Geospatial assessment of soil thermal conductivity for geothermal energy systems in Ecuador

Abstract

This study presents a detailed cartographic assessment of soil thermal conductivity in continental Ecuador using an adapted methodology based on the THERMOMAP project and Kersten's (1949) model. Soil thermal conductivity is essential for geothermal energy applications, particularly for designing efficient ground-source heat pump (GSHP) systems. Accurate mapping requires an analysis of soil texture, bulk density, and moisture content, applying mathematical correlations to estimate conductivity across different depths and regions. Climatic parameters (temperature and precipitation data from 2013–2022) and pedological data (soil texture and density) were processed through Geographic Information System (GIS) tools to create a thermal conductivity map. Results revealed soil thermal conductivity values ranging from 0.87 W/mK to 2.30 W/mK, with 95.34% of the surveyed area exhibiting values above 1.0 W/mK. Conductivity distribution was primarily within the ranges of 1.00–1.25 W/mK (54.36%) and 1.50–1.75 W/mK (33.48%). The Andean region demonstrated the highest geothermal potential, with 70.35% of its soils exceeding 1.25 W/mK, whereas coastal and eastern regions had lower proportions (37.99% and 28.10%, respectively). These findings align with previous research, highlighting significant variability driven by soil composition, moisture dynamics, and geological formations. The resulting map is valuable for identifying sites where knowledge of shallow soil thermal properties (less than 1 meter depth) is crucial for closed-loop geothermal system design. It supports optimal location selection for geothermal heat pumps, contributing to reliable heating and cooling in urban and rural areas, promoting sustainable energy diversification, and enhancing environmental sustainability in Ecuador.