Experimental analysis of earth air heat exchanger for space cooling: A clean energy approach

Abstract

In response to the rising energy demands and increasing reliance on air conditioning due to extreme heat in India, this study attempts to investigate the thermal performance and sustainability of a horizontally configured Earth Air Heat Exchanger (EAHE) system. Thermal modeling was developed using MATLAB R2024b and has been experimentally validated for a 4 ft. × 4 ft. × 4 ft. room. This setup was installed in Dadri, India and experimentally tested for 3 days under varying air flow velocities. The system demonstrated significant cooling potential, with temperature drop of up to 7.3°C between the inlet and outlet air of EAHE. The correlation coefficient ( r  = 0.84 to 0.89) and root mean square percent deviation (<4%) between the theoretical and experimental values confirms the reliability of the model. The validated theoretical model was then applied to a realistic sized room of 12 ft × 12 ft × 12 ft, showing an average reduction of 480 W in cooling load of room which corresponded to a seasonal energy saving of 468 kWh. The Energy Payback Time (EPBT) of EAHE was calculated to be 4.42 years and a potential carbon mitigation of 43.5 ton over 50 years and a carbon credit value of $435. This study highlights the potential of EAHE as a sustainable, low energy solution for passive cooling in India, resulting in reduced electricity consumption and carbon emissions which is aligned with UN goals namely, SDG 7, SDG 11, SDG12, and SDG 13.