Review of soil thermal conductivity and predictive models

Accurate prediction of soil thermal conductivity is crucial to the design of geothermal related structures such as ground source heat pumps (GSHPs), borehole thermal energy storage (BTES), etc. A critical review of soil thermal conductivity and predictive models was carried out in this study. Thirteen alternative soil thermal conductivity predictive models were reviewed and assessed with respect to the advantages, disadvantages and application conditions. Comparative model performance on sands was also conducted by predicting sand thermal conductivity and comparing with the measured values collected from literature. Linear regression analyses and root-mean square error (RMSE) analyses were performed to further evaluate the model performance. It is concluded that Zhang et al. (2015b), Chen (2008) and Haigh (2012) models are highly recommended to predict sand thermal conductivity for geothermal applications.