A Study on the Heat Exchange Performance of Hybrid Solar Collector with Air to Water Heat Exchanger Type

Abstract

Solar assisted heat pump system is the heat pump system using solar thermal energy as a heat source of evaporator of the heat pump and most of these systems have been used ordinary solar collector that can get a thermal energy only from solar radiation. Thus, the hybrid solar collector that has air to water heat exchanger of fin-and-tube type have been developed for obtaining thermal energy from not only solar radiation but also ambient air. It is the flat plate solar collector installed fin-and-tube heat exchanger beneath absorbing plate. Thus the thermal energy obtained from ambient air can be supplied to evaporator of heat pump when the solar radiation is not enough. At this time, heat exchange performance between air and circulated water is one of most important factor. Hence, in this study, heat exchange performance of hybrid solar collector and effect of parameters that affect heat exchange performance were investigated experimentally. As a result, heat transfer rate between air and water was shown from 180 W to 820 W and it was increased linearly with increment of temperature difference between inlet air and water. In case of effectiveness, it was shown from 0.5 to 0.6 and it was increased by decrement of air mass flow rate independently on temperature difference between inlet air and water. From these results, heat exchange performance of the collector is considered as a sufficient capacity for applying for heat pump system and it also could be confirmed that optimal operation condition of solar assisted heat pump system integrated with hybrid solar collector need to be established base on the relationship obtained from this research as a further study.