AC-83-11-4 -- Heat Pump Performance Parametric Studies Using Seasonal Performance Model (SPM) PDF

The Heat Pump Seasonal Performance Model (SPM) previously developed for the DOE has been refined and made more flexible. The model uses a double bin hour method of heat pump load and performance calculation. The current model is a combined version of two formerly independent models for cooling and heating performance simulation, allowing annual performance to be evaluated for a given equipment/building combination. A defrost control system model was added that computes energy consumption for eight types of defrost controls Other modifications include addition of an improved thermostat model, which accounts for the interaction between cyclic degradation and equipment on-time, and a flexible method of heat pump and/or building size specification.

Various parametric studies are presented demonstrating the applicability of the model and investigating the effects of defrost losses, cyclic losses, thermostat characteristics, and equipment rating-point data relationships on heat pump performance. Thermostat characteristics and equipment time constants are shown to cause large variations in seasonal energy usage. The effects of changes in system capacity and efficiency with outdoor temperature are demonstrated to be important considerations in optimization of heat pump sizing and selection methods.