Vertical ground heat exchangers: A review of heat flow models

Paper in proceeding, 2009

The ground may be used as a heat source, a heat sink or as a heat storage medium by means of vertical ground heat exchangers. Over the years various analytical and numerical models of varying complexity have been developed and used as design and research tools to predict, among others, the heat transfer mechanism inside a borehole, the conductive heat transfer from a borehole and the thermal interferences between boreholes. This paper is based on reviews of scientific work and provides a state-of-the-art review of analytical and hybrid models for the vertical ground heat exchangers. It details and compares various models for short and long term analysis of heat transfer in a borehole. The paper also highlights the strengths and limitations of these models from design and research points of view.