Earth-to-air Heat Exchanger for Cooling Applications in a Hot and Dry Climate: Numerical and Experimental Study

Shallow geothermal energy, by an earth-to-air heat exchanger (EAHE), is utilized to cool buildings with minimal energy usage. Significant parameters affecting the exchanger's performance must be investigated obtain a suitable design. This article numerically and experimentally investigates effect of pipe diameter, length, inlet air temperature, soil airflow velocity, thermal conductivity on under hot dry climate conditions. The temperature distribution was measured from surface depth 7 m in city Karbala (center Iraq) summer season. experimental test for EAHE carried out water-saturated ambient temperatures 41 ºC, 45 49.5 ºC at four different velocities. percentage drop outlet 9 m/s 28.3%, 25.5%, 19.5%, respectively. Also, three-dimensional model created, simulation results were compared results, which good agreement. An equation found as function diameter around pipe, conductivity. resulted current reported data inliterature. As result, very agreement observed. showed that parameter L (length pipe) causes strongest nonlinear behavior equation. For cases considered, diameters 75 100 mm, approximate linear length required achieve specific It can concluded changing type one (k=0.5 W/m K) saturated (case city, k=1.5 about 25% reduction pipe. velocity 7m/s, 26 62.1 55% higher than case 29 (39.9m).