Heat pump high density thermal storage (HPT) analysis: space and water heating.

This work analyzed an air-source heat pump with an integrated adsorption thermal storage component for residential applications. The application of high density storage materials allows a building to meet its onpeak heating and cooling demands without interruption using thermal energy stored during off-peak hours. A simulation model was developed using Engineering Equation Solver (EES) to predict the performance of the system in four different climate zones: Chicago, San Francisco, Bern, and Tokyo. R134a and CO2 (R744) were considered as heat pump working fluids. The analysis was conducted assuming the heat pump would provide for space heating, and hot water heating. The results show that thermal energy saved during offpeak hours can be applied during on-peak hours, effectively reducing the maximum electricity demand and annual utility costs. The CO2 heat pump system has a higher seasonal performance factor (SPF) than the R134a heat pump system due to higher compressor efficiency. Additionally, a cost-benefit analysis shows that the payback period for the thermal energy storage components strongly depends on an on-peak/offpeak electricity charge difference.