A numerical and experimental investigation of three-dimensional ground heat transfer

Abstract

A three-dimensional numerical simulation of transient heat transfer behaviour measured during a full-scale experiment is presented. The experimental data, provided by others, was measured at a purpose built, full-scale test-house, over a 5-year period. The paper addresses some of the practical problems associated with undertaking multi-dimensional simulations, even when the problem is reasonably well defined. Comparisons are made between numerical results and measured data over an annual cycle. Good correlation of results has been achieved. Phase lag of ground temperature variations was also accurately represented in the simulation. The need to pre-condition the simulation to arrive at realistic initial conditions is shown to be necessary in this class of problem. Practical application: At the design stage a predictive assessment of building energy consumption and dissipation is clearly of value. However, the accuracy of any simulation fundamentally depends on the precision with which relevant factors are included. Above-ground insulation of buildings has steadily improved and as a consequence thermal losses due to earth-contact have become proportionally more important. Within this context, this paper aims to provide a case study for validation of models against full-scale field-measured data. The work will also contribute to innovative design that may utilize the thermal mass of foundation materials to achieve the required thermal performance.