Research on solar-air source heat pump coupled heating system based on heat network in severe cold regions of China

• Coupled heating system combining renewable energy with traditional energy. • District heating multi-energy coupling (NH-SASHP) systems are used in cold regions. • The NH-SASHP is compared with the air source heat pump heating system(ASHP). In the application of clean energy heating, the development of a low-carbon winter heat supply in severe cold regions of China is hindered by the stability of heat sources. To ensure the smooth transformation of traditional energy to clean energy heating modes, the feasibility of a heating system coupling traditional and clean energies was studied using the heating system of an office building in a cold region of China as the research object. The air-source heat pump (ASHP) heating system used in the office building in this study was field-tested. The problems existing in the heating system were analysed using testing data combined with the existing conditions of the building. Solar-air source heat pump coupled heating system based on heat grid (NH-SASHP) was proposed, and the system model was established using TRNSYS software. The operation effect of the NH-SASHP coupling system was analysed, and the control strategy of the coupling system was optimized. The results showed that NH-SASHP system possessed certain advantages over the ASHP system during the heating season, and the energy saving rate is 50.79 % compared with the ASHP system. Under the most unfavourable working conditions in the middle of severe cold, the indoor temperature compliance rate was 100 %. The average coefficient of performance of the heat pump system (COP sys ) of NH-SASHP system and ASHP system were 6.27 and 3.55, respectively. The operating cost of the NH-SASHP system is approximately 72.3 % of the ASHP system.