Thermal storage exchanger based on phase change material applying to solar fresh air system

Heat storage device can regulate solar fresh air temperature and extend the supply hours in winter. In this paper, a kind of thermal storage exchanger using phase change material was established and experimentally investigated. Capric acid was used as the phase change material and differential scanning calorimetry tests with extremely slow heating rate were applied to show its thermal characteristic with improved accuracy. A new method of adding low-cost float stones was used to increase the thermal conductivity of the phase change material. Temperature variations of phase change material and the inlet and outlet of the thermal storage exchanger were measured. It is proved that float stones are quite helpful for the performance enhancement. Using the thermal storage exchanger, the highest temperature of fresh air getting in the room changed from 51 to 32.8 degrees C when the outside temperature was between -9 and 0 degrees C, and obviously more hours of providing fresh air was achieved.