Study on heating performance of large flat plate solar collector coupled dual-source heat pump system and temporal-spatial partitioning energy-saving potential in cold regions

Solar-assisted heat pump systems are promising for clean heating, but high operational costs remain the greatest barrier to widespread adoption in rural cold regions. Installation space constraints have resulted in heating relying on the heat pump as primary device, with solar energy only auxiliary. Considering abundant solar resources and ample available space in rural Northwest China, this study proposes large flat plate solar collector coupled with dual-source heat pump system (LFPC-DSHP). The heating performance and energy-saving potential under temporal-spatial partitioning (TSP) strategy based on building functional zoning and occupants’ day-night occupancy patterns were analyzed by simulation. Field measurements achieved a solar fraction of 36.5% and a heat collection efficiency of 40.3%, significantly reducing reliance on the heat pump during the coldest month. The system achieved an average daily effective solar heat collection of 45.9 kWh, with a heat supply of 126.9 kWh and energy efficiency ratio of 3.13. Compared with the whole house continuous heating, the TSP strategy decreased the cumulative heat supply and total electricity consumption by 23.3% and 19.2% in heating season, respectively, shortening the payback period to 6.61 years. The enhanced solar energy utilization on the heat-source side was further integrated with the TSP heating control strategy on demand-side, improving solar energy utilization and economic performance of the system. This study provides a valuable reference for the stable and cost-effective operation of solar-assisted dual-source heat pump heating systems in cold regions.