Numerical simulation of heat-storage performance of filling body with uniformly mixed phase change paraffin

Abstract

A PCM was added to filling materials in an appropriate proportion to realize the effective collection and storage of geothermal energy. Based on the theory of heat transfer and similarity, the heat-storage performance of filling body was numerically simulated in different states, then, the influences of paraffin proportion, initial temperature of filling body, surrounding rock temperature, stope air-flow temperature, and velocity on the heat-storage behavior of filling body were analyzed. The results revealed that reducing the initial heat-storage temperature of filling body, increasing surrounding rock temperature, and increasing the air-flow temperature in the stope all effectively increased the heatstorage capacity of filling body. In which the influence of initial temperature and surrounding rock temperature were more significant. At the end of 16 hours heatstorage period, when the initial temperature of filling body was reduced from 24?C to 18?C, the heat transfer capacity of filling body without paraffin and that with 5% paraffin decreased by 2.85 ? 103 kJ and 2.40 ? 103 kJ, respectively. When surrounding rock temperature increased from 35?C to 45?C, the amount of heat stored by two bodies increased by 3.89 ? 103 kJ and 4.51 ? 103 kJ, respectively.