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Building Integration of Micro-Generation Technologies

Giovanni Angrisani, Carlo Roselli, Maurizio Sasso

UNIVERSITA’ del SANNIO, ItaliaDING (Dipartimento di INGegneria)

Corso di Laurea in Ingegneria Energetica

Assessing Micro-Gen in Italy

2

Aims

Introduction;

Commercial status;

Policy instruments;

R&D activity;

Conclusions

Prof. M. Sasso, 27 October 2010, - NIST, Gaithersburg, MD

33

MCHP & MCCHPIn the North of Italy small scale cogenerations, MCHP (<15 kWe) is able toguarantee energy savings, avoided CO2 emissions and economic advantages.In the mild climate (South) to increase the annual operation hours, MCHP must beupgrade to provide space and process cooling capacity (MCCHP).

Prof. M. Sasso, 27 October 2010, NIST, Gaithersburg, MD, USA

MCCHPs are Distributed Generationsystems located close to the point ofend use. They can contribute todecrease Transmission andDistribution losses.

Further benefits of gas fuelled CCHP with respect to the reference separateenergy “production” are• primary energy saving;• low pollutant emissions;• reduction of operating costs;• shift from electricity to gas demands during warm seasons (gas cooling)

ALIZED SION

TRASMISSION CENTRALIZED CONVERSION

COMMUNITY INTEREST

Primary energy

LOSSES

4

CCHP: the components

EXH

AU

ST G

AS

CO

OLI

NG

HOT WATER

PM G

THP

ELECTRIC ENERGY

HEATING ENERGY

ENG

INE

CO

OLI

NG

CHILLED WATER

COOLING ENERGY

HEAT REJECTED

HEAT REJECTED

CCHP CHP

AMBIENT

AMBIENT

PRIMARY ENERGY

A CCHP consists of four basiccomponents:• a prime mover;• an electricity generator, G;• a thermal recovery system(exhaust gas and enginecooling liquid);• a cooling energy “production”system.

The “heart” of energy conversion systems, Prime Mover (Stirling, Reciprocating InternalCombustion, Fuel Cell, Gas Turbine):• stationary conditions for a long time;• high efficiency and very low pollutant emissions;• small installation space;• high thermal efficiency;• low noise and vibrations levels,• low maintenance and long life service.

Prof. M. Sasso, 27 October 2010, NIST, Gaithersburg, MD, USA

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CCHP: the cooling systemIt is usually adopted:• a Thermally activated Heat Pump (absorption and adsorption), CHP/THP, fuelled bythermal energy.

Further technologies allow to satisfy cooling demands using CHP mechanical energyoutputs:• mechanically-driven system, CHP/HP: an Heat Pump (HP) activated by mechanical energy supplied by PM (Trigeneration Gas Engine Heat Pump);• electrically-driven system, CHP/EHP: a conventional Electric Heat Pump driven by G.

CHP

EHP

HP

THP

Electric energy

Mechanical energy

Thermal energy

Primary energy

Prof. M. Sasso, 27 October 2010, NIST, Gaithersburg, MD, USA

66

CCHP: non conventional HVAC system based on desiccant wheelIn an air conditioning system outside air is usually cooled below the dew point by a largeelectric driven compression chiller for dehumidifying and, subsequently, it is heated up todesired supplied temperature.In a desiccant assisted system, moist air is dehumidified by means of a Desiccant Wheel,DW, increasing overall system energy efficiency by avoiding overcooling air andprecluding oversized capacity to meet dehumidification load. The process air streamflows through the desiccant material (such as silica gel) that retains the moisture of theair; the desiccant capacity of this material can be restored through its regeneration via aheated air stream, usually supplied by a boiler.

Advantages:• sensible and latent loads can be controlled separately;• the chiller is smaller and it operates at a small temperature lift with a greater COP;• consistent energy savings can be obtained;• humidity and IAQ control are better;• environmental impact is reduced.The drawbacks of this technology are high investment costs.The waste heat of a small cogeneration plant can be used effectively to regenerate desiccant material, and also the cogenerator electricity can drive a chiller to meet room sensible load.

Prof. M. Sasso, 27 October 2010, NIST, Gaithersburg, MD, USA

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In 1973 FIAT group started a research project, headed by Eng.Palazzetti, aimed to develop a MCHP system, the Totem (Total EnergyModule) :• on the market in 1978;• 15 kWel and 39 kWth.;• Internal Combustion Engine:• natural gas and biogas;• 903 cm3.

TOTEM: the first MCHP 1/2

Prof. M. Sasso, 27 October 2010, NIST, Gaithersburg, MD, USA

The last version of TOTEM, TANDEM, is based on a FIAT engine with adisplacement of 1.200 cm3 and supplies 20 kWel and 44 kWth

19%

11%

10%

9%13%

12%

9%

8%

1%

1%

1%

6%residential

hotels

restaurant

swimming pool and sport centers

hospitals

industry

urban sewage treatment plants

agribusiness

protected crops (greenhouses)

camping and tourist villages

research laboratories

other applications

33%

6%

2%4%

5%4%8%

4%

18%

6%

7%3%

ItalyAustriaBelgiumDenmark Sweden France Germany England Holland Spain Swiss Other countries

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Year 1992 MCHP TOTEM installed:

ITALY 1283 units:

Austria 215Belgium 70Denmark 140Sweden 190France 140Germany 300England 150Holland 700Spain 210Swiss 250Other countries 100

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TOTEM: the first MCHP 2/2

Prof. M. Sasso, 27 October 2010, NIST, Gaithersburg, MD, USA

MCHPs (ICE) available on the market

Vaillant-EcopowerMarathon engine, 272 cm3

SenertecSachs engine, 579 cm3Aisin

Toyota engine, 952 cm3

Power: 5,5 kWThermal power: 12,5 kWEfficiencyel 27%total 88%

Power: 4,7 kWThermal power: 12,5 kWEfficiencyel 25%total 90%

Power: 6 kWThermal power: 11,7 kWEfficiencyel 28,8%total 85%

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For CHP plants the directive 2004/8/EC introduces the Primary Energy Saving(PES) index:

Bth

CHPth

PPel

CHPelPES

,

,

,

,

11

ηη

ηη

+−=

•ηel,CHP annual average electrical efficiency of the CHP;•ηth,CHP annual average thermal efficiency of the CHP;•ηel,PP reference electrical efficiency (separate production);•ηth,B reference thermal efficiency (separate production).

In particular, the value of the electric reference efficiency is a function of the year ofconstruction of a cogeneration unit, the climatic condition, the electricity used on-site and the avoided grid losses due to decentralized production, while the thermalefficiency is a function of the fuel used to feed the CHP system.

The European Directive define as ‘micro-cogeneration unit’ a cogeneration unitwith a maximum capacity below 50 kWel.

If MCHP electric power is less than 50 kW, the PES has to be higher than zero inorder to recognize this system as a cogeneration system.

European Directive

Prof. M. Sasso, 27 October 2010, NIST, Gaithersburg, MD, USA

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The Policy instruments proposed in Italy are based on:

• Energy Efficiency obligation: Tradable White Certificate (TWC);

• Renewable Energy obligation: Green Certificate (GC);

• financial instruments: feed-in tariffs, fuel tax reduction;

• net-metering.

Policy instruments

A MCHP unit fuelled by natural gas, satisfying the high efficiency criteria(PES>0), can have different advantages: dispatching priority, TWC, tax reductionon fuel purchased and net metering.

Prof. M. Sasso, 27 October 2010, NIST, Gaithersburg, MD, USA

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Tradable White and Green CertificatesTWCs, introduced by some European Union Member (Italy, UK, France),are tradable certificates, to improve the diffusion of efficient technologiesthat can guarantee primary energy saving.

TWCs depend on the primary energy saving, evaluated in terms of Tonsof Oil Equivalent, TOE, that CHP can guarantee with respect to separate“production”.

A TWCs has actually a value of about 80 €/TOE.

If MCHP system is fuelled by renewable energy (wood pellets, vegetableoil, biogas) the system can obtain Green Certificate or a particular feed-in tariff, on the basis of the choice of the end user.

The value of green certificates is defined by the market, while the valueof feed-in tariff is fixed and depends on the renewable source.

Prof. M. Sasso, 27 October 2010, NIST, Gaithersburg, MD, USA

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As regards the fuel tax reduction a quantity of natural gas equal to 0.25 Nm3 per kWhof electric energy delivered can obtained a tax reduction.

Other mechanisms

Prof. M. Sasso, 27 October 2010, NIST, Gaithersburg, MD, USA

Net-metering has been introduced in Italy to support RET, such as PhotoVoltaic (PV): this mechanism enables customers to use electric energy produced in excess of the their demand by PV system to cover their consumption in period of the day in which PV system does not work.The same mechanism has been extended to MCHP systems that have a rated electric power lower than 200 kW.

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FRIGNANO (CE)MCHP/EHP-MCHP/ABHPplantsin-situ office building

BENEVENTOMCHP/HVAC-DWplantTest- facility

NAPOLIMCHP and MCHP/EHPplantstest-facility for residentialapplication

Research: activity in Campania

Prof. M. Sasso, 27 October 2010, NIST,

Gaithersburg, MD, USA

Since ’90, some research groups are analysing MCHPs and MCCHPs:1993: Field analysis of residential engine driven natural gas heat pump in an office

application", M. Sasso et al., Heat Pumps for Energy Efficiency and EnvironmentalProgress, Ed. J. Bosma, Elsevier Science Publishers, Olanda

1996: The future perspective of micro-CHP, M. Sasso et al., Proc. of III° Int. Conf.Energy and Environment Towards the Year 2000, Capri

2003: test starting of the first microcogenerator AISIN available in Europe with aninternal combustion engine derived by a Gas engine driven Heat Pump.

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Research: MCHP/EHP Test plant_Napoli

data acquisition and elaboration central unit

•Heaters with electric resistances;•Washing machines and wash-dishes with suitable input for preheated water•80 l water heater and 200 l accumulation boiler, both with electric resistances and internal coil heat exchanger•3 fan coils•Heat exchanger for hydronic hot water plant•Sensors for the measurement of electrical, thermal and flow quantities

Prof. M. Sasso, 27 October 2010, NIST, Gaithersburg, MD, USA

Electric power [kW]

2,0 2,5 3,0 3,5 4,0 4,5 5,0 5,5 6,0

Therma

l powe

r [kW]

0

2

4

6

8

10

12

0 10 20 30 40 50 60 70 80

PER as a function of electric and thermal power.

Source: Sasso et al., 2006, “Experimental analysis of micro-cogeneration units based on reciprocating internal combustion engine”, Energy and buildings, Vol. 38, pp. 1417-1422.

Research: MCHP/EHP Test plant_Napoli, results

With the support of:

Prof. M. Sasso, 27 October 2010, NIST, Gaithersburg, MD, USA

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heating mode

3.6 kW

11.7 kW

6.7 kWcooling mode

3.6 kW

2.4 kW

Nominal El. power_6 kW

Nominal Th. power_11.7 kW11.7 kW

5.8 kW

Research: MCHP/EHP Test plant_Napoli

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Prof. M. Sasso, 27 October 2010, NIST, Gaithersburg, MD, USA

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Research: MCHP/EHP Test plant_Napoli, results

0%10%20%30%40%50%60%70%80%90%

100%

0,03 0,43 0,86 1,36 1,83 2,38 3,03 3,43 3,51 3,75

Electric Power MCHP/EHP [kW]

Thermal power MCHP

Cooling power EHP

Electric power MCHP

5

10

15

20

25

30

0,0 0,5 1,0 1,5 2,0 2,5 3,0 3,5 4,0Electric Power MCHP/EHP [kW]

[%]

-15

-10

-5

0

5

10

15

20

25

30

40 50 60 70 80 90 100

Thermal power supplied to the end-user [%][%

]Avoided CO2 emissions

Primary Energy Saving

1818

Prof. M. Sasso, 27 October 2010, NIST, Gaithersburg, MD, USA

1919

Research: MCHP/EHP Office building application_Frignano

ACWC

MCHP

The system supplies thermal (heating and hotwater, 12 kW), electrical (6 kW) and cooling energy(7.5 kW) to a part of a building with offices andlaboratories.

During summer season the MCHP can activatealso an absorption heat pump (10 kW) .

Department DCP&Built Environment Control Laboratory_RiAS

Small polygeneration system based on gas fuelled internal combustion engine

coupled with an Air Cooled Water Chiller, ACWC

Prof. M. Sasso, 27 October 2010, NIST, Gaithersburg, MD, USA

2020

MCHP(Micro Combined Heat and Power)

Coolingpower

Hot water storage

Electricpower

Domestic hotwater

2 Offices

Building

Natural gas

MCHP(Micro Combined Heat and Power)

Hot water storage

Electricpower

Domestic hotwater

2 Offices

Building

Natural gasAbsorption

HeatPump Cooling

power

Research: Frignano, cooling season

Prof. M. Sasso, 27 October 2010, NIST, Gaithersburg, MD, USA

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Research: MCHP/HVAC-DW Test plant_Benevento

advanced desiccant air handling unit coupled toa reciprocating internal combustion.The air handling unit allows, during summeroperation to process 800 m3/h of wet air.

The MCHP supplies thermal energy (12 kW) tothe regeneration of the sorption material (silicagel) of the desiccant wheel.

Cogeneration power (6 kW) is used to supplyelectricity for air handling self consumptions (fans,pumps, …), to drive the electric chiller and finallyfor the external devices. The MCHP/HVAC-DWsystem is able to import or to export electricity tothe external grid.

Prof. M. Sasso, 27 October 2010, NIST, Gaithersburg, MD, USA

2222

TTA7

VENTILATORE 2

E2

E4

FT-HTC2

TTW5 TTW6

VENTILATORE 1

TTA8 E1

DV

R-A

1

Pd1

TTW1 TTW2

FT-CTC

UM

IDIF

ICAT

OR

E

TTA6

FT-HTC1

TTW3 TTW4

E3

VENTILATORE 3

Pd2

DV

R-A

2D

VR

-A3

Pd3

TTA5

MTA2TTA2TTA1

MTA0

TTA4 MTA4

TTA3 MTA3

GAS NATURALEGAS NATURALE

ESAUSTI ES

AU

STI

FT-HB

CA

LDA

IA

CH

ILLE

R

FT-CPMC

HP

E7

FTA1

FTA2

E5

RE

TE ID

RIC

A

Ta1, ... 8

UR2, ... 5

Tw1, ... 6 temperatura acqua

temperatura aria

Va1,2 velocità dell'aria

SIEMENS

SIEMENS

SIEMENS

UR1 umidità relativa aria esterna HUMITRAC

GESENSING

GESENSING

umidità relativa da condotto HUMITRAC

Vw1, ... 3 portata volumetrica acqua SF10 DWYER

Pd1, ... 3 pressione differenziale 694 INDUSTRIETECH.

Mg1,2 portata massica gas BAGGI

E1, ... 9 contatore energia elettrica GOSSEN M.

E6

PO

MPA

UM

ID.

MTA1

RUOTADEUMIDIFICATRICE

FILT

RO

1

FILT

RO

2

SCAMB.

FILT

RO

3

BA

TTE

RIA

FR

ED

DA

BA

TTE

RIA

C

ALD

A 1

BA

TTE

RIA

C

ALD

A 2

E8E7

UNITA' DI TRATTAMENTO ARIA

ARIA DIRIGENERAZIONE

ARIA DIPROCESSO

ARIA DIRAFFREDDAMENTO

ARIA DIPROCESSO

ARIA DIRAFFREDDAMENTO

ARIA DIRIGENERAZIONE

1 2

3 4

1567

18

9

w1 w2w5 w6 w3w4 w7

ARIA DI RAFFREDDAMENTO

ARIA DI RAFFREDDAMENTO

Ta

Tw

UR

UR

Va

Pd

E

VALVOLA A SARACINESCA

VALVOLA DI BILANCIAMENTO

FILTRO

LEGENDA SENSORI

LEGENDA ACCESSORI

VALVOLA A TRE VIE

POMPA

E9

Process AirCooling AirRegeneration Air

Research: Benevento, Experimental test plant

Prof. M. Sasso, 27 October 2010, NIST, Gaithersburg, MD, USA

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The following analysis have been

carried out:

Identification of outdoor air

conditions that give a positive PES;

Sensitivity analysis: PES as a

function of electric grid efficiency.

Source: G. Angrisani, F. Minichiello, C. Roselli,M. Sasso, Experimental investigation tooptimise a desiccant HVAC system coupled toa small size cogenerator, Applied ThermalEngineering 2010, in press.

0 5 10 15 20 25 30 35 40

Hum

idity

Rat

io [k

g H

2O/k

g dr

y ai

r]

Dry Bulb Temperature [°C]

PES>0

PES<0

RH = 100% 90%

80% 70%

60% 50%

40% 30%

20% 10%

0

10

20

30

40

0.36 0.40 0.44 0.48 0.52 0.56 0.60

PES

[%]

Electric grid efficiency [-]

Research: Benevento, Experimental test plant, results

Prof. M. Sasso, 27 October 2010, NIST, Gaithersburg, MD, USA

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Development I/II

Prof. M. Sasso, 27 October 2010, NIST, Gaithersburg, MD, USA

o Gas Utility: gas utilities plan to supply not only natural gas but also energyconversion systems: Gas cooling technology (ABHP, GHP),microcogenerators) according to an Energy Service COmpany approach

BAXI Ecogen: Stirling Engine 1 kWe

o Manufacturers: many R&D projects are in progress

Development II/II

M. Sasso, October 26th, 2010, NIST, Gaithersburg, USA25

o Standard: testing procedure is in a draft phase to provide testmethods for determining the performance of MCHP.

o This effort is mainly due to:o the quick diffusion of microcogenerators;o the introduction of energy labeling procedure;o the need to define ex-ante their efficiency to quantify the

financial tools to support MCHP diffusion.

Impianti di piccola cogenerazione alimentati a combustibili liquidi e gassosi. Misurazione ex-ante delle prestazioni energetiche(Micro cogeneration plants. Ex-ante analisys of energy performance)

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Conclusions• Distributed MCHP&MCCHP systems allow benefits with respect to the referenceseparate energy “production”:

• primary energy saving;• low pollutant emissions;• reduction of operating costs.

• At the moment small devices based on ICE are available on the market

• Aiming a large diffusion of high efficiency technologies, such as MCHP&MCCHP,in Italy there are the following policy instruments:

• financial instruments, such as economic grants, taxes reduction, feed-intariffs;• Net-metering;• Energy Efficiency and Renewable Energy obligations, such as TradableWhite Certificates and Green Certificates.

• R&D activities are in progress with respect to:• experimental and test analysis;•gas utility;•manufacturers;•standard rating.

Prof. M. Sasso, 27 October 2010, NIST, Gaithersburg, MD, USA

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Prof. Maurizio SassoFacoltà di IngegneriaUniversità degli Studi del Sannio

Tel. +390824305509Fax +390824325246E-mail: sasso@unisannio.it