Question-and-Answer Resource for the Building Energy Modeling Community
 | 1 | initial version |
It depends on what type of heat pump you are using. OS-HPXML can model different types of HPs as indicated here.
https://openstudio-hpxml.readthedocs.io/en/latest/workflow_inputs.html#hpxml-heat-pumps
Performance curves (https://bigladdersoftware.com/epx/docs/24-1/engineering-reference/performance-curves.html) are used to adjust rated capacity and efficiency depending on environmental conditions, regarding your question about effect of outdoor air temperature on heat pump efficiency.
This reference describes how performance curves are used in the context of residential single speed equipment.
https://bigladdersoftware.com/epx/docs/24-1/engineering-reference/coils.html#single-speed-electric-dx-air-cooling-coil
