Special situation – 45 degrees Celsius in the underground
The sustainable approach for the building complex is based in every respect on the latest technologies. This also includes the subsoil – one of the main factors was a heating and cooling system based on renewable energies. One-third of the enormous amount of energy required to provide heating and cooling is provided by geothermal energy, with the basic load provided continuously throughout the entire year. The leading planning and drilling company Geo Concept designed the geothermal heating and cooling system in line with the building requirements.
Two large Carrier Aquaforce heat pumps provide 2.2 megawatts of heating and cooling power. Before a thermal simulation was able to be carried out to dimension the field of boreholes with the EED software, a thermal response test (TRT) of the substrate was performed. This not only provided important information on thermal conductivity, but also unearthed a special hydrogeological situation: During the TRT, temperatures of 45°C were measured at a depth of 120 m. This meant that only high-temperature geothermal systems that are absolutely reliable in terms of long-term durability were able to be used at this location. The sustainable overall concept drawn up by Jansen comprised JANSEN geotwin shark geothermal probes as well as pipes, manifolds and fittings made from high-temperature-resistant PE-RT. From the probes to the heat pumps via the chambers: a complete system that allows for 45°C water to be circulated constantly for a service life of 50 years.
Due to the foundations no geothermal probes were placed under the tower. These were installed in other locations, i.e. 220 probes were placed at a depth of 100 metres underneath the five-floor office complex and 90 were installed at a depth of 120 metres next to the building. All in all, this means 32,800 metres of geotwin shark U loops. Using more than 21,000 metres of PE-RT pipes, these heat exchangers were connected to the plant room. In comparison, Lake Balaton in Hungary is approximately 79 kilometres long, which means all of the pipes installed in the MOL Campus could stretch from one side of the lake to the other. The probes are connected via six manifold chambers; the largest chamber holds 55 circuits and is 4.5 metres long.