A design criterion for a solar-assisted heat pump system

We model a solar-assisted heat pump (SAHP) system in order to develop a design criterion. A steady-state model is chosen, which lends itself to optimal analytic solutions. From a physical understanding of these solutions, a design criterion is developed. This criterion reveals that, for optimum performance, the ratio of output to input terms (η) must always be equal to 1. The size of the heat pump is the main parameter that governs the maximum savings from SAHP systems. Based on the initial results, it appears that we may use the design criterion to size also the components of dynamic SAHP systems.