Centrifugal R-134a Air Conditioning Unit
Centrifugal R-134a Air Conditioning Unit
(OP)
Hello all,
I have a 200 ton unit designed for chilled water at 720 gpm and 44F supply.
What happens to the compressor power consumption/efficiency if I increase the flow to 900 gpm but keep the same load and supply temperature?
Simply put, from a kW/ton perspective is it better to have a higher inlet(return) temperature and lower flow? (Assuming UA of the evaporator is constant)
Thanks in advance
I have a 200 ton unit designed for chilled water at 720 gpm and 44F supply.
What happens to the compressor power consumption/efficiency if I increase the flow to 900 gpm but keep the same load and supply temperature?
Simply put, from a kW/ton perspective is it better to have a higher inlet(return) temperature and lower flow? (Assuming UA of the evaporator is constant)
Thanks in advance





RE: Centrifugal R-134a Air Conditioning Unit
Aside from addressing the other issues relating to pushing 25% excess flow through a chiller, Your system efficiency will also be reduced: You are pumping more water through the system, your end-user equipment delta-t's are reduced, and your system pressure is higher - particularly in your chiller.
RE: Centrifugal R-134a Air Conditioning Unit
Q = m Cp Delta T.
If "m" goes up, Delta T come down.
HVAC68
RE: Centrifugal R-134a Air Conditioning Unit
I understand that I have decreased overall efficincy because the chill water (CW) flow and pumping power is greater than the design flow for the given load.
I am trying to build a case to add a heat exchanger with a much greater temperature rise than that normally seen with an HVAC cooling coil.
I have power consumption curves for varying condenser cooling water inlet and CW outlet temperatures. But I don't have any for varying CW inlet temperature.
If the evaporator is designed for an average (CW)temperature of 47.35 F with an exit temperature of 44F what happens to power consumption if the CW inlet (and average) temperature is increased for the same load?
RE: Centrifugal R-134a Air Conditioning Unit
Chillers also reduce efficiency for both increased Cond water supply temp and reduced CHW supply temp.