presentation - ali farhan
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الله بسمالرحيم الرحمن
In the name of God the merciful
AL-Mustansiriyah University College of Engineering Mechanical Engineering Department
Study and Evaluation of the Operation Characteristics for the Condensation Load Distribution in Hybrid Systems on the Condenser
Side By
Ali Farhan Muwayez
(B.Sc.2007)
Previous Studies:
Kutscher and Costenaro (2002): Developed a four pre-cooling methods for supplemental evaporative cooling to boost the summer performance of ACC. Spray nozzles, Munters media, Combination of nozzles and Munters, Direct deluge cooling. Wilber and Zammit (2005): Outlines the problems associated with the operation of ACC. They investigated the performance requirements for ITD and back pressure in the range of (14) to (33.3) °C and (2.5) to (7) Hga, respectively. and the ambient temperature of (-17.7) to (43.3) °C.
Gadhamshetty (2006): pre-cool the inflow air to the ACC by using a chilled water storage system on 171 MW plant. This proposed system saves (2.5 %) of the power without using any water.Tarrad (2010): Developed a numerical model for performance prediction of ACC. The improvement in condenser load was (23%) when the air pre-cooling mode applied to decrease the inflow air temperature from (45) to (28)°C.NR EL (2011): Studied the using of air and water hybrid system to assess how they mitigate the net power decrease in hot ambient.
Previous Studies:
Aims of Study:
1 .building an experimental rig to provide a proper operation conditions for the ACC and WCC.
2 .investigating the performance enhancement of ACC with pre-cooling of inflow air at hot ambient conditions (summer in Iraq).
3 .building a computer program (Theoretical Model) for each of the condenser used in the present work.
4 .Providing an assessment for the advantage of using the combined cooling system to improve the ACC performance
and mitigate the water scarcity effect.
Experimental Apparatus:
An experimental facility was constructed to allow two types of condensing system worked together as a test arrangement. Each one represents a separate unit having all of the specifications and instruments that allows condensation data to be collected over a range of operating conditions. The Apparatus elements are:
1 .Steam Generator.
2 .Condensers (Air Cooled Condenser, Water cooled condenser).
3 .Duct system with Heating unit.
4 .Water Feeding tank with water pump, valves and pipes.
5 .Expansion Valve ( Boiler to condenser line ).
6 .Emergency tank ( Cold and Hot water feeding).
7 .Measurement device: temperatures, pressure and water flow rate.
Photographic views of the experimental test facility.
Steam Generator
Cooler
Duct System Water feeding tank with accessories
Measurements
WCC
ACC
Water Loop
Schematic diagram of experimental set-up.
Steam Generator:
Duct System:
Coiled duct heater /2 pass: 10 kW - 220 V
Wings (by pass preventive)
Air inflow section with instruments
ACC
Experimental Results:Air:Without Pre-cooling:
Inlet DbTemp. : (20.7°C – 42°C)Inlet Wb Temp. : (14 °C-23.3°C)Boiler Pressure: (1.2 – 1.8) baraAir flow rate: (1200 – 2400) CFMWith Pre-cooling:
Inlet DbTemp.:(27°C-37°C)Inlet Wb Temp.: (24.5 °C-23°C)
Wb efficiency ≈ 67% Boiler Pressure;(1.2-1.8) baraAir flow rate : (1200- 2400) CFM
Water:Inlet Temperature: (15°C-23°C)Flow rate: (200 – 1000) L/hBoiler Pressure: fixed (1.8 bara)
Hybrid:Air Inlet DbTemp.: (31°C- 42°C)Air Inlet Wb Temp.: (21 °C-24°C)Air flow rate: fixed 1200 CFMWater inlet temperature; 30°C
Water flow rate: (20- 40)% of TFR.*Boiler pressure: fixed (1.8 bara).
Cooling Mode
Db :Dry-bulb
Wb :Wet-bulb
TFR: Total flow rate
Steam Load Variation:
15
17.5
20
22.5
25
27.5
30
32.5
35
37.5
19 22 25 28 31 34 37 40 43 46
Entering Air Dry-Bulb Temperature (°C)
Con
dens
er S
team
Loa
ding
(k
g/hr
)
Air Velocity (6 m/s)
Air Velocity (3 m/s)
Poly. (Air Velocity (6m/s))
Poly. (Air Velocity (3m/s))
15
17.5
20
22.5
25
27.5
30
32.5
35
37.5
19 22 25 28 31 34 37 40 43 46
Entering Air Dry-Bulb Temperature (°C)
Con
dens
er S
team
Loa
ding
(k
g/hr
)
Air Velocity (6 m/s)
Air Velocity (3 m/s)
Poly. (Air Velocity (6m/s))
Poly. (Air Velocity (3m/s))
15
17.5
20
22.5
25
27.5
30
32.5
35
37.5
19 22 25 28 31 34 37 40 43 46
Entering Air Dry-Bulb Temperature (°C)
Con
dens
er S
team
Loa
ding
(k
g/hr
)
Air velocity (6 m/s)
Air velocity (3 m/s)
Poly. (Air velocity (6m/s))
Poly. (Air velocity (3m/s))
15
17.5
20
22.5
25
27.5
30
32.5
35
19 22 25 28 31 34 37 40 43 46
Entering Air Dry-Bulb Temperature (°C)
Con
dens
er S
team
Loa
ding
(k
g/hr
)
Air Velocity (6 m/s)
Air Velocity (3 m/s)
Poly. (Air Velocity (6m/s))
Poly. (Air Velocity (3m/s))
20.7°C – 21%
31°C- 27.3%
42°C-23.5%
20.7°C – 19.4%
31°C- 27.8%
42°C-24.3%
20.7°C – 18%
31°C- 27%
42°C-20.3%
20.7°C – 20.9%
31°C- 24%
42°C-16.4%
B.Pr. : 1.8 bara B.Pr. : 1.6 bara
B.Pr. : 1.2 baraB.Pr. : 1.4 bara
Condenser Load Variation:
10
12
14
16
18
20
22
24
19 22 25 28 31 34 37 40 43 46
Entering Air Dry-Bulb Temperature (°C)
Con
dens
er L
oad
(kW
)
Air Velocity (6 m/s)
Air Velocity (3 m/s)
Poly. (Air Velocity (3m/s))Poly. (Air Velocity (6m/s))
10
12
14
16
18
20
22
24
19 22 25 28 31 34 37 40 43 46
Entering Air Dry-Bulb Temperature (°C)
Con
dens
er L
oad
(kW
)
Air Velocity (6 m/s)
Air Velocity (3 m/s)
Poly. (Air Velocity (3m/s))Poly. (Air Velocity (6m/s))
10
12
14
16
18
20
22
24
19 22 25 28 31 34 37 40 43 46
Entering Air Dry-Bulb Temperature (°C)
Con
dens
er L
oad
(kW
)
Air Velocity (6 m/s)
Air Velocity (3 m/s)
Poly. (Air Velocity (3m/s))Poly. (Air Velocity (6m/s))
10
12
14
16
18
20
22
19 22 25 28 31 34 37 40 43 46
Entering Air Dry-Bulb Temperature (°C)
Con
dens
er L
oad
(kW
)
Air Velocity (6 m/s)
Air Velocity (3 m/s)
Poly. (Air Velocity (3m/s))Poly. (Air Velocity (6m/s))
20.7°C- 21.4%
31°C – 27.2%
42°C – 23.7%
20.7°C- 19.2%
31°C – 27%
42°C – 21%
20.7°C-21.4%
31°C – 24%
42°C – 16.8%
20.7°C- 19.2%
31°C – 27.9%
42°C – 24.6%
B.Pr.: 1.8 bara
B.Pr.: 1.2 baraB.Pr.: 1.4 bara
B.Pr.: 1.6 bara
Steam load variation with entering air temperature:
Experimental results for steam loading variation exhibited a non-linear variation with entering air dry-bulb temperature to the ACC. By using the group average method to fit an approximate straight line described the steam loading variation under recommended air velocity of (3 m/s) as:
naim KT
In the mathematical work that deal with the steam loading variation with air entering dry-bulb temperature. Tarrad (2010) found that the ACC steam loading varies linearly with entering air temperature with constants (K = 759.12 , n = -0.4644 ).
K - range (163.79 – 97.82) , n - range (- 0.5490) to (- 0.4061)
Pre-cooling of Inlet Air:Steam Loading Condenser Load
3) m/s( 6 ) m/s(
10
11
12
13
14
15
16
17
18
22 25 28 31 34 37 40
Air Entering Dry-Bulb Temperature (°C)
Co
nd
ense
r L
oad
(kW
)
Boiler Pr. = 1.8 bara
Boiler Pr. = 1.6 bara
Boiler Pr. = 1.4 bara
Boiler Pr. = 1.2 bara
35.4°C-27°C:
18.7%- 22%
26% - 28.8% 10
12
14
16
18
20
22
22 25 28 31 34 37 40
Air Entering Dry-Bulb Temperature (°C)
Co
nd
en
ser
Lo
ad
(kW
)
Boiler Pr. = 1.8 bara
Boiler Pr. = 1.6 bara
Boiler Pr. = 1.4 bara
Boiler Pr. = 1.2 bara
35.4°C-27°C:
16.4%- 16.7%
18.2% - 20.9%
15
19
23
27
31
20 23 26 29 32 35 38 41
Entering Air Dry-Bulb Temperature (°C)
Co
nd
ense
r S
team
Lo
adin
g (
kg/h
r)
Boiler Pr. =1.8 bara
Boiler Pr. =1.6 bara
Boiler Pr. =1.4 bara
Boiler Pr. =1.2 bara
35.4°C-27°C:
18.4%- 22%
25.8% - 31.3%
15
19
23
27
31
35
20 23 26 29 32 35 38 41
Entering Air Dry-Bulb Temperature (°C)
Co
nd
en
ser
Ste
am
Lo
ad
ing
(kg
/hr) Boiler Pr. = 1.8 bara
Boiler Pr. = 1.6 bara
Boiler Pr. = 1.4 bara
Boiler Pr. = 1.2 bara
35.4°C-27°C:
16%- 16.4%
18% - 23.4%
At 27°C:
23.5 - % 20.6%
At 27°C:
19.5 - % 20.6%
Water Cooled Condenser:
Steam Loading Condenser Load
0
2.5
5
7.5
10
12.5
15
17.5
20
22.5
25
27.5
200 400 600 800 1000
Cooling Water Flow Rate (L/hr)
Cond
ense
r Ste
am L
oadi
ng (k
g/hr
)
Inlet Water at 15 °C
Inlet Water at 19 °C
Inlet Water at 23 °C
0
3
6
9
12
15
18
21
200 400 600 800 1000
Cooling Water Flow Rate (L/hr)
Con
dens
er L
oad
(kW
)
Inlet Water at 15°C
Inlet Water at 19°C
Inlet Water at 23°C
Hybrid (ACC and WCC):200 L/h 400 L/h
0
2.5
5
7.5
10
12.5
15
17.5
20
22.5
25
27.5
Co
nd
en
se
r S
tea
m L
oa
din
g
(kg
/hr)
31 36.5 38.3 42
Entering Air Dry-Bulb Temperature (°C)
ACC WCC
0
2.5
5
7.5
10
12.5
15
17.5
20
22.5
25
27.5
Co
nd
en
se
r S
tea
m L
oa
din
g
(kg
/hr)
31 36.5 38.3 42
Entering Air Dry-Bulb Temperature (°C)
ACC WCC
0
2.5
5
7.5
10
12.5
15
17.5
Co
nd
ense
r L
oad
(kW
)
31 36.5 38.3 42
Entering Air Dry-Bulb Temperature (°C)
ACC WCC
0
2.5
5
7.5
10
12.5
15
17.5
Co
nd
ense
r L
oad
(kW
)
31 36.5 38.3 42
Entering Air Dry-Bulb Temperature (°C)
ACC WCC
9.9-% 10.8%-16.4%
5.4-% 15.5-% 17.9%-28.2%
ACC and WCC Percentage Contribution in Total Load:
0
10
20
30
40
50
60
70
80
15.5 16 16.5 17 17.5 18
Total Hybrid System Load (kW)
Pe
rce
nta
ge
Co
ntr
ibu
tio
n (
%)
ACC
WCC
Linear (ACC)
Linear (WCC)
42 °C38.3 °C
36.5 °C
31°C
0
10
20
30
40
50
60
70
80
15.5 16 16.5 17 17.5 18
Total Hybrid System Load (kW)
Perc
en
tag
e C
on
trib
uti
on
(%
)
ACC
WCC
Linear (ACC)
Linear (WCC)
42 °C38.3 °C
36.5 °C
31°C
40
45
50
55
60
65
70
75
80
85
15 20 25 30 35
Condenser Steam Loading (kg/hr)
Ove
rall
Heat
Tra
nsfe
r Coe
ffic
ient
(W
/m2.
°C)
U = 60
U = 77.5
OHTC ( U ): At different operation conditions ( Temperatures, steam loading ).
Water: 200 l/h – 30°C Water: 400 l/h – 30°C
50
55
60
65
70
75
80
85
90
95
100
15 17.5 20 22.5 25 27.5 30 32.5 35 37.5
Condenser Steam Loading (kg/hr)
Ove
rall
Heat
Tra
nsfe
r Coe
ffici
ent
(W/m
2.°C
)
U = 89
U = 64.74
0
100
200
300
400
500
600
700
800
900
1000
5 7.5 10 12.5 15 17.5 20 22.5 25 27.5
Condenser Steam Loading (kg/hr)
Ove
rall
Hea
t Tra
nsfe
r C
oeffi
cien
t (W
/m2
.°C
)
U = 196
U = 835
ACC- (3 m/s) ACC- (6 m/s) WCC
Model Representation:
Air Cooled Condenser
Water Cooled Condenser
OHT (U) Theoretical Samples:
60
62
64
66
68
70
72
74
76
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35
Tube Length (m)
Ove
rall
Hea
t T
ran
sfer
Co
effi
cien
t (W
/m2.
°C)
Row 1
Row 2
60
65
70
75
80
85
90
95
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35
Tube Length (m)
Ove
rall
Hea
t T
ran
sfer
Co
effi
cien
t (W
/m2.
°C)
Row 1
Row 2
0
100
200
300
400
500
600
700
800
900
1000
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35
Tube Length (m)
Ove
rall
He
at
Tra
nsfe
r C
oe
ffic
ien
t (W
/m2.
°C)
WCC
ACC
Comparison of ( Texit and Q):
10
15
20
25
10 15 20 25
Experimental Load (kW)
Th
eore
tica
l L
oad
(kW
)
Thermal Load (kW)
+ 12%
-5%
30
35
40
45
50
55
60
65
70
30 35 40 45 50 55 60 65 70
Experimental Exit Temperature (°C)
Th
eo
reti
cal
Exit
Tem
pera
ture
(°C
)
Air Exit Temperature (°C)
- 5%
5
7
9
11
13
15
17
19
5 7 9 11 13 15 17 19
Experimental Load (kW)
Th
ero
reti
cal
Lo
ad
(kW
)
Thermal Load (kW)
+ 13%
-10%
20
25
30
35
40
45
50
55
60
20 25 30 35 40 45 50 55 60
Experimental Exit Temperature (°C)
Th
eo
reti
cal
Exit
Tem
pera
ture
(°C
)
Water Exit Temperature (°C)
- 5%
+ 5%
Conclusions:
1. The increasing of air flow rate by (50%) increased average steam loading by (17.5%) and corresponding load by (17.6%) with air temperature reduction of (42-20.7 °C).
2. Pre-cooling of air gives an increase in ACC steam loading of (0.58-0.66) kg/hr per each degree reduction of air temperature between (37.5°C) to (27°C).
3. Increasing of air flow rate with pre-cooling increased the average steam loading by (18.2%) and thermal load by (18.46%) with air temperature reduction of (37.5°C) to (27°C).
4. At air flow velocity of (3 m/s) the ACC load increased by (11%) with temperature reduction from (31 to 20.7°C) while the increased in load was (33.6%) with temperature reduction from (42 to 20.7°C) %). Thus, above (30°C) ACC need an assist cooling strategy to reduce the performance deterioration.
5. Increasing of the water flow rate from (200-1000 L/h) increase the steam loading by (54%) and (48%) for inlet temperature variation from (15°C) to (23°C).
6. With hybrid combination steam loading of ACC at (42°C) increased by (14.2%) and thermal load by (22%) with water assist.
Thank You
Ali Farhan Muwayez
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