The Thermal Behavior of a Dual-Function Solar Collector Integrated with Building: An Experimental and Numerical Study on the Air Heating Mode

This paper presented a novel solar collector that can work in air or water heating mode depending on the seasonal requirement. The dual-function solar collector (DFSC) integrated with a building as well as a reference building without the DFSC were built to test thermal behavior in passive air heating mode during winter. The buildings were equipped with an apparatus to control the room temperature. During the testing procedure, experimental study on the DFSC system was carried out under two conditions, where the indoor temperature was controlled and non-controlled. The results showed that the average temperature of the test room was about 3.43 °C higher than that of the reference room under the non-controlled condition. When the room temperature was controlled at 18 °C, the power consumptions of the test room and reference room were 4.322 kWh and 7.796 kWh, respectively. Consequently, the corresponding daily power consumption saved could reach up to around 3.5 kWh. Moreover, a dynamic numerical model on the DFSC along with the building was developed taking the fin effect of the Cu-tubes into account. The numerical results are found to be well consistent with the measured data. A parametric study on with/without Cu-tubes and depth of the air channel was carried out. It is found that the existing Cu-tubes functioning as water heating can enhance the air heating efficiency when the depth of air channel is of a suitable size.