7_070908 Spray Enhance Presentation Day 2_Zammit.pdf

Spray Cooling for Performance Enhancement of

Air-Cooled CondensersJ.S. MaulbetschM. N. DiFilippoK. D. Zammit

EPRI Advanced Cooling WorkshopCharlotte, North Carolina

August 9, 2008

Alternative Solutions

Hybrid wet-dry systems Commonly used for plume abatement Several design options

Spray-enhanced dry cooling Technology adaptation from

gas turbine units

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

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

Chinese Camp

ACC at Chinese Camp

Sprays in operation

Mist entering fan

Spray Enhancement

Spray Enhancement Test Setup

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

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

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

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

(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

El Dorado Energy Center

El Dorado ACC

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

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

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?