Economic analysis of the solar thermal and air source heat pump combined system for energy demand of buildings in China

Abstract

This study focus on the economy of the solar thermal and air source heat pump combined system supplying the same demand of SH and DHW for a city household at different locations in China, namely; Beijing, Xi’an and Nanjing. These three locations represent the climatic conditions variety in China with different outdoor temperatures and solar radiation. At each location, the optimized simulations are carried out to recognize the most economical configurations. The results show that, for a 15-year running time, the system comprising 10m2 solar collectors and 5 kW air source heat pump is the best configuration having the minimum cost for all three cities, but the minimum cost of which is different for each location. At Nanjing, the system has the lowest cost of all the three cities, and the payback time of which is also the shortest. However, the payback time of the optimum system in Beijing is 15.9 years exceeding its running time, due to the lowest central heating fee included in the cost of the traditional heating method.