相变材料太阳能蓄热水箱热特性实验研究
Experimental Study on Thermal Characteristics of Solar Heat Storage Water Tank with Phase Change Material

蓄热水箱是太阳能热利用系统中的关键部件之一。为提高太阳能热水系统效率，在蓄热水箱中添加八水氢氧化钡相变材料，在初始水温为80 ℃、进水温度为5 ℃的工况下，研究相变材料对蓄热水箱热特性的影响。结果表明：相变材料使蓄热水箱的蓄热量从18.81 MJ提高至19.07 MJ，随着进口体积流量的增大，蓄热水箱混合数先减小后增大，而有效释热效率先增大后减小且在3 L/min时达到峰值92.2%。相变材料的加入能够提高蓄热水箱的有效释热效率，同时能够提高水箱的热分层特性，且位置越靠近进口改善效果越好。
The heat storage tank is an indispensable component in a solar thermal utilization system. To improve the efficiency of a solar water heating system, phase change material Ba(OH)2?8H2O was added to a heat storage tank. The thermal properties of the heat storage tank were then studied through experiments when the initial water temperature was 80 ℃ and the inlet temperature was 5 ℃. Results showed that the heat storage of the water tank increased from 18.81 to 19.07 MJ when adding the phase change material. With the increase in the inlet volume flow rate, the MIX number of the water tank initially decreased and then increased, whereas the effective heat release efficiency first increased and then decreased. The maximum efficiency of 92.2% occurred at a flow rate of 3 L/min. The addition of the phase change material could increase the heat release efficiency and heat stratification characteristics of the heat storage tank, and the closer the position of phase change material is to the inlet, the better the improvement is