Sustainable cities: Geothermal technology for greener heating and cooling

The RTBF-VRT public broadcasting building headquarters in Brussels, Belgium, dubbed Mediasquare, will be equipped with an environmentally friendly geothermal heating and cooling system. The choice was clear from the start, in line with the myriad of energy-saving options chosen to make the future 38,000m2, six-story square building as sustainable as possible. Mediasquare is slated to open its doors in 2025.

 

The new public broadcasting building in Brussels, Belgium will be prime example of sustainable urban infrastructure

Geothermal technology uses the ground’s naturally occurring solar energy to heat and cool buildings in an energy-efficient manner. Mediasquare will be equipped with a borehole thermal energy storage (BTES) system, whereby holes drilled in the ground transfer heat to the surrounding material, allowing the energy to be stored.

The BTES installation will consist of over 40 vertical geothermal probes reaching a depth of 80 meters. This drilling field is planned under the logistics hall located at the back of the building. The closed-circuit geothermal probes will be connected to a collector on basement level -3 via a network of pipes placed below the invert.

 


The network of pipes connected to a temporary collector to test the system for watertightness

 

The wells are connected by threes, following the principle of the Tichelmann loop, which allows for even, reliable heating. This ensures a hydraulic self-balancing of the whole installation, allowing optimal exploitation of the field. 

Reversible heat pump for flexible heating

A reversible water heat pump of 155kW connected to the geothermal field ensures priority production of heat or cold depending on the season. Conventional systems, a condensation boiler and chiller, will provide additional heating or cooling. Thanks to the reversible heat pump, the injection and withdrawal of heat throughout the year is more flexible, which helps prevent the thermal exhaustion of the soil. In case of imbalance, it is possible to restore the neutrality of the ground through additional heat or cold.

 


The connection of the probes according to the Tichelmann loop principle

 

“Our team is passionate about bringing sustainable technologies like geothermal to such a large building that will be a Brussels landmark.
The emissions it will save compared to traditionally heating and cooling a large structure of this magnitude are significant.” 

Guy Mouton - Senior Project Leader - Rachel Dutrieue - Project Manager