Browse > Article

Effect of Soil Thermal Conductivity and Moisture Content on Design Length of Horizontal Ground Heat Exchanger  

Sohn, Byong-Hu (Green Building Research Division, Korea Institute if Construction Technology)
Publication Information
Journal of the Korean Society for Geothermal and Hydrothermal Energy / v.8, no.1, 2012 , pp. 21-31 More about this Journal
Abstract
This paper reviewed and evaluated some of the commonly used prediction models for thermal conductivity of soils with the experimental data. Semi-theoretical models for two-component materials were found inappropriate to estimate the thermal conductivity of dry state soils. It came out that the model developed by Cote and Konrad gave the best overall prediction results for unsaturated soils available in the literature. However, it still needs to be improved to cover a wider range of soil types and degrees of saturation. In the present study, parametric analysis is also conducted to investigate the effect of soil type and moisture content on the horizontal ground heat exchanger design. The analysis shows that horizontal ground heat exchanger pipe length is reduced with the increase of soil thermal conductivity and water content. The calculation results also show that horizontal ground heat exchanger size can be reduced to a certain extent by using backfilling material with a higher thermal conductivity of solid particles.
Keywords
Horizontal ground heat exchanger; Soil thermal conductivity; Soil water content; Predicting model;
Citations & Related Records
Times Cited By KSCI : 2  (Citation Analysis)
연도 인용수 순위
1 Benli, H. and Durmus, A., 2009, Evaluation of ground-source heat pump combined latent heat storage system performance in greenhouse heating, Energy and Buildings, Vol. 41, pp. 220 -228.   DOI
2 Esen, H., Inalli, M., Esen, M. and Pihtili, K., 2007, Energy and exergy analysis of a ground-coupled heat pump system with two horizontal ground heat exchangers, Building and Environment, Vol. 42, pp. 3606-3615.   DOI
3 Tarnawski, V. R., Leong, W. H., Momose, T. and Hamada, Y., 2009, Analysis of ground source heat pumps with horizontal ground heat exchangers for northern Japan, Renewable Energy, Vol. 34, pp. 127-134.   DOI
4 Lee, T. J., Shim, B. O. and Song, Y., 2010, Monitoring of subsurface temperature variation as geothermal utilization, Transactions of the Korea Society of Geothermal Energy Engineers, Vol. 6, No. 1, pp. 29-35.
5 Lee, C., Lee, K., Choi, H. and Choi, H., 2009, Thermal conductivity and viscosity of graphite-added bentonite grout for backfilling ground heat exchanger, Transactions of the Korea Society of Geothermal Energy Engineers, Vol. 5, No. 1, pp. 19-24.
6 Sohn, B. and Choi, H., 2011, Thermal diffusivity measurement of backfilling materials for horizontal ground heat exchanger using dual-probe method, Transactions of the Korea Society of Geothermal Energy Engineers, Vol. 7, No. 2, pp. 51-59.
7 Sohn, B., 2008, Thermal conductivity measurement of sand-water mixtures used for backfilling materials of vertical boreholes or horizontal trenches, Korean Journal of Air-Conditioning and Refrigeration Engineering, Vol. 20, No. 5, pp. 342-350.
8 Wang, J., Carson, J. K., North, M. K. and Cleland, D. J., 2006, A new approach to modelling the effective thermal conductivity of heterogeneous materials, International Journal of Heat and Mass Transfer, Vol. 49, pp. 3075-3083.   DOI
9 Kersten, M. S., 1949, Laboratory research for the determination of the thermal properties of soils, Research Laboratory Investigations, Engineering Experiment Station, Technical Report 23, University of Minnesota, Minneapolis, MN, USA.
10 Johansen, O., 1975, Thermal Conductivity of Soils, Ph.D. thesis, University of Trondheim, Trondheim, Norway. (CRREL Draft English Translation 637, US Army Corps of Engineers, Cold Regions Research and Engineering Laboratory, Hanover, NH, USA.)
11 Cote, J. and Konrad, J. M., 2005, A generalized thermal conductivity model for soils and construction materials, Canadian Geotechnical Journal, Vol. 42, pp. 443-458.   DOI
12 Lu, S., Ren, T., Gong, Y. and Horton, R., 2007, An improved model for predicting soil thermal conductivity from water content at room temperature, Soil Science Society of America Journal, Vol. 71, No. 1, pp. 8-14.   DOI