Presentation - Ali Farhan

‫الرحمن‬ ‫هللا‬ ‫بسم‬‫الرحيم‬
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.

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) bara
Air flow rate: (1200 – 2400) CFM
With 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) bara
Air flow rate : (1200- 2400) CFM
Water:
Inlet Temperature: (15°C-23°C)
Flow rate: (200 – 1000) L/h
Boiler 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 CFM
Water 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)
CondenserSteamLoading
(kg/hr)
Air Velocity (6 m/s)
Poly. (Air Velocity (6
m/s))
m/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
(°C)
(kg/hr)
m/s))
m/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
(°C)
(kg/hr)
Air velocity (6 m/s)
Air velocity (3 m/s)
Poly. (Air velocity (6
m/s))
Poly. (Air velocity (3
m/s))
15
17.5
20
22.5
25
27.5
30
32.5
35
19 22 25 28 31 34 37 40 43 46
(°C)
(kg/hr)
m/s))
m/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)
CondenserLoad(kW)
m/s))
m/s))
10
12
14
16
18
20
22
24
19 22 25 28 31 34 37 40 43 46
CondenserLoad(kW)
m/s))
m/s))
10
12
14
16
18
20
22
24
19 22 25 28 31 34 37 40 43 46
CondenserLoad(kW)
m/s))
m/s))
10
12
14
16
18
20
22
19 22 25 28 31 34 37 40 43 46
CondenserLoad(kW)
m/s))
m/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:
n
aim 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)
CondenserLoad(kW)
Boiler Pr. = 1.8 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)
CondenserLoad(kW)
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
CondenserSteamLoading(kg/hr)
Boiler Pr. =1.8 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
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)
Inlet Water at 15 °C
0
3
6
9
12
15
18
21
200 400 600 800 1000
Cooling Water Flow Rate (L/hr)
CondenserLoad(kW)
Inlet Water at 15°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
(kg/hr)
31 36.5 38.3 42
ACC WCC
0
2.5
5
7.5
10
12.5
15
17.5
20
22.5
25
27.5
(kg/hr)
31 36.5 38.3 42
ACC WCC
0
2.5
5
7.5
10
12.5
15
17.5
CondenserLoad(kW)
31 36.5 38.3 42
ACC WCC
0
2.5
5
7.5
10
12.5
15
17.5
CondenserLoad(kW)
31 36.5 38.3 42
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)
PercentageContribution(%)
ACC
WCC
Linear (ACC)
Linear (WCC)
42 °C
38.3 °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)
PercentageContribution(%)
ACC
WCC
Linear (ACC)
Linear (WCC)
42 °C
38.3 °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)
OverallHeatTransferCoefficient
(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
(W/m2.°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
OverallHeatTransferCoefficient(W/m2.°C)
U = 196
U = 835
ACC- (3 m/s) ACC- (6 m/s) WCC

Model Representation:
Air 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)
(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)
(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)
OverallHeatTransferCoefficient(W/m2.°C)
WCC
ACC

Comparison of ( Texit and Q):
10
15
20
25
10 15 20 25
Experimental Load (kW)
TheoreticalLoad(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)
TheoreticalExitTemperature(°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)
TheroreticalLoad(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)
TheoreticalExitTemperature(°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.

Presentation - Ali Farhan

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