Renewable thermal energy systems: closed (BTES) or open source (ATES)

Shallow geothermal energy (between approximately 50 and 150 m deep) is particularly economically viable today. Moreover, such shallow geothermal energy offers a solution for both heating and cooling. Depending on the application and the geological characteristics of the ground, either a closed system (BTES) or an open source system (ATES) can be applied.


During the summer, the cold within the ground is delivered to the building, usually without the use of the heat pump. This causes the ground temperature to increase again with a few degrees. This cycle is repeated year after year.

In the case of thorough design and operation, such systems are very energy efficient and lead to a very important reduction of CO2 emissions.

More than just a source of renewable energy, BTES and ATES systems provide seasonal thermal energy storage that is applicable for heating and cooling of buildings.

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