Thermal Analysis of a Generic Earth-to-Air Heat Exchanger Coupled with a Room during the Summer Season in a Desert Climate

Abstract

This work reports a numerical study of the thermal performance of a representative room coupled with a generic earth–air heat exchanger (EAHE) in a city with a desert climate. The EAHE system was designed/selected based on previous results reported in the literature. A detailed validation was made by comparing it with experimental and numerical data reported in the literature under similar climatic conditions. A study was carried out to determine the appropriate air velocity inlet of the EAHE, based on the velocity that would provide the best cooling in the room. It also helped us to select the best air inlet and outlet configuration in the cooled space. The transient cooling capacity of an EAHE system coupled with a representative room was investigated under three different cases. It was found that the most favorable case was when the entering heat flux is by one vertical wall only. In this case, the average temperature in the room was less than the comfort temperature. Also, the flow patterns, temperature fields, heat transfer coefficients, and heat fluxes are reported for the different room configurations. The studied EAHE-Room decreases the ambient temperature by 8.4±2.6 K with a maximum of 11.3 K (Roof Case), 9.6±3 K with a maximum of 12.9 K (Wall Case), and 8.2±2.4 K with a maximum of 11 K (Mixed Case). The average coefficient of performance (COP) is compared for the situations analyzed (COP varied between 210 and 277). It was found that the COP of the EAHE is affected by the thermal load of the ventilated room.