Renewable energy has become a relevant alternative to solve energy and environmental problems worldwide. The characterisation of the geothermal resource is fundamental for an efficient and sustainable extraction of heat. In this study, thermal conductivity λ, volumetric heat capacity C and thermal diffusivity α of two soils from Chile, namely Bío Bío sand and Maicillo residual soil, are analysed. Bío Bío sand is a uniform and clean sand which is mainly constituted by basaltic particles, whereas Maicillo is a silty and clayey sand with a high content of quartz. Samples were tested with a thermal needle probe at varying water content and density. Measurements to obtain λ, C and α were undertaken. These results allowed the study of patterns and relationships between geotechnical and heat transfer parameters. It was found that dry soil conditions led to the lowest values of λ, whereas saturated soil conditions led to the highest values. Moreover, Maicillo has higher capabilities to transfer heat than Bío Bío sand, which can reach up to 50% in λ for dense soil and saturated conditions. This is due to its quarzitic and clayey mineralogy and non-uniform grain size distribution. The results from this research represent an important contribution for industrial applications.

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