Effect study of various shapes for earth-air heat exchanger performance: Numerical analysis

Due to the excess use of air conditioning systems led to significantly increase the demand for electric power in the household sector. Therefore, to decrease energy consumption, it can use an Earth-Air Heat Exchanger (EAHE); it has been demonstrated to be promising method for heating and cooling applications. In this paper, simulation study was performed using ANSYS FLUENT 19.0 (CFD) program as a numerical analysis on the impact of different pipe shape and air velocity on the performance according to the climatic conditions of Baghdad-Iraq in the summer and winter seasons. The pipes shapes in EAHE system that were used are spiral, wave and straight at the same length and diameter, and it has been studied their impact on performance at different speeds (5, 10 and 15 m / s). The results of numerical analysis showed that the shape of pipes and velocity of inlet air have an effect for the temperature of outlet air and performance of EAHE. Through the results obtained, it was found that the shape of straight tube presents the best performance compared to the other two shapes of spiral and wave. Therefore, the better performance for EAHE can be achieved on operating the system at low air velocity together with straight shape for the exchanger pipe.