Soil properties have a significant impact on the performance of ground heat exchangers. Exchangers cooperating with heat pumps are a reliable and efficient source of renewable energy. In the article U-shaped vertical ground heat exchanger are analysed, which are the most common applications cooperating with heat pumps. Soil and ground properties have great  importance during sizing the system, i.e.: determining the length, configuration and deployment of ground heat exchangers. Typical length of the vertical ground heat exchangers used in systems dedicated to residential buildings is about 20 to 100 m. With the depth the soil/ground type and its properties can change significantly. In addition, occurrence of a ground water can influence physical and thermal properties. Determination of soil type present at different depths in a specific location is possible by performing a soil profile. The article presents an analysis of the impact of several soil profiles on the efficiency of the vertical ground heat exchanger. The analysis was performed based on the model of a single heat exchanger made using CFD (Computational Fluid Dynamics) program. The model is divided into two parts: model of heat exchanger together with grout filling the borehole, second axially symmetric model of the ground surrounding the exchanger. Both models are coupled by second-type boundary condition. Simulations of ground heat exchanger work are made for a full heating season period. The calculation results were compared to reference one with uniform ground profiles.

DOI: https://doi.org/10.3846/enviro.2017.253