Integrated Approach for Detecting Convection Effects in Geothermal Environments Based on TIR Camera Measurements

Susana Del Pozo,Ignacio Martín Nieto,Susana Lagüela,Cristina Sáez Blázquez

doi:10.3390/app11073185

Susana Del Pozo, Ignacio Martín Nieto + Show 2 more

Open Access

https://doi.org/10.3390/app11073185

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Abstract

Thermal characterization of soils is essential for many applications, including design of geothermal systems. Traditional devices focus on the computation of thermal conductivity, omitting the analysis of the convection effect, which is important for horizontal geothermal systems. In this paper, a procedure based on the monitoring of the surface of the soil with a thermal infrared (TIR) camera is developed for the evaluation of the global thermal imbalance on the surface and in-depth. This procedure allows for the computation of thermal conductivity and global convection heat rate, consequently constituting a complete thermal characterization of the geothermal system. The validation of the results is performed through the evaluation of the radiometric calibration of the thermal infrared camera used for the monitoring and the comparison of the thermal conductivity values obtained in-depth, with traditional methods, and for the surface of the system.

Highlights

Soils are essential elements for life, due to their contribution to Ecosystem Services as providers of food production, water and climate regulation, energy provision and biodiversity [1]
Among many parameters considered as soil quality indicators [2], knowing the thermal conditions of the soil is important for several reasons: (i) soil temperature has an effect on soil biota for plant growth [3], (ii) thermal conductivity is critical in different fields, such as the automotive and aerospace industries, ceramics, glass and building materials sectors and the energy one, especially in geothermal applications, in which this parameter conditions the performance of the underground thermal exchange [4], (iii) the thermal properties of the soil are directly related with soil moisture [5] and (iv) soil thermal properties are the main factors for mass and energy exchange processes on
This paper presents a novel approach for the thermal characterization of geothermal environments

Summary

Introduction

Soils are essential elements for life, due to their contribution to Ecosystem Services as providers of food production, water and climate regulation, energy provision and biodiversity [1]. In the geotechnical context, controlling the thermal conductivity of the ground could act as a support for defining changes in composition, humidity and other influential properties such as porosity, resistance to freezing, etc. When trying to measure the thermal conductivity of the soil, practice problems are mainly linked to difficulties for covering a representative volume of the sample, in which the variations in the composition and properties are reflected. In this sense, there are many different models for the determination of thermal conductivity of soil, both theoretical and experimental [7].

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