A Numerical Investigation on the Performance of an Earth Air Heat Exchanger System for the Indian District of Nagpur

The performance of an Earth-Air Heat Exchanger (EAHE) system to be operated in climatic and soil conditions prevailing in the Indian district of Nagpur is modeled numerically. To do so, a CFD model is developed in ANSYS Fluent 12.1. The validation of the CFD model is carried out using data obtained from published literature and good agreement is established between the simulation results and published experimental data. An earth pipe of length 60 m and internal diameter 0.1 m is chosen for validating the model and this validated model is used to further investigate for three different lengths of the pipe - 40 m, 35 m and 30 m. The 3-dimensional flow field through the earth air heat exchanger is studied numerically by solving the appropriate governing equations namely: continuity, momentum and energy equations and a finite volume CFD code is employed for solving the same. An air inlet velocity of 2 m/s is maintained and the inlet temperature was varied between 308.1 K and 315 K for each chosen length. The decrease in temperature along the pipe length is plotted.