Comparative Study on Cooling Performance of Two PCM-Assisted EAHEs and Traditional EAHE

It is well known that the sensible heat storage/release process is accompanied by significant changes in the temperature of storage medium. However, this feature of the sensible heat storage medium, namely soil, is unfavorable to fully exert the potential of traditional EAHE. To overcome this deficiency, two phase change material(PCM)-assisted EAHEs are proposed, one is the hollow cylindrical PCM-assisted EAHE and the other is the cylindrical PCM-assisted EAHE. In order to investigate the actual cooling performance of these novel systems in summer, a three-dimensional numerical model based on the effective heat capacity method is established by FLUENT 16.0. And the calculation results of this model have been validated in previous studies. Then, under the condition of equal air volume, a comparative study between these PCM-assisted EAHEs and the Traditional EAHE has been conducted to evaluate their cooling performance under the high-temperature meteorological conditions in Chongqing (China). The results indicate that the cooling performance of these PCM-assisted EAHE systems has been significantly improved when compared with the Traditional EAHE. And in terms of the improvement on cooling performance, the cylindrical PCM-assisted EAHE performs better than the hollow cylindrical PCM-assisted EAHE. More specifically, the total cooling capacities contributed by the hollow cylindrical PCM-assisted EAHE and cylindrical PCM-assisted EAHE have been respectively improved by 17.68% and 20.05% during the 20-days investigated period. The excellent performance of cylindrical PCM-assisted EAHE ultimately limits the temperature fluctuation of fresh air introduced by this novel system to less than 1 °C