Performance analysis of an Earth-Air Heat Exchanger applied to the ventilation of a near Zero Energy Building

Abstract

Abstract Introducing near Zero Energy Buildings (nZEBs) in the European Union involves integrating new renewable energy technologies into buildings. Geothermal energy is one of them that can be exploited through the application of the Earth-Air Heat Exchanger (EAHX). It is basically constituted of a series of pipes buried underground at a particular depth. It utilizes the soil as a heat source or sinks to supply cooling or heating to the building. This type of exchanger can offer many advantages in terms of energy savings for the air-conditioning requirements and for assuring the indoor thermal comfort. This paper presents a performance analysis of an EAHX applied to the ventilation of a near Zero Energy Building situated in Spain. The proposed considered the thermo-physical proprieties of the soil in the region under investigation. The purpose is to study the effect of changing the depth in the ground, the pipe length, the pipe diameter, and the air velocity on the outlet air temperature. The mean efficiency of the EAHX is detailed then. The numerical model is implemented using Matlab environment. Results showed that, for specific parameters, the daily average cooling capacity can reach 1.7 KWh, and the EAHX can provide an energy saving of approximately 152 MWh for one year.