 119865119898

is the correction coefficient forthe component materials The values of 119861

1 1198612 and 119865

119898are

presented in Table 4119865119901represents the pressure correction coefficient and is

calculated by

lg119865119901= 1198621+ 1198622times lg119901 + 119862

3times (lg119901)2 (10)

The coefficients of 1198621 1198622 and 119862

3are also shown in

Table 4

Thus the cost of the AWM system in the year 1996119862AWM1996 can be evaluated as follows

119862AWM1996 = 119862119867+ 119862119864+ 119862119901 (11)

According to the time value of money the cost of closedBrayton system in the year of 2006 and the AWM system inthe year of 1996 are converted into the capital costs in the yearof 2015 respectively and the total cost of the combined cycle(1198622015

) is their sum as follows

1198622015

= 1198621198612006

CEPCI2015

CEPCI2006

+ 119862AWM1996CEPCI

2015

CEPCI1996

(12)

where CEPCI1996

CEPCI2006

and CEPCI2015

are the chemi-cal plant cost indexes in the years 1996 2006 and 2015 andthe values are 382 510 and 592 respectively [30]

The capital recovery factor (CRF) is defined as follows

CRF = 119894 (1 + 119894)119879119904

(1 + 119894)119879119904 minus 1

(13)

In this equation 119894 is the discount rate and is 5 with inflationrate zero [21] The economic life of the combined system (119879

119904)

is 40 yearsFor each year the operation hour of the system is

calculated as follows

OP119904= 365 times 24 times 119871

119891 (14)

In the combined system the levelized energy cost (LEC)can be calculated by (14) One has

LEC =CRF times 119862

2015+ COM

119904

(119882net +119882cool) timesOP119904

(15)

where COM119904is the system operation and maintenance cost

and is 15 of 1198622015

The load factor 119871119891is taken as 075 [31]

33 Optimization Model A simple thermodynamic opti-mization or economical optimization might draw differ-ent results because it is difficult to ensure a global cost-effective cycle design Thus the optimizations on both thethermodynamics and economics are simultaneously neededin the assessment of the combined cycle Regarding thisoverall efficiency 120578overallCombinedcycle and levelized energy cost(LEC) are selected to build a multiobjective function asthe performance indicator in this paper The multiobjectiveoptimization model is constructed as follows

The first objective function 1198651(119883) is expressed by the

following

min 1198651(119883) =

1

120578overallCombinedcycle (16)

6 Science and Technology of Nuclear Installations

34 36 38 40 42 44280

281

282

283

284

285

Pow

er o

utpu

t (M

W)

Absorber pressure (bar)

x8 = 0555

x8 = 0530

x8 = 0480

p14 = 17bar

Ta = 288KΔTpinch = 5K

T14 = 352K

Figure 2 Variation of power output of combined cycle withabsorber pressure

The second objective function 1198652(119883) is expressed by the

following

min 1198652(119883) = LEC (17)

The first objective function 1198651(119883) represents system

thermodynamic property and the second objective function1198652(119883) is the thermoeconomic propertyIn this paper the method of linear weighted evaluation

function is adopted to solve the objective function optimiza-tion model [28] which contains more than two performanceindicators The multiobjective function 119865(119883) is given by thefollowing

119865 (119883) = 1205721198651(119883) + 120573119865

2(119883) (18)

where120572 and120573 are theweight coefficients of objective functionand amethod proposed byP1aSAkK5 is applied to solve thesetwo weight coefficients [32]

120572 =

(1198651

2minus 1198652

2)

[(1198652

1minus 1198651

1) + (119865

1

2minus 1198652

2)]

120573 =

(1198652

1minus 1198651

1)

[(1198652

1minus 1198651

1) + (119865

1

2minus 1198652

2)]

(19)

4 Results and Discussion

41 Effect of Absorber Pressure The absorber pressure is theoutlet pressure of ammonia-water turbine If the absorberpressure is high the working fluid cannot expand fully inthe turbine and both the power output and overall efficiencydecrease in turn (Figures 2 and 3) Figure 4 shows that LECincreases with increasing absorber pressure The reason is

34 36 38 40 42 44472

473

474

475

476

477

478

479

480

Absorber pressure (bar)

120578ov

eral

lcom

bine

dcyc

le(

)

x8 = 0555

x8 = 0530

x8 = 0480

p14 = 17barT14 = 352K

ΔTpinch = 5KTa = 288K

Figure 3 Variation of overall efficiency of combined cycle withabsorber pressure

34 36 38 40 42 440070

0071

0072

0073

0074

0075

Absorber pressure (bar)

LEC C

ombi

nedc

ycle(U

SDk

Wh)

x8 = 0555

x8 = 0530

x8 = 0480

p14 = 17bar

T14 = 352K

ΔTpinch = 5KTa = 288K

Figure 4 Variation of LEC of combined cycle with absorberpressure

that the higher absorber pressure leads to less power outputwhich causes the increase in LEC However if absorberpressure is far less than 35 bar the working fluid at the outletof the absorber will change into vapor-liquid mixture Thisincreases the pump power consumption greatlyThe relation-ships of 119865(119883) with the absorber pressure are demonstratedin Figure 5 119865(119883) increases monotonically with increasingabsorber pressure Because the lowest 119865(119883) means the bestperformance the lower absorber pressure is beneficial for thethermodynamic and economic performances

Science and Technology of Nuclear Installations 7

34 36 38 40 42 44002160

002165

002170

002175

002180

002185

002190

F(X

)

Absorber pressure (bar)

x8 = 0555

x8 = 0530

x8 = 0480

p14 = 17bar

T14 = 352K

ΔTpinch = 5KTa = 288K

Figure 5 Variation of 119865(119883) of combined cycle with absorberpressure

15 20 25 30 35276

278

280

282

284

Pow

er o

utpu

t (M

W)

Turbine inlet pressure (bar)

x8 = 0555x8 = 0530

x8 = 0480

T14 = 352K

ΔTpinch = 5KTa = 288K

p8 = 35bar

Figure 6 Variation of power output of combined cycle with turbineinlet pressure

42 Effect of Turbine Inlet Pressure As shown in Figures 6 and7 the variations of the power output and overall efficiencywith the turbine inlet pressure are presented The enthalpydrop across the turbine increases as the turbine inlet pressureincreases However the enthalpy gains because of increasingturbine inlet pressure cannot compensate for the drop in thevapor flow rate Thus the turbine work output decreasesOwing to the decrease of vapor flow rate both the coolingcapacity and the equivalent work of cooling capacity (119882cool)increase first and then decrease However the equivalentwork of cooling capacity is too little comparedwith the poweroutput of the combined cycle Hence the power output andoverall efficiency decrease with the increasing turbine inlettemperature

15 20 25 30 35

466

468

470

472

474

476

478

480

Turbine inlet pressure (bar)

x8 = 0555x8 = 0530

x8 = 0480

T14 = 352K

ΔTpinch = 5KTa = 288K

p8 = 35bar120578ov

eral

lcom

bine

dcyc

le(

)

Figure 7 Variation of overall efficiency of combined cycle withturbine inlet pressure

15 20 25 30 3500710

00715

00720

00725

00730

00735

00740

Turbine inlet pressure (bar)

LEC C

ombi

nedc

ycle(U

SDk

Wh)

x8 = 0555x8 = 0530

x8 = 0480

T14 = 352K

ΔTpinch = 5KTa = 288K

p8 = 35bar

Figure 8 Variation of LEC of combined cycle with turbine inletpressure

As shown in Figure 8 LEC decreases at first and thenincreases with increasing turbine inlet pressure When theammonia mass fraction is 0555 LEC reaches the minimumof 00712USD(kWh) with the turbine inlet pressure of 305bar Figure 9 shows that 119865(119883) decreases first and increaseswith the increasing turbine inlet pressure when the ammoniamass fraction is 053 or 0555 Thus an optimal turbine inletpressure is present and the optimal turbine inlet pressurevalue is changing with the ammonia mass fraction

43 Effect of Turbine Inlet Temperature Figure 10 showsthat the power output increases with increasing turbine

8 Science and Technology of Nuclear Installations

15 20 25 30 3500216

00217

00218

00219

00220

00221

00222

F(X

)

Turbine inlet pressure (bar)

x8 = 0555x8 = 0530

x8 = 0480

T14 = 352K

ΔTpinch = 5KTa = 288K

p8 = 35bar

Figure 9 Variation of 119865(119883) of combined cycle with turbine inletpressure

345 348 351 354 357 360280

281

282

283

284

285

Turbine inlet temperature (K)

Pow

er o

utpu

t (M

W)

x8 = 0555x8 = 0530

x8 = 0480

ΔTpinch = 5KTa = 288K

p8 = 35barp14 = 17bar

Figure 10 Variation of power output of combined cyclewith turbineinlet temperature

inlet temperature With fixed pressure ratio increase in inlettemperature leads to higher inlet enthalpy of working fluidThe exit enthalpy of working fluid also increases at thesame time because of high exit temperature But the increasein enthalpy caused by the increase in inlet temperature ismore than that because of the increase in exit temperatureHence the turbine work output rises up as the turbine inlettemperature increases

Because the increasing turbine inlet temperatureincreases cooler inlet temperature the equivalent work ofcooling capacity (119882cool) declines However the increase ofpower output compensates for the drop in the equivalent

345 348 351 354 357 360

472

474

476

478

480

Turbine inlet temperature (K)

x8 = 0555x8 = 0530

x8 = 0480

ΔTpinch = 5KTa = 288K

p8 = 35barp14 = 17bar

120578ov

eral

lcom

bine

dcyc

le(

)

Figure 11 Variation of overall efficiency of combined cycle withturbine inlet temperature

345 348 351 354 357 3600070

0071

0072

0073

0074

0075

Turbine inlet temperature (K)

x8 = 0555x8 = 0530

x8 = 0480

ΔTpinch = 5KTa = 288K

p8 = 35barp14 = 17bar

LEC C

ombi

nedc

ycle(U

SDk

Wh)

Figure 12 Variation of LEC of combined cycle with turbine inlettemperature

work of cooling capacity This fact results in the slightincrease of overall efficiency (Figure 11)

As shown in Figure 12 LEC increases with increasingturbine inlet temperature monotonously This fact impliesthat the lower inlet temperature results in better economicperformance Figure 13 shows that 119865(119883) changes very slightlywhen the turbine inlet temperature is lower than 253K

44 Effect of AmmoniaMass Fraction Figures 14 and 15 revealthat the power output and overall efficiency will benefit fromincreased ammonia mass fraction Increasing the ammoniamass fraction will improve the thermodynamic performanceof the combined cycle because the higher the ammonia

Science and Technology of Nuclear Installations 9

345 348 351 354 357 360

002156

002163

002170

002177

002184

F(X

)

Turbine inlet temperature (K)

x8 = 0555x8 = 0530

x8 = 0480

ΔTpinch = 5KTa = 288K

p8 = 35barp14 = 17bar

Figure 13 Variation of 119865(119883) of combined cycle with turbine inlettemperature

035 040 045 050 055274

276

278

280

282

284

Pow

er o

utpu

t (M

W)

Ammonia mass fraction

p14 = 17barp14 = 23barp14 = 28bar

p8 = 35barT14 = 352K

ΔTpinch = 5KTa = 288K

Figure 14 Variation of power output of combined cycle withammonia mass fraction

concentration the greater the ammonia vapor flow rateexpanding in the turbine However if the ammonia massfraction is too high the pump power consumption willincrease greatly because the ammonia liquid mixture at theoutlet of the absorber (state 8) will change into the vapor-liquid mixture

Figure 16 shows the effect of ammonia mass fractionon LEC With the increase of ammonia mass fraction LECdecreases initially and then increases The higher the turbineinlet pressure the smaller the optimal ammonia mass frac-tion When the turbine inlet pressure is 17 bar LEC reachesthe minimum of 00716USD(kWh) with an ammonia massfraction of 0405 When the turbine inlet pressure is 17bar LEC reaches the minimum of 00713USD(kWh) with

035 040 045 050 055

465

468

471

474

477

480

Ammonia mass fraction

120578ov

eral

lcom

bine

dcyc

le(

)

p14 = 17barp14 = 23barp14 = 28bar

p8 = 35barT14 = 352K

ΔTpinch = 5KTa = 288K

Figure 15 Variation of overall efficiency of combined cycle withammonia mass fraction

035 040 045 050 055

0071

0072

0073

0074

0075

Ammonia mass fraction

p14 = 17barp14 = 23barp14 = 28bar

p8 = 35barT14 = 352K

ΔTpinch = 5KTa = 288K

LEC C

ombi

nedc

ycle(U

SDk

Wh)

Figure 16 Variation of LEC of combined cycle with ammonia massfraction

an ammonia mass fraction of 0545 Figure 17 presentsthe variations of 119865(119883) with ammonia mass fraction 119865(119883)decreases rapidly with increasing ammonia mass fraction

45 System Optimization In this work SA (SimulatedAnnealing) is employed to obtain the optimum combinationof the key parameters For the optimization the constraintsare simplified as follows

Subject to

170 ⩽ 11990114(bar) ⩽ 340

345 ⩽ 11987914(K) ⩽ 375

036 ⩽ 1199098⩽ 0555

10 Science and Technology of Nuclear Installations

035 040 045 050 05500216

00218

00220

00222

00224

00226

F(X

)

Ammonia mass fraction

p14 = 17barp14 = 23barp14 = 28bar

p8 = 35barT14 = 352K

ΔTpinch = 5KTa = 288K

Figure 17 Variation of F(X) of combined cycle with ammonia massfraction

288 ⩽ 119879119886(K) ⩽ 300

0 ⩽11989810

1198989

⩽ 1

0 ⩽11989812

1198981

⩽ 1

(11987917minus 11987910) ⩾ 5K

(1198794minus 11987911) ⩾ 5K

(1198793minus 119879Boiler) ⩾ 5K

119879Boiler ⩾ 119879Rectifier

119876cool gt 0

11990114⩾ 1199018

(20)

The selection of the above-mentioned parameters for thisoptimization is according to the literatures [6 9 13]

Table 6 shows some results of the closed Brayton cycle Tocompare the thermodynamic and economic performances ofthe combined cycle with those of the closed Brayton cyclethree parameters are defined as follows

RV119882net

=

(119882netCombinedcycle minus119882netBrayton)

119882netBrayton

RV120578overall

=

(120578overallCombinedcycle minus 120578overallBrayton)

120578overallBrayton

RVLEC =

(LECCombinedcycle minus LECBrayton)

LECBrayton

(21)

Table 6 Results of the closed Brayton cycle

Parameters Value119876core (MW) 59364120578overall119861 466119882net119861 (MW) 27690LEC119861(USD(kWh)) 00711

Table 7 Optimization results

Parameters Optimization results

Δ119879pinch = 5K 1199018= 35 bar

11990114= 181 bar 119879

14= 345K

1199098= 0555

F(X) = 002164119882netCombinedcycle = 28356MWRV119882net

= 241120578overallCombinedcycle = 4791RV

120578overall= 243LECCombinedcycle =00706USD(kWh) RVLEC =minus073

Table 7 lists the result of the parameters for the optimiza-tion The optimized power output and overall efficiency forthe combined cycle are 28356MW and 4791 respectivelyThese values are 241 and 243 higher than those of theclosedBrayton cycle respectively Both the lower average heataddition temperature and the higher back pressure of turbinein AWM cycle result in less power output and lower overallefficiency of the combined cycle

Comparingwith closedBrayton cycle the combined cyclereduces the LEC slightly The optimized LEC of combinedcycle is 073 lower than that of the closed Brayton cycleThereason is that the AWM utilizes the waste heat and adds thepower output and the cooling capacity to the closed Braytoncycle However the total capital investment increases due tothe combined AWM system

5 Conclusions

In this paper a combined cycle which combines AWM cycleand a nuclear closed Brayton cycle to recover the wasteheat rejected from the precooler is proposed A detailedparametric study and optimization are carried out for thiscombined cycle according to the thermodynamics and eco-nomics performances The combined cycle can potentiallybe used to improve the power output and overall efficiencyThe power output and overall efficiency of the combinedcycle increase with increasing turbine inlet temperature andammonia mass fraction but the turbine inlet temperatureand the ammonia mass fraction are limited by the heatsource temperature and the absorb pressure respectivelyCompared with the closed Brayton cycle the optimizedpower output and overall efficiency increase by 241 and243 respectively LEC increases with decreasing absorberpressure and turbine inlet temperature The optimized LECof the combined cycle is 00706USD(kWh) which is 073lower than those of the closed Brayton cycle

Science and Technology of Nuclear Installations 11

Competing Interests

The authors declare that there are no competing interestsregarding the publication of this paper and regarding thefunding that they have received

Acknowledgments

This present research was supported by the Chinese NaturalScience Fund (Project no 51306216) and the FundamentalResearch Funds for the Central University (Project noCDJ2R13140016)

References

[1] A Soroureddin A S Mehr S M S Mahmoudi and M YarildquoThermodynamic analysis of employing ejector and organicRankine cycles for GT-MHR waste heat utilization A Compar-ative Studyrdquo Energy Conversion and Management vol 67 pp125ndash137 2013

[2] S Dardour S Nisan and F Charbit ldquoUtilisation of waste heatfrom GT-MHR and PBMR reactors for nuclear desalinationrdquoDesalination vol 205 no 1ndash3 pp 254ndash268 2007

[3] A I Kalina ldquoCombined-cycle system with novel bottomingcyclerdquo Journal of Engineering for Gas Turbines and Power vol106 no 4 pp 737ndash742 1984

[4] D Y Goswami ldquoSolar thermal power technology present statusand ideas for the futurerdquo Energy Sources vol 20 no 2 pp 137ndash145 1998

[5] D S Ayou J C Bruno R Saravanan and A Coronas ldquoAnoverview of combined absorption power and cooling cyclesrdquoRenewable and Sustainable Energy Reviews vol 21 pp 728ndash7482013

[6] R V Padilla G Demirkaya D Y Goswami E Stefanakos andM M Rahman ldquoAnalysis of power and cooling cogenerationusing ammonia-water mixturerdquo Energy vol 35 no 12 pp4649ndash4657 2010

[7] S Lu and D Y Goswami ldquoOptimization of a novel combinedpowerrefrigeration thermodynamic cyclerdquo Journal of SolarEnergy Engineering vol 125 no 2 pp 212ndash217 2003

[8] M Pouraghaie K Atashkari S M Besarati and N Nariman-zadeh ldquoThermodynamic performance optimization of a com-bined powercooling cyclerdquo Energy Conversion and Manage-ment vol 51 no 1 pp 204ndash211 2010

[9] G Demirkaya R Vasquez Padilla D Y Goswami E Ste-fanakos and M M Rahman ldquoAnalysis of a combined powerand cooling cycle for low-grade heat sourcesrdquo InternationalJournal of Energy Research vol 35 no 13 pp 1145ndash1157 2011

[10] L S Vieira J L Donatelli and M E Cruz ldquoExergoeconomicimprovement of a complex cogeneration system integratedwith a professional process simulatorrdquo Energy Conversion andManagement vol 50 no 8 pp 1955ndash1967 2009

[11] Z ShengjunWHuaixin andG Tao ldquoPerformance comparisonand parametric optimization of subcritical Organic RankineCycle (ORC) and transcritical power cycle system for low-temperature geothermal power generationrdquoApplied Energy vol88 no 8 pp 2740ndash2754 2011

[12] T Guo H X Wang and S J Zhang ldquoFluids and parametersoptimization for a novel cogeneration system driven by low-temperature geothermal sourcesrdquo Energy vol 36 no 5 pp2639ndash2649 2011

[13] A Coskun A Bolatturk and M Kanoglu ldquoThermodynamicand economic analysis and optimization of power cycles for amedium temperature geothermal resourcerdquo Energy Conversionand Management vol 78 pp 39ndash49 2014

[14] V Zare S M S Mahmoudi and M Yari ldquoOn the exergoe-conomic assessment of employing Kalina cycle for GT-MHRwaste heat utilizationrdquoEnergy Conversion andManagement vol90 pp 364ndash374 2015

[15] K Bahlouli R Khoshbakhti Saray andN Sarabchi ldquoParametricinvestigation and thermo-economic multi-objective optimiza-tion of an ammonia-water powercooling cycle coupled withan HCCI (homogeneous charge compression ignition) enginerdquoEnergy vol 86 pp 672ndash684 2015

[16] Y Feng Y Zhang B Li J Yang and Y Shi ldquoSensitivity analysisand thermoeconomic comparison of ORCs (organicRankinecycles) for low temperature waste heat recoveryrdquo Energy vol82 pp 664ndash677 2015

[17] F Xu D Y Goswami and S S Bhagwat ldquoA combinedpowercooling cyclerdquo Energy vol 25 no 3 pp 233ndash246 2000

[18] F Xu and D Y Goswami ldquoThermodynamic properties ofammonia-watermixtures for power-cycle applicationsrdquo Energyvol 24 no 6 pp 525ndash536 1999

[19] M S El-Genk and J-M Tournier ldquoNoble gas binary mixturesfor gas-cooled reactor power plantsrdquo Nuclear Engineering andDesign vol 238 no 6 pp 1353ndash1372 2008

[20] F W Yu K T Chan R K Y Sit et al ldquoReview of standardsfor energy performance of chiller systems serving commercialbuildingsrdquo Energy Procedia vol 61 pp 2778ndash2782 2014

[21] S Nisan and S Dardour ldquoEconomic evaluation of nucleardesalination systemsrdquo Desalination vol 205 no 1ndash3 pp 231ndash242 2007

[22] L E Herranz J I Linares and B Y Moratilla ldquoPower cycleassessment of nuclear high temperature gas-cooled reactorsrdquoApplied Thermal Engineering vol 29 no 8-9 pp 1759ndash17652009

[23] HDMadhawaHettiarachchiMGolubovicWMWorek andY Ikegami ldquoOptimum design criteria for an Organic Rankinecycle using low-temperature geothermal heat sourcesrdquo Energyvol 32 no 9 pp 1698ndash1706 2007

[24] Y T Zhu W H Qu and P Y Yu Chemical Equipment DesignManual Chemical Industry Press 2005

[25] Q Songwen Heat Exchanger Design Handbook ChemicalIndustry Press 2002

[26] R Turton R C Bailie W B Whiting et al Analysis Synthesisand Design of Chemical Processes Prentice Hall Upper SaddleRiver NJ USA 1997

[27] F Taboas M Valles M Bourouis and A Coronas ldquoFlowboiling heat transfer of ammoniawater mixture in a plate heatexchangerrdquo International Journal of Refrigeration vol 33 no 4pp 695ndash705 2010

[28] L Xiao S-Y Wu T-T Yi C Liu and Y-R Li ldquoMulti-objectiveoptimization of evaporation and condensation temperatures forsubcritical organic Rankine cyclerdquo Energy vol 83 pp 723ndash7332015

[29] C E Campos Rodrıguez J C Escobar Palacio O J Venturiniet al ldquoExergetic and economic comparison of ORC and Kalinacycle for low temperature enhanced geothermal system inBrazilrdquo Applied Thermal Engineering vol 52 no 1 pp 109ndash1192013

[30] D Mignard ldquoCorrelating the chemical engineering plant costindex with macro-economic indicatorsrdquo Chemical EngineeringResearch and Design vol 92 no 2 pp 285ndash294 2014

12 Science and Technology of Nuclear Installations

[31] httpwwwneimagazinecomnewsnewsnuclear-reactor-per-formance-by-vendors-agrs-23

[32] H W Tang Practical Introduction to Mathematical Program-ming Dalian Institute of Technology Press 1986

[33] V Zare S M S Mahmoudi and M Yari ldquoAn exergoeconomicinvestigation of waste heat recovery from the Gas Turbine-Modular Helium Reactor (GT-MHR) employing an ammonia-water powercooling cyclerdquo Energy vol 61 pp 397ndash409 2013

TribologyAdvances in

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

International Journal of

AerospaceEngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

FuelsJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal ofPetroleum Engineering

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Industrial EngineeringJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Power ElectronicsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in

CombustionJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Renewable Energy

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

StructuresJournal of

International Journal of

RotatingMachinery

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

EnergyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporation httpwwwhindawicom

Journal ofEngineeringVolume 2014

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

International Journal ofPhotoenergy

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Nuclear InstallationsScience and Technology of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Solar EnergyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Wind EnergyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Nuclear EnergyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

High Energy PhysicsAdvances in

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

4 Science and Technology of Nuclear Installations

Table 2 Comparison between the properties of the present work and those from the published literature [17]

State T (K) p (bar) h (kJkg) s (kJkg K) x119886lowast

119887lowast

119886lowast

119887lowast

119886lowast

119887lowast

8 2800 20 minus2141 minus2144 minus01060 minus01061 053 0539 2800 300 minus2114 minus2116 minus01083 minus01084 053 05311 3781 300 2463 2467 12907 12924 053 05312 4000 300 15472 15498 46102 46223 09432 0945113 3600 300 2058 2061 11185 11201 06763 0676014 3600 300 13732 13741 41520 41546 09921 0993815 2570 20 11489 11776 45558 46702 09921 0993816 2800 20 12787 12846 50461 50734 09921 0993817 4000 300 3482 3479 15544 15563 04147 0426918 3000 300 minus1190 minus1207 02125 02105 04147 04269119886lowast the thermodynamic properties presented in literature [17]119887lowast the thermodynamic properties calculated in this work

The cooling capacity is converted to equivalent power and canbe expressed as

119882cool =119876coolcop

(3)

where cop is the coefficient of performance and set as 4 [20]

311 Verification of Ammonia-Water Thermodynamic Prop-erties To verify the developed thermodynamic models forAWM cycle the available data in the literature are usedThe comparisons between the simulation results and thosereported in the published literature are presented in Table 2For AWM cycle the data in Table 2 indicate a very goodagreement between simulation results of this paper and thosein published literature [17] and the maximum deviation isonly 25

32 Economic Modeling To evaluate the thermoeconomicperformance of the combined cycle levelized energy cost(LEC) is analyzed in this paper Because the aim of this paperis to evaluate the effect of AWM cycle on the thermodynamicand economic performances of the combined cycle theHTGRplant (closed Brayton cycle) specific cost is assumed tobe 1073$kW [21] A cost of 8$MWh is assumed for nuclearfuel [22]

Then the capital investment of AWM cycle is calculatedAccording to the literature [23] the heat exchangers pumpand turbine contribute largely to the total cost We assumethat all of the heat exchangers in AWM system are shell-and-tube heat exchanger [24 25]

The heat exchanger area can be expressed as follows

119860 =119876

(119880Δ119879119898)

Δ119879119898=

(Δ119879max minus Δ119879min)

ln (Δ119879maxΔ119879min)

(4)

where 119876 represents the heat exchanger heat load 119880 standsfor the overall heat transfer coefficient and Δ119879

119898is the log-

arithmic mean temperature difference The heat transfer

Table 3 Heat transfer coefficients for heat exchangers [33]

Component Heat transfer coefficient (Wm2K)Absorber 800Separator 900Cooler 1000Recuperator 800

coefficients of some heat exchangers inAWMcycle are shownin Table 3

The overall heat transfer coefficient of the boiler can becalculated as follows [26]

1

119880=

1

ℎHe+120575

119896+

1

ℎaw+ 119877 (5)

where ℎHe is the heat transfer coefficient of the heliumℎaw is the ammonia-water heat transfer coefficient and is2000W(m2K) [27] according to the characteristic of thecycle 120575 is the thickness of the heat exchanger tube 119896 is theheat conductivity of the tube 119877 is the heat resistance of thetube

The heat transfer coefficient of the helium in the shell iscalculated by the following equations

NuHe = 0023Re08HePr065

He (119879119908

119879119887

)

minus119888

119888 = 057 minus (159

119897119889)

ℎHe =Nu 120582119889

(6)

For the above equations Re and Pr are Reynolds numberand Prandtl number respectively 119879

119908and 119879

119887are the temper-

atures of the shell and tube respectively 120582 is the thermalconductivity coefficient 119889 is the diameter or equivalenthydraulic diameter of the heat exchanger 119897 is the length ofthe tube

Science and Technology of Nuclear Installations 5

Table 4 Coefficients required for the cost evaluation for each component [26]

Components 1198701

1198702

1198703

1198621

1198622

1198623

1198611

1198612

119865119898

119865119887119898

Turbine 315140 05890 0 0 0 0 0 0 0 350Pump 35790 03210 00290 01680 03480 04840 180 151 180 Equation (9)Heat exchanger 32138 02688 007961 minus0064991 005025 001474 180 150 125 Equation (9)

Table 5 Specifications of the combined cycle [19]

Parameters Valuem1(kgs) 3588

120578119904119875

085T1(K) 11791

T5(K) 301

p1(bar) 676

120578119904119879

085120578119904119862

085T3(K) 3988

T7(K) 8554

p2(bar) 310

The capital costs of the AWM system consist of the heatexchanger pump and turbine costs and are expressed asfollows [26 28]

lg119862119887= 1198701+ 1198702lg119885 + 119870

3(lg119885)2 (7)

where 119862119887is the estimated component cost based on US

dollars in the year of 1996 119885 is a parameter related to cyclecomponents For the heat exchanger 119885 refers to the areaof heat exchanger 119860 For the pump 119885 means the powerconsumption in pump119882

119901 For the turbine 119885 represents the

power output 119882out The coefficients of 1198701 1198702 and 119870

3are

listed in Table 4The capital cost 119862 which is corrected according to the

component materials and the pressure is determined by (8)as follows

119862 = 119862119887119865119887119898 (8)

where the coefficient 119865119887119898

is 35 for the turbine and thecoefficients 119865

119887119898for other components are calculated by (9)

[29] as follows

119865119887119898

= 1198611+ 1198612119865119898119865119901 (9)

where 1198611and 119861

2are the coefficients of different types of

the components and 119865119898

is the correction coefficient forthe component materials The values of 119861

1 1198612 and 119865

119898are

presented in Table 4119865119901represents the pressure correction coefficient and is

calculated by

lg119865119901= 1198621+ 1198622times lg119901 + 119862

3times (lg119901)2 (10)

The coefficients of 1198621 1198622 and 119862

3are also shown in

Table 4

Thus the cost of the AWM system in the year 1996119862AWM1996 can be evaluated as follows

119862AWM1996 = 119862119867+ 119862119864+ 119862119901 (11)

According to the time value of money the cost of closedBrayton system in the year of 2006 and the AWM system inthe year of 1996 are converted into the capital costs in the yearof 2015 respectively and the total cost of the combined cycle(1198622015

) is their sum as follows

1198622015

= 1198621198612006

CEPCI2015

CEPCI2006

+ 119862AWM1996CEPCI

2015

CEPCI1996

(12)

where CEPCI1996

CEPCI2006

and CEPCI2015

are the chemi-cal plant cost indexes in the years 1996 2006 and 2015 andthe values are 382 510 and 592 respectively [30]

The capital recovery factor (CRF) is defined as follows

CRF = 119894 (1 + 119894)119879119904

(1 + 119894)119879119904 minus 1

(13)

In this equation 119894 is the discount rate and is 5 with inflationrate zero [21] The economic life of the combined system (119879

119904)

is 40 yearsFor each year the operation hour of the system is

calculated as follows

OP119904= 365 times 24 times 119871

119891 (14)

In the combined system the levelized energy cost (LEC)can be calculated by (14) One has

LEC =CRF times 119862

2015+ COM

119904

(119882net +119882cool) timesOP119904

(15)

where COM119904is the system operation and maintenance cost

and is 15 of 1198622015

The load factor 119871119891is taken as 075 [31]

33 Optimization Model A simple thermodynamic opti-mization or economical optimization might draw differ-ent results because it is difficult to ensure a global cost-effective cycle design Thus the optimizations on both thethermodynamics and economics are simultaneously neededin the assessment of the combined cycle Regarding thisoverall efficiency 120578overallCombinedcycle and levelized energy cost(LEC) are selected to build a multiobjective function asthe performance indicator in this paper The multiobjectiveoptimization model is constructed as follows

The first objective function 1198651(119883) is expressed by the

following

min 1198651(119883) =

1

120578overallCombinedcycle (16)

6 Science and Technology of Nuclear Installations

34 36 38 40 42 44280

281

282

283

284

285

Pow

er o

utpu

t (M

W)

Absorber pressure (bar)

x8 = 0555

x8 = 0530

x8 = 0480

p14 = 17bar

Ta = 288KΔTpinch = 5K

T14 = 352K

Figure 2 Variation of power output of combined cycle withabsorber pressure

The second objective function 1198652(119883) is expressed by the

following

min 1198652(119883) = LEC (17)

The first objective function 1198651(119883) represents system

thermodynamic property and the second objective function1198652(119883) is the thermoeconomic propertyIn this paper the method of linear weighted evaluation

function is adopted to solve the objective function optimiza-tion model [28] which contains more than two performanceindicators The multiobjective function 119865(119883) is given by thefollowing

119865 (119883) = 1205721198651(119883) + 120573119865

2(119883) (18)

where120572 and120573 are theweight coefficients of objective functionand amethod proposed byP1aSAkK5 is applied to solve thesetwo weight coefficients [32]

120572 =

(1198651

2minus 1198652

2)

[(1198652

1minus 1198651

1) + (119865

1

2minus 1198652

2)]

120573 =

(1198652

1minus 1198651

1)

[(1198652

1minus 1198651

1) + (119865

1

2minus 1198652

2)]

(19)

4 Results and Discussion

41 Effect of Absorber Pressure The absorber pressure is theoutlet pressure of ammonia-water turbine If the absorberpressure is high the working fluid cannot expand fully inthe turbine and both the power output and overall efficiencydecrease in turn (Figures 2 and 3) Figure 4 shows that LECincreases with increasing absorber pressure The reason is

34 36 38 40 42 44472

473

474

475

476

477

478

479

480

Absorber pressure (bar)

120578ov

eral

lcom

bine

dcyc

le(

)

x8 = 0555

x8 = 0530

x8 = 0480

p14 = 17barT14 = 352K

ΔTpinch = 5KTa = 288K

Figure 3 Variation of overall efficiency of combined cycle withabsorber pressure

34 36 38 40 42 440070

0071

0072

0073

0074

0075

Absorber pressure (bar)

LEC C

ombi

nedc

ycle(U

SDk

Wh)

x8 = 0555

x8 = 0530

x8 = 0480

p14 = 17bar

T14 = 352K

ΔTpinch = 5KTa = 288K

Figure 4 Variation of LEC of combined cycle with absorberpressure

that the higher absorber pressure leads to less power outputwhich causes the increase in LEC However if absorberpressure is far less than 35 bar the working fluid at the outletof the absorber will change into vapor-liquid mixture Thisincreases the pump power consumption greatlyThe relation-ships of 119865(119883) with the absorber pressure are demonstratedin Figure 5 119865(119883) increases monotonically with increasingabsorber pressure Because the lowest 119865(119883) means the bestperformance the lower absorber pressure is beneficial for thethermodynamic and economic performances

Science and Technology of Nuclear Installations 7

34 36 38 40 42 44002160

002165

002170

002175

002180

002185

002190

F(X

)

Absorber pressure (bar)

x8 = 0555

x8 = 0530

x8 = 0480

p14 = 17bar

T14 = 352K

ΔTpinch = 5KTa = 288K

Figure 5 Variation of 119865(119883) of combined cycle with absorberpressure

15 20 25 30 35276

278

280

282

284

Pow

er o

utpu

t (M

W)

Turbine inlet pressure (bar)

x8 = 0555x8 = 0530

x8 = 0480

T14 = 352K

ΔTpinch = 5KTa = 288K

p8 = 35bar

Figure 6 Variation of power output of combined cycle with turbineinlet pressure

42 Effect of Turbine Inlet Pressure As shown in Figures 6 and7 the variations of the power output and overall efficiencywith the turbine inlet pressure are presented The enthalpydrop across the turbine increases as the turbine inlet pressureincreases However the enthalpy gains because of increasingturbine inlet pressure cannot compensate for the drop in thevapor flow rate Thus the turbine work output decreasesOwing to the decrease of vapor flow rate both the coolingcapacity and the equivalent work of cooling capacity (119882cool)increase first and then decrease However the equivalentwork of cooling capacity is too little comparedwith the poweroutput of the combined cycle Hence the power output andoverall efficiency decrease with the increasing turbine inlettemperature

15 20 25 30 35

466

468

470

472

474

476

478

480

Turbine inlet pressure (bar)

x8 = 0555x8 = 0530

x8 = 0480

T14 = 352K

ΔTpinch = 5KTa = 288K

p8 = 35bar120578ov

eral

lcom

bine

dcyc

le(

)

Figure 7 Variation of overall efficiency of combined cycle withturbine inlet pressure

15 20 25 30 3500710

00715

00720

00725

00730

00735

00740

Turbine inlet pressure (bar)

LEC C

ombi

nedc

ycle(U

SDk

Wh)

x8 = 0555x8 = 0530

x8 = 0480

T14 = 352K

ΔTpinch = 5KTa = 288K

p8 = 35bar

Figure 8 Variation of LEC of combined cycle with turbine inletpressure

As shown in Figure 8 LEC decreases at first and thenincreases with increasing turbine inlet pressure When theammonia mass fraction is 0555 LEC reaches the minimumof 00712USD(kWh) with the turbine inlet pressure of 305bar Figure 9 shows that 119865(119883) decreases first and increaseswith the increasing turbine inlet pressure when the ammoniamass fraction is 053 or 0555 Thus an optimal turbine inletpressure is present and the optimal turbine inlet pressurevalue is changing with the ammonia mass fraction

43 Effect of Turbine Inlet Temperature Figure 10 showsthat the power output increases with increasing turbine

8 Science and Technology of Nuclear Installations

15 20 25 30 3500216

00217

00218

00219

00220

00221

00222

F(X

)

Turbine inlet pressure (bar)

x8 = 0555x8 = 0530

x8 = 0480

T14 = 352K

ΔTpinch = 5KTa = 288K

p8 = 35bar

Figure 9 Variation of 119865(119883) of combined cycle with turbine inletpressure

345 348 351 354 357 360280

281

282

283

284

285

Turbine inlet temperature (K)

Pow

er o

utpu

t (M

W)

x8 = 0555x8 = 0530

x8 = 0480

ΔTpinch = 5KTa = 288K

p8 = 35barp14 = 17bar

Figure 10 Variation of power output of combined cyclewith turbineinlet temperature

inlet temperature With fixed pressure ratio increase in inlettemperature leads to higher inlet enthalpy of working fluidThe exit enthalpy of working fluid also increases at thesame time because of high exit temperature But the increasein enthalpy caused by the increase in inlet temperature ismore than that because of the increase in exit temperatureHence the turbine work output rises up as the turbine inlettemperature increases

Because the increasing turbine inlet temperatureincreases cooler inlet temperature the equivalent work ofcooling capacity (119882cool) declines However the increase ofpower output compensates for the drop in the equivalent

345 348 351 354 357 360

472

474

476

478

480

Turbine inlet temperature (K)

x8 = 0555x8 = 0530

x8 = 0480

ΔTpinch = 5KTa = 288K

p8 = 35barp14 = 17bar

120578ov

eral

lcom

bine

dcyc

le(

)

Figure 11 Variation of overall efficiency of combined cycle withturbine inlet temperature

345 348 351 354 357 3600070

0071

0072

0073

0074

0075

Turbine inlet temperature (K)

x8 = 0555x8 = 0530

x8 = 0480

ΔTpinch = 5KTa = 288K

p8 = 35barp14 = 17bar

LEC C

ombi

nedc

ycle(U

SDk

Wh)

Figure 12 Variation of LEC of combined cycle with turbine inlettemperature

work of cooling capacity This fact results in the slightincrease of overall efficiency (Figure 11)

As shown in Figure 12 LEC increases with increasingturbine inlet temperature monotonously This fact impliesthat the lower inlet temperature results in better economicperformance Figure 13 shows that 119865(119883) changes very slightlywhen the turbine inlet temperature is lower than 253K

44 Effect of AmmoniaMass Fraction Figures 14 and 15 revealthat the power output and overall efficiency will benefit fromincreased ammonia mass fraction Increasing the ammoniamass fraction will improve the thermodynamic performanceof the combined cycle because the higher the ammonia

Science and Technology of Nuclear Installations 9

345 348 351 354 357 360

002156

002163

002170

002177

002184

F(X

)

Turbine inlet temperature (K)

x8 = 0555x8 = 0530

x8 = 0480

ΔTpinch = 5KTa = 288K

p8 = 35barp14 = 17bar

Figure 13 Variation of 119865(119883) of combined cycle with turbine inlettemperature

035 040 045 050 055274

276

278

280

282

284

Pow

er o

utpu

t (M

W)

Ammonia mass fraction

p14 = 17barp14 = 23barp14 = 28bar

p8 = 35barT14 = 352K

ΔTpinch = 5KTa = 288K

Figure 14 Variation of power output of combined cycle withammonia mass fraction

concentration the greater the ammonia vapor flow rateexpanding in the turbine However if the ammonia massfraction is too high the pump power consumption willincrease greatly because the ammonia liquid mixture at theoutlet of the absorber (state 8) will change into the vapor-liquid mixture

Figure 16 shows the effect of ammonia mass fractionon LEC With the increase of ammonia mass fraction LECdecreases initially and then increases The higher the turbineinlet pressure the smaller the optimal ammonia mass frac-tion When the turbine inlet pressure is 17 bar LEC reachesthe minimum of 00716USD(kWh) with an ammonia massfraction of 0405 When the turbine inlet pressure is 17bar LEC reaches the minimum of 00713USD(kWh) with

035 040 045 050 055

465

468

471

474

477

480

Ammonia mass fraction

120578ov

eral

lcom

bine

dcyc

le(

)

p14 = 17barp14 = 23barp14 = 28bar

p8 = 35barT14 = 352K

ΔTpinch = 5KTa = 288K

Figure 15 Variation of overall efficiency of combined cycle withammonia mass fraction

035 040 045 050 055

0071

0072

0073

0074

0075

Ammonia mass fraction

p14 = 17barp14 = 23barp14 = 28bar

p8 = 35barT14 = 352K

ΔTpinch = 5KTa = 288K

LEC C

ombi

nedc

ycle(U

SDk

Wh)

Figure 16 Variation of LEC of combined cycle with ammonia massfraction

an ammonia mass fraction of 0545 Figure 17 presentsthe variations of 119865(119883) with ammonia mass fraction 119865(119883)decreases rapidly with increasing ammonia mass fraction

45 System Optimization In this work SA (SimulatedAnnealing) is employed to obtain the optimum combinationof the key parameters For the optimization the constraintsare simplified as follows

Subject to

170 ⩽ 11990114(bar) ⩽ 340

345 ⩽ 11987914(K) ⩽ 375

036 ⩽ 1199098⩽ 0555

10 Science and Technology of Nuclear Installations

035 040 045 050 05500216

00218

00220

00222

00224

00226

F(X

)

Ammonia mass fraction

p14 = 17barp14 = 23barp14 = 28bar

p8 = 35barT14 = 352K

ΔTpinch = 5KTa = 288K

Figure 17 Variation of F(X) of combined cycle with ammonia massfraction

288 ⩽ 119879119886(K) ⩽ 300

0 ⩽11989810

1198989

⩽ 1

0 ⩽11989812

1198981

⩽ 1

(11987917minus 11987910) ⩾ 5K

(1198794minus 11987911) ⩾ 5K

(1198793minus 119879Boiler) ⩾ 5K

119879Boiler ⩾ 119879Rectifier

119876cool gt 0

11990114⩾ 1199018

(20)

The selection of the above-mentioned parameters for thisoptimization is according to the literatures [6 9 13]

Table 6 shows some results of the closed Brayton cycle Tocompare the thermodynamic and economic performances ofthe combined cycle with those of the closed Brayton cyclethree parameters are defined as follows

RV119882net

=

(119882netCombinedcycle minus119882netBrayton)

119882netBrayton

RV120578overall

=

(120578overallCombinedcycle minus 120578overallBrayton)

120578overallBrayton

RVLEC =

(LECCombinedcycle minus LECBrayton)

LECBrayton

(21)

Table 6 Results of the closed Brayton cycle

Parameters Value119876core (MW) 59364120578overall119861 466119882net119861 (MW) 27690LEC119861(USD(kWh)) 00711

Table 7 Optimization results

Parameters Optimization results

Δ119879pinch = 5K 1199018= 35 bar

11990114= 181 bar 119879

14= 345K

1199098= 0555

F(X) = 002164119882netCombinedcycle = 28356MWRV119882net

= 241120578overallCombinedcycle = 4791RV

120578overall= 243LECCombinedcycle =00706USD(kWh) RVLEC =minus073

Table 7 lists the result of the parameters for the optimiza-tion The optimized power output and overall efficiency forthe combined cycle are 28356MW and 4791 respectivelyThese values are 241 and 243 higher than those of theclosedBrayton cycle respectively Both the lower average heataddition temperature and the higher back pressure of turbinein AWM cycle result in less power output and lower overallefficiency of the combined cycle

Comparingwith closedBrayton cycle the combined cyclereduces the LEC slightly The optimized LEC of combinedcycle is 073 lower than that of the closed Brayton cycleThereason is that the AWM utilizes the waste heat and adds thepower output and the cooling capacity to the closed Braytoncycle However the total capital investment increases due tothe combined AWM system

5 Conclusions

In this paper a combined cycle which combines AWM cycleand a nuclear closed Brayton cycle to recover the wasteheat rejected from the precooler is proposed A detailedparametric study and optimization are carried out for thiscombined cycle according to the thermodynamics and eco-nomics performances The combined cycle can potentiallybe used to improve the power output and overall efficiencyThe power output and overall efficiency of the combinedcycle increase with increasing turbine inlet temperature andammonia mass fraction but the turbine inlet temperatureand the ammonia mass fraction are limited by the heatsource temperature and the absorb pressure respectivelyCompared with the closed Brayton cycle the optimizedpower output and overall efficiency increase by 241 and243 respectively LEC increases with decreasing absorberpressure and turbine inlet temperature The optimized LECof the combined cycle is 00706USD(kWh) which is 073lower than those of the closed Brayton cycle

Science and Technology of Nuclear Installations 11

Competing Interests

The authors declare that there are no competing interestsregarding the publication of this paper and regarding thefunding that they have received

Acknowledgments

This present research was supported by the Chinese NaturalScience Fund (Project no 51306216) and the FundamentalResearch Funds for the Central University (Project noCDJ2R13140016)

References

[1] A Soroureddin A S Mehr S M S Mahmoudi and M YarildquoThermodynamic analysis of employing ejector and organicRankine cycles for GT-MHR waste heat utilization A Compar-ative Studyrdquo Energy Conversion and Management vol 67 pp125ndash137 2013

[2] S Dardour S Nisan and F Charbit ldquoUtilisation of waste heatfrom GT-MHR and PBMR reactors for nuclear desalinationrdquoDesalination vol 205 no 1ndash3 pp 254ndash268 2007

[3] A I Kalina ldquoCombined-cycle system with novel bottomingcyclerdquo Journal of Engineering for Gas Turbines and Power vol106 no 4 pp 737ndash742 1984

[4] D Y Goswami ldquoSolar thermal power technology present statusand ideas for the futurerdquo Energy Sources vol 20 no 2 pp 137ndash145 1998

[5] D S Ayou J C Bruno R Saravanan and A Coronas ldquoAnoverview of combined absorption power and cooling cyclesrdquoRenewable and Sustainable Energy Reviews vol 21 pp 728ndash7482013

[6] R V Padilla G Demirkaya D Y Goswami E Stefanakos andM M Rahman ldquoAnalysis of power and cooling cogenerationusing ammonia-water mixturerdquo Energy vol 35 no 12 pp4649ndash4657 2010

[7] S Lu and D Y Goswami ldquoOptimization of a novel combinedpowerrefrigeration thermodynamic cyclerdquo Journal of SolarEnergy Engineering vol 125 no 2 pp 212ndash217 2003

[8] M Pouraghaie K Atashkari S M Besarati and N Nariman-zadeh ldquoThermodynamic performance optimization of a com-bined powercooling cyclerdquo Energy Conversion and Manage-ment vol 51 no 1 pp 204ndash211 2010

[9] G Demirkaya R Vasquez Padilla D Y Goswami E Ste-fanakos and M M Rahman ldquoAnalysis of a combined powerand cooling cycle for low-grade heat sourcesrdquo InternationalJournal of Energy Research vol 35 no 13 pp 1145ndash1157 2011

[10] L S Vieira J L Donatelli and M E Cruz ldquoExergoeconomicimprovement of a complex cogeneration system integratedwith a professional process simulatorrdquo Energy Conversion andManagement vol 50 no 8 pp 1955ndash1967 2009

[11] Z ShengjunWHuaixin andG Tao ldquoPerformance comparisonand parametric optimization of subcritical Organic RankineCycle (ORC) and transcritical power cycle system for low-temperature geothermal power generationrdquoApplied Energy vol88 no 8 pp 2740ndash2754 2011

[12] T Guo H X Wang and S J Zhang ldquoFluids and parametersoptimization for a novel cogeneration system driven by low-temperature geothermal sourcesrdquo Energy vol 36 no 5 pp2639ndash2649 2011

[13] A Coskun A Bolatturk and M Kanoglu ldquoThermodynamicand economic analysis and optimization of power cycles for amedium temperature geothermal resourcerdquo Energy Conversionand Management vol 78 pp 39ndash49 2014

[14] V Zare S M S Mahmoudi and M Yari ldquoOn the exergoe-conomic assessment of employing Kalina cycle for GT-MHRwaste heat utilizationrdquoEnergy Conversion andManagement vol90 pp 364ndash374 2015

[15] K Bahlouli R Khoshbakhti Saray andN Sarabchi ldquoParametricinvestigation and thermo-economic multi-objective optimiza-tion of an ammonia-water powercooling cycle coupled withan HCCI (homogeneous charge compression ignition) enginerdquoEnergy vol 86 pp 672ndash684 2015

[16] Y Feng Y Zhang B Li J Yang and Y Shi ldquoSensitivity analysisand thermoeconomic comparison of ORCs (organicRankinecycles) for low temperature waste heat recoveryrdquo Energy vol82 pp 664ndash677 2015

[17] F Xu D Y Goswami and S S Bhagwat ldquoA combinedpowercooling cyclerdquo Energy vol 25 no 3 pp 233ndash246 2000

[18] F Xu and D Y Goswami ldquoThermodynamic properties ofammonia-watermixtures for power-cycle applicationsrdquo Energyvol 24 no 6 pp 525ndash536 1999

[19] M S El-Genk and J-M Tournier ldquoNoble gas binary mixturesfor gas-cooled reactor power plantsrdquo Nuclear Engineering andDesign vol 238 no 6 pp 1353ndash1372 2008

[20] F W Yu K T Chan R K Y Sit et al ldquoReview of standardsfor energy performance of chiller systems serving commercialbuildingsrdquo Energy Procedia vol 61 pp 2778ndash2782 2014

[21] S Nisan and S Dardour ldquoEconomic evaluation of nucleardesalination systemsrdquo Desalination vol 205 no 1ndash3 pp 231ndash242 2007

[22] L E Herranz J I Linares and B Y Moratilla ldquoPower cycleassessment of nuclear high temperature gas-cooled reactorsrdquoApplied Thermal Engineering vol 29 no 8-9 pp 1759ndash17652009

[23] HDMadhawaHettiarachchiMGolubovicWMWorek andY Ikegami ldquoOptimum design criteria for an Organic Rankinecycle using low-temperature geothermal heat sourcesrdquo Energyvol 32 no 9 pp 1698ndash1706 2007

[24] Y T Zhu W H Qu and P Y Yu Chemical Equipment DesignManual Chemical Industry Press 2005

[25] Q Songwen Heat Exchanger Design Handbook ChemicalIndustry Press 2002

[26] R Turton R C Bailie W B Whiting et al Analysis Synthesisand Design of Chemical Processes Prentice Hall Upper SaddleRiver NJ USA 1997

[27] F Taboas M Valles M Bourouis and A Coronas ldquoFlowboiling heat transfer of ammoniawater mixture in a plate heatexchangerrdquo International Journal of Refrigeration vol 33 no 4pp 695ndash705 2010

[28] L Xiao S-Y Wu T-T Yi C Liu and Y-R Li ldquoMulti-objectiveoptimization of evaporation and condensation temperatures forsubcritical organic Rankine cyclerdquo Energy vol 83 pp 723ndash7332015

[29] C E Campos Rodrıguez J C Escobar Palacio O J Venturiniet al ldquoExergetic and economic comparison of ORC and Kalinacycle for low temperature enhanced geothermal system inBrazilrdquo Applied Thermal Engineering vol 52 no 1 pp 109ndash1192013

[30] D Mignard ldquoCorrelating the chemical engineering plant costindex with macro-economic indicatorsrdquo Chemical EngineeringResearch and Design vol 92 no 2 pp 285ndash294 2014

12 Science and Technology of Nuclear Installations

[31] httpwwwneimagazinecomnewsnewsnuclear-reactor-per-formance-by-vendors-agrs-23

[32] H W Tang Practical Introduction to Mathematical Program-ming Dalian Institute of Technology Press 1986

[33] V Zare S M S Mahmoudi and M Yari ldquoAn exergoeconomicinvestigation of waste heat recovery from the Gas Turbine-Modular Helium Reactor (GT-MHR) employing an ammonia-water powercooling cyclerdquo Energy vol 61 pp 397ndash409 2013

TribologyAdvances in

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

International Journal of

AerospaceEngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

FuelsJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal ofPetroleum Engineering

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Industrial EngineeringJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Power ElectronicsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in

CombustionJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Renewable Energy

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

StructuresJournal of

International Journal of

RotatingMachinery

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

EnergyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporation httpwwwhindawicom

Journal ofEngineeringVolume 2014

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

International Journal ofPhotoenergy

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Nuclear InstallationsScience and Technology of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Solar EnergyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Wind EnergyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Nuclear EnergyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

High Energy PhysicsAdvances in

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Science and Technology of Nuclear Installations 5

Table 4 Coefficients required for the cost evaluation for each component [26]

Components 1198701

1198702

1198703

1198621

1198622

1198623

1198611

1198612

119865119898

119865119887119898

Turbine 315140 05890 0 0 0 0 0 0 0 350Pump 35790 03210 00290 01680 03480 04840 180 151 180 Equation (9)Heat exchanger 32138 02688 007961 minus0064991 005025 001474 180 150 125 Equation (9)

Table 5 Specifications of the combined cycle [19]

Parameters Valuem1(kgs) 3588

120578119904119875

085T1(K) 11791

T5(K) 301

p1(bar) 676

120578119904119879

085120578119904119862

085T3(K) 3988

T7(K) 8554

p2(bar) 310

The capital costs of the AWM system consist of the heatexchanger pump and turbine costs and are expressed asfollows [26 28]

lg119862119887= 1198701+ 1198702lg119885 + 119870

3(lg119885)2 (7)

where 119862119887is the estimated component cost based on US

dollars in the year of 1996 119885 is a parameter related to cyclecomponents For the heat exchanger 119885 refers to the areaof heat exchanger 119860 For the pump 119885 means the powerconsumption in pump119882

119901 For the turbine 119885 represents the

power output 119882out The coefficients of 1198701 1198702 and 119870

3are

listed in Table 4The capital cost 119862 which is corrected according to the

component materials and the pressure is determined by (8)as follows

119862 = 119862119887119865119887119898 (8)

where the coefficient 119865119887119898

is 35 for the turbine and thecoefficients 119865

119887119898for other components are calculated by (9)

[29] as follows

119865119887119898

= 1198611+ 1198612119865119898119865119901 (9)

where 1198611and 119861

2are the coefficients of different types of

the components and 119865119898

is the correction coefficient forthe component materials The values of 119861

1 1198612 and 119865

119898are

presented in Table 4119865119901represents the pressure correction coefficient and is

calculated by

lg119865119901= 1198621+ 1198622times lg119901 + 119862

3times (lg119901)2 (10)

The coefficients of 1198621 1198622 and 119862

3are also shown in

Table 4

Thus the cost of the AWM system in the year 1996119862AWM1996 can be evaluated as follows

119862AWM1996 = 119862119867+ 119862119864+ 119862119901 (11)

According to the time value of money the cost of closedBrayton system in the year of 2006 and the AWM system inthe year of 1996 are converted into the capital costs in the yearof 2015 respectively and the total cost of the combined cycle(1198622015

) is their sum as follows

1198622015

= 1198621198612006

CEPCI2015

CEPCI2006

+ 119862AWM1996CEPCI

2015

CEPCI1996

(12)

where CEPCI1996

CEPCI2006

and CEPCI2015

are the chemi-cal plant cost indexes in the years 1996 2006 and 2015 andthe values are 382 510 and 592 respectively [30]

The capital recovery factor (CRF) is defined as follows

CRF = 119894 (1 + 119894)119879119904

(1 + 119894)119879119904 minus 1

(13)

In this equation 119894 is the discount rate and is 5 with inflationrate zero [21] The economic life of the combined system (119879

119904)

is 40 yearsFor each year the operation hour of the system is

calculated as follows

OP119904= 365 times 24 times 119871

119891 (14)

In the combined system the levelized energy cost (LEC)can be calculated by (14) One has

LEC =CRF times 119862

2015+ COM

119904

(119882net +119882cool) timesOP119904

(15)

where COM119904is the system operation and maintenance cost

and is 15 of 1198622015

The load factor 119871119891is taken as 075 [31]

33 Optimization Model A simple thermodynamic opti-mization or economical optimization might draw differ-ent results because it is difficult to ensure a global cost-effective cycle design Thus the optimizations on both thethermodynamics and economics are simultaneously neededin the assessment of the combined cycle Regarding thisoverall efficiency 120578overallCombinedcycle and levelized energy cost(LEC) are selected to build a multiobjective function asthe performance indicator in this paper The multiobjectiveoptimization model is constructed as follows

The first objective function 1198651(119883) is expressed by the

following

min 1198651(119883) =

1

120578overallCombinedcycle (16)

6 Science and Technology of Nuclear Installations

34 36 38 40 42 44280

281

282

283

284

285

Pow

er o

utpu

t (M

W)

Absorber pressure (bar)

x8 = 0555

x8 = 0530

x8 = 0480

p14 = 17bar

Ta = 288KΔTpinch = 5K

T14 = 352K

Figure 2 Variation of power output of combined cycle withabsorber pressure

The second objective function 1198652(119883) is expressed by the

following

min 1198652(119883) = LEC (17)

The first objective function 1198651(119883) represents system

thermodynamic property and the second objective function1198652(119883) is the thermoeconomic propertyIn this paper the method of linear weighted evaluation

function is adopted to solve the objective function optimiza-tion model [28] which contains more than two performanceindicators The multiobjective function 119865(119883) is given by thefollowing

119865 (119883) = 1205721198651(119883) + 120573119865

2(119883) (18)

where120572 and120573 are theweight coefficients of objective functionand amethod proposed byP1aSAkK5 is applied to solve thesetwo weight coefficients [32]

120572 =

(1198651

2minus 1198652

2)

[(1198652

1minus 1198651

1) + (119865

1

2minus 1198652

2)]

120573 =

(1198652

1minus 1198651

1)

[(1198652

1minus 1198651

1) + (119865

1

2minus 1198652

2)]

(19)

4 Results and Discussion

41 Effect of Absorber Pressure The absorber pressure is theoutlet pressure of ammonia-water turbine If the absorberpressure is high the working fluid cannot expand fully inthe turbine and both the power output and overall efficiencydecrease in turn (Figures 2 and 3) Figure 4 shows that LECincreases with increasing absorber pressure The reason is

34 36 38 40 42 44472

473

474

475

476

477

478

479

480

Absorber pressure (bar)

120578ov

eral

lcom

bine

dcyc

le(

)

x8 = 0555

x8 = 0530

x8 = 0480

p14 = 17barT14 = 352K

ΔTpinch = 5KTa = 288K

Figure 3 Variation of overall efficiency of combined cycle withabsorber pressure

34 36 38 40 42 440070

0071

0072

0073

0074

0075

Absorber pressure (bar)

LEC C

ombi

nedc

ycle(U

SDk

Wh)

x8 = 0555

x8 = 0530

x8 = 0480

p14 = 17bar

T14 = 352K

ΔTpinch = 5KTa = 288K

Figure 4 Variation of LEC of combined cycle with absorberpressure

that the higher absorber pressure leads to less power outputwhich causes the increase in LEC However if absorberpressure is far less than 35 bar the working fluid at the outletof the absorber will change into vapor-liquid mixture Thisincreases the pump power consumption greatlyThe relation-ships of 119865(119883) with the absorber pressure are demonstratedin Figure 5 119865(119883) increases monotonically with increasingabsorber pressure Because the lowest 119865(119883) means the bestperformance the lower absorber pressure is beneficial for thethermodynamic and economic performances

Science and Technology of Nuclear Installations 7

34 36 38 40 42 44002160

002165

002170

002175

002180

002185

002190

F(X

)

Absorber pressure (bar)

x8 = 0555

x8 = 0530

x8 = 0480

p14 = 17bar

T14 = 352K

ΔTpinch = 5KTa = 288K

Figure 5 Variation of 119865(119883) of combined cycle with absorberpressure

15 20 25 30 35276

278

280

282

284

Pow

er o

utpu

t (M

W)

Turbine inlet pressure (bar)

x8 = 0555x8 = 0530

x8 = 0480

T14 = 352K

ΔTpinch = 5KTa = 288K

p8 = 35bar

Figure 6 Variation of power output of combined cycle with turbineinlet pressure

42 Effect of Turbine Inlet Pressure As shown in Figures 6 and7 the variations of the power output and overall efficiencywith the turbine inlet pressure are presented The enthalpydrop across the turbine increases as the turbine inlet pressureincreases However the enthalpy gains because of increasingturbine inlet pressure cannot compensate for the drop in thevapor flow rate Thus the turbine work output decreasesOwing to the decrease of vapor flow rate both the coolingcapacity and the equivalent work of cooling capacity (119882cool)increase first and then decrease However the equivalentwork of cooling capacity is too little comparedwith the poweroutput of the combined cycle Hence the power output andoverall efficiency decrease with the increasing turbine inlettemperature

15 20 25 30 35

466

468

470

472

474

476

478

480

Turbine inlet pressure (bar)

x8 = 0555x8 = 0530

x8 = 0480

T14 = 352K

ΔTpinch = 5KTa = 288K

p8 = 35bar120578ov

eral

lcom

bine

dcyc

le(

)

Figure 7 Variation of overall efficiency of combined cycle withturbine inlet pressure

15 20 25 30 3500710

00715

00720

00725

00730

00735

00740

Turbine inlet pressure (bar)

LEC C

ombi

nedc

ycle(U

SDk

Wh)

x8 = 0555x8 = 0530

x8 = 0480

T14 = 352K

ΔTpinch = 5KTa = 288K

p8 = 35bar

Figure 8 Variation of LEC of combined cycle with turbine inletpressure

As shown in Figure 8 LEC decreases at first and thenincreases with increasing turbine inlet pressure When theammonia mass fraction is 0555 LEC reaches the minimumof 00712USD(kWh) with the turbine inlet pressure of 305bar Figure 9 shows that 119865(119883) decreases first and increaseswith the increasing turbine inlet pressure when the ammoniamass fraction is 053 or 0555 Thus an optimal turbine inletpressure is present and the optimal turbine inlet pressurevalue is changing with the ammonia mass fraction

43 Effect of Turbine Inlet Temperature Figure 10 showsthat the power output increases with increasing turbine

8 Science and Technology of Nuclear Installations

15 20 25 30 3500216

00217

00218

00219

00220

00221

00222

F(X

)

Turbine inlet pressure (bar)

x8 = 0555x8 = 0530

x8 = 0480

T14 = 352K

ΔTpinch = 5KTa = 288K

p8 = 35bar

Figure 9 Variation of 119865(119883) of combined cycle with turbine inletpressure

345 348 351 354 357 360280

281

282

283

284

285

Turbine inlet temperature (K)

Pow

er o

utpu

t (M

W)

x8 = 0555x8 = 0530

x8 = 0480

ΔTpinch = 5KTa = 288K

p8 = 35barp14 = 17bar

Figure 10 Variation of power output of combined cyclewith turbineinlet temperature

inlet temperature With fixed pressure ratio increase in inlettemperature leads to higher inlet enthalpy of working fluidThe exit enthalpy of working fluid also increases at thesame time because of high exit temperature But the increasein enthalpy caused by the increase in inlet temperature ismore than that because of the increase in exit temperatureHence the turbine work output rises up as the turbine inlettemperature increases

Because the increasing turbine inlet temperatureincreases cooler inlet temperature the equivalent work ofcooling capacity (119882cool) declines However the increase ofpower output compensates for the drop in the equivalent

345 348 351 354 357 360

472

474

476

478

480

Turbine inlet temperature (K)

x8 = 0555x8 = 0530

x8 = 0480

ΔTpinch = 5KTa = 288K

p8 = 35barp14 = 17bar

120578ov

eral

lcom

bine

dcyc

le(

)

Figure 11 Variation of overall efficiency of combined cycle withturbine inlet temperature

345 348 351 354 357 3600070

0071

0072

0073

0074

0075

Turbine inlet temperature (K)

x8 = 0555x8 = 0530

x8 = 0480

ΔTpinch = 5KTa = 288K

p8 = 35barp14 = 17bar

LEC C

ombi

nedc

ycle(U

SDk

Wh)

Figure 12 Variation of LEC of combined cycle with turbine inlettemperature

work of cooling capacity This fact results in the slightincrease of overall efficiency (Figure 11)

As shown in Figure 12 LEC increases with increasingturbine inlet temperature monotonously This fact impliesthat the lower inlet temperature results in better economicperformance Figure 13 shows that 119865(119883) changes very slightlywhen the turbine inlet temperature is lower than 253K

44 Effect of AmmoniaMass Fraction Figures 14 and 15 revealthat the power output and overall efficiency will benefit fromincreased ammonia mass fraction Increasing the ammoniamass fraction will improve the thermodynamic performanceof the combined cycle because the higher the ammonia

Science and Technology of Nuclear Installations 9

345 348 351 354 357 360

002156

002163

002170

002177

002184

F(X

)

Turbine inlet temperature (K)

x8 = 0555x8 = 0530

x8 = 0480

ΔTpinch = 5KTa = 288K

p8 = 35barp14 = 17bar

Figure 13 Variation of 119865(119883) of combined cycle with turbine inlettemperature

035 040 045 050 055274

276

278

280

282

284

Pow

er o

utpu

t (M

W)

Ammonia mass fraction

p14 = 17barp14 = 23barp14 = 28bar

p8 = 35barT14 = 352K

ΔTpinch = 5KTa = 288K

Figure 14 Variation of power output of combined cycle withammonia mass fraction

concentration the greater the ammonia vapor flow rateexpanding in the turbine However if the ammonia massfraction is too high the pump power consumption willincrease greatly because the ammonia liquid mixture at theoutlet of the absorber (state 8) will change into the vapor-liquid mixture

Figure 16 shows the effect of ammonia mass fractionon LEC With the increase of ammonia mass fraction LECdecreases initially and then increases The higher the turbineinlet pressure the smaller the optimal ammonia mass frac-tion When the turbine inlet pressure is 17 bar LEC reachesthe minimum of 00716USD(kWh) with an ammonia massfraction of 0405 When the turbine inlet pressure is 17bar LEC reaches the minimum of 00713USD(kWh) with

035 040 045 050 055

465

468

471

474

477

480

Ammonia mass fraction

120578ov

eral

lcom

bine

dcyc

le(

)

p14 = 17barp14 = 23barp14 = 28bar

p8 = 35barT14 = 352K

ΔTpinch = 5KTa = 288K

Figure 15 Variation of overall efficiency of combined cycle withammonia mass fraction

035 040 045 050 055

0071

0072

0073

0074

0075

Ammonia mass fraction

p14 = 17barp14 = 23barp14 = 28bar

p8 = 35barT14 = 352K

ΔTpinch = 5KTa = 288K

LEC C

ombi

nedc

ycle(U

SDk

Wh)

Figure 16 Variation of LEC of combined cycle with ammonia massfraction

an ammonia mass fraction of 0545 Figure 17 presentsthe variations of 119865(119883) with ammonia mass fraction 119865(119883)decreases rapidly with increasing ammonia mass fraction

45 System Optimization In this work SA (SimulatedAnnealing) is employed to obtain the optimum combinationof the key parameters For the optimization the constraintsare simplified as follows

Subject to

170 ⩽ 11990114(bar) ⩽ 340

345 ⩽ 11987914(K) ⩽ 375

036 ⩽ 1199098⩽ 0555

10 Science and Technology of Nuclear Installations

035 040 045 050 05500216

00218

00220

00222

00224

00226

F(X

)

Ammonia mass fraction

p14 = 17barp14 = 23barp14 = 28bar

p8 = 35barT14 = 352K

ΔTpinch = 5KTa = 288K

Figure 17 Variation of F(X) of combined cycle with ammonia massfraction

288 ⩽ 119879119886(K) ⩽ 300

0 ⩽11989810

1198989

⩽ 1

0 ⩽11989812

1198981

⩽ 1

(11987917minus 11987910) ⩾ 5K

(1198794minus 11987911) ⩾ 5K

(1198793minus 119879Boiler) ⩾ 5K

119879Boiler ⩾ 119879Rectifier

119876cool gt 0

11990114⩾ 1199018

(20)

The selection of the above-mentioned parameters for thisoptimization is according to the literatures [6 9 13]

Table 6 shows some results of the closed Brayton cycle Tocompare the thermodynamic and economic performances ofthe combined cycle with those of the closed Brayton cyclethree parameters are defined as follows

RV119882net

=

(119882netCombinedcycle minus119882netBrayton)

119882netBrayton

RV120578overall

=

(120578overallCombinedcycle minus 120578overallBrayton)

120578overallBrayton

RVLEC =

(LECCombinedcycle minus LECBrayton)

LECBrayton

(21)

Table 6 Results of the closed Brayton cycle

Parameters Value119876core (MW) 59364120578overall119861 466119882net119861 (MW) 27690LEC119861(USD(kWh)) 00711

Table 7 Optimization results

Parameters Optimization results

Δ119879pinch = 5K 1199018= 35 bar

11990114= 181 bar 119879

14= 345K

1199098= 0555

F(X) = 002164119882netCombinedcycle = 28356MWRV119882net

= 241120578overallCombinedcycle = 4791RV

120578overall= 243LECCombinedcycle =00706USD(kWh) RVLEC =minus073

Table 7 lists the result of the parameters for the optimiza-tion The optimized power output and overall efficiency forthe combined cycle are 28356MW and 4791 respectivelyThese values are 241 and 243 higher than those of theclosedBrayton cycle respectively Both the lower average heataddition temperature and the higher back pressure of turbinein AWM cycle result in less power output and lower overallefficiency of the combined cycle

Comparingwith closedBrayton cycle the combined cyclereduces the LEC slightly The optimized LEC of combinedcycle is 073 lower than that of the closed Brayton cycleThereason is that the AWM utilizes the waste heat and adds thepower output and the cooling capacity to the closed Braytoncycle However the total capital investment increases due tothe combined AWM system

5 Conclusions

In this paper a combined cycle which combines AWM cycleand a nuclear closed Brayton cycle to recover the wasteheat rejected from the precooler is proposed A detailedparametric study and optimization are carried out for thiscombined cycle according to the thermodynamics and eco-nomics performances The combined cycle can potentiallybe used to improve the power output and overall efficiencyThe power output and overall efficiency of the combinedcycle increase with increasing turbine inlet temperature andammonia mass fraction but the turbine inlet temperatureand the ammonia mass fraction are limited by the heatsource temperature and the absorb pressure respectivelyCompared with the closed Brayton cycle the optimizedpower output and overall efficiency increase by 241 and243 respectively LEC increases with decreasing absorberpressure and turbine inlet temperature The optimized LECof the combined cycle is 00706USD(kWh) which is 073lower than those of the closed Brayton cycle

Science and Technology of Nuclear Installations 11

Competing Interests

The authors declare that there are no competing interestsregarding the publication of this paper and regarding thefunding that they have received

Acknowledgments

This present research was supported by the Chinese NaturalScience Fund (Project no 51306216) and the FundamentalResearch Funds for the Central University (Project noCDJ2R13140016)

References

[1] A Soroureddin A S Mehr S M S Mahmoudi and M YarildquoThermodynamic analysis of employing ejector and organicRankine cycles for GT-MHR waste heat utilization A Compar-ative Studyrdquo Energy Conversion and Management vol 67 pp125ndash137 2013

[2] S Dardour S Nisan and F Charbit ldquoUtilisation of waste heatfrom GT-MHR and PBMR reactors for nuclear desalinationrdquoDesalination vol 205 no 1ndash3 pp 254ndash268 2007

[3] A I Kalina ldquoCombined-cycle system with novel bottomingcyclerdquo Journal of Engineering for Gas Turbines and Power vol106 no 4 pp 737ndash742 1984

[4] D Y Goswami ldquoSolar thermal power technology present statusand ideas for the futurerdquo Energy Sources vol 20 no 2 pp 137ndash145 1998

[5] D S Ayou J C Bruno R Saravanan and A Coronas ldquoAnoverview of combined absorption power and cooling cyclesrdquoRenewable and Sustainable Energy Reviews vol 21 pp 728ndash7482013

[6] R V Padilla G Demirkaya D Y Goswami E Stefanakos andM M Rahman ldquoAnalysis of power and cooling cogenerationusing ammonia-water mixturerdquo Energy vol 35 no 12 pp4649ndash4657 2010

[7] S Lu and D Y Goswami ldquoOptimization of a novel combinedpowerrefrigeration thermodynamic cyclerdquo Journal of SolarEnergy Engineering vol 125 no 2 pp 212ndash217 2003

[8] M Pouraghaie K Atashkari S M Besarati and N Nariman-zadeh ldquoThermodynamic performance optimization of a com-bined powercooling cyclerdquo Energy Conversion and Manage-ment vol 51 no 1 pp 204ndash211 2010

[9] G Demirkaya R Vasquez Padilla D Y Goswami E Ste-fanakos and M M Rahman ldquoAnalysis of a combined powerand cooling cycle for low-grade heat sourcesrdquo InternationalJournal of Energy Research vol 35 no 13 pp 1145ndash1157 2011

[10] L S Vieira J L Donatelli and M E Cruz ldquoExergoeconomicimprovement of a complex cogeneration system integratedwith a professional process simulatorrdquo Energy Conversion andManagement vol 50 no 8 pp 1955ndash1967 2009

[11] Z ShengjunWHuaixin andG Tao ldquoPerformance comparisonand parametric optimization of subcritical Organic RankineCycle (ORC) and transcritical power cycle system for low-temperature geothermal power generationrdquoApplied Energy vol88 no 8 pp 2740ndash2754 2011

[12] T Guo H X Wang and S J Zhang ldquoFluids and parametersoptimization for a novel cogeneration system driven by low-temperature geothermal sourcesrdquo Energy vol 36 no 5 pp2639ndash2649 2011

[13] A Coskun A Bolatturk and M Kanoglu ldquoThermodynamicand economic analysis and optimization of power cycles for amedium temperature geothermal resourcerdquo Energy Conversionand Management vol 78 pp 39ndash49 2014

[14] V Zare S M S Mahmoudi and M Yari ldquoOn the exergoe-conomic assessment of employing Kalina cycle for GT-MHRwaste heat utilizationrdquoEnergy Conversion andManagement vol90 pp 364ndash374 2015

[15] K Bahlouli R Khoshbakhti Saray andN Sarabchi ldquoParametricinvestigation and thermo-economic multi-objective optimiza-tion of an ammonia-water powercooling cycle coupled withan HCCI (homogeneous charge compression ignition) enginerdquoEnergy vol 86 pp 672ndash684 2015

[16] Y Feng Y Zhang B Li J Yang and Y Shi ldquoSensitivity analysisand thermoeconomic comparison of ORCs (organicRankinecycles) for low temperature waste heat recoveryrdquo Energy vol82 pp 664ndash677 2015

[17] F Xu D Y Goswami and S S Bhagwat ldquoA combinedpowercooling cyclerdquo Energy vol 25 no 3 pp 233ndash246 2000

[18] F Xu and D Y Goswami ldquoThermodynamic properties ofammonia-watermixtures for power-cycle applicationsrdquo Energyvol 24 no 6 pp 525ndash536 1999

[19] M S El-Genk and J-M Tournier ldquoNoble gas binary mixturesfor gas-cooled reactor power plantsrdquo Nuclear Engineering andDesign vol 238 no 6 pp 1353ndash1372 2008

[20] F W Yu K T Chan R K Y Sit et al ldquoReview of standardsfor energy performance of chiller systems serving commercialbuildingsrdquo Energy Procedia vol 61 pp 2778ndash2782 2014

[21] S Nisan and S Dardour ldquoEconomic evaluation of nucleardesalination systemsrdquo Desalination vol 205 no 1ndash3 pp 231ndash242 2007

[22] L E Herranz J I Linares and B Y Moratilla ldquoPower cycleassessment of nuclear high temperature gas-cooled reactorsrdquoApplied Thermal Engineering vol 29 no 8-9 pp 1759ndash17652009

[23] HDMadhawaHettiarachchiMGolubovicWMWorek andY Ikegami ldquoOptimum design criteria for an Organic Rankinecycle using low-temperature geothermal heat sourcesrdquo Energyvol 32 no 9 pp 1698ndash1706 2007

[24] Y T Zhu W H Qu and P Y Yu Chemical Equipment DesignManual Chemical Industry Press 2005

[25] Q Songwen Heat Exchanger Design Handbook ChemicalIndustry Press 2002

[26] R Turton R C Bailie W B Whiting et al Analysis Synthesisand Design of Chemical Processes Prentice Hall Upper SaddleRiver NJ USA 1997

[27] F Taboas M Valles M Bourouis and A Coronas ldquoFlowboiling heat transfer of ammoniawater mixture in a plate heatexchangerrdquo International Journal of Refrigeration vol 33 no 4pp 695ndash705 2010

[28] L Xiao S-Y Wu T-T Yi C Liu and Y-R Li ldquoMulti-objectiveoptimization of evaporation and condensation temperatures forsubcritical organic Rankine cyclerdquo Energy vol 83 pp 723ndash7332015

[29] C E Campos Rodrıguez J C Escobar Palacio O J Venturiniet al ldquoExergetic and economic comparison of ORC and Kalinacycle for low temperature enhanced geothermal system inBrazilrdquo Applied Thermal Engineering vol 52 no 1 pp 109ndash1192013

[30] D Mignard ldquoCorrelating the chemical engineering plant costindex with macro-economic indicatorsrdquo Chemical EngineeringResearch and Design vol 92 no 2 pp 285ndash294 2014

12 Science and Technology of Nuclear Installations

[31] httpwwwneimagazinecomnewsnewsnuclear-reactor-per-formance-by-vendors-agrs-23

[32] H W Tang Practical Introduction to Mathematical Program-ming Dalian Institute of Technology Press 1986

[33] V Zare S M S Mahmoudi and M Yari ldquoAn exergoeconomicinvestigation of waste heat recovery from the Gas Turbine-Modular Helium Reactor (GT-MHR) employing an ammonia-water powercooling cyclerdquo Energy vol 61 pp 397ndash409 2013

TribologyAdvances in

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

International Journal of

AerospaceEngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

FuelsJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal ofPetroleum Engineering

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Industrial EngineeringJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Power ElectronicsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in

CombustionJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Renewable Energy

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

StructuresJournal of

International Journal of

RotatingMachinery

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

EnergyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporation httpwwwhindawicom

Journal ofEngineeringVolume 2014

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

International Journal ofPhotoenergy

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Nuclear InstallationsScience and Technology of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Solar EnergyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Wind EnergyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Nuclear EnergyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

High Energy PhysicsAdvances in

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

6 Science and Technology of Nuclear Installations

34 36 38 40 42 44280

281

282

283

284

285

Pow

er o

utpu

t (M

W)

Absorber pressure (bar)

x8 = 0555

x8 = 0530

x8 = 0480

p14 = 17bar

Ta = 288KΔTpinch = 5K

T14 = 352K

Figure 2 Variation of power output of combined cycle withabsorber pressure

The second objective function 1198652(119883) is expressed by the

following

min 1198652(119883) = LEC (17)

The first objective function 1198651(119883) represents system

thermodynamic property and the second objective function1198652(119883) is the thermoeconomic propertyIn this paper the method of linear weighted evaluation

function is adopted to solve the objective function optimiza-tion model [28] which contains more than two performanceindicators The multiobjective function 119865(119883) is given by thefollowing

119865 (119883) = 1205721198651(119883) + 120573119865

2(119883) (18)

where120572 and120573 are theweight coefficients of objective functionand amethod proposed byP1aSAkK5 is applied to solve thesetwo weight coefficients [32]

120572 =

(1198651

2minus 1198652

2)

[(1198652

1minus 1198651

1) + (119865

1

2minus 1198652

2)]

120573 =

(1198652

1minus 1198651

1)

[(1198652

1minus 1198651

1) + (119865

1

2minus 1198652

2)]

(19)

4 Results and Discussion

41 Effect of Absorber Pressure The absorber pressure is theoutlet pressure of ammonia-water turbine If the absorberpressure is high the working fluid cannot expand fully inthe turbine and both the power output and overall efficiencydecrease in turn (Figures 2 and 3) Figure 4 shows that LECincreases with increasing absorber pressure The reason is

34 36 38 40 42 44472

473

474

475

476

477

478

479

480

Absorber pressure (bar)

120578ov

eral

lcom

bine

dcyc

le(

)

x8 = 0555

x8 = 0530

x8 = 0480

p14 = 17barT14 = 352K

ΔTpinch = 5KTa = 288K

Figure 3 Variation of overall efficiency of combined cycle withabsorber pressure

34 36 38 40 42 440070

0071

0072

0073

0074

0075

Absorber pressure (bar)

LEC C

ombi

nedc

ycle(U

SDk

Wh)

x8 = 0555

x8 = 0530

x8 = 0480

p14 = 17bar

T14 = 352K

ΔTpinch = 5KTa = 288K

Figure 4 Variation of LEC of combined cycle with absorberpressure

that the higher absorber pressure leads to less power outputwhich causes the increase in LEC However if absorberpressure is far less than 35 bar the working fluid at the outletof the absorber will change into vapor-liquid mixture Thisincreases the pump power consumption greatlyThe relation-ships of 119865(119883) with the absorber pressure are demonstratedin Figure 5 119865(119883) increases monotonically with increasingabsorber pressure Because the lowest 119865(119883) means the bestperformance the lower absorber pressure is beneficial for thethermodynamic and economic performances

Science and Technology of Nuclear Installations 7

34 36 38 40 42 44002160

002165

002170

002175

002180

002185

002190

F(X

)

Absorber pressure (bar)

x8 = 0555

x8 = 0530

x8 = 0480

p14 = 17bar

T14 = 352K

ΔTpinch = 5KTa = 288K

Figure 5 Variation of 119865(119883) of combined cycle with absorberpressure

15 20 25 30 35276

278

280

282

284

Pow

er o

utpu

t (M

W)

Turbine inlet pressure (bar)

x8 = 0555x8 = 0530

x8 = 0480

T14 = 352K

ΔTpinch = 5KTa = 288K

p8 = 35bar

Figure 6 Variation of power output of combined cycle with turbineinlet pressure

42 Effect of Turbine Inlet Pressure As shown in Figures 6 and7 the variations of the power output and overall efficiencywith the turbine inlet pressure are presented The enthalpydrop across the turbine increases as the turbine inlet pressureincreases However the enthalpy gains because of increasingturbine inlet pressure cannot compensate for the drop in thevapor flow rate Thus the turbine work output decreasesOwing to the decrease of vapor flow rate both the coolingcapacity and the equivalent work of cooling capacity (119882cool)increase first and then decrease However the equivalentwork of cooling capacity is too little comparedwith the poweroutput of the combined cycle Hence the power output andoverall efficiency decrease with the increasing turbine inlettemperature

15 20 25 30 35

466

468

470

472

474

476

478

480

Turbine inlet pressure (bar)

x8 = 0555x8 = 0530

x8 = 0480

T14 = 352K

ΔTpinch = 5KTa = 288K

p8 = 35bar120578ov

eral

lcom

bine

dcyc

le(

)

Figure 7 Variation of overall efficiency of combined cycle withturbine inlet pressure

15 20 25 30 3500710

00715

00720

00725

00730

00735

00740

Turbine inlet pressure (bar)

LEC C

ombi

nedc

ycle(U

SDk

Wh)

x8 = 0555x8 = 0530

x8 = 0480

T14 = 352K

ΔTpinch = 5KTa = 288K

p8 = 35bar

Figure 8 Variation of LEC of combined cycle with turbine inletpressure

As shown in Figure 8 LEC decreases at first and thenincreases with increasing turbine inlet pressure When theammonia mass fraction is 0555 LEC reaches the minimumof 00712USD(kWh) with the turbine inlet pressure of 305bar Figure 9 shows that 119865(119883) decreases first and increaseswith the increasing turbine inlet pressure when the ammoniamass fraction is 053 or 0555 Thus an optimal turbine inletpressure is present and the optimal turbine inlet pressurevalue is changing with the ammonia mass fraction

43 Effect of Turbine Inlet Temperature Figure 10 showsthat the power output increases with increasing turbine

8 Science and Technology of Nuclear Installations

15 20 25 30 3500216

00217

00218

00219

00220

00221

00222

F(X

)

Turbine inlet pressure (bar)

x8 = 0555x8 = 0530

x8 = 0480

T14 = 352K

ΔTpinch = 5KTa = 288K

p8 = 35bar

Figure 9 Variation of 119865(119883) of combined cycle with turbine inletpressure

345 348 351 354 357 360280

281

282

283

284

285

Turbine inlet temperature (K)

Pow

er o

utpu

t (M

W)

x8 = 0555x8 = 0530

x8 = 0480

ΔTpinch = 5KTa = 288K

p8 = 35barp14 = 17bar

Figure 10 Variation of power output of combined cyclewith turbineinlet temperature

inlet temperature With fixed pressure ratio increase in inlettemperature leads to higher inlet enthalpy of working fluidThe exit enthalpy of working fluid also increases at thesame time because of high exit temperature But the increasein enthalpy caused by the increase in inlet temperature ismore than that because of the increase in exit temperatureHence the turbine work output rises up as the turbine inlettemperature increases

Because the increasing turbine inlet temperatureincreases cooler inlet temperature the equivalent work ofcooling capacity (119882cool) declines However the increase ofpower output compensates for the drop in the equivalent

345 348 351 354 357 360

472

474

476

478

480

Turbine inlet temperature (K)

x8 = 0555x8 = 0530

x8 = 0480

ΔTpinch = 5KTa = 288K

p8 = 35barp14 = 17bar

120578ov

eral

lcom

bine

dcyc

le(

)

Figure 11 Variation of overall efficiency of combined cycle withturbine inlet temperature

345 348 351 354 357 3600070

0071

0072

0073

0074

0075

Turbine inlet temperature (K)

x8 = 0555x8 = 0530

x8 = 0480

ΔTpinch = 5KTa = 288K

p8 = 35barp14 = 17bar

LEC C

ombi

nedc

ycle(U

SDk

Wh)

Figure 12 Variation of LEC of combined cycle with turbine inlettemperature

work of cooling capacity This fact results in the slightincrease of overall efficiency (Figure 11)

As shown in Figure 12 LEC increases with increasingturbine inlet temperature monotonously This fact impliesthat the lower inlet temperature results in better economicperformance Figure 13 shows that 119865(119883) changes very slightlywhen the turbine inlet temperature is lower than 253K

44 Effect of AmmoniaMass Fraction Figures 14 and 15 revealthat the power output and overall efficiency will benefit fromincreased ammonia mass fraction Increasing the ammoniamass fraction will improve the thermodynamic performanceof the combined cycle because the higher the ammonia

Science and Technology of Nuclear Installations 9

345 348 351 354 357 360

002156

002163

002170

002177

002184

F(X

)

Turbine inlet temperature (K)

x8 = 0555x8 = 0530

x8 = 0480

ΔTpinch = 5KTa = 288K

p8 = 35barp14 = 17bar

Figure 13 Variation of 119865(119883) of combined cycle with turbine inlettemperature

035 040 045 050 055274

276

278

280

282

284

Pow

er o

utpu

t (M

W)

Ammonia mass fraction

p14 = 17barp14 = 23barp14 = 28bar

p8 = 35barT14 = 352K

ΔTpinch = 5KTa = 288K

Figure 14 Variation of power output of combined cycle withammonia mass fraction

concentration the greater the ammonia vapor flow rateexpanding in the turbine However if the ammonia massfraction is too high the pump power consumption willincrease greatly because the ammonia liquid mixture at theoutlet of the absorber (state 8) will change into the vapor-liquid mixture

Figure 16 shows the effect of ammonia mass fractionon LEC With the increase of ammonia mass fraction LECdecreases initially and then increases The higher the turbineinlet pressure the smaller the optimal ammonia mass frac-tion When the turbine inlet pressure is 17 bar LEC reachesthe minimum of 00716USD(kWh) with an ammonia massfraction of 0405 When the turbine inlet pressure is 17bar LEC reaches the minimum of 00713USD(kWh) with

035 040 045 050 055

465

468

471

474

477

480

Ammonia mass fraction

120578ov

eral

lcom

bine

dcyc

le(

)

p14 = 17barp14 = 23barp14 = 28bar

p8 = 35barT14 = 352K

ΔTpinch = 5KTa = 288K

Figure 15 Variation of overall efficiency of combined cycle withammonia mass fraction

035 040 045 050 055

0071

0072

0073

0074

0075

Ammonia mass fraction

p14 = 17barp14 = 23barp14 = 28bar

p8 = 35barT14 = 352K

ΔTpinch = 5KTa = 288K

LEC C

ombi

nedc

ycle(U

SDk

Wh)

Figure 16 Variation of LEC of combined cycle with ammonia massfraction

an ammonia mass fraction of 0545 Figure 17 presentsthe variations of 119865(119883) with ammonia mass fraction 119865(119883)decreases rapidly with increasing ammonia mass fraction

45 System Optimization In this work SA (SimulatedAnnealing) is employed to obtain the optimum combinationof the key parameters For the optimization the constraintsare simplified as follows

Subject to

170 ⩽ 11990114(bar) ⩽ 340

345 ⩽ 11987914(K) ⩽ 375

036 ⩽ 1199098⩽ 0555

10 Science and Technology of Nuclear Installations

035 040 045 050 05500216

00218

00220

00222

00224

00226

F(X

)

Ammonia mass fraction

p14 = 17barp14 = 23barp14 = 28bar

p8 = 35barT14 = 352K

ΔTpinch = 5KTa = 288K

Figure 17 Variation of F(X) of combined cycle with ammonia massfraction

288 ⩽ 119879119886(K) ⩽ 300

0 ⩽11989810

1198989

⩽ 1

0 ⩽11989812

1198981

⩽ 1

(11987917minus 11987910) ⩾ 5K

(1198794minus 11987911) ⩾ 5K

(1198793minus 119879Boiler) ⩾ 5K

119879Boiler ⩾ 119879Rectifier

119876cool gt 0

11990114⩾ 1199018

(20)

The selection of the above-mentioned parameters for thisoptimization is according to the literatures [6 9 13]

Table 6 shows some results of the closed Brayton cycle Tocompare the thermodynamic and economic performances ofthe combined cycle with those of the closed Brayton cyclethree parameters are defined as follows

RV119882net

=

(119882netCombinedcycle minus119882netBrayton)

119882netBrayton

RV120578overall

=

(120578overallCombinedcycle minus 120578overallBrayton)

120578overallBrayton

RVLEC =

(LECCombinedcycle minus LECBrayton)

LECBrayton

(21)

Table 6 Results of the closed Brayton cycle

Parameters Value119876core (MW) 59364120578overall119861 466119882net119861 (MW) 27690LEC119861(USD(kWh)) 00711

Table 7 Optimization results

Parameters Optimization results

Δ119879pinch = 5K 1199018= 35 bar

11990114= 181 bar 119879

14= 345K

1199098= 0555

F(X) = 002164119882netCombinedcycle = 28356MWRV119882net

= 241120578overallCombinedcycle = 4791RV

120578overall= 243LECCombinedcycle =00706USD(kWh) RVLEC =minus073

Table 7 lists the result of the parameters for the optimiza-tion The optimized power output and overall efficiency forthe combined cycle are 28356MW and 4791 respectivelyThese values are 241 and 243 higher than those of theclosedBrayton cycle respectively Both the lower average heataddition temperature and the higher back pressure of turbinein AWM cycle result in less power output and lower overallefficiency of the combined cycle

Comparingwith closedBrayton cycle the combined cyclereduces the LEC slightly The optimized LEC of combinedcycle is 073 lower than that of the closed Brayton cycleThereason is that the AWM utilizes the waste heat and adds thepower output and the cooling capacity to the closed Braytoncycle However the total capital investment increases due tothe combined AWM system

5 Conclusions

In this paper a combined cycle which combines AWM cycleand a nuclear closed Brayton cycle to recover the wasteheat rejected from the precooler is proposed A detailedparametric study and optimization are carried out for thiscombined cycle according to the thermodynamics and eco-nomics performances The combined cycle can potentiallybe used to improve the power output and overall efficiencyThe power output and overall efficiency of the combinedcycle increase with increasing turbine inlet temperature andammonia mass fraction but the turbine inlet temperatureand the ammonia mass fraction are limited by the heatsource temperature and the absorb pressure respectivelyCompared with the closed Brayton cycle the optimizedpower output and overall efficiency increase by 241 and243 respectively LEC increases with decreasing absorberpressure and turbine inlet temperature The optimized LECof the combined cycle is 00706USD(kWh) which is 073lower than those of the closed Brayton cycle

Science and Technology of Nuclear Installations 11

Competing Interests

The authors declare that there are no competing interestsregarding the publication of this paper and regarding thefunding that they have received

Acknowledgments

This present research was supported by the Chinese NaturalScience Fund (Project no 51306216) and the FundamentalResearch Funds for the Central University (Project noCDJ2R13140016)

References

[1] A Soroureddin A S Mehr S M S Mahmoudi and M YarildquoThermodynamic analysis of employing ejector and organicRankine cycles for GT-MHR waste heat utilization A Compar-ative Studyrdquo Energy Conversion and Management vol 67 pp125ndash137 2013

[2] S Dardour S Nisan and F Charbit ldquoUtilisation of waste heatfrom GT-MHR and PBMR reactors for nuclear desalinationrdquoDesalination vol 205 no 1ndash3 pp 254ndash268 2007

[3] A I Kalina ldquoCombined-cycle system with novel bottomingcyclerdquo Journal of Engineering for Gas Turbines and Power vol106 no 4 pp 737ndash742 1984

[4] D Y Goswami ldquoSolar thermal power technology present statusand ideas for the futurerdquo Energy Sources vol 20 no 2 pp 137ndash145 1998

[5] D S Ayou J C Bruno R Saravanan and A Coronas ldquoAnoverview of combined absorption power and cooling cyclesrdquoRenewable and Sustainable Energy Reviews vol 21 pp 728ndash7482013

[6] R V Padilla G Demirkaya D Y Goswami E Stefanakos andM M Rahman ldquoAnalysis of power and cooling cogenerationusing ammonia-water mixturerdquo Energy vol 35 no 12 pp4649ndash4657 2010

[7] S Lu and D Y Goswami ldquoOptimization of a novel combinedpowerrefrigeration thermodynamic cyclerdquo Journal of SolarEnergy Engineering vol 125 no 2 pp 212ndash217 2003

[8] M Pouraghaie K Atashkari S M Besarati and N Nariman-zadeh ldquoThermodynamic performance optimization of a com-bined powercooling cyclerdquo Energy Conversion and Manage-ment vol 51 no 1 pp 204ndash211 2010

[9] G Demirkaya R Vasquez Padilla D Y Goswami E Ste-fanakos and M M Rahman ldquoAnalysis of a combined powerand cooling cycle for low-grade heat sourcesrdquo InternationalJournal of Energy Research vol 35 no 13 pp 1145ndash1157 2011

[10] L S Vieira J L Donatelli and M E Cruz ldquoExergoeconomicimprovement of a complex cogeneration system integratedwith a professional process simulatorrdquo Energy Conversion andManagement vol 50 no 8 pp 1955ndash1967 2009

[11] Z ShengjunWHuaixin andG Tao ldquoPerformance comparisonand parametric optimization of subcritical Organic RankineCycle (ORC) and transcritical power cycle system for low-temperature geothermal power generationrdquoApplied Energy vol88 no 8 pp 2740ndash2754 2011

[12] T Guo H X Wang and S J Zhang ldquoFluids and parametersoptimization for a novel cogeneration system driven by low-temperature geothermal sourcesrdquo Energy vol 36 no 5 pp2639ndash2649 2011

[13] A Coskun A Bolatturk and M Kanoglu ldquoThermodynamicand economic analysis and optimization of power cycles for amedium temperature geothermal resourcerdquo Energy Conversionand Management vol 78 pp 39ndash49 2014

[14] V Zare S M S Mahmoudi and M Yari ldquoOn the exergoe-conomic assessment of employing Kalina cycle for GT-MHRwaste heat utilizationrdquoEnergy Conversion andManagement vol90 pp 364ndash374 2015

[15] K Bahlouli R Khoshbakhti Saray andN Sarabchi ldquoParametricinvestigation and thermo-economic multi-objective optimiza-tion of an ammonia-water powercooling cycle coupled withan HCCI (homogeneous charge compression ignition) enginerdquoEnergy vol 86 pp 672ndash684 2015

[16] Y Feng Y Zhang B Li J Yang and Y Shi ldquoSensitivity analysisand thermoeconomic comparison of ORCs (organicRankinecycles) for low temperature waste heat recoveryrdquo Energy vol82 pp 664ndash677 2015

[17] F Xu D Y Goswami and S S Bhagwat ldquoA combinedpowercooling cyclerdquo Energy vol 25 no 3 pp 233ndash246 2000

[18] F Xu and D Y Goswami ldquoThermodynamic properties ofammonia-watermixtures for power-cycle applicationsrdquo Energyvol 24 no 6 pp 525ndash536 1999

[19] M S El-Genk and J-M Tournier ldquoNoble gas binary mixturesfor gas-cooled reactor power plantsrdquo Nuclear Engineering andDesign vol 238 no 6 pp 1353ndash1372 2008

[20] F W Yu K T Chan R K Y Sit et al ldquoReview of standardsfor energy performance of chiller systems serving commercialbuildingsrdquo Energy Procedia vol 61 pp 2778ndash2782 2014

[21] S Nisan and S Dardour ldquoEconomic evaluation of nucleardesalination systemsrdquo Desalination vol 205 no 1ndash3 pp 231ndash242 2007

[22] L E Herranz J I Linares and B Y Moratilla ldquoPower cycleassessment of nuclear high temperature gas-cooled reactorsrdquoApplied Thermal Engineering vol 29 no 8-9 pp 1759ndash17652009

[23] HDMadhawaHettiarachchiMGolubovicWMWorek andY Ikegami ldquoOptimum design criteria for an Organic Rankinecycle using low-temperature geothermal heat sourcesrdquo Energyvol 32 no 9 pp 1698ndash1706 2007

[24] Y T Zhu W H Qu and P Y Yu Chemical Equipment DesignManual Chemical Industry Press 2005

[25] Q Songwen Heat Exchanger Design Handbook ChemicalIndustry Press 2002

[26] R Turton R C Bailie W B Whiting et al Analysis Synthesisand Design of Chemical Processes Prentice Hall Upper SaddleRiver NJ USA 1997

[27] F Taboas M Valles M Bourouis and A Coronas ldquoFlowboiling heat transfer of ammoniawater mixture in a plate heatexchangerrdquo International Journal of Refrigeration vol 33 no 4pp 695ndash705 2010

[28] L Xiao S-Y Wu T-T Yi C Liu and Y-R Li ldquoMulti-objectiveoptimization of evaporation and condensation temperatures forsubcritical organic Rankine cyclerdquo Energy vol 83 pp 723ndash7332015

[29] C E Campos Rodrıguez J C Escobar Palacio O J Venturiniet al ldquoExergetic and economic comparison of ORC and Kalinacycle for low temperature enhanced geothermal system inBrazilrdquo Applied Thermal Engineering vol 52 no 1 pp 109ndash1192013

[30] D Mignard ldquoCorrelating the chemical engineering plant costindex with macro-economic indicatorsrdquo Chemical EngineeringResearch and Design vol 92 no 2 pp 285ndash294 2014

12 Science and Technology of Nuclear Installations

[31] httpwwwneimagazinecomnewsnewsnuclear-reactor-per-formance-by-vendors-agrs-23

[32] H W Tang Practical Introduction to Mathematical Program-ming Dalian Institute of Technology Press 1986

[33] V Zare S M S Mahmoudi and M Yari ldquoAn exergoeconomicinvestigation of waste heat recovery from the Gas Turbine-Modular Helium Reactor (GT-MHR) employing an ammonia-water powercooling cyclerdquo Energy vol 61 pp 397ndash409 2013

TribologyAdvances in

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

International Journal of

AerospaceEngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

FuelsJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal ofPetroleum Engineering

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Industrial EngineeringJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Power ElectronicsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in

CombustionJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Renewable Energy

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

StructuresJournal of

International Journal of

RotatingMachinery

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

EnergyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporation httpwwwhindawicom

Journal ofEngineeringVolume 2014

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

International Journal ofPhotoenergy

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Nuclear InstallationsScience and Technology of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Solar EnergyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Wind EnergyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Nuclear EnergyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

High Energy PhysicsAdvances in

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Science and Technology of Nuclear Installations 7

34 36 38 40 42 44002160

002165

002170

002175

002180

002185

002190

F(X

)

Absorber pressure (bar)

x8 = 0555

x8 = 0530

x8 = 0480

p14 = 17bar

T14 = 352K

ΔTpinch = 5KTa = 288K

Figure 5 Variation of 119865(119883) of combined cycle with absorberpressure

15 20 25 30 35276

278

280

282

284

Pow

er o

utpu

t (M

W)

Turbine inlet pressure (bar)

x8 = 0555x8 = 0530

x8 = 0480

T14 = 352K

ΔTpinch = 5KTa = 288K

p8 = 35bar

Figure 6 Variation of power output of combined cycle with turbineinlet pressure

42 Effect of Turbine Inlet Pressure As shown in Figures 6 and7 the variations of the power output and overall efficiencywith the turbine inlet pressure are presented The enthalpydrop across the turbine increases as the turbine inlet pressureincreases However the enthalpy gains because of increasingturbine inlet pressure cannot compensate for the drop in thevapor flow rate Thus the turbine work output decreasesOwing to the decrease of vapor flow rate both the coolingcapacity and the equivalent work of cooling capacity (119882cool)increase first and then decrease However the equivalentwork of cooling capacity is too little comparedwith the poweroutput of the combined cycle Hence the power output andoverall efficiency decrease with the increasing turbine inlettemperature

15 20 25 30 35

466

468

470

472

474

476

478

480

Turbine inlet pressure (bar)

x8 = 0555x8 = 0530

x8 = 0480

T14 = 352K

ΔTpinch = 5KTa = 288K

p8 = 35bar120578ov

eral

lcom

bine

dcyc

le(

)

Figure 7 Variation of overall efficiency of combined cycle withturbine inlet pressure

15 20 25 30 3500710

00715

00720

00725

00730

00735

00740

Turbine inlet pressure (bar)

LEC C

ombi

nedc

ycle(U

SDk

Wh)

x8 = 0555x8 = 0530

x8 = 0480

T14 = 352K

ΔTpinch = 5KTa = 288K

p8 = 35bar

Figure 8 Variation of LEC of combined cycle with turbine inletpressure

As shown in Figure 8 LEC decreases at first and thenincreases with increasing turbine inlet pressure When theammonia mass fraction is 0555 LEC reaches the minimumof 00712USD(kWh) with the turbine inlet pressure of 305bar Figure 9 shows that 119865(119883) decreases first and increaseswith the increasing turbine inlet pressure when the ammoniamass fraction is 053 or 0555 Thus an optimal turbine inletpressure is present and the optimal turbine inlet pressurevalue is changing with the ammonia mass fraction

43 Effect of Turbine Inlet Temperature Figure 10 showsthat the power output increases with increasing turbine

8 Science and Technology of Nuclear Installations

15 20 25 30 3500216

00217

00218

00219

00220

00221

00222

F(X

)

Turbine inlet pressure (bar)

x8 = 0555x8 = 0530

x8 = 0480

T14 = 352K

ΔTpinch = 5KTa = 288K

p8 = 35bar

Figure 9 Variation of 119865(119883) of combined cycle with turbine inletpressure

345 348 351 354 357 360280

281

282

283

284

285

Turbine inlet temperature (K)

Pow

er o

utpu

t (M

W)

x8 = 0555x8 = 0530

x8 = 0480

ΔTpinch = 5KTa = 288K

p8 = 35barp14 = 17bar

Figure 10 Variation of power output of combined cyclewith turbineinlet temperature

inlet temperature With fixed pressure ratio increase in inlettemperature leads to higher inlet enthalpy of working fluidThe exit enthalpy of working fluid also increases at thesame time because of high exit temperature But the increasein enthalpy caused by the increase in inlet temperature ismore than that because of the increase in exit temperatureHence the turbine work output rises up as the turbine inlettemperature increases

Because the increasing turbine inlet temperatureincreases cooler inlet temperature the equivalent work ofcooling capacity (119882cool) declines However the increase ofpower output compensates for the drop in the equivalent

345 348 351 354 357 360

472

474

476

478

480

Turbine inlet temperature (K)

x8 = 0555x8 = 0530

x8 = 0480

ΔTpinch = 5KTa = 288K

p8 = 35barp14 = 17bar

120578ov

eral

lcom

bine

dcyc

le(

)

Figure 11 Variation of overall efficiency of combined cycle withturbine inlet temperature

345 348 351 354 357 3600070

0071

0072

0073

0074

0075

Turbine inlet temperature (K)

x8 = 0555x8 = 0530

x8 = 0480

ΔTpinch = 5KTa = 288K

p8 = 35barp14 = 17bar

LEC C

ombi

nedc

ycle(U

SDk

Wh)

Figure 12 Variation of LEC of combined cycle with turbine inlettemperature

work of cooling capacity This fact results in the slightincrease of overall efficiency (Figure 11)

As shown in Figure 12 LEC increases with increasingturbine inlet temperature monotonously This fact impliesthat the lower inlet temperature results in better economicperformance Figure 13 shows that 119865(119883) changes very slightlywhen the turbine inlet temperature is lower than 253K

44 Effect of AmmoniaMass Fraction Figures 14 and 15 revealthat the power output and overall efficiency will benefit fromincreased ammonia mass fraction Increasing the ammoniamass fraction will improve the thermodynamic performanceof the combined cycle because the higher the ammonia

Science and Technology of Nuclear Installations 9

345 348 351 354 357 360

002156

002163

002170

002177

002184

F(X

)

Turbine inlet temperature (K)

x8 = 0555x8 = 0530

x8 = 0480

ΔTpinch = 5KTa = 288K

p8 = 35barp14 = 17bar

Figure 13 Variation of 119865(119883) of combined cycle with turbine inlettemperature

035 040 045 050 055274

276

278

280

282

284

Pow

er o

utpu

t (M

W)

Ammonia mass fraction

p14 = 17barp14 = 23barp14 = 28bar

p8 = 35barT14 = 352K

ΔTpinch = 5KTa = 288K

Figure 14 Variation of power output of combined cycle withammonia mass fraction

concentration the greater the ammonia vapor flow rateexpanding in the turbine However if the ammonia massfraction is too high the pump power consumption willincrease greatly because the ammonia liquid mixture at theoutlet of the absorber (state 8) will change into the vapor-liquid mixture

Figure 16 shows the effect of ammonia mass fractionon LEC With the increase of ammonia mass fraction LECdecreases initially and then increases The higher the turbineinlet pressure the smaller the optimal ammonia mass frac-tion When the turbine inlet pressure is 17 bar LEC reachesthe minimum of 00716USD(kWh) with an ammonia massfraction of 0405 When the turbine inlet pressure is 17bar LEC reaches the minimum of 00713USD(kWh) with

035 040 045 050 055

465

468

471

474

477

480

Ammonia mass fraction

120578ov

eral

lcom

bine

dcyc

le(

)

p14 = 17barp14 = 23barp14 = 28bar

p8 = 35barT14 = 352K

ΔTpinch = 5KTa = 288K

Figure 15 Variation of overall efficiency of combined cycle withammonia mass fraction

035 040 045 050 055

0071

0072

0073

0074

0075

Ammonia mass fraction

p14 = 17barp14 = 23barp14 = 28bar

p8 = 35barT14 = 352K

ΔTpinch = 5KTa = 288K

LEC C

ombi

nedc

ycle(U

SDk

Wh)

Figure 16 Variation of LEC of combined cycle with ammonia massfraction

an ammonia mass fraction of 0545 Figure 17 presentsthe variations of 119865(119883) with ammonia mass fraction 119865(119883)decreases rapidly with increasing ammonia mass fraction

45 System Optimization In this work SA (SimulatedAnnealing) is employed to obtain the optimum combinationof the key parameters For the optimization the constraintsare simplified as follows

Subject to

170 ⩽ 11990114(bar) ⩽ 340

345 ⩽ 11987914(K) ⩽ 375

036 ⩽ 1199098⩽ 0555

10 Science and Technology of Nuclear Installations

035 040 045 050 05500216

00218

00220

00222

00224

00226

F(X

)

Ammonia mass fraction

p14 = 17barp14 = 23barp14 = 28bar

p8 = 35barT14 = 352K

ΔTpinch = 5KTa = 288K

Figure 17 Variation of F(X) of combined cycle with ammonia massfraction

288 ⩽ 119879119886(K) ⩽ 300

0 ⩽11989810

1198989

⩽ 1

0 ⩽11989812

1198981

⩽ 1

(11987917minus 11987910) ⩾ 5K

(1198794minus 11987911) ⩾ 5K

(1198793minus 119879Boiler) ⩾ 5K

119879Boiler ⩾ 119879Rectifier

119876cool gt 0

11990114⩾ 1199018

(20)

The selection of the above-mentioned parameters for thisoptimization is according to the literatures [6 9 13]

Table 6 shows some results of the closed Brayton cycle Tocompare the thermodynamic and economic performances ofthe combined cycle with those of the closed Brayton cyclethree parameters are defined as follows

RV119882net

=

(119882netCombinedcycle minus119882netBrayton)

119882netBrayton

RV120578overall

=

(120578overallCombinedcycle minus 120578overallBrayton)

120578overallBrayton

RVLEC =

(LECCombinedcycle minus LECBrayton)

LECBrayton

(21)

Table 6 Results of the closed Brayton cycle

Parameters Value119876core (MW) 59364120578overall119861 466119882net119861 (MW) 27690LEC119861(USD(kWh)) 00711

Table 7 Optimization results

Parameters Optimization results

Δ119879pinch = 5K 1199018= 35 bar

11990114= 181 bar 119879

14= 345K

1199098= 0555

F(X) = 002164119882netCombinedcycle = 28356MWRV119882net

= 241120578overallCombinedcycle = 4791RV

120578overall= 243LECCombinedcycle =00706USD(kWh) RVLEC =minus073

Table 7 lists the result of the parameters for the optimiza-tion The optimized power output and overall efficiency forthe combined cycle are 28356MW and 4791 respectivelyThese values are 241 and 243 higher than those of theclosedBrayton cycle respectively Both the lower average heataddition temperature and the higher back pressure of turbinein AWM cycle result in less power output and lower overallefficiency of the combined cycle

Comparingwith closedBrayton cycle the combined cyclereduces the LEC slightly The optimized LEC of combinedcycle is 073 lower than that of the closed Brayton cycleThereason is that the AWM utilizes the waste heat and adds thepower output and the cooling capacity to the closed Braytoncycle However the total capital investment increases due tothe combined AWM system

5 Conclusions

In this paper a combined cycle which combines AWM cycleand a nuclear closed Brayton cycle to recover the wasteheat rejected from the precooler is proposed A detailedparametric study and optimization are carried out for thiscombined cycle according to the thermodynamics and eco-nomics performances The combined cycle can potentiallybe used to improve the power output and overall efficiencyThe power output and overall efficiency of the combinedcycle increase with increasing turbine inlet temperature andammonia mass fraction but the turbine inlet temperatureand the ammonia mass fraction are limited by the heatsource temperature and the absorb pressure respectivelyCompared with the closed Brayton cycle the optimizedpower output and overall efficiency increase by 241 and243 respectively LEC increases with decreasing absorberpressure and turbine inlet temperature The optimized LECof the combined cycle is 00706USD(kWh) which is 073lower than those of the closed Brayton cycle

Science and Technology of Nuclear Installations 11

Competing Interests

The authors declare that there are no competing interestsregarding the publication of this paper and regarding thefunding that they have received

Acknowledgments

This present research was supported by the Chinese NaturalScience Fund (Project no 51306216) and the FundamentalResearch Funds for the Central University (Project noCDJ2R13140016)

References

[1] A Soroureddin A S Mehr S M S Mahmoudi and M YarildquoThermodynamic analysis of employing ejector and organicRankine cycles for GT-MHR waste heat utilization A Compar-ative Studyrdquo Energy Conversion and Management vol 67 pp125ndash137 2013

[2] S Dardour S Nisan and F Charbit ldquoUtilisation of waste heatfrom GT-MHR and PBMR reactors for nuclear desalinationrdquoDesalination vol 205 no 1ndash3 pp 254ndash268 2007

[3] A I Kalina ldquoCombined-cycle system with novel bottomingcyclerdquo Journal of Engineering for Gas Turbines and Power vol106 no 4 pp 737ndash742 1984

[4] D Y Goswami ldquoSolar thermal power technology present statusand ideas for the futurerdquo Energy Sources vol 20 no 2 pp 137ndash145 1998

[5] D S Ayou J C Bruno R Saravanan and A Coronas ldquoAnoverview of combined absorption power and cooling cyclesrdquoRenewable and Sustainable Energy Reviews vol 21 pp 728ndash7482013

[6] R V Padilla G Demirkaya D Y Goswami E Stefanakos andM M Rahman ldquoAnalysis of power and cooling cogenerationusing ammonia-water mixturerdquo Energy vol 35 no 12 pp4649ndash4657 2010

[7] S Lu and D Y Goswami ldquoOptimization of a novel combinedpowerrefrigeration thermodynamic cyclerdquo Journal of SolarEnergy Engineering vol 125 no 2 pp 212ndash217 2003

[8] M Pouraghaie K Atashkari S M Besarati and N Nariman-zadeh ldquoThermodynamic performance optimization of a com-bined powercooling cyclerdquo Energy Conversion and Manage-ment vol 51 no 1 pp 204ndash211 2010

[9] G Demirkaya R Vasquez Padilla D Y Goswami E Ste-fanakos and M M Rahman ldquoAnalysis of a combined powerand cooling cycle for low-grade heat sourcesrdquo InternationalJournal of Energy Research vol 35 no 13 pp 1145ndash1157 2011

[10] L S Vieira J L Donatelli and M E Cruz ldquoExergoeconomicimprovement of a complex cogeneration system integratedwith a professional process simulatorrdquo Energy Conversion andManagement vol 50 no 8 pp 1955ndash1967 2009

[11] Z ShengjunWHuaixin andG Tao ldquoPerformance comparisonand parametric optimization of subcritical Organic RankineCycle (ORC) and transcritical power cycle system for low-temperature geothermal power generationrdquoApplied Energy vol88 no 8 pp 2740ndash2754 2011

[12] T Guo H X Wang and S J Zhang ldquoFluids and parametersoptimization for a novel cogeneration system driven by low-temperature geothermal sourcesrdquo Energy vol 36 no 5 pp2639ndash2649 2011

[13] A Coskun A Bolatturk and M Kanoglu ldquoThermodynamicand economic analysis and optimization of power cycles for amedium temperature geothermal resourcerdquo Energy Conversionand Management vol 78 pp 39ndash49 2014

[14] V Zare S M S Mahmoudi and M Yari ldquoOn the exergoe-conomic assessment of employing Kalina cycle for GT-MHRwaste heat utilizationrdquoEnergy Conversion andManagement vol90 pp 364ndash374 2015

[15] K Bahlouli R Khoshbakhti Saray andN Sarabchi ldquoParametricinvestigation and thermo-economic multi-objective optimiza-tion of an ammonia-water powercooling cycle coupled withan HCCI (homogeneous charge compression ignition) enginerdquoEnergy vol 86 pp 672ndash684 2015

[16] Y Feng Y Zhang B Li J Yang and Y Shi ldquoSensitivity analysisand thermoeconomic comparison of ORCs (organicRankinecycles) for low temperature waste heat recoveryrdquo Energy vol82 pp 664ndash677 2015

[17] F Xu D Y Goswami and S S Bhagwat ldquoA combinedpowercooling cyclerdquo Energy vol 25 no 3 pp 233ndash246 2000

[18] F Xu and D Y Goswami ldquoThermodynamic properties ofammonia-watermixtures for power-cycle applicationsrdquo Energyvol 24 no 6 pp 525ndash536 1999

[19] M S El-Genk and J-M Tournier ldquoNoble gas binary mixturesfor gas-cooled reactor power plantsrdquo Nuclear Engineering andDesign vol 238 no 6 pp 1353ndash1372 2008

[20] F W Yu K T Chan R K Y Sit et al ldquoReview of standardsfor energy performance of chiller systems serving commercialbuildingsrdquo Energy Procedia vol 61 pp 2778ndash2782 2014

[21] S Nisan and S Dardour ldquoEconomic evaluation of nucleardesalination systemsrdquo Desalination vol 205 no 1ndash3 pp 231ndash242 2007

[22] L E Herranz J I Linares and B Y Moratilla ldquoPower cycleassessment of nuclear high temperature gas-cooled reactorsrdquoApplied Thermal Engineering vol 29 no 8-9 pp 1759ndash17652009

[23] HDMadhawaHettiarachchiMGolubovicWMWorek andY Ikegami ldquoOptimum design criteria for an Organic Rankinecycle using low-temperature geothermal heat sourcesrdquo Energyvol 32 no 9 pp 1698ndash1706 2007

[24] Y T Zhu W H Qu and P Y Yu Chemical Equipment DesignManual Chemical Industry Press 2005

[25] Q Songwen Heat Exchanger Design Handbook ChemicalIndustry Press 2002

[26] R Turton R C Bailie W B Whiting et al Analysis Synthesisand Design of Chemical Processes Prentice Hall Upper SaddleRiver NJ USA 1997

[27] F Taboas M Valles M Bourouis and A Coronas ldquoFlowboiling heat transfer of ammoniawater mixture in a plate heatexchangerrdquo International Journal of Refrigeration vol 33 no 4pp 695ndash705 2010

[28] L Xiao S-Y Wu T-T Yi C Liu and Y-R Li ldquoMulti-objectiveoptimization of evaporation and condensation temperatures forsubcritical organic Rankine cyclerdquo Energy vol 83 pp 723ndash7332015

[29] C E Campos Rodrıguez J C Escobar Palacio O J Venturiniet al ldquoExergetic and economic comparison of ORC and Kalinacycle for low temperature enhanced geothermal system inBrazilrdquo Applied Thermal Engineering vol 52 no 1 pp 109ndash1192013

[30] D Mignard ldquoCorrelating the chemical engineering plant costindex with macro-economic indicatorsrdquo Chemical EngineeringResearch and Design vol 92 no 2 pp 285ndash294 2014

12 Science and Technology of Nuclear Installations

[31] httpwwwneimagazinecomnewsnewsnuclear-reactor-per-formance-by-vendors-agrs-23

[32] H W Tang Practical Introduction to Mathematical Program-ming Dalian Institute of Technology Press 1986

[33] V Zare S M S Mahmoudi and M Yari ldquoAn exergoeconomicinvestigation of waste heat recovery from the Gas Turbine-Modular Helium Reactor (GT-MHR) employing an ammonia-water powercooling cyclerdquo Energy vol 61 pp 397ndash409 2013

TribologyAdvances in

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

International Journal of

AerospaceEngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

FuelsJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal ofPetroleum Engineering

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Industrial EngineeringJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Power ElectronicsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in

CombustionJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Renewable Energy

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

StructuresJournal of

International Journal of

RotatingMachinery

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

EnergyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporation httpwwwhindawicom

Journal ofEngineeringVolume 2014

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

International Journal ofPhotoenergy

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Nuclear InstallationsScience and Technology of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Solar EnergyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Wind EnergyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Nuclear EnergyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

High Energy PhysicsAdvances in

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

8 Science and Technology of Nuclear Installations

15 20 25 30 3500216

00217

00218

00219

00220

00221

00222

F(X

)

Turbine inlet pressure (bar)

x8 = 0555x8 = 0530

x8 = 0480

T14 = 352K

ΔTpinch = 5KTa = 288K

p8 = 35bar

Figure 9 Variation of 119865(119883) of combined cycle with turbine inletpressure

345 348 351 354 357 360280

281

282

283

284

285

Turbine inlet temperature (K)

Pow

er o

utpu

t (M

W)

x8 = 0555x8 = 0530

x8 = 0480

ΔTpinch = 5KTa = 288K

p8 = 35barp14 = 17bar

Figure 10 Variation of power output of combined cyclewith turbineinlet temperature

inlet temperature With fixed pressure ratio increase in inlettemperature leads to higher inlet enthalpy of working fluidThe exit enthalpy of working fluid also increases at thesame time because of high exit temperature But the increasein enthalpy caused by the increase in inlet temperature ismore than that because of the increase in exit temperatureHence the turbine work output rises up as the turbine inlettemperature increases

Because the increasing turbine inlet temperatureincreases cooler inlet temperature the equivalent work ofcooling capacity (119882cool) declines However the increase ofpower output compensates for the drop in the equivalent

345 348 351 354 357 360

472

474

476

478

480

Turbine inlet temperature (K)

x8 = 0555x8 = 0530

x8 = 0480

ΔTpinch = 5KTa = 288K

p8 = 35barp14 = 17bar

120578ov

eral

lcom

bine

dcyc

le(

)

Figure 11 Variation of overall efficiency of combined cycle withturbine inlet temperature

345 348 351 354 357 3600070

0071

0072

0073

0074

0075

Turbine inlet temperature (K)

x8 = 0555x8 = 0530

x8 = 0480

ΔTpinch = 5KTa = 288K

p8 = 35barp14 = 17bar

LEC C

ombi

nedc

ycle(U

SDk

Wh)

Figure 12 Variation of LEC of combined cycle with turbine inlettemperature

work of cooling capacity This fact results in the slightincrease of overall efficiency (Figure 11)

As shown in Figure 12 LEC increases with increasingturbine inlet temperature monotonously This fact impliesthat the lower inlet temperature results in better economicperformance Figure 13 shows that 119865(119883) changes very slightlywhen the turbine inlet temperature is lower than 253K

44 Effect of AmmoniaMass Fraction Figures 14 and 15 revealthat the power output and overall efficiency will benefit fromincreased ammonia mass fraction Increasing the ammoniamass fraction will improve the thermodynamic performanceof the combined cycle because the higher the ammonia

Science and Technology of Nuclear Installations 9

345 348 351 354 357 360

002156

002163

002170

002177

002184

F(X

)

Turbine inlet temperature (K)

x8 = 0555x8 = 0530

x8 = 0480

ΔTpinch = 5KTa = 288K

p8 = 35barp14 = 17bar

Figure 13 Variation of 119865(119883) of combined cycle with turbine inlettemperature

035 040 045 050 055274

276

278

280

282

284

Pow

er o

utpu

t (M

W)

Ammonia mass fraction

p14 = 17barp14 = 23barp14 = 28bar

p8 = 35barT14 = 352K

ΔTpinch = 5KTa = 288K

Figure 14 Variation of power output of combined cycle withammonia mass fraction

concentration the greater the ammonia vapor flow rateexpanding in the turbine However if the ammonia massfraction is too high the pump power consumption willincrease greatly because the ammonia liquid mixture at theoutlet of the absorber (state 8) will change into the vapor-liquid mixture

Figure 16 shows the effect of ammonia mass fractionon LEC With the increase of ammonia mass fraction LECdecreases initially and then increases The higher the turbineinlet pressure the smaller the optimal ammonia mass frac-tion When the turbine inlet pressure is 17 bar LEC reachesthe minimum of 00716USD(kWh) with an ammonia massfraction of 0405 When the turbine inlet pressure is 17bar LEC reaches the minimum of 00713USD(kWh) with

035 040 045 050 055

465

468

471

474

477

480

Ammonia mass fraction

120578ov

eral

lcom

bine

dcyc

le(

)

p14 = 17barp14 = 23barp14 = 28bar

p8 = 35barT14 = 352K

ΔTpinch = 5KTa = 288K

Figure 15 Variation of overall efficiency of combined cycle withammonia mass fraction

035 040 045 050 055

0071

0072

0073

0074

0075

Ammonia mass fraction

p14 = 17barp14 = 23barp14 = 28bar

p8 = 35barT14 = 352K

ΔTpinch = 5KTa = 288K

LEC C

ombi

nedc

ycle(U

SDk

Wh)

Figure 16 Variation of LEC of combined cycle with ammonia massfraction

an ammonia mass fraction of 0545 Figure 17 presentsthe variations of 119865(119883) with ammonia mass fraction 119865(119883)decreases rapidly with increasing ammonia mass fraction

45 System Optimization In this work SA (SimulatedAnnealing) is employed to obtain the optimum combinationof the key parameters For the optimization the constraintsare simplified as follows

Subject to

170 ⩽ 11990114(bar) ⩽ 340

345 ⩽ 11987914(K) ⩽ 375

036 ⩽ 1199098⩽ 0555

10 Science and Technology of Nuclear Installations

035 040 045 050 05500216

00218

00220

00222

00224

00226

F(X

)

Ammonia mass fraction

p14 = 17barp14 = 23barp14 = 28bar

p8 = 35barT14 = 352K

ΔTpinch = 5KTa = 288K

Figure 17 Variation of F(X) of combined cycle with ammonia massfraction

288 ⩽ 119879119886(K) ⩽ 300

0 ⩽11989810

1198989

⩽ 1

0 ⩽11989812

1198981

⩽ 1

(11987917minus 11987910) ⩾ 5K

(1198794minus 11987911) ⩾ 5K

(1198793minus 119879Boiler) ⩾ 5K

119879Boiler ⩾ 119879Rectifier

119876cool gt 0

11990114⩾ 1199018

(20)

The selection of the above-mentioned parameters for thisoptimization is according to the literatures [6 9 13]

Table 6 shows some results of the closed Brayton cycle Tocompare the thermodynamic and economic performances ofthe combined cycle with those of the closed Brayton cyclethree parameters are defined as follows

RV119882net

=

(119882netCombinedcycle minus119882netBrayton)

119882netBrayton

RV120578overall

=

(120578overallCombinedcycle minus 120578overallBrayton)

120578overallBrayton

RVLEC =

(LECCombinedcycle minus LECBrayton)

LECBrayton

(21)

Table 6 Results of the closed Brayton cycle

Parameters Value119876core (MW) 59364120578overall119861 466119882net119861 (MW) 27690LEC119861(USD(kWh)) 00711

Table 7 Optimization results

Parameters Optimization results

Δ119879pinch = 5K 1199018= 35 bar

11990114= 181 bar 119879

14= 345K

1199098= 0555

F(X) = 002164119882netCombinedcycle = 28356MWRV119882net

= 241120578overallCombinedcycle = 4791RV

120578overall= 243LECCombinedcycle =00706USD(kWh) RVLEC =minus073

Table 7 lists the result of the parameters for the optimiza-tion The optimized power output and overall efficiency forthe combined cycle are 28356MW and 4791 respectivelyThese values are 241 and 243 higher than those of theclosedBrayton cycle respectively Both the lower average heataddition temperature and the higher back pressure of turbinein AWM cycle result in less power output and lower overallefficiency of the combined cycle

Comparingwith closedBrayton cycle the combined cyclereduces the LEC slightly The optimized LEC of combinedcycle is 073 lower than that of the closed Brayton cycleThereason is that the AWM utilizes the waste heat and adds thepower output and the cooling capacity to the closed Braytoncycle However the total capital investment increases due tothe combined AWM system

5 Conclusions

In this paper a combined cycle which combines AWM cycleand a nuclear closed Brayton cycle to recover the wasteheat rejected from the precooler is proposed A detailedparametric study and optimization are carried out for thiscombined cycle according to the thermodynamics and eco-nomics performances The combined cycle can potentiallybe used to improve the power output and overall efficiencyThe power output and overall efficiency of the combinedcycle increase with increasing turbine inlet temperature andammonia mass fraction but the turbine inlet temperatureand the ammonia mass fraction are limited by the heatsource temperature and the absorb pressure respectivelyCompared with the closed Brayton cycle the optimizedpower output and overall efficiency increase by 241 and243 respectively LEC increases with decreasing absorberpressure and turbine inlet temperature The optimized LECof the combined cycle is 00706USD(kWh) which is 073lower than those of the closed Brayton cycle

Science and Technology of Nuclear Installations 11

Competing Interests

The authors declare that there are no competing interestsregarding the publication of this paper and regarding thefunding that they have received

Acknowledgments

This present research was supported by the Chinese NaturalScience Fund (Project no 51306216) and the FundamentalResearch Funds for the Central University (Project noCDJ2R13140016)

References

[1] A Soroureddin A S Mehr S M S Mahmoudi and M YarildquoThermodynamic analysis of employing ejector and organicRankine cycles for GT-MHR waste heat utilization A Compar-ative Studyrdquo Energy Conversion and Management vol 67 pp125ndash137 2013

[2] S Dardour S Nisan and F Charbit ldquoUtilisation of waste heatfrom GT-MHR and PBMR reactors for nuclear desalinationrdquoDesalination vol 205 no 1ndash3 pp 254ndash268 2007

[3] A I Kalina ldquoCombined-cycle system with novel bottomingcyclerdquo Journal of Engineering for Gas Turbines and Power vol106 no 4 pp 737ndash742 1984

[4] D Y Goswami ldquoSolar thermal power technology present statusand ideas for the futurerdquo Energy Sources vol 20 no 2 pp 137ndash145 1998

[5] D S Ayou J C Bruno R Saravanan and A Coronas ldquoAnoverview of combined absorption power and cooling cyclesrdquoRenewable and Sustainable Energy Reviews vol 21 pp 728ndash7482013

[6] R V Padilla G Demirkaya D Y Goswami E Stefanakos andM M Rahman ldquoAnalysis of power and cooling cogenerationusing ammonia-water mixturerdquo Energy vol 35 no 12 pp4649ndash4657 2010

[7] S Lu and D Y Goswami ldquoOptimization of a novel combinedpowerrefrigeration thermodynamic cyclerdquo Journal of SolarEnergy Engineering vol 125 no 2 pp 212ndash217 2003

[8] M Pouraghaie K Atashkari S M Besarati and N Nariman-zadeh ldquoThermodynamic performance optimization of a com-bined powercooling cyclerdquo Energy Conversion and Manage-ment vol 51 no 1 pp 204ndash211 2010

[9] G Demirkaya R Vasquez Padilla D Y Goswami E Ste-fanakos and M M Rahman ldquoAnalysis of a combined powerand cooling cycle for low-grade heat sourcesrdquo InternationalJournal of Energy Research vol 35 no 13 pp 1145ndash1157 2011

[10] L S Vieira J L Donatelli and M E Cruz ldquoExergoeconomicimprovement of a complex cogeneration system integratedwith a professional process simulatorrdquo Energy Conversion andManagement vol 50 no 8 pp 1955ndash1967 2009

[11] Z ShengjunWHuaixin andG Tao ldquoPerformance comparisonand parametric optimization of subcritical Organic RankineCycle (ORC) and transcritical power cycle system for low-temperature geothermal power generationrdquoApplied Energy vol88 no 8 pp 2740ndash2754 2011

[12] T Guo H X Wang and S J Zhang ldquoFluids and parametersoptimization for a novel cogeneration system driven by low-temperature geothermal sourcesrdquo Energy vol 36 no 5 pp2639ndash2649 2011

[13] A Coskun A Bolatturk and M Kanoglu ldquoThermodynamicand economic analysis and optimization of power cycles for amedium temperature geothermal resourcerdquo Energy Conversionand Management vol 78 pp 39ndash49 2014

[14] V Zare S M S Mahmoudi and M Yari ldquoOn the exergoe-conomic assessment of employing Kalina cycle for GT-MHRwaste heat utilizationrdquoEnergy Conversion andManagement vol90 pp 364ndash374 2015

[15] K Bahlouli R Khoshbakhti Saray andN Sarabchi ldquoParametricinvestigation and thermo-economic multi-objective optimiza-tion of an ammonia-water powercooling cycle coupled withan HCCI (homogeneous charge compression ignition) enginerdquoEnergy vol 86 pp 672ndash684 2015

[16] Y Feng Y Zhang B Li J Yang and Y Shi ldquoSensitivity analysisand thermoeconomic comparison of ORCs (organicRankinecycles) for low temperature waste heat recoveryrdquo Energy vol82 pp 664ndash677 2015

[17] F Xu D Y Goswami and S S Bhagwat ldquoA combinedpowercooling cyclerdquo Energy vol 25 no 3 pp 233ndash246 2000

[18] F Xu and D Y Goswami ldquoThermodynamic properties ofammonia-watermixtures for power-cycle applicationsrdquo Energyvol 24 no 6 pp 525ndash536 1999

[19] M S El-Genk and J-M Tournier ldquoNoble gas binary mixturesfor gas-cooled reactor power plantsrdquo Nuclear Engineering andDesign vol 238 no 6 pp 1353ndash1372 2008

[20] F W Yu K T Chan R K Y Sit et al ldquoReview of standardsfor energy performance of chiller systems serving commercialbuildingsrdquo Energy Procedia vol 61 pp 2778ndash2782 2014

[21] S Nisan and S Dardour ldquoEconomic evaluation of nucleardesalination systemsrdquo Desalination vol 205 no 1ndash3 pp 231ndash242 2007

[22] L E Herranz J I Linares and B Y Moratilla ldquoPower cycleassessment of nuclear high temperature gas-cooled reactorsrdquoApplied Thermal Engineering vol 29 no 8-9 pp 1759ndash17652009

[23] HDMadhawaHettiarachchiMGolubovicWMWorek andY Ikegami ldquoOptimum design criteria for an Organic Rankinecycle using low-temperature geothermal heat sourcesrdquo Energyvol 32 no 9 pp 1698ndash1706 2007

[24] Y T Zhu W H Qu and P Y Yu Chemical Equipment DesignManual Chemical Industry Press 2005

[25] Q Songwen Heat Exchanger Design Handbook ChemicalIndustry Press 2002

[26] R Turton R C Bailie W B Whiting et al Analysis Synthesisand Design of Chemical Processes Prentice Hall Upper SaddleRiver NJ USA 1997

[27] F Taboas M Valles M Bourouis and A Coronas ldquoFlowboiling heat transfer of ammoniawater mixture in a plate heatexchangerrdquo International Journal of Refrigeration vol 33 no 4pp 695ndash705 2010

[28] L Xiao S-Y Wu T-T Yi C Liu and Y-R Li ldquoMulti-objectiveoptimization of evaporation and condensation temperatures forsubcritical organic Rankine cyclerdquo Energy vol 83 pp 723ndash7332015

[29] C E Campos Rodrıguez J C Escobar Palacio O J Venturiniet al ldquoExergetic and economic comparison of ORC and Kalinacycle for low temperature enhanced geothermal system inBrazilrdquo Applied Thermal Engineering vol 52 no 1 pp 109ndash1192013

[30] D Mignard ldquoCorrelating the chemical engineering plant costindex with macro-economic indicatorsrdquo Chemical EngineeringResearch and Design vol 92 no 2 pp 285ndash294 2014

12 Science and Technology of Nuclear Installations

[31] httpwwwneimagazinecomnewsnewsnuclear-reactor-per-formance-by-vendors-agrs-23

[32] H W Tang Practical Introduction to Mathematical Program-ming Dalian Institute of Technology Press 1986

[33] V Zare S M S Mahmoudi and M Yari ldquoAn exergoeconomicinvestigation of waste heat recovery from the Gas Turbine-Modular Helium Reactor (GT-MHR) employing an ammonia-water powercooling cyclerdquo Energy vol 61 pp 397ndash409 2013

TribologyAdvances in

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

International Journal of

AerospaceEngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

FuelsJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal ofPetroleum Engineering

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Industrial EngineeringJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Power ElectronicsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in

CombustionJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Renewable Energy

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

StructuresJournal of

International Journal of

RotatingMachinery

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

EnergyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporation httpwwwhindawicom

Journal ofEngineeringVolume 2014

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

International Journal ofPhotoenergy

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Nuclear InstallationsScience and Technology of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Solar EnergyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Wind EnergyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Nuclear EnergyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

High Energy PhysicsAdvances in

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Science and Technology of Nuclear Installations 9

345 348 351 354 357 360

002156

002163

002170

002177

002184

F(X

)

Turbine inlet temperature (K)

x8 = 0555x8 = 0530

x8 = 0480

ΔTpinch = 5KTa = 288K

p8 = 35barp14 = 17bar

Figure 13 Variation of 119865(119883) of combined cycle with turbine inlettemperature

035 040 045 050 055274

276

278

280

282

284

Pow

er o

utpu

t (M

W)

Ammonia mass fraction

p14 = 17barp14 = 23barp14 = 28bar

p8 = 35barT14 = 352K

ΔTpinch = 5KTa = 288K

Figure 14 Variation of power output of combined cycle withammonia mass fraction

concentration the greater the ammonia vapor flow rateexpanding in the turbine However if the ammonia massfraction is too high the pump power consumption willincrease greatly because the ammonia liquid mixture at theoutlet of the absorber (state 8) will change into the vapor-liquid mixture

Figure 16 shows the effect of ammonia mass fractionon LEC With the increase of ammonia mass fraction LECdecreases initially and then increases The higher the turbineinlet pressure the smaller the optimal ammonia mass frac-tion When the turbine inlet pressure is 17 bar LEC reachesthe minimum of 00716USD(kWh) with an ammonia massfraction of 0405 When the turbine inlet pressure is 17bar LEC reaches the minimum of 00713USD(kWh) with

035 040 045 050 055

465

468

471

474

477

480

Ammonia mass fraction

120578ov

eral

lcom

bine

dcyc

le(

)

p14 = 17barp14 = 23barp14 = 28bar

p8 = 35barT14 = 352K

ΔTpinch = 5KTa = 288K

Figure 15 Variation of overall efficiency of combined cycle withammonia mass fraction

035 040 045 050 055

0071

0072

0073

0074

0075

Ammonia mass fraction

p14 = 17barp14 = 23barp14 = 28bar

p8 = 35barT14 = 352K

ΔTpinch = 5KTa = 288K

LEC C

ombi

nedc

ycle(U

SDk

Wh)

Figure 16 Variation of LEC of combined cycle with ammonia massfraction

an ammonia mass fraction of 0545 Figure 17 presentsthe variations of 119865(119883) with ammonia mass fraction 119865(119883)decreases rapidly with increasing ammonia mass fraction

45 System Optimization In this work SA (SimulatedAnnealing) is employed to obtain the optimum combinationof the key parameters For the optimization the constraintsare simplified as follows

Subject to

170 ⩽ 11990114(bar) ⩽ 340

345 ⩽ 11987914(K) ⩽ 375

036 ⩽ 1199098⩽ 0555

10 Science and Technology of Nuclear Installations

035 040 045 050 05500216

00218

00220

00222

00224

00226

F(X

)

Ammonia mass fraction

p14 = 17barp14 = 23barp14 = 28bar

p8 = 35barT14 = 352K

ΔTpinch = 5KTa = 288K

Figure 17 Variation of F(X) of combined cycle with ammonia massfraction

288 ⩽ 119879119886(K) ⩽ 300

0 ⩽11989810

1198989

⩽ 1

0 ⩽11989812

1198981

⩽ 1

(11987917minus 11987910) ⩾ 5K

(1198794minus 11987911) ⩾ 5K

(1198793minus 119879Boiler) ⩾ 5K

119879Boiler ⩾ 119879Rectifier

119876cool gt 0

11990114⩾ 1199018

(20)

The selection of the above-mentioned parameters for thisoptimization is according to the literatures [6 9 13]

Table 6 shows some results of the closed Brayton cycle Tocompare the thermodynamic and economic performances ofthe combined cycle with those of the closed Brayton cyclethree parameters are defined as follows

RV119882net

=

(119882netCombinedcycle minus119882netBrayton)

119882netBrayton

RV120578overall

=

(120578overallCombinedcycle minus 120578overallBrayton)

120578overallBrayton

RVLEC =

(LECCombinedcycle minus LECBrayton)

LECBrayton

(21)

Table 6 Results of the closed Brayton cycle

Parameters Value119876core (MW) 59364120578overall119861 466119882net119861 (MW) 27690LEC119861(USD(kWh)) 00711

Table 7 Optimization results

Parameters Optimization results

Δ119879pinch = 5K 1199018= 35 bar

11990114= 181 bar 119879

14= 345K

1199098= 0555

F(X) = 002164119882netCombinedcycle = 28356MWRV119882net

= 241120578overallCombinedcycle = 4791RV

120578overall= 243LECCombinedcycle =00706USD(kWh) RVLEC =minus073

Table 7 lists the result of the parameters for the optimiza-tion The optimized power output and overall efficiency forthe combined cycle are 28356MW and 4791 respectivelyThese values are 241 and 243 higher than those of theclosedBrayton cycle respectively Both the lower average heataddition temperature and the higher back pressure of turbinein AWM cycle result in less power output and lower overallefficiency of the combined cycle

Comparingwith closedBrayton cycle the combined cyclereduces the LEC slightly The optimized LEC of combinedcycle is 073 lower than that of the closed Brayton cycleThereason is that the AWM utilizes the waste heat and adds thepower output and the cooling capacity to the closed Braytoncycle However the total capital investment increases due tothe combined AWM system

5 Conclusions

In this paper a combined cycle which combines AWM cycleand a nuclear closed Brayton cycle to recover the wasteheat rejected from the precooler is proposed A detailedparametric study and optimization are carried out for thiscombined cycle according to the thermodynamics and eco-nomics performances The combined cycle can potentiallybe used to improve the power output and overall efficiencyThe power output and overall efficiency of the combinedcycle increase with increasing turbine inlet temperature andammonia mass fraction but the turbine inlet temperatureand the ammonia mass fraction are limited by the heatsource temperature and the absorb pressure respectivelyCompared with the closed Brayton cycle the optimizedpower output and overall efficiency increase by 241 and243 respectively LEC increases with decreasing absorberpressure and turbine inlet temperature The optimized LECof the combined cycle is 00706USD(kWh) which is 073lower than those of the closed Brayton cycle

Science and Technology of Nuclear Installations 11

Competing Interests

The authors declare that there are no competing interestsregarding the publication of this paper and regarding thefunding that they have received

Acknowledgments

This present research was supported by the Chinese NaturalScience Fund (Project no 51306216) and the FundamentalResearch Funds for the Central University (Project noCDJ2R13140016)

References

[1] A Soroureddin A S Mehr S M S Mahmoudi and M YarildquoThermodynamic analysis of employing ejector and organicRankine cycles for GT-MHR waste heat utilization A Compar-ative Studyrdquo Energy Conversion and Management vol 67 pp125ndash137 2013

[2] S Dardour S Nisan and F Charbit ldquoUtilisation of waste heatfrom GT-MHR and PBMR reactors for nuclear desalinationrdquoDesalination vol 205 no 1ndash3 pp 254ndash268 2007

[3] A I Kalina ldquoCombined-cycle system with novel bottomingcyclerdquo Journal of Engineering for Gas Turbines and Power vol106 no 4 pp 737ndash742 1984

[4] D Y Goswami ldquoSolar thermal power technology present statusand ideas for the futurerdquo Energy Sources vol 20 no 2 pp 137ndash145 1998

[5] D S Ayou J C Bruno R Saravanan and A Coronas ldquoAnoverview of combined absorption power and cooling cyclesrdquoRenewable and Sustainable Energy Reviews vol 21 pp 728ndash7482013

[6] R V Padilla G Demirkaya D Y Goswami E Stefanakos andM M Rahman ldquoAnalysis of power and cooling cogenerationusing ammonia-water mixturerdquo Energy vol 35 no 12 pp4649ndash4657 2010

[7] S Lu and D Y Goswami ldquoOptimization of a novel combinedpowerrefrigeration thermodynamic cyclerdquo Journal of SolarEnergy Engineering vol 125 no 2 pp 212ndash217 2003

[8] M Pouraghaie K Atashkari S M Besarati and N Nariman-zadeh ldquoThermodynamic performance optimization of a com-bined powercooling cyclerdquo Energy Conversion and Manage-ment vol 51 no 1 pp 204ndash211 2010

[9] G Demirkaya R Vasquez Padilla D Y Goswami E Ste-fanakos and M M Rahman ldquoAnalysis of a combined powerand cooling cycle for low-grade heat sourcesrdquo InternationalJournal of Energy Research vol 35 no 13 pp 1145ndash1157 2011

[10] L S Vieira J L Donatelli and M E Cruz ldquoExergoeconomicimprovement of a complex cogeneration system integratedwith a professional process simulatorrdquo Energy Conversion andManagement vol 50 no 8 pp 1955ndash1967 2009

[11] Z ShengjunWHuaixin andG Tao ldquoPerformance comparisonand parametric optimization of subcritical Organic RankineCycle (ORC) and transcritical power cycle system for low-temperature geothermal power generationrdquoApplied Energy vol88 no 8 pp 2740ndash2754 2011

[12] T Guo H X Wang and S J Zhang ldquoFluids and parametersoptimization for a novel cogeneration system driven by low-temperature geothermal sourcesrdquo Energy vol 36 no 5 pp2639ndash2649 2011

[13] A Coskun A Bolatturk and M Kanoglu ldquoThermodynamicand economic analysis and optimization of power cycles for amedium temperature geothermal resourcerdquo Energy Conversionand Management vol 78 pp 39ndash49 2014

[14] V Zare S M S Mahmoudi and M Yari ldquoOn the exergoe-conomic assessment of employing Kalina cycle for GT-MHRwaste heat utilizationrdquoEnergy Conversion andManagement vol90 pp 364ndash374 2015

[15] K Bahlouli R Khoshbakhti Saray andN Sarabchi ldquoParametricinvestigation and thermo-economic multi-objective optimiza-tion of an ammonia-water powercooling cycle coupled withan HCCI (homogeneous charge compression ignition) enginerdquoEnergy vol 86 pp 672ndash684 2015

[16] Y Feng Y Zhang B Li J Yang and Y Shi ldquoSensitivity analysisand thermoeconomic comparison of ORCs (organicRankinecycles) for low temperature waste heat recoveryrdquo Energy vol82 pp 664ndash677 2015

[17] F Xu D Y Goswami and S S Bhagwat ldquoA combinedpowercooling cyclerdquo Energy vol 25 no 3 pp 233ndash246 2000

[18] F Xu and D Y Goswami ldquoThermodynamic properties ofammonia-watermixtures for power-cycle applicationsrdquo Energyvol 24 no 6 pp 525ndash536 1999

[19] M S El-Genk and J-M Tournier ldquoNoble gas binary mixturesfor gas-cooled reactor power plantsrdquo Nuclear Engineering andDesign vol 238 no 6 pp 1353ndash1372 2008

[20] F W Yu K T Chan R K Y Sit et al ldquoReview of standardsfor energy performance of chiller systems serving commercialbuildingsrdquo Energy Procedia vol 61 pp 2778ndash2782 2014

[21] S Nisan and S Dardour ldquoEconomic evaluation of nucleardesalination systemsrdquo Desalination vol 205 no 1ndash3 pp 231ndash242 2007

[22] L E Herranz J I Linares and B Y Moratilla ldquoPower cycleassessment of nuclear high temperature gas-cooled reactorsrdquoApplied Thermal Engineering vol 29 no 8-9 pp 1759ndash17652009

[23] HDMadhawaHettiarachchiMGolubovicWMWorek andY Ikegami ldquoOptimum design criteria for an Organic Rankinecycle using low-temperature geothermal heat sourcesrdquo Energyvol 32 no 9 pp 1698ndash1706 2007

[24] Y T Zhu W H Qu and P Y Yu Chemical Equipment DesignManual Chemical Industry Press 2005

[25] Q Songwen Heat Exchanger Design Handbook ChemicalIndustry Press 2002

[26] R Turton R C Bailie W B Whiting et al Analysis Synthesisand Design of Chemical Processes Prentice Hall Upper SaddleRiver NJ USA 1997

[27] F Taboas M Valles M Bourouis and A Coronas ldquoFlowboiling heat transfer of ammoniawater mixture in a plate heatexchangerrdquo International Journal of Refrigeration vol 33 no 4pp 695ndash705 2010

[28] L Xiao S-Y Wu T-T Yi C Liu and Y-R Li ldquoMulti-objectiveoptimization of evaporation and condensation temperatures forsubcritical organic Rankine cyclerdquo Energy vol 83 pp 723ndash7332015

[29] C E Campos Rodrıguez J C Escobar Palacio O J Venturiniet al ldquoExergetic and economic comparison of ORC and Kalinacycle for low temperature enhanced geothermal system inBrazilrdquo Applied Thermal Engineering vol 52 no 1 pp 109ndash1192013

[30] D Mignard ldquoCorrelating the chemical engineering plant costindex with macro-economic indicatorsrdquo Chemical EngineeringResearch and Design vol 92 no 2 pp 285ndash294 2014

12 Science and Technology of Nuclear Installations

[31] httpwwwneimagazinecomnewsnewsnuclear-reactor-per-formance-by-vendors-agrs-23

[32] H W Tang Practical Introduction to Mathematical Program-ming Dalian Institute of Technology Press 1986

[33] V Zare S M S Mahmoudi and M Yari ldquoAn exergoeconomicinvestigation of waste heat recovery from the Gas Turbine-Modular Helium Reactor (GT-MHR) employing an ammonia-water powercooling cyclerdquo Energy vol 61 pp 397ndash409 2013

TribologyAdvances in

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

International Journal of

AerospaceEngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

FuelsJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal ofPetroleum Engineering

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Industrial EngineeringJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Power ElectronicsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in

CombustionJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Renewable Energy

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

StructuresJournal of

International Journal of

RotatingMachinery

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

EnergyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporation httpwwwhindawicom

Journal ofEngineeringVolume 2014

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

International Journal ofPhotoenergy

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Nuclear InstallationsScience and Technology of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Solar EnergyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Wind EnergyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Nuclear EnergyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

High Energy PhysicsAdvances in

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

10 Science and Technology of Nuclear Installations

035 040 045 050 05500216

00218

00220

00222

00224

00226

F(X

)

Ammonia mass fraction

p14 = 17barp14 = 23barp14 = 28bar

p8 = 35barT14 = 352K

ΔTpinch = 5KTa = 288K

Figure 17 Variation of F(X) of combined cycle with ammonia massfraction

288 ⩽ 119879119886(K) ⩽ 300

0 ⩽11989810

1198989

⩽ 1

0 ⩽11989812

1198981

⩽ 1

(11987917minus 11987910) ⩾ 5K

(1198794minus 11987911) ⩾ 5K

(1198793minus 119879Boiler) ⩾ 5K

119879Boiler ⩾ 119879Rectifier

119876cool gt 0

11990114⩾ 1199018

(20)

The selection of the above-mentioned parameters for thisoptimization is according to the literatures [6 9 13]

Table 6 shows some results of the closed Brayton cycle Tocompare the thermodynamic and economic performances ofthe combined cycle with those of the closed Brayton cyclethree parameters are defined as follows

RV119882net

=

(119882netCombinedcycle minus119882netBrayton)

119882netBrayton

RV120578overall

=

(120578overallCombinedcycle minus 120578overallBrayton)

120578overallBrayton

RVLEC =

(LECCombinedcycle minus LECBrayton)

LECBrayton

(21)

Table 6 Results of the closed Brayton cycle

Parameters Value119876core (MW) 59364120578overall119861 466119882net119861 (MW) 27690LEC119861(USD(kWh)) 00711

Table 7 Optimization results

Parameters Optimization results

Δ119879pinch = 5K 1199018= 35 bar

11990114= 181 bar 119879

14= 345K

1199098= 0555

F(X) = 002164119882netCombinedcycle = 28356MWRV119882net

= 241120578overallCombinedcycle = 4791RV

120578overall= 243LECCombinedcycle =00706USD(kWh) RVLEC =minus073

Table 7 lists the result of the parameters for the optimiza-tion The optimized power output and overall efficiency forthe combined cycle are 28356MW and 4791 respectivelyThese values are 241 and 243 higher than those of theclosedBrayton cycle respectively Both the lower average heataddition temperature and the higher back pressure of turbinein AWM cycle result in less power output and lower overallefficiency of the combined cycle

Comparingwith closedBrayton cycle the combined cyclereduces the LEC slightly The optimized LEC of combinedcycle is 073 lower than that of the closed Brayton cycleThereason is that the AWM utilizes the waste heat and adds thepower output and the cooling capacity to the closed Braytoncycle However the total capital investment increases due tothe combined AWM system

5 Conclusions

In this paper a combined cycle which combines AWM cycleand a nuclear closed Brayton cycle to recover the wasteheat rejected from the precooler is proposed A detailedparametric study and optimization are carried out for thiscombined cycle according to the thermodynamics and eco-nomics performances The combined cycle can potentiallybe used to improve the power output and overall efficiencyThe power output and overall efficiency of the combinedcycle increase with increasing turbine inlet temperature andammonia mass fraction but the turbine inlet temperatureand the ammonia mass fraction are limited by the heatsource temperature and the absorb pressure respectivelyCompared with the closed Brayton cycle the optimizedpower output and overall efficiency increase by 241 and243 respectively LEC increases with decreasing absorberpressure and turbine inlet temperature The optimized LECof the combined cycle is 00706USD(kWh) which is 073lower than those of the closed Brayton cycle

Science and Technology of Nuclear Installations 11

Competing Interests

The authors declare that there are no competing interestsregarding the publication of this paper and regarding thefunding that they have received

Acknowledgments

This present research was supported by the Chinese NaturalScience Fund (Project no 51306216) and the FundamentalResearch Funds for the Central University (Project noCDJ2R13140016)

References

[1] A Soroureddin A S Mehr S M S Mahmoudi and M YarildquoThermodynamic analysis of employing ejector and organicRankine cycles for GT-MHR waste heat utilization A Compar-ative Studyrdquo Energy Conversion and Management vol 67 pp125ndash137 2013

[2] S Dardour S Nisan and F Charbit ldquoUtilisation of waste heatfrom GT-MHR and PBMR reactors for nuclear desalinationrdquoDesalination vol 205 no 1ndash3 pp 254ndash268 2007

[3] A I Kalina ldquoCombined-cycle system with novel bottomingcyclerdquo Journal of Engineering for Gas Turbines and Power vol106 no 4 pp 737ndash742 1984

[4] D Y Goswami ldquoSolar thermal power technology present statusand ideas for the futurerdquo Energy Sources vol 20 no 2 pp 137ndash145 1998

[5] D S Ayou J C Bruno R Saravanan and A Coronas ldquoAnoverview of combined absorption power and cooling cyclesrdquoRenewable and Sustainable Energy Reviews vol 21 pp 728ndash7482013

[6] R V Padilla G Demirkaya D Y Goswami E Stefanakos andM M Rahman ldquoAnalysis of power and cooling cogenerationusing ammonia-water mixturerdquo Energy vol 35 no 12 pp4649ndash4657 2010

[7] S Lu and D Y Goswami ldquoOptimization of a novel combinedpowerrefrigeration thermodynamic cyclerdquo Journal of SolarEnergy Engineering vol 125 no 2 pp 212ndash217 2003

[8] M Pouraghaie K Atashkari S M Besarati and N Nariman-zadeh ldquoThermodynamic performance optimization of a com-bined powercooling cyclerdquo Energy Conversion and Manage-ment vol 51 no 1 pp 204ndash211 2010

[9] G Demirkaya R Vasquez Padilla D Y Goswami E Ste-fanakos and M M Rahman ldquoAnalysis of a combined powerand cooling cycle for low-grade heat sourcesrdquo InternationalJournal of Energy Research vol 35 no 13 pp 1145ndash1157 2011

[10] L S Vieira J L Donatelli and M E Cruz ldquoExergoeconomicimprovement of a complex cogeneration system integratedwith a professional process simulatorrdquo Energy Conversion andManagement vol 50 no 8 pp 1955ndash1967 2009

[11] Z ShengjunWHuaixin andG Tao ldquoPerformance comparisonand parametric optimization of subcritical Organic RankineCycle (ORC) and transcritical power cycle system for low-temperature geothermal power generationrdquoApplied Energy vol88 no 8 pp 2740ndash2754 2011

[12] T Guo H X Wang and S J Zhang ldquoFluids and parametersoptimization for a novel cogeneration system driven by low-temperature geothermal sourcesrdquo Energy vol 36 no 5 pp2639ndash2649 2011

[13] A Coskun A Bolatturk and M Kanoglu ldquoThermodynamicand economic analysis and optimization of power cycles for amedium temperature geothermal resourcerdquo Energy Conversionand Management vol 78 pp 39ndash49 2014

[14] V Zare S M S Mahmoudi and M Yari ldquoOn the exergoe-conomic assessment of employing Kalina cycle for GT-MHRwaste heat utilizationrdquoEnergy Conversion andManagement vol90 pp 364ndash374 2015

[15] K Bahlouli R Khoshbakhti Saray andN Sarabchi ldquoParametricinvestigation and thermo-economic multi-objective optimiza-tion of an ammonia-water powercooling cycle coupled withan HCCI (homogeneous charge compression ignition) enginerdquoEnergy vol 86 pp 672ndash684 2015

[16] Y Feng Y Zhang B Li J Yang and Y Shi ldquoSensitivity analysisand thermoeconomic comparison of ORCs (organicRankinecycles) for low temperature waste heat recoveryrdquo Energy vol82 pp 664ndash677 2015

[17] F Xu D Y Goswami and S S Bhagwat ldquoA combinedpowercooling cyclerdquo Energy vol 25 no 3 pp 233ndash246 2000

[18] F Xu and D Y Goswami ldquoThermodynamic properties ofammonia-watermixtures for power-cycle applicationsrdquo Energyvol 24 no 6 pp 525ndash536 1999

[19] M S El-Genk and J-M Tournier ldquoNoble gas binary mixturesfor gas-cooled reactor power plantsrdquo Nuclear Engineering andDesign vol 238 no 6 pp 1353ndash1372 2008

[20] F W Yu K T Chan R K Y Sit et al ldquoReview of standardsfor energy performance of chiller systems serving commercialbuildingsrdquo Energy Procedia vol 61 pp 2778ndash2782 2014

[21] S Nisan and S Dardour ldquoEconomic evaluation of nucleardesalination systemsrdquo Desalination vol 205 no 1ndash3 pp 231ndash242 2007

[22] L E Herranz J I Linares and B Y Moratilla ldquoPower cycleassessment of nuclear high temperature gas-cooled reactorsrdquoApplied Thermal Engineering vol 29 no 8-9 pp 1759ndash17652009

[23] HDMadhawaHettiarachchiMGolubovicWMWorek andY Ikegami ldquoOptimum design criteria for an Organic Rankinecycle using low-temperature geothermal heat sourcesrdquo Energyvol 32 no 9 pp 1698ndash1706 2007

[24] Y T Zhu W H Qu and P Y Yu Chemical Equipment DesignManual Chemical Industry Press 2005

[25] Q Songwen Heat Exchanger Design Handbook ChemicalIndustry Press 2002

[26] R Turton R C Bailie W B Whiting et al Analysis Synthesisand Design of Chemical Processes Prentice Hall Upper SaddleRiver NJ USA 1997

[27] F Taboas M Valles M Bourouis and A Coronas ldquoFlowboiling heat transfer of ammoniawater mixture in a plate heatexchangerrdquo International Journal of Refrigeration vol 33 no 4pp 695ndash705 2010

[28] L Xiao S-Y Wu T-T Yi C Liu and Y-R Li ldquoMulti-objectiveoptimization of evaporation and condensation temperatures forsubcritical organic Rankine cyclerdquo Energy vol 83 pp 723ndash7332015

[29] C E Campos Rodrıguez J C Escobar Palacio O J Venturiniet al ldquoExergetic and economic comparison of ORC and Kalinacycle for low temperature enhanced geothermal system inBrazilrdquo Applied Thermal Engineering vol 52 no 1 pp 109ndash1192013

[30] D Mignard ldquoCorrelating the chemical engineering plant costindex with macro-economic indicatorsrdquo Chemical EngineeringResearch and Design vol 92 no 2 pp 285ndash294 2014

12 Science and Technology of Nuclear Installations

[31] httpwwwneimagazinecomnewsnewsnuclear-reactor-per-formance-by-vendors-agrs-23

[32] H W Tang Practical Introduction to Mathematical Program-ming Dalian Institute of Technology Press 1986

[33] V Zare S M S Mahmoudi and M Yari ldquoAn exergoeconomicinvestigation of waste heat recovery from the Gas Turbine-Modular Helium Reactor (GT-MHR) employing an ammonia-water powercooling cyclerdquo Energy vol 61 pp 397ndash409 2013

TribologyAdvances in

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

International Journal of

AerospaceEngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

FuelsJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal ofPetroleum Engineering

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Industrial EngineeringJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Power ElectronicsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in

CombustionJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Renewable Energy

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

StructuresJournal of

International Journal of

RotatingMachinery

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

EnergyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporation httpwwwhindawicom

Journal ofEngineeringVolume 2014

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

International Journal ofPhotoenergy

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Nuclear InstallationsScience and Technology of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Solar EnergyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Wind EnergyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Nuclear EnergyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

High Energy PhysicsAdvances in

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Science and Technology of Nuclear Installations 11

Competing Interests

The authors declare that there are no competing interestsregarding the publication of this paper and regarding thefunding that they have received

Acknowledgments

This present research was supported by the Chinese NaturalScience Fund (Project no 51306216) and the FundamentalResearch Funds for the Central University (Project noCDJ2R13140016)

References

[1] A Soroureddin A S Mehr S M S Mahmoudi and M YarildquoThermodynamic analysis of employing ejector and organicRankine cycles for GT-MHR waste heat utilization A Compar-ative Studyrdquo Energy Conversion and Management vol 67 pp125ndash137 2013

[2] S Dardour S Nisan and F Charbit ldquoUtilisation of waste heatfrom GT-MHR and PBMR reactors for nuclear desalinationrdquoDesalination vol 205 no 1ndash3 pp 254ndash268 2007

[3] A I Kalina ldquoCombined-cycle system with novel bottomingcyclerdquo Journal of Engineering for Gas Turbines and Power vol106 no 4 pp 737ndash742 1984

[4] D Y Goswami ldquoSolar thermal power technology present statusand ideas for the futurerdquo Energy Sources vol 20 no 2 pp 137ndash145 1998

[5] D S Ayou J C Bruno R Saravanan and A Coronas ldquoAnoverview of combined absorption power and cooling cyclesrdquoRenewable and Sustainable Energy Reviews vol 21 pp 728ndash7482013

[6] R V Padilla G Demirkaya D Y Goswami E Stefanakos andM M Rahman ldquoAnalysis of power and cooling cogenerationusing ammonia-water mixturerdquo Energy vol 35 no 12 pp4649ndash4657 2010

[7] S Lu and D Y Goswami ldquoOptimization of a novel combinedpowerrefrigeration thermodynamic cyclerdquo Journal of SolarEnergy Engineering vol 125 no 2 pp 212ndash217 2003

[8] M Pouraghaie K Atashkari S M Besarati and N Nariman-zadeh ldquoThermodynamic performance optimization of a com-bined powercooling cyclerdquo Energy Conversion and Manage-ment vol 51 no 1 pp 204ndash211 2010

[9] G Demirkaya R Vasquez Padilla D Y Goswami E Ste-fanakos and M M Rahman ldquoAnalysis of a combined powerand cooling cycle for low-grade heat sourcesrdquo InternationalJournal of Energy Research vol 35 no 13 pp 1145ndash1157 2011

[10] L S Vieira J L Donatelli and M E Cruz ldquoExergoeconomicimprovement of a complex cogeneration system integratedwith a professional process simulatorrdquo Energy Conversion andManagement vol 50 no 8 pp 1955ndash1967 2009

[11] Z ShengjunWHuaixin andG Tao ldquoPerformance comparisonand parametric optimization of subcritical Organic RankineCycle (ORC) and transcritical power cycle system for low-temperature geothermal power generationrdquoApplied Energy vol88 no 8 pp 2740ndash2754 2011

[12] T Guo H X Wang and S J Zhang ldquoFluids and parametersoptimization for a novel cogeneration system driven by low-temperature geothermal sourcesrdquo Energy vol 36 no 5 pp2639ndash2649 2011

[13] A Coskun A Bolatturk and M Kanoglu ldquoThermodynamicand economic analysis and optimization of power cycles for amedium temperature geothermal resourcerdquo Energy Conversionand Management vol 78 pp 39ndash49 2014

[14] V Zare S M S Mahmoudi and M Yari ldquoOn the exergoe-conomic assessment of employing Kalina cycle for GT-MHRwaste heat utilizationrdquoEnergy Conversion andManagement vol90 pp 364ndash374 2015

[15] K Bahlouli R Khoshbakhti Saray andN Sarabchi ldquoParametricinvestigation and thermo-economic multi-objective optimiza-tion of an ammonia-water powercooling cycle coupled withan HCCI (homogeneous charge compression ignition) enginerdquoEnergy vol 86 pp 672ndash684 2015

[16] Y Feng Y Zhang B Li J Yang and Y Shi ldquoSensitivity analysisand thermoeconomic comparison of ORCs (organicRankinecycles) for low temperature waste heat recoveryrdquo Energy vol82 pp 664ndash677 2015

[17] F Xu D Y Goswami and S S Bhagwat ldquoA combinedpowercooling cyclerdquo Energy vol 25 no 3 pp 233ndash246 2000

[18] F Xu and D Y Goswami ldquoThermodynamic properties ofammonia-watermixtures for power-cycle applicationsrdquo Energyvol 24 no 6 pp 525ndash536 1999

[19] M S El-Genk and J-M Tournier ldquoNoble gas binary mixturesfor gas-cooled reactor power plantsrdquo Nuclear Engineering andDesign vol 238 no 6 pp 1353ndash1372 2008

[20] F W Yu K T Chan R K Y Sit et al ldquoReview of standardsfor energy performance of chiller systems serving commercialbuildingsrdquo Energy Procedia vol 61 pp 2778ndash2782 2014

[21] S Nisan and S Dardour ldquoEconomic evaluation of nucleardesalination systemsrdquo Desalination vol 205 no 1ndash3 pp 231ndash242 2007

[22] L E Herranz J I Linares and B Y Moratilla ldquoPower cycleassessment of nuclear high temperature gas-cooled reactorsrdquoApplied Thermal Engineering vol 29 no 8-9 pp 1759ndash17652009

[23] HDMadhawaHettiarachchiMGolubovicWMWorek andY Ikegami ldquoOptimum design criteria for an Organic Rankinecycle using low-temperature geothermal heat sourcesrdquo Energyvol 32 no 9 pp 1698ndash1706 2007

[24] Y T Zhu W H Qu and P Y Yu Chemical Equipment DesignManual Chemical Industry Press 2005

[25] Q Songwen Heat Exchanger Design Handbook ChemicalIndustry Press 2002

[26] R Turton R C Bailie W B Whiting et al Analysis Synthesisand Design of Chemical Processes Prentice Hall Upper SaddleRiver NJ USA 1997

[27] F Taboas M Valles M Bourouis and A Coronas ldquoFlowboiling heat transfer of ammoniawater mixture in a plate heatexchangerrdquo International Journal of Refrigeration vol 33 no 4pp 695ndash705 2010

[28] L Xiao S-Y Wu T-T Yi C Liu and Y-R Li ldquoMulti-objectiveoptimization of evaporation and condensation temperatures forsubcritical organic Rankine cyclerdquo Energy vol 83 pp 723ndash7332015

[29] C E Campos Rodrıguez J C Escobar Palacio O J Venturiniet al ldquoExergetic and economic comparison of ORC and Kalinacycle for low temperature enhanced geothermal system inBrazilrdquo Applied Thermal Engineering vol 52 no 1 pp 109ndash1192013

[30] D Mignard ldquoCorrelating the chemical engineering plant costindex with macro-economic indicatorsrdquo Chemical EngineeringResearch and Design vol 92 no 2 pp 285ndash294 2014

12 Science and Technology of Nuclear Installations

[31] httpwwwneimagazinecomnewsnewsnuclear-reactor-per-formance-by-vendors-agrs-23

[32] H W Tang Practical Introduction to Mathematical Program-ming Dalian Institute of Technology Press 1986

[33] V Zare S M S Mahmoudi and M Yari ldquoAn exergoeconomicinvestigation of waste heat recovery from the Gas Turbine-Modular Helium Reactor (GT-MHR) employing an ammonia-water powercooling cyclerdquo Energy vol 61 pp 397ndash409 2013

TribologyAdvances in

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

International Journal of

AerospaceEngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

FuelsJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal ofPetroleum Engineering

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Industrial EngineeringJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Power ElectronicsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in

CombustionJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Renewable Energy

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

StructuresJournal of

International Journal of

RotatingMachinery

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

EnergyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporation httpwwwhindawicom

Journal ofEngineeringVolume 2014

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

International Journal ofPhotoenergy

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Nuclear InstallationsScience and Technology of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Solar EnergyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Wind EnergyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Nuclear EnergyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

High Energy PhysicsAdvances in

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

12 Science and Technology of Nuclear Installations

[31] httpwwwneimagazinecomnewsnewsnuclear-reactor-per-formance-by-vendors-agrs-23

[32] H W Tang Practical Introduction to Mathematical Program-ming Dalian Institute of Technology Press 1986

[33] V Zare S M S Mahmoudi and M Yari ldquoAn exergoeconomicinvestigation of waste heat recovery from the Gas Turbine-Modular Helium Reactor (GT-MHR) employing an ammonia-water powercooling cyclerdquo Energy vol 61 pp 397ndash409 2013

TribologyAdvances in

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

International Journal of

AerospaceEngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

FuelsJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal ofPetroleum Engineering

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Industrial EngineeringJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Power ElectronicsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in

CombustionJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Renewable Energy

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

StructuresJournal of

International Journal of

RotatingMachinery

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

EnergyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporation httpwwwhindawicom

Journal ofEngineeringVolume 2014

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

International Journal ofPhotoenergy

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Nuclear InstallationsScience and Technology of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Solar EnergyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Wind EnergyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Nuclear EnergyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

High Energy PhysicsAdvances in

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

TribologyAdvances in

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

International Journal of

AerospaceEngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

FuelsJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal ofPetroleum Engineering

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Industrial EngineeringJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Power ElectronicsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in

CombustionJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Renewable Energy

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

StructuresJournal of

International Journal of

RotatingMachinery

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

EnergyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporation httpwwwhindawicom

Journal ofEngineeringVolume 2014

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

International Journal ofPhotoenergy

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Nuclear InstallationsScience and Technology of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Solar EnergyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Wind EnergyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Nuclear EnergyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

High Energy PhysicsAdvances in

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014