Experimental research on indoor thermal environment of new rural residence with active solar water heating system and external wall insulation

From the perspective of enlarging the utilization of renewable energy and reducing the energy loss of building envelopes, an active solar water heating system (SWHs) coupled with coal-fired boiler applied to a new rural residence (experiment residence) insulated with 60 mm extruded polystyrene was compared with the traditional mini coal-fired boiler for heating in a reference new rural residence (reference residence) without external wall insulation during heating period in Minqin, Gansu province, China. Comparative experiment on indoor thermal environment and energy consumption for heating of the two residences through field tests was conducted. The results show that the indoor average temperature and the mean radiant temperature inside the experiment residence are higher than that in the reference residence by 5.4 degrees C and 3.3 degrees C, respectively, when the outdoor minimum temperature is -16.2 degrees C. The indoor relative humidity is 58%, which is suitable for residents. The active solar heating system and the external wall insulation increase 14.5% of the initial cost of the new rural residence, the energy saving fraction is 78.0%, and the payback period of additional cost is about 4.4 years. It is shown that the application of SWHs and external wall insulation is affordable and feasible to the new rural buildings in the northwest rural regions of China. (C) 2015 Elsevier Ltd. All rights reserved.