Heat exchangers at the BRGM's experimental geothermal energy platform (Orléans, 2009). © BRGM

Innovative geothermal solutions for buildings

Geothermal energy via heat pumps has the most potential to cover three needs in housing and the tertiary sector: heating, cooling and domestic hot water. Through its research work and support to public authorities and professionals, the BRGM is contributing to this sector's development. The BRGM's geothermal platform has been testing the performance of heat exchangers for nearly ten years and developing new tools for very low enthalpy geothermal systems for individual housing.

Microgeo: a complete geothermal heat pump system for around 10 000 €

The platform recently completed a project, Microgeo, to design an efficient and affordable geothermal system for new individual housing complying with Low Energy standards. The system covers the three main needs for thermal energy: hot water, heating and cooling, for an investment of around €10 000.

Four new "tube-type" heat exchangers have been tested for performance to validate the innovations introduced by the manufacturer, Terrendis France. These heat exchangers can now be purchased by heat pump installers.

On the completion of this project in 2012, a computerised tool was designed and will be available on line at the end of 2016.  As well as the BRGM and Terrendis France, the project was partnered by: CIAT (heat pumps), EDF, CEA-INES (solar power for buildings), the CETIAT technical centre and Proxiserve (heating).

Construction of a copper geothermal tube exchanger in the BRGM workshop under the ANR-ECLIPSE project.

A testing and optimisation platform for shallow geothermal heat exchangers

This project is being followed up by the BRGM with study to better understand the influence of the subsoil on heat exchanges. Tests have begun, under the Corgeosola project, by installing two Terrendis France models in two different soils, one optimised by compaction and the other non-compacted. The aim is to assess the soil conditions, including soil moisture, that are favourable to heat exchange, in order to optimise the location of heat exchangers and therefore thier performance.

The originality of the BRGM's experimental platform is the possibility for connecting up different types of exchangers with thermodynamic machinery capable of reproducing constraints on the heat-pump/building system as a whole. The platform is equipped with a weather station and sophisticated instruments, including a fibre optic network to measure subsoil temperatures.

Using an auger to position a polyethylene tube exchanger at the BRGM's geothermal energy platform in Orléans, during the ANR-ECLIPSE project.

BRGM - 3 avenue Claude-Guillemin - BP 36009 45060 Orléans Cedex 2 - France Tel.: +33 (0)2 38 64 34 34