Experimental Study On The Medium Temperure Phase Change Heat Storager Of Gravity Heat Pipe Type

In order to run the solar air conditioning system based on thetechnology of the medium and high temperature solar collectingthroughout the day, a novel heat storager containing porous phase changematerial of heat pipe type is presented. Instead of referring to the processof PCM undergoing when store or release heat, the concept of phasechange in the designed heat storager particularly underlines the heattransfer pattern that HTF undergoes between the PCM and the heat/coldsource. In this novel heat storager which resembles the heat pipe,water/steam as the HTF flows among the porous filling layer formed bythe granular PCM. This heat transfer pattern, which is similar andsuperior to that of a gravity heat pipe, breaks the bottleneck carried out bythe low thermal conductivity of PCM and endows the heat storager withhigh thermal performance. During the research, the method of producegranular form-stable PCM in large quantity is first developed and thephysical properties such as the latent heat, porosity of the PCM developedare tested. On the basis of theoretical analysis of heating time, power distribution, temperature difference between the inside and outside of thegranular PCM and flow resistance, a series of experiments are carried outto study the properties of the designed phase change heat storager. Boththe theoretical and experimental results show that in comparison with thetraditional heat storage, thermal performance of the newly designed phasechange heat storager is no longer limited by the low thermal conductivityof the PCM. The granular form-stable PCM can store and release heat ina short time, temperature difference between the PCM and the HTF ismerely2℃around and temperature difference between the PCM and thecoolant water is only about6℃.