Yearly Thermal Analysis of a Residential Earth-Tube Heat Exchanger

Abstract

A finite element program has been written to solve the three-dimensional Fourier equation for the periodic annual temperature field in the ground surrounding an earth tube connected to the heated basement of a residence situated in a northern community. The results indicate that the presence of the earth tube has a marginal influence on the heat losses from the basement to the ground. They also show that the continuous operation of the earth tube throughout the year is not recommended for the climatological conditions under consideration. An appropriate control strategy is therefore formulated. Correlations for the heat gain during winter operation and heat rejection during summer operation are presented in terms of the relevant design characteristics.