VDI 4640 – a German guideline for shallow geothermal energy use

Abstract

The first draft (“Gründruck”, green print) of VDI* 4640 “Thermal Use of the Underground” already was published in 1998. At that time it responded to the growing interest in ground source heat pumps (GSHP) in Germany, and to the need for setting some basic technical standards. VDI 4640 successfully accompanied the GSHP technology from a status of trial and error, of limited knowledge and of small companies, to an industrial stage with clear technical boundaries. VDI 4640 in the first round of publication consisted of four parts (the publication date is for the final version, “Weissdruck”, white print): VDI 4640-1 Fundamentals, approvals, environmental aspects 2000/12 VDI 4640-2 Ground source heat pumps 2001/09 VDI 4640-3 Underground thermal energy storage 2001/06 VDI 4640-4 Direct uses 2004/09 In the meantime, part 1 was revised and the new edition was published in 2010/06. Currently the guideline commission VDI 4640 is working on the revision of part 2, which needs major updates in particular in the design methods. The experiences of a decade of development and market growth are not reflected in the current version from 2001. However, the revision faced so many new items and some yet unsolved technical questions that the revision process itself became long and tedious. A new draft (Gründruck) now is expected for late 2013. In order to speed up the process for some individual aspects, a new part 5 on Thermal Response Test (TRT) was drafted. A subgroup has started last year the revision of part 3 on UTES, parallel to part 2.