Performance and Optimization of Novel Solar-Assisted Heat Pump System with Hybrid Thermal Energy Storage

In this study, a novel solar-assisted heat pump (SAHP) system with hybrid thermal energy storage is proposed. The system can address the problems of large space requirements and the unstable heating of solar heating systems and tackle the energy-efficient degradation of air source heat pumps (ASHPs) in winter. This study utilized TRNSYS18 software to establish a dynamic simulation model of the system, including the system’s model construction and the control scheme’s design. This performance study focused on analyzing the effects of the collector area and thermal energy storage (TES). The results show that with the increase in the collector area, the collector and power generation efficiencies decrease, and the system performance coefficient improves; the rise in the volume of TES leads to the collector and power generation efficiencies first increasing, and then they tend to stabilize, and the performance coefficient shows a trend of firstly increasing, and then decreasing. In terms of parameter optimization, a target optimization scheme and an evaluation model are constructed. The results indicate that the heating demand for a 116-square-meter building in the Tianjin area is met. The equivalent annual cost (EAC) of the system cost is the lowest, which is CNY 3963, when the collector area of the system is 31 square meters, the heat storage tank (HST) volume is 0.4 cubic meters and the phase-change energy storage (PCES) volume is 0.2 cubic meters. The payback period of the system is 10.59 years, which was compared to that of the ASHP. The further comparison of the economic feasibility of the system in the Lhasa, Shenyang, and Tianjin regions shows that the Lhasa region has the lowest EAC and payback period of CNY 1579 and 8.53 years, respectively, while the payback periods of Tianjin and Shenyang are 10.59 and 10.3 years, with EACs of CNY 3963 and CNY 5096, respectively.