I am modeling a geothermal heat pump system with a geothermal heat pump DOAS unit. The DOAS unit will be connected to the geothermal loop and will only provide 75 degree outside air to each heat pump within its zone. The heat pumps will all be connected to the OA duct work. The OA will mix with the room return and be supplied to each zone. I am having issues finding a way to model the efficiencies of each piece of equipment. I understand that I will have to probably average all the zone heat pump efficiencies for the plant energy rate. What I am not sure of is how to include the DOAS unit efficiency. It is rated at a much higher COP than the zone heat pumps but they are all included in the geothermal loop plant.

Thanks,