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.
Asked: 2023-07-19 15:22:25 -0600
Seen: 109 times
Last updated: Jul 19 '23
