Tradewinds
10-01-2022, 05:37 PM
Evening all,
Just have a question about the sizing of heat exchangers in water/water heat pumps.
If a system is 'cooling only' and the cooling capacity was 6000BTU then I would select a 6000BTU Evaporator, 6000BTU compressor and a 7500BTU Condenser (cooling capacity +heat of compression).
But what happens when it switches over to heating mode? I imagine this sized indoor coil would then be too small and the system pressures would increase.
So is it better to:
A. Size the coils based on cooling only mode and just let the pressure increase in heating mode
OR
B. Size both of the heat exchangers to the condenser capacity (in cooling mode) and therefore a 6000BTU unit would have 2x 7500BTU heat exchangers. Note that they are fixed speed seawater pumps so the flow rate through the condenser doesnt change and neither does the chilled water flow rate.
Also,
Is there any software that you can recommend to make the component selection process easier.
ie you have a cooling capacity of 6000BTU therefore you need this size compressor, condenser, evaporator etc. Im using Danfoss, Copeland and Bitzer software but was wondering if there is something more specific to reverse cycle air conditioning.
Just have a question about the sizing of heat exchangers in water/water heat pumps.
If a system is 'cooling only' and the cooling capacity was 6000BTU then I would select a 6000BTU Evaporator, 6000BTU compressor and a 7500BTU Condenser (cooling capacity +heat of compression).
But what happens when it switches over to heating mode? I imagine this sized indoor coil would then be too small and the system pressures would increase.
So is it better to:
A. Size the coils based on cooling only mode and just let the pressure increase in heating mode
OR
B. Size both of the heat exchangers to the condenser capacity (in cooling mode) and therefore a 6000BTU unit would have 2x 7500BTU heat exchangers. Note that they are fixed speed seawater pumps so the flow rate through the condenser doesnt change and neither does the chilled water flow rate.
Also,
Is there any software that you can recommend to make the component selection process easier.
ie you have a cooling capacity of 6000BTU therefore you need this size compressor, condenser, evaporator etc. Im using Danfoss, Copeland and Bitzer software but was wondering if there is something more specific to reverse cycle air conditioning.