I'm looking at the new heatpump input options for Beopt 3.0.1. There is no longer a field for putting in the performance and capacity at cold temps - how is beopt calculating the cold temperature capacity of the system?
The upcoming version of BEopt (3.1.0), expected next month, will include a number of new heat pump inputs, including heating capacity retention for both mini-split and central air source heat pumps. It will also have some updated performance curves and assumptions, particularly for variable speed heat pumps.
It will look something like this:
The default heating capacity retention fractions in BEopt 3.0.1 are:
They will change a bit in BEopt 3.1.0.
That said, note that for a given rated HSPF, the heating capacity retention fraction will generally not have a significant effect on annual energy consumption because a higher fraction will result in a lower heat pump COP in order to achieve the specified rated performance. However, a higher retention fraction can result in a significantly smaller heat pump capacity, and therefore cost, for simulations with autosized equipment.
Got it, thanks! Will users need to input COP at part load capacity as in beopt 2.8?
No, they will not.
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