Two HFC-134a high-performance turbo-compressors power the Brussels Engie Tower (previously called GDF Suez Tower) air conditioning system. They are almost 50% more efficient than conventional cooling equipment, and can also be used as a heat pump for recovering lost heat, which is then fed back into the heating circuit.
Free cooling is used to reduce power consumption in winter and as soon as the air temperature falls below 10°C, by using fresh air from outside the building instead of running the air conditioning units. And during the summer, night-time ventilation can dissipate the heat that has built up inside the building during the day.
In addition, renewable energy has been provided to the system thanks to 189 geothermal wells drilled under the building to a depth of 92 m. These provide an average renewable energy output equivalent to 1.4 GWh, 50% of the building’s 3 GWh heating requirements in the winter and 2.4 GWh cooling in the summer.