The Influence of Soil Moisture in the Unsaturated Zone on the Heat Loss from Buildings via the Ground

In calculations of building heat loss via the ground, the coupling with soil moisture transfer is generally ignored, an important hypothesis which will be falsified in this paper. Results from coupled simulations – coupled soil heat and moisture transfer equations and complete surface heat and moisture balances – are compared to results from linear simulations. It is shown that the coupled calculations give notably higher heat losses. Surface temperature, the driving force for heat loss via the ground, is identified as a first important source for these deviations: it is shown that while the averages of the surface temperature are almost equal in coupled and linear calculations, the amplitude in the coupled simulation is considerably higher. A further study reveals that variation of the thermal properties with moisture content also contributes partially to the observed differences. Transfer and storage of sensible heat linked to moisture in the liquid phase was shown to be the last important influencing factor.

[1]  M. Schaap,et al.  Neural network analysis for hierarchical prediction of soil hydraulic properties , 1998 .

[2]  E. Anderson,et al.  A point energy and mass balance model of a snow cover , 1975 .

[3]  B. R. Anderson.  The effect of edge insulation on the steady-state heat loss through a slab-on-ground floor , 1993 .

[4]  P. Milly,et al.  The coupled transport of water and heat in a vertical soil column under atmospheric excitation. , 1980 .

[5]  Baruch Givoni,et al.  Earth temperatures and underground buildings , 1985 .

[6]  Omar T Farouki,et al.  Evaluation of Methods for Calculating Soil Thermal Conductivity , 1982 .

[7]  W. E. Larson,et al.  Predicting Temperatures of Bare and Residue Covered Soils With and Without a Corn Crop , 1981 .

[8]  D. Ogura,et al.  Analysis of Heat and Moisture Behavior in Underground Space by Quasilinearized Method , 1998 .

[9]  B. R. Anderson.  Calculation of the steady-state heat transfer through a slab-on-ground floor , 1991 .

[10]  Carl-Eric Hagentoft,et al.  Heat loss to the ground from a building—II. Slab on the ground , 1991 .

[11]  T. Kusuda,et al.  EARTH TEMPERATURE AND THERMAL DIFFUSIVITY AT SELECTED STATIONS IN THE UNITED STATES , 1965 .

[12]  D. D. Vries,et al.  Simultaneous transfer of heat and moisture in porous media , 1958 .

[13]  Henry E Robinson,et al.  Measurements of heat losses from slab floors , 1945 .

[14]  Harlan D. Bareither,et al.  Temperature and Heat Loss Characteristics of Concrete Floors Lain on the Ground , 1948 .

[15]  J. R. Philip,et al.  Moisture movement in porous materials under temperature gradients , 1957 .

[16]  A three-dimensional numerical study of slab-on-grade heat transfer , 1990 .

[17]  Atsushi Iwamae,et al.  An analysis of temperature and moisture variations in the ground under natural climatic conditions , 1988 .

[18]  An investigation of transient, two-dimensional coupled heat and moisture flow in soils , 1990 .

[19]  Hywel Rhys Thomas,et al.  The influence of soil moisture content variations on heat losses from earth-contact structures: an initial assessment , 2001 .

[20]  N. K. Bansal,et al.  Temperature distribution inside ground for various surface conditions , 1981 .