Experimental Investigation of Flow Uniformity in a Bank-Type Earth-Air Heat Exchanger

The airflow in earth-air heat exchangers with different types of flow was examined at various inlet velocities. The results show that there is a significant variation in the mass flow rate of air through the holes for both induced and forced flow. The mass flow rate ranges from 0.013 to 0.119 kg s(-1) for forced flow and from 0.018 to 0.128 kg s(-1) for induced flow at a velocity of 4.1 m s(-1). In contrast, the variation in the mass flow rate through the pipes is significant only for forced flow and almost negligible for induced flow. The mass flow rate ranges from 0.029 to 0.054 kg s(-1) for forced flow and from 0.043 to 0.045 kg s(-1) for induced flow at the same velocity, indicating that induced flow may be a valuable method for optimizing the earth-air heat exchanger performance.