The decrease in heat pump heating mode capacity will result in the additional heating load being picked up by the backup heating equipment.ĪSHRAE Standard 90.1 does not provide a heating capacity curve for air-to-air heat pumps. The equipment capacity curve will reduce the capacity of the associated equipment as the outdoor air dry bulb temperature decreases from 40F to 17F. However, most of the equipment in the TRACE library assumes a constant capacity and this normally yields valid results. In reality, the output capacity of most equipment changes based on operating conditions. It is the third curve used in conjunction with the power consumed and ambient modification curves.
The equipment capacity curve can be seen in the Cooling Equipment library. Input an equipment capacity curve as illustrated below: Step 1: Create an Equipment Capacity Curve
Therfore, the curve doesn't need to be manually generated and applied to equipment.
This curve is part of the 90.1 heat pump libraries that can be downloaded from the CDS HVAC Design Software Download Center at.
