The outdoor panel of the ambient-energy heat pump can exploit solar energy, infrared radiation, convection, and mass transfer for its heat sources and sinks. To calculate heat exchange of the panel, its fin was divided into several elements and their simultaneous equations were solved in iterative method. As a recent panel consists of multiple fins to improve air-source capability, the numerical model became complicated. This problems were alleviated by using sol-air temperature and fin efficiency in its heat-exchange equations. Sol-air temperature was extended to accommodate mass-transfer. A computer program that adopts this mathematical model was developed. Preliminary runs of the simulation program gave us some insights to improve COP of this ambient-energy heat pump.
