Steady-state heat losses from a building floor slab with vertical edge insulation—I

Abstract

The steady-state heat loss from an infinitely long slab-on-ground floor, insulated at its edges by vertical insulation into the ground, is calculated in two dimensions from a Fourier series solution of the temperature field in the ground. The temperature at the surface of the ground is assumed to change linearly from the inside of the building to the outside over a distance representing the wall thickness. The heat loss is calculated as a function of d/L, where d is the insulation depth and L is the building half-width. As d/L increases, there is a fairly rapid decrease in the heat loss at small values of d/L, and a much slower decrease beyond d/L = 1. The results indicate that it would be necessary to install an impracticably large depth of insulation to achieve a reduction in the floor heat loss comparable to that obtainable by insulating a wall.