Optimization of spatially distributed soil conductivities for horizontal ground heat exchangers

Abstract

Horizontal ground source heat pumps have the potential to significantly reduce the operating energy utilized for space heating and cooling thus reducing greenhouse gases and pollution. However, the amount of land required for the installation of these systems is often a drawback in widespread implementation. It follows, therefore, that any considerable increase in ground heat exchanger performance would reduce the necessary footprint thereby making these systems more attractive. This paper presents an algorithm to determine the optimal spatial distribution of heterogeneous soil conductivities to increase the performance of ground heat exchangers. The algorithm utilizes a gradient-based optimization approach. Using this algorithm, the heat extraction rate for straight pipe and slinky configurations was significantly increased for winter conditions.