Numerical Study of a New Configuration Earth–Air Heat Exchanger in Hot Arid Climates

The increasing in energy demand, the decreasing of energy sources and the pollution of the environment imply developing alternative sources of energy cleaner than fossil and conventional energy sources’. Therefore, renewable energy presents the best solution. Thermal applications are one of numerous renewable energy applications. This work investigates by numerical calculations (CFD) a geothermal cooling/heating system. We focused mainly on the earth-air heat exchanger (EAHE) located in an arid and hot region to improve both the performance of the air conditioning system and to minimize the area occupied by the (EAHE). A new configuration of the (EAHE) (horizontal spiral) was evaluated. The FVM was used to solve the governing equations in a computational domain. Commercial CFD software (ANSYS FLUENT 16.2) has been used for this work. A transient three-dimensional model for predicting the temperature distribution in the (EAHE) was carried out. First, validation of the numerical model has been investigated. Good agreements have been noted between the obtained results and those of experiment and numerical studies widely cited in the literature. Then, comparison between spirals shaped and other geometry has been carried out to illustrate the best configuration and the more compact structure that occupies less space in the soil. Finally, parametric study of the new geometry (horizontal spiral) by considering different pitch and depth has been presented. Also, the effects of pitches as well as the pipe length on the outlet air temperature of the (EAHE) have been discussed and presented.