Analysis of transient heat loss in earth-sheltered structures

The two-dimensional transient Fourier heat-conduction equation has been solved in cartesian coordinates using an alternating-direction, implicit-finite-difference technique for several earth-sheltered-building configurations. The computer program has been verified by comparing results with data taken from an instrumented conventional residence basement. The present model considers variable soil properties, different types of below-grade configurations, and various types, thicknesses, and locations of insulation. The program has been used to analyze the thermal impact of varying levels of interior and exterior insulation on conventional basements, earth-bermed walls, and earthcovered structures, although only results for the earth-covered structures are presented in this paper. Heat loss and gain through the exterior building envelope versus location and time of year are given as functions of construction materials, insulation, and soil geometry. Temperature distributions within the building envelope material and in the surrounding soil are presented in relation to time of year. An economic analysis is also given to indicate the cost-effectiveness of the insulation levels analyzed.