Constant Speed Pump

[salehima]

Hello

I have a MNECB baseline in both eQuest and IES-VE. I looked up the pump power and flow rate in the eQuest .SIM file and calculated the specific pump power which was 562 W/(l/s). I used this number in my HW loop dialog box in ApacheHVAC and tried to keep everything else (supply temp, loop temperature difference, etc) the same between eQuest and IES-VE. I selected a constant speed pump and in the performance curve set C0 to 1 and C1, C2, C3 to zero. Still when I look at the results, in eQuest the pump power is constant, but in IES-VE it modulates with the hot water loop load. Does anyone know why?

Thanks,