Parametric study on thermal performance of earth-to-air heat exchanger used for cooling of buildings

A transient one-dimensional model was developed for studying the thermal performance of earth-to-air heat exchangers (EAHE) for summer cooling under the Algerian Sahara. The effect of extremities was also taken into account. The model validation against both theoretical and experimental data of other researchers showed a good agreement. In addition, a detailed sensitive study was carried out in order to investigate the influence of geometrical and dynamical parameters on the thermal performance of EAHE. Results showed that the air outlet temperature decreases with increasing of pipe length but it increases with increasing of pipe cross section and air velocity. However, the daily mean efficiency increases when the length of pipe increases but it decreases when the cross section area of pipe or air velocity increases. It is also observed that the coefficient of performance drops quickly with increasing of air velocity. Considering as reference the thermal performance of EAHE under steady state conditions, the investigation of Derating Factor reveals that the thermal performance of EAHE in transient conditions is more influenced by the variation of operating duration, pipe diameter and air velocity.