Temperatures in and under a slab-on-ground floor: two- and three-dimensional numerical simulations and comparison with experimental data

This paper presents the results of a numerical simulation of measured tempe ratures in a ground floor slab and the soil beneath it. Two- and three-dime nsional calculations (2D and 3D) are performed using a widely utilised whol e building thermal simulation program. A multi-dimensional numerical conduc tive heat transfer module has been added to this program and this current w ork is intended to show (i) whether the model is capable of successfully mo delling the system and (ii) whether the use of 2D analysis is justified or if a 3D simulation is more appropriate for this type of slab. The predictio ns of the finite-volume model are compared with one year of measured data f rom a real building. A Differential Sensitivity Analysis is made in an atte mpt to account for uncertainties in some input parameters (i.e. thermal con ductivities). It seems that in this case, where the slab is large, the 2D m odel is capable of satisfactorily predicting the transient temperature vari ations in the soil. However, it is shown that near the corners of the slab a 3D model is necessary to accurately simulate heat flows for periods invol ving high heat fluxes; i.e. during the heating season. (C) 2000 Elsevier Sc ience Ltd. All rights reserved.