Experimental study of a combined system of solar Kang and solar air collector

• A combined system of solar Kang and solar air collector is proposed.
• An experimental study on the combined system is made.
• The mean air temperature reaches 18.5 °C and maintains above 18 °C for 13 h.
• The corresponding mean indoor air temperature of the reference room is 8.9 °C.
• The Kang surface temperature reaches 27 °C and maintains above 18 °C for 23 h.

Chinese Kang is widely used as heated bed and for heat recovery of cooking stove in Northern China. However there are main drawbacks of indoor and outdoor air pollutant generation and heavy demands on solid fuel handling. A novel combined Kang system, which integrates solar Kang and solar air collector, is here proposed. Experiments were conducted to examine the alternative operating modes: (i) only solar air collector in service, (ii) only solar Kang in service, and (iii) both solar Kang and solar air collector in service. The results show that these three modes behave differently and have distinct effects on room thermal environment in winter. When this pollution-free system operates under the third combined mode, the room temperature increases significantly and the vertical temperature gradient reduces. The Kang surface temperature increases and its uniformity is improved. It is also found that the room air temperature is closely related to the Kang surface temperature. Furthermore, most of the time the thermal environment meets the occupant need. This paper reports the experimental work and investigates into the effects on indoor thermal environment as in rural residences in Northern China.