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Signhild E. A. Gehlin, Ph.D., Swedish Centre for Shallow Geothermal Energy
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Jeffrey Spitler, Ph.D., P.E., Oklahoma State University
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Göran Hellström, Ph.D., Lund University of Technology
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Ground source heat pump (GSHP) systems are commonly used in Sweden for both residential and commercial buildings. However, there are several key differences with GSHP systems utilized in the USA. Scandinavian systems are often heating-only, and instead of using grouted boreholes, groundwater-filled boreholes are often used. These boreholes are cased from the ground surface to the usually-shallow bedrock. A single or double U-tube is commonly suspended in the borehole. These boreholes are often deeper than those commonly used in the USA. This paper reviews current Scandinavian practice for borehole design and discusses several installations with boreholes 250 – 300 m (820-984 ft) deep or deeper.
