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NREL / EnergyPlus

EnergyPlus™ is a whole building energy simulation program that engineers, architects, and researchers use to model both energy consumption and water use in buildings.
https://energyplus.net
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WaterHeater Heatpump sizing issue #8922

Open wta12 opened 3 years ago

wta12 commented 3 years ago

Issue overview

I tried to hard sized WaterHeater:HeatPump:PumpedCondenser object but still get bypass factor Psychrometric function calculation error. There is similar issue (#8412) but it's Stratified Tank object. Not sure if WaterHeater:HeatPump:PumpedCondenser/Coil:WaterHeating:AirToWaterHeatPump:Pumped have same issue - The error log did not point to particular object. Did turn off sizing option in simulation control but keeps fail

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Myoldmopar commented 3 years ago

EnergyPlus was actually giving quite a bit of information in the error file. The combination of flow rates, shr, and power were causing a calculation of outlet conditions to be invalid. The heating rates seemed pretty high. The two heat pump objects in the file were named 40gal Heat Pump Water Heater - 8kBtu/hr Coil and 40gal Heat Pump Water Heater - 31kBtu/hr Coil. But they had rated heating capacities of 36708 W and 9209 W, respectively. Unless I'm missing something those are not right. 30kBtu/h is more like 9085 W. 9085 W still caused an invalid outlet condition, but it was much closer. So I put the rated heating capacity at 8500 W and that heat pump worked fine. I then scaled the other heat pump accordingly, down from 9209 to 2500 W and the whole simulation works just fine. No other changes required.

wta12 commented 3 years ago

@Myoldmopar : Thanks, I corrected capacity input and got most of files work. However, some file stills have issue with sizing (updated title and link) with Psychrometric functions. The Routine is unknown. Is there anyway to check ?