Spray Cooling for Performance Enhancement of Air-Cooled Condensers - - PowerPoint PPT Presentation

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Spray Cooling for Performance Enhancement of Air-Cooled Condensers J.S. Maulbetsch M. N. DiFilippo K. D. Zammit EPRI Advanced Cooling Workshop Charlotte, North Carolina August 9, 2008 Alternative Solutions Hybrid wet-dry systems

SLIDE 1

Spray Cooling for Performance Enhancement of Air-Cooled Condensers

J.S. Maulbetsch

M. N. DiFilippo
K. D. Zammit

EPRI Advanced Cooling Workshop Charlotte, North Carolina August 9, 2008

SLIDE 2

Alternative Solutions

Hybrid wet-dry systems

– Commonly used for plume abatement – Several design options

Spray-enhanced dry cooling

– Technology adaptation from gas turbine units

SLIDE 3

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

SLIDE 4

Spray-Enhanced Dry Cooling

Without pre-cooling, ambient T increase from ~55º to 90ºF 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

SLIDE 5

Chinese Camp

SLIDE 6

ACC at Chinese Camp

SLIDE 7

Sprays in

peration

SLIDE 8

Mist entering fan

SLIDE 9

Spray Enhancement

SLIDE 10

SLIDE 11

Spray Enhancement Test Setup

SLIDE 12

Hot Day Performance

Average DB Temperature Profiles

Crockett 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

DB Temperature, F

Deck DB Fan Outlet DB B Exch DB Glycol Deck WB Fan Oultlet WB

SLIDE 13

Maximum Cooling Effect

Maximum Cooling Effect for Cell B Airflow 2 4 6 8 10 12 14 16 18 5 10 15 20 25

Wet Bulb Depression, deg F Cooling Effect, deg F

10 gpm 15 gpm 20 gom 25 gpm 5 gpm

SLIDE 14

Cooling Effect Results

Cooling Effect vs. Wet Bulb Depression

2 4 6 8 10 12 14 13.5 14 14.5 15 15.5 16 16.5

Wet Bulb Depression, deg F

Cooling Effect, deg F

Spray rate = 19 gpm

SLIDE 15

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 te

S ingle-C ell T es ting, C roc k ett 2 4 6 8 10 12 14 50 100 150 200 250 300 350 400 450 500 (T D eck D B -T D ec kW B )x S p ra y R a te , F x g p m TDeckDB-TFanDB , F

Data Correlation

SLIDE 16

(T De ck DB-T Fan DB)/(T De ck DB-T De ck W B) v s S p ra y R a te

S ingle-C ell T es ting, C roc k ett 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 (TDeckDB-TFanDB)/(TDeckDB-TDeckWB)

Correlation vs. Spray Rate

SLIDE 17

El Dorado Energy Center

SLIDE 18

El Dorado ACC

SLIDE 19

Effect on Backpressure

Turbine Back Pressure vs Spray Rate - July

ElDorado LLC 2 3 4 5 6 7 20 40 60 80 100 120 Spray Rate, gpm/cell Back Pressure, "Hg

Amb DB = 115 F 110 F 105 F 100 F 95 F 90 F

Steam Flow = 1,067,000 #/hr

SLIDE 20

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 Recov Power, MWHr

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

SLIDE 21

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