---
title: "Information required to calculate the heat extraction capacity in accordance with VDI 4640 (Geothermal energy)"
slug: entzugsleistung-vdi-4640
legacy:
  type: help
  code: ZC4MG5
links:
  related:
    - EUSVLR
    - YNKXP4
  glossary:
    - JG8Z49
lang: en
source:
  origin_lang: de
  origin_file: 02_product/de/help/ZC4MG5_entzugsleistung-vdi-4640.md
  origin_hash:
    algorithm: sha256
    value: C6AF45BDE6481846F1223EEFCB249B65685987E9AED784F36AB792472D2F60F7
translation:
  target_lang: en
  generated_at: "2026-07-15T12:01:22.373604001Z"
---


# Information required to calculate the heat extraction capacity in accordance with VDI 4640 (Geothermal energy)

![Heat extraction capacity according to VDI 4640](/assets/img/samples/de_entzugsleistung_vdi4640_komplett.png)
![Editing a single soil layer](/assets/img/screenshots/de_drillsite_demo01_list_of_layers_part03.png)
![Thermal properties of a soil layer](/assets/img/screenshots/de_drillsite_demo01_list_of_layers_part06.png)

The data for the **calculation in accordance with VDI 4640** is derived from the **stratigraphic index** for the respective borehole.

The data is entered within the individual soil layers. A **specific heat extraction rate** can be specified for each layer there.

To ensure a reliable calculation, the layers must be described in a structured manner along the borehole depth and assessed for technical plausibility.

The data is maintained as follows:

- **stratigraphic index**: The geological layers are defined by depth intervals. Soil types and properties can be recorded for each layer.
- **Specific heat extraction rate**: A specific thermal heat extraction rate in W/m can be specified for each layer.
- **Automatic recommendation**: Based on the stored soil composition, a recommendation in accordance with VDI 4640 is displayed. This serves as a guide for selecting suitable values.
- **Restriction on free text**: If the layer description is entered exclusively as free text, no automatic assignment to the VDI recommendations can be made.
- **Annual full-load hours**: The selection of annual full-load hours is made separately and is taken into account in the calculation.

The overall assessment is derived from the combination of the individual layers along the borehole depth.

Notes on data maintenance:

- Enter the layers in as structured a manner as possible, rather than solely as free text.
- Check the suggested values critically and only accept them if they are technically consistent with borehole profile.
- Ensure that the depth intervals for the strata are complete and consistent.
- Take the annual full-load hours into account, as they influence the calculation result.

If the geological layers have not yet been maintained, please read the help text **stratigraphic index** first. The help text **borehole profile (Geothermal Energy)** is also relevant for the overall geothermal representation of the borehole.