Thermal Performance of Earth-Air Heat Exchanger Systems for Cooling Applications in Residential Buildings

This paper addresses the thermal performance of integrating Earth Air Heat Exchanger (EAHE) systems with the conventional air conditioning systems in residential buildings in UAE. The proposed system was designed and simulated using a transient analysis tool TRNSYS. The system components were optimized by evaluating the effect of varying several design parameters on the performance of the system. It was found that the optimized design of the earth tubes could potentially reduce the temperature of the ambient air from 46 °C to around 29 °C, when the earth tubes were buried at 4 meters depth below the ground surface. This pre-cooled fresh (atmospheric) air from earth tubes was then mixed with the return air in the mixing chamber of conventional air cooling systems before supply to the building. In order to assess the system feasibility, the proposed system was modelled and implemented on a realistic case study represented by a four-floor residential building located in Dubai. This building comprised a total roof area of 400 m² and an annual cooling load requirement of 366 kW. The results showed good potential of savings in terms of lowering the Annual Energy Consumption (AEC) and the consequent reduction in CO₂ emissions.