EVALUATING THE INFLUENCE OF SOME DESIGN AND ENVIRONMENTAL PARAMETERS ON THE PERFORMANCE OF EARTH TO AIR HEAT EXCHANGER

The earth to air heat exchangers (EAHE) is effective passive cooling and heating techniques for buildings. This paper studies numerically the effect of some design and environmental parameters (moist content of soil, pipe material and thickness of pipe wall) on the overall performance of EAHE system. Three types of soil were selected (dry soil, moist soil and saturated soil) with two pipe materials PVC and steel and three thicknesses of pipe wall (2, 3 and 6 mm). This numerical study has been done for summer and winter seasons according to the weather conditions for Nasiriyah city in southern of Iraq. First the built numerical model was validated against experimental model and the results of comparison showed good agreement. After the validation the overall performance of EAHE system with selected parameters was analyzed with ranges of air velocity, inlet temperature and pipe length of 50 m. The simulated results showed that the very moist or saturated soil gives the best overall performance of EAHE system compare with other soils, Furthermore there is no significant effect of pipe material and wall thickness on the overall performance.