Collection and Analysis of Soil Thermal Property Data under Minnesota's Local Conditions

Abstract

The aim of this research was to collect and collate soil thermal property data across Minnesota to support the ongoing modelling of Ground Source Heat Pump systems (GSHPs). The soil properties of interest essential in the numerical modelling of GSHPs are thermal conductivity, density, specific heat capacity, soil layers by depth and water content. With the knowledge of these properties, the precise performance of a GSHP at a given location can be numerically established. Soil thermal property data was obtained by reaching out to Northern Groundsource Inc which is a geothermal systems company in Minnesota. Data was also obtained from the Minnesota State Climatology Office, University of Minnesota Extension, Minnesota Emergency Communications Board and Minnesota Pollution Control Agency by searching their databases and websites. The predominant soils in Southwest and South-central Minnesota which are loamy soils exhibited the highest thermal conductivity as compared to other regions. The properties were measured up to a depth of 1.83 meters and would be suitable for the design of horizontal GSHPs which are usually installed between 1.524 m and 3.048 m.