Setting Electric Heat Lockout Temperature in BEopt

asked 2018-10-12 14:03:58 -0500

dburdjal
131 ●1 ●1 ●2

Hello,

I was wondering regarding the correct way to set the lockout temperature for electric strip heat. The only fields provided in the BEopt option editor for heat pumps are "Min Temp" (OAT below which compressor turns off, default of 0F) and "Crankcase Max Temp" (OAT above which compressor crankcase heating is disabled, default of 55F). Neither of these fields provide a way to set the temperature above which the supplemental/strip heat shuts off (Typically about 30-40*F, can be colder for cold-climate heat pumps).

answered 2018-10-12 14:10:37 -0500

Eric Wilson

1853 ●12 ●8 https://resstock.nrel.gov/

I don't think there is a lockout temperature, but rather electric strip heat will only be used if the heat pump along cannot meet the heating load.

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Comments

Thank you for your reply, Eric! Trying to model heat pumps in cold climates is challenging, and locking out the strip heat past a certain temperature is required by WA State energy code. The simulation should also consider the de-rated performance below that temperature (like in the NEEP cold climate ASHP specification). As a point of interest, does EnergyPlus allow you to do it in any other way/outside of BEopt? Thank you for your support.

Regards,

Dimitry

dburdjal ( 2018-10-12 14:22:44 -0500 )edit

Are you seeing strip heat energy use at temps above 30F in your BEopt results? (try a DView scatter plot)

The ASHP and MSHP models do consider performance as a function of temperature. There is more variation in that performance in the MSHP models in BEopt, which can use data from the NEEP spec. See https://unmethours.com/question/30956...