Analysis and modeling of a large borehole system in Sweden

Abstract

This paper presents a study on the thermal simulation of a large existing borehole thermal energy storage (BTES) system located in Stockholm, Sweden. The bore field investigated presents an uneven pattern, which comprises vertical and inclined boreholes, for a total of 130 units. Such complex bore field geometry cannot be modeled with the current available commercial design tools. The test case presented is utilized to explore the influence of boundary conditions and level of detail utilized for representing the model geometry on the output of the simulation. Two boundary conditions and three geometrical configurations were studied. The results show that, in the considered case, the results obtained with the tested models give a marginal difference, hence also the greatest level of simplification can be utilized without loosing accuracy in the analysis.