Chiller-Tower Optimization Do It Right! - TRANE KOREA · 2008-06-09 · 400-ton [1400 kW] chiller 0.58 kW/ton [6.06 COP] 85°-95°F [29.4°-35°C] condenser water temperature differential

© American Standard Inc. 2006© American Standard Inc. 2006

Chiller–Tower Optimization …

Do It Right!

Chiller–Tower Optimization …

Do It Right!

The Trane CompanyLa Crosse, Wisconsin


chiller–tower optimizationThe Question …

“알맞은”냉각수온도는몇도인가?


Simple Case(Constant Water Flow)

LoadCW TempChiller Design

Wet BulbLoadCW TempTower Design


Link Is Condenser Water Temperature

CondenserWater Temp Chiller kW Tower kW Total kW

??


Or Said Another Way …

0

50

100

150

200

250

300

350

72 73 74 75 76 77 78 79 80 81 82 83 84 85

Chiller kWTower kWTotal kW

Condenser Water Temperature

kW

( 29.5 C)( 22.5 C)


각각의시스템구성요소보다는전체 System 관점에서생각해야한다.


chiller–tower optimizationCondenser Water Control

Hot? (85°F [30°C])

Cold? (55°F [13°C])

Wet Bulb + 5°F [3°C]?

Optimized?


Optimization? Optimization?


a simple case …Component Models

ChillerChiller design

ARI-certified selections

Polynomials (다항식)f(Design kW, % Load)f(CW temperature)

ConstantsCondenser water flowChilled water temperature

Cooling TowerTower design

CTI-certified selections

FunctionsWet bulbHeat rejectedTower airflow

ConstantCondenser water flow


Where’s The Meter?

A. On the building.

B. On the chiller.


What’s The Bottom Line?

400-ton [1400 kW] chiller

0.58 kW/ton [6.06 COP]

85°-95°F [29.4°-35°C] condenser water temperature differential

78°F [25.6°C] designwet-bulb temperature

“ARI unloading” …Full load 17% of the time75% load 39% of the time50% load 33% of the time25% load 11% of the time

Economics …$0.08 per kWh$12.00 per kW1,300 equivalent full-load hours


The Bottom Line … $

Minimumtempera ture

Design CW WB + 5degrees

Optimized$47,500.00

$48,000.00

$48,500.00

$49,000.00

$49,500.00

$50,000.00

$50,500.00

$51,000.00

Minimumtempera ture


Optimized

Chiller+Tower Yearly Estimated Operating Cost OK


The Bottom Line … 71°F WB

Minimumtempera ture


Optimized$42,500.00

$43,000.00

$43,500.00

$44,000.00

$44,500.00

$45,000.00

$45,500.00

$46,000.00

$46,500.00

$47,000.00

Minimumtempera ture


Optimized



Minimumtempera ture

Des ign CW WB + 5degrees

Optimized$39,500.00

$40,000.00

$40,500.00

$41,000.00

$41,500.00

$42,000.00

$42,500.00

$43,000.00

$43,500.00

$44,000.00

$44,500.00

Minimumtempera ture

Des ign CW WB + 5degrees

Optimized


The Bottom Line … 65°F WB


But The Chiller Must Work Harder!


where’s the meter?The Only Possible Response …

On the building!On the building!


chiller–tower optimizationThe REAL Bottom Line …

Our customers shouldn’t have to pay more!


Plant Power vs CWS

0.0

200.0

400.0

600.0

800.0

1,000.0

1,200.0

60 62 64 66 68 70 72 74 76 78 80 82 84 86 88

Condenser Water Setpoint ( )캟

Pow

er (k

W)

Lowest condenser water temperature available from tower at this load and wet-bulb temperature

Chillers cannot meet load above this condenser water temperature

Optimal operation

1,550 tons, 65 Wet-bulb 캟

T t

1,160 tons, 59 Wet-bulb 캟

T

730 tons, 54 Wet-bulb Temperature캟

Braun, Diderrich

Hydeman, Gillespie, Kammerud

Schwedler,ASHRAE Journal

Hydeman, et. al. Pacific Gas and Electric. Used with permission.

chiller–tower optimizationIs It Real?


chiller–tower optimizationHow Do You Do It?

With real-life controls!


chiller–tower optimizationHow Do You Calculate Savings?

System Analyzer™


chiller–tower optimizationHow Do You Calculate Savings?

TRACE® 700


chiller–tower optimizationWhat Else Should You Know?

신규또는개보수시설모두적용가능

About 30 installations

최적의 set point는

냉동기 type에따라변한다

Two-speed 또는variable-speed cooling tower fan이좋은방법이다.


chiller–tower optimizationIn Summary …

냉각수온도가저온일수록더이로운것은아니다.

중요한것은최적운전제어이며이를통해비용절감효과를거둘수있다.

비용절감은사실이고측정되어질수있다.

다양한제어방식이가능하다!


Do it right!Chiller–Tower Optimization

Questions and answers …

Chiller-Tower Optimization Do It Right! - TRANE KOREA · 2008-06-09 · 400-ton [1400 kW] chiller 0.58 kW/ton [6.06 COP] 85°-95°F [29.4°-35°C] condenser water temperature differential

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