Research on equipment parameter optimization of photovoltaic andthermal collector-air source heat pump hybrid heatingsystem for rural houses in cold plateau areas

Due to the high altitude and low atmospheric pressure in Tibet, the performance of solar heating system equipment may decline. Therefore, taking a rural house in the Naqu region as the research object, and considering the impact of altitude on equipment performance, this paper designs a photovoltaic and thermal collector-air source heat pump (PVTC-ASHP) hybrid heating system. With the objectives of achieving the highest annual average coefficient of performance (COP), the lowest total investment cost, and the highest annual cumulative electricity generation, the key equipment parameters are optimized using a non-dominated sorting genetic algorithm. The equipment parameters of the system under three conditions are obtained: uncorrected and unoptimized, corrected but unoptimized, and both corrected and optimized. The operation and energy consumption of the system under typical meteorological year conditions are simulated using TRNSYS software. The analysis shows that when determining the rated parameters of heating system equipment in plateau areas, the impact of altitude should be considered; otherwise, the heating needs of users cannot be met. After considering both altitude correction and optimization, the PVTC area, ASHP heating capacity, and hot water storage tank volume of the system are 24 m2, 8.8 kW, and 2.1 m3, respectively. The operation duration of the PVTC during the heating season increases by 39 hours, while that of the ASHP decreases by 122.5 hours. The annual average COP of the system is 4.08, and the static payback period is 7.86 years.