Steady-state heat losses from a building floor slab with horizontal edge insulation

Abstract

The steady-state heat loss from a slab-on-ground floor insulated at its edges by horizontal insulation under the slab is calculated in two dimensions from a Fourier series solution of the temperature field in the ground. The temperature above 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 h 1, h 2/h 1 and δ/( L+2 ϵ), where h 1 and h 2 are measures of the surface film conductance, where h 2 includes the effect of the insulation, δ is the insulation length, L the building half-width and 2ϵ is the wall thickness. For small values of h 2/h 1, there is a fairly rapid decrease in the heat loss at small values of δ/( L+2 ϵ), and a slow decrease beyond δ/( L+2 ϵ)=0.3. As h 2/ h 1 increases, the rate of decrease in the heat loss becomes correspondingly slower.