On the application of the energy balance equation to predict ground temperature profiles

A complete model is used in this study for the prediction of the daily and annual variation of ground surface temperature. This model is based on the transient heat conduction differential equation using as boundary condition the energy balance equation at the ground surface. The energy balance equation involves the convective energy exchange between air and soil, the solar radiation absorbed by the ground surface, the latent heat flux due to evaporation at the ground surface as well the long-wave radiation. The model is validated against various extensive sets of measurements for bare and short-grass covered soil in Athens and Dublin and its results are compared with the corresponding results of models based on Fourier analysis. Furthermore, a sensitivity investigation was carried out in order to evaluate the impact of various factors involved in the energy balance equation at the ground surface on the soil temperature distribution. The overall analysis is useful for the prediction of the thermal performance of buildings in direct contact with the soil as well as for the prediction of the energy efficiency of earth-to-air heat exchangers. (C) 1997 Elsevier Science Ltd.