---
title: "Explanation: Calculation of heat extraction capacity in accordance with VDI 4640 (geothermal energy)"
slug: doc-ew-vdi4640
legacy:
  type: glossary
  code: JG8Z49
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    - ZC4MG5
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lang: en
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  origin_file: 02_product/de/glossary/doc_ew_vdi4640.md
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  generated_at: "2026-07-15T12:01:07.074224381Z"
---


# Explanation: Calculation of heat extraction capacity in accordance with VDI 4640 (geothermal energy)

The calculation of heat extraction capacity in accordance with VDI 4640 is a technical document for determining the usable heat output from the ground for geothermal systems. It is based on the VDI 4640 guideline, which standardises the planning and design of geothermal systems.

Typically, the calculation includes:

- details of geological strata, including a description of soil types and their moisture content
- thicknesses of the individual strata along the borehole depth
- specific heat extraction rates in W/m, which vary depending on the soil type
- the calculation of the heat extraction rate per stratum, as well as a total rate for the borehole
- design constraints, e.g. assumed operating hours per year

The document serves as the basis for the sizing of geothermal boreholes and ensures that heat extraction is carried out efficiently and in accordance with technical guidelines.