Cannot calculate evaporator hot side effectiveness because cold side inlet temperature is out of bounds for hot side fluid.

[ronitd07]

Hello,

I am trying to simulate a heat pump cycle but I get below error when running the code
Cannot calculate evaporator hot side effectiveness because cold side inlet temperature is out of bounds for hot side fluid.

But these are my temperature of the refrigerant which is cold side and the water which is hotside in evaporator
Refrigerant output temp : -0.08
Refrigerant input temp : -1.515681625162756
Water in temp : 7.01002102325026
Water out temp : 3.7

The refrigerant input temperature is very low -1.5 degC than the water inlet temp 7.01 degC to have proper heat transfer.
But I am not able to understand why I get the error for evaporator hot side effectiveness.
Can someone please help.

Thanks,
Ronit

[fwitte]

Hi @ronitd07,

the hot (and cold) side effectiveness values are just postprocessing results. They indicate how near the hot side outlet temperature reached to the theoretical minimum (=cold side inlet temperature). For that, the water (hot side) enthalpy would need to be calculated at the evaporation temperature of the refrigerant. That is outside of the fluid property tables for water in CoolProp, therefore not possible. That is why you get this warning, so nothing to worry about. However, one could consider to downgrade that information to debug instead of prompting a warning... I will think about it for a bit and update you.

Francesco