Foundation heat loss from heated concrete slab-on-grade floors

In recent years, there has been a renewed interest in heated concrete slab floors to provide for space heating in both residential and commercial buil dings. The existing design procedures for these heating systems are based o n simplified thermal models with several assumptions. In particular, the si mplified models assume that both the upper and the lower concrete slab surf ace are isothermal and that the heat transfer through the bottom of the sla b surfaces is uniformly distributed over the entire surface. In this paper, a more realistic and flexible model for heated or cooled concrete slab flo ors is considered to determine the heat transfer between the concrete slab and the ground. In particular, steady-stare and steady-periodic semi-analyt ical solutions are developed to determine the temperature field within the ground medium and within the concrete slab-on-grade floor where hot or chil led water pipes are embedded. The solution presented in this paper is appli ed to determine the ground heat loss/gain for a heated or cooled floor unde r various design conditions including the Level of floor insulation, and th e temperature of the water pipes. These solutions are obtained using the in terzone temperature profile estimation (ITPE) procedure. Detailed analysis is presented to determine the effect of the slab insulation configuration o n soil and slab temperature field and on the monthly variation of the total slab heat loss. (C) 2001 Elsevier Science Ltd. All rights reserved.