Steady-state heat losses from the core and perimeter regions of a slab-on-ground floor

Abstract

In order to assess the likely effectiveness of insulating a concrete slab floor laid on the ground, it is useful to be able to estimate the relative magnitudes of the heat losses from the core and perimeter regions, where the latter is usually a strip of constant width. New analytical expressions are derived for such losses in the steady-state, as a function of the slab dimensions, wall thickness, soil conductivity, and average surface film conductance. A simplified expression, useful for hand calculations, is given for rectangular floors, and the ratio of core to total heat loss is presented graphically for some typical cases. The results support the generally held view that most of the losses occur from a relatively narrow perimeter region.