Study on Optimization of Two-Stage Phase Change Heat Storage Coupled Solar-Air Source Heat Pump Heating System in Severe Cold Region

: The development of efficient and clean heating technologies is crucial for reducing carbon emissions in regions with severe cold regions. This research designs a novel two-stage phase change heat storage coupled solar-air source heat pump heating system structure that is specifically designed for such regions. The two-stage heat storage device in this heating system expands the storage temperature range of solar heat. The utilization of the two-stage heat storage device not only makes up for the instability of the solar heating system, but can also directly meet the building heating temperature, and can reduce the influence of low-temperature outdoor environments in severe cold regions on the heating performance of the air source heat pump by using solar energy. Therefore, the two-stage phase change heat storage coupled to the solar energy-air source heat pump heating system effectively improves the utilization rate of solar energy. A numerical model of the system components and their integration was developed using TRNSYS software in this study, and various performance aspects of the system were simulated and analyzed. The simulation results demonstrated that the two-stage heat storage device can effectively store solar energy, enabling its hierarchical utilization. The low-temperature solar energy stored by the two-stage phase change heat storage device enhances the coefficient of performance of the air source heat pump by 11.1% in severe cold conditions. Using the Hooke-Jeeves optimization method, the annual cost and carbon emissions are taken as optimization objectives, with the optimized solar heat supply accounting for 52.5%. This study offers valuable insights into operational strategies and site selection for engineering applications, providing a solid theoretical foundation for the widespread implementation of this system in severe cold regions.