Thermal Performance of An Integrated Earth-Air Tunnel System with Building’s External Wall in UAE

This paper addresses the evaluation of the thermal performance of integrating the Earth-Air Tunnel System (EATS) with the building’s external composite walls. The potential heat gains reductions through the buildings’ envelop as well as the consequence reduction of cooling demand were estimated. EnergyPlus simulation program was used to estimate the EATS outlet temperature. The EATS was sized to supply a flow rate of 0.52 m³/s of air which was used primarily to ventilate the air gap inside the external composite wall of the building. The obtained results revealed that the soil temperature at 6 meters depth is about 30 °C and remains relatively constant across the year. Also it was found that the air temperature inside the EATS dropped from 47.0 °C to 32.3 °C and the ventilated external wall’s overall heat transfer coefficient reduced from 0.538 to 0.474 W/m²K, accordingly. The proposed design was implemented for the case study of an office building located in Dubai. It was found that the proposed EATS model contributed to 11 % reduction in the Annual Energy Consumption (AEC) and cut off CO2 emissions by about 7 tons/year.