Evaluation of Conventional Prediction Model for Soil Thermal Conductivity to Design Horizontal Ground Heat Exchanger

수평형 지중열교환기 설계를 위한 토양 열전도도 예측 모델 평가

  • Sohn, Byong-Hu (Plant Research Division, Korea Institute of Construction Technology) ;
  • Wi, Ji-Hae (School of Civil, Environmental and Architectural Engineering, Korea University) ;
  • Han, Eun-Seon (School of Civil, Environmental and Architectural Engineering, Korea University) ;
  • Lim, Jee-Hee (School of Civil, Environmental and Architectural Engineering, Korea University) ;
  • Choi, Hang-Seok (School of Civil, Environmental and Architectural Engineering, Korea University)
  • 손병후 (한국건설기술연구원 설비플랜트연구실) ;
  • 위지혜 (고려대학교 건축사회환경공학부) ;
  • 한은선 (고려대학교 건축사회환경공학부) ;
  • 임지희 (고려대학교 건축사회환경공학부) ;
  • 최항석 (고려대학교 건축사회환경공학부)
  • Published : 2010.09.09

Abstract

Thermal conductivity of soils is one of the most important parameters to design horizontal ground heat exchangers. It is well known that the thermal conductivity of soil is strongly influenced by its density and water content because of soil's particulate structure. This paper reviewed and evaluated some of the commonly used prediction models for thermal conductivity of soils with the experimental data available in the literature. Semi-theoretical models for two-component materials were found inappropriate to estimate the thermal conductivity of dry state sands. It came out that the model developed by Cote and Konrad gave the best overall prediction for unsaturated sands available in the literature. Also, a parametric analysis is conducted to investigate the effect of thermal conductivity and water content, soil type on the horizontal ground heat exchanger design. The analysis shows that a required pipe length for the horizontal ground heat exchanger is reduced with the increase of soil thermal conductivity and water content. The calculation results also show that the dimension of the horizontal ground heat exchanger can be reduced to a certain extent by using backfilling material with a higher thermal conductivity of solid particles.

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