Groundwater is pumped from deep wells in the ground using an electric pump in a closed circuit, conducted through a heat exchanger and seeps away again in a so-called absorption well at the other end of the premises. Cold is extracted from the groundwater using the heat exchanger and used to cool the cooling water for the production machines in a secondary circuit. The only energy requirement is the energy for the submerged pump for pumping of the groundwater.

The cooling energy, which would otherwise have to be generated through cooling units using electricity, is already stored in the groundwater. The cooling water in the secondary circuit is conducted through a large cooling sail which is installed in the raw materials warehouse under the hall ceiling. The cold therefore starts at the warmest point below the hall ceiling and then flows down according to the laws of physics. There is also an air circulation system in the raw materials warehouse which promotes active air exchange within the hall and thus encourages an even temperature distribution. Suction and absorption wells must be as far apart from one another as possible. It is important to ensure that new groundwater is consistently able to flow in and the same water is not transported back to the surface over and over again.