7_070908 Spray Enhance Presentation Day 2_Zammit.pdf
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Transcript of 7_070908 Spray Enhance Presentation Day 2_Zammit.pdf
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Spray Cooling for Performance Enhancement of
Air-Cooled CondensersJ.S. MaulbetschM. N. DiFilippoK. D. Zammit
EPRI Advanced Cooling WorkshopCharlotte, North Carolina
August 9, 2008
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Alternative Solutions
Hybrid wet-dry systems Commonly used for plume abatement Several design options
Spray-enhanced dry cooling Technology adaptation from
gas turbine units
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Spray-Enhanced Dry Cooling
In gas turbines, inlet air cooling racks used to enhance efficiency Pre-cooling spray nozzles
introduce fine mist
In dry cooling systems, approach could be applied to pre-cool inlet air Reduce capacity loss Water use intermittent; rate
~25% full wet cooling
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Spray-Enhanced Dry Cooling
Without pre-cooling, ambient T increase from ~55 to 90F reduces capacity For 235-MW unit, lose 10 to
12 MW (~5%)
If air pre-cooled to 70% relative humidity, capacity loss reduced For 235-MW unit, lose only
3 to 5 MW
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Chinese Camp
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ACC at Chinese Camp
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Sprays in operation
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Mist entering fan
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Spray Enhancement
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Spray Enhancement Test Setup
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Hot Day Performance
Average DB Temperature ProfilesCrockett Single-Cell Spray Testing
60
65
70
75
80
85
90
95
100
12:00 PM 1:00 PM 2:00 PM 3:00 PM 4:00 PM 5:00 PM
D
B
T
e
m
p
e
r
a
t
u
r
e
,
F
Deck DB
Fan Outlet DB
B Exch DB
Glycol
Deck WB
Fan Oultlet WB
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Maximum Cooling Effect
Maximum Cooling Effect for Cell B Airflow
02
468
101214
1618
0 5 10 15 20 25
Wet Bulb Depression, deg F
C
o
o
l
i
n
g
E
f
f
e
c
t
,
d
e
g
F
10 gpm 15 gpm 20 gom 25 gpm 5 gpm
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Cooling Effect Results
Cooling Effect vs. Wet Bulb Depression
0
2
4
6
8
10
12
14
13.5 14 14.5 15 15.5 16 16.5
Wet Bulb Depression, deg F
C
o
o
l
i
n
g
E
f
f
e
c
t
,
d
e
g
F
Spray rate = 19 gpm
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T De ck DB-T Fan DB v s (T De ck DB-T De ck W B) x S p ra y R a teS ing le -C e ll T es t ing , C roc k e t t
0
2
4
6
8
10
12
14
0 50 100 150 200 250 300 350 400 450 500
(T D e c k D B -T D e c k W B )x S p ra y R a te , F x g p m
T
D
e
c
k
D
B
-
T
F
a
n
D
B
,
F
Data Correlation
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(T De ck DB-T Fan DB)/(T De ck DB-T De ck W B) v s S p ra y R a teS ing le -C e ll T es t ing , C roc k e t t
0 .0
0 .2
0 .4
0 .6
0 .8
0 .0 5 .0 10 .0 15 .0 20 .0 25 .0
S p ra y R a te , g p m
(
T
D
e
c
k
D
B
-
T
F
a
n
D
B
)
/
(
T
D
e
c
k
D
B
-
T
D
e
c
k
W
B
)
Correlation vs. Spray Rate
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El Dorado Energy Center
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El Dorado ACC
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Effect on Backpressure
Turbine Back Pressure vs Spray Rate - JulyElDorado LLC
2
3
4
5
6
7
0 20 40 60 80 100 120
Spray Rate, gpm/cell
B
a
c
k
P
r
e
s
s
u
r
e
,
"
H
g
Amb DB = 115 F
110 F
105 F
100 F
95 F
90 F
Steam Flow = 1,067,000 #/hr
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Power Recovery
Recovered Power vs Start Temp vs Spray Period
2,400
2,600
2,800
3,000
3,200
3,400
3,600
3,800
4,000
85 90 95 100 105
Start Temperature for Spraying, F
R
e
c
o
v
P
o
w
e
r
,
M
W
H
r
10am to 7:59pm
10am-8:59pm
10am-6:59pm
11am-6:59pm
Water Budget = 35,210,000 gallons
Spray Period - 10am-8:59pm
Water Budget = 26,410,000 gallons
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Now What?
Showstoppers
- Surface wetting
- Rainback
- Cost (Approx $0.5 M for 40 cell, plus $0.7 M to 2.0M for water treatment and storage)
Approaches
- Nozzle choice/location
- Flow modeling
- Demisters
Spray Cooling for Performance Enhancement of Air-Cooled CondensersAlternative Solutions Spray-Enhanced Dry CoolingSpray-Enhanced Dry CoolingChinese CampACC at Chinese CampSprays in operationMist entering fanSpray EnhancementSlide Number 10Spray Enhancement Test SetupHot Day PerformanceMaximum Cooling EffectCooling Effect ResultsData CorrelationCorrelation vs. Spray RateEl Dorado Energy CenterEl Dorado ACCEffect on BackpressurePower RecoveryNow What?