calculation relating chiller efficiency to condenser water temperatur 1

[watrdoc]

Can anyone give me an equation relating increase in chiller efficiency to a reduction in condenser water temperature?

 

[KiwiMace]

The short answer is about 2% per degree around the nominal temperature at full load.

The added value answer is that the percentage changes by an even 5% per degree after this, or about 0.1% more or less. ie. 1.9%, 2.0%, 2.1% for 31, 30, 29degC resp. at full load.

The long form answer based on a 490ton york watercooled centrif I had a lot of data from, and a big formula:
General Form of Formula
=b0+(b1*H)+(b2*H^2)+(b3*H*T)+(b4*H*T^2)+(b5*T*H^2)+(b6*T^2*H^2)

Cut and pastable formula for 490RT Chiller:
Y1=71.0386772738436+(0.0269652151347899*H)+(-2.39003754235369E-05*H*H)+(-0.00041048542279596*H*T)+(9.03792835699315E-05*H*T*T)+(3.99319518356307E-06*T*H*H)+(-8.16652652582714E-08*T*T*H*H);}
Y1=71.0386772738436+(0.0269652151347899*H)+(-2.39003754235369E-05*H*H)+(-0.00041048542279596*H*T)+(9.03792835699315E-05*H*T*T)+(3.99319518356307E-06*T*H*H)+(-8.16652652582714E-08*T*T*H*H);}

T is CWST in degC, H is (part) load in kW.