Theoretical, experimental and numerical analysis of horizontal earth-air heat exchanger

Earth-air heat exchangers (EAHXs) are a highly efficient renewable energy technology system. This system use the ground as a heat supplier in the winter seasons or as a heat absorb in the summer seasons. So we can use (EAHXs) to decrease heating or cooling loads by pre-conditioning supply air in underground pipes. This is useful to reduce the energy demand of buildings. This study was focused on the development of a design model, which is largely used by engineers for the purpose of calculating heating or cooling loads in the design of buildings. This model can also be used for all cities of Turkey after the introduction of the correct values for the weather and soil where the earth air heat exchanger is used. The model used has been built at the University of Uşak in Turkey at altitude 38° 31′ 26″ North, longitude 29° 20′ 31″ East , for the purpose of experimental data. These data was taken for two months in the summer season and two months in the winter season. After that the results was compared theoretically and numerically and showed a high accuracy. For the purpose of numerical analysis we used in this study the (CFD ANSYS FLUENT) software package v. 17 and 19. Also the study investigated theoretically and numerically the effect of design parameters on horizontal earth air heat exchanger performance like the pipe diameter, the flow rate of fluid in the pipe, the length of pipe and the depth of underground heat exchanger. Finally we calculated the outlet temperature theoretically and numerically by using two different materials like (PVC and HDPE) as a case study to compare the results with the material being studied, which is galvanized steel.