The field test and optimization of a solar assisted heat pump system for space heating in extremely cold area

As a kind of sustainable energy source, solar energy is becoming highly valued. Especially in extremely cold areas, the amount of energy consumed for space heating is huge, and the conventional coal heating has polluted the environment seriously, therefore solar heating is significant on both energy and environment conservation. In this study, a solar assisted heat pump (SAHP) system was investigated for space heating under extremely cold climatic condition. The system principle and operation modes was presented, and then the project profile and design procedure were introduced, and finally the system performance was evaluated by field test on typical winter days and modeling via TRNSYS simulation environment. The results show that the solar collector efficiency was 51%, and the solar fraction can reach 66% in December. Economic analysis was also performed and the heating expenses for the present SAHP system was 18 RMB/m(2). Finally, the temperatures of solar energy for both direct heating and storage and only for direct heating (T-1A and T-1B) were simulated and optimized, which have important significance on the operation time of different operation modes. (C) 2014 Published by Elsevier Ltd.