Bedrock-source

Bedrock-source systems are mainly applied in the Nordic countries and Switzerland. Typical drilling depths are 70-200 m with diameters of 125 mm. For a house, one hole is usually sufficient. Boreholes are not filled with grouting material. They are filled with groundwater for good thermal coupling, also under freezing conditions. Grouting is applied in other regions of Europe, notably Switzerland and Austria, and in areas with unstable bedrock. In the Nordic countries usually two loops (40 mm) are inserted in each borehole; elsewhere 4 loops are sometimes applied (32 mm).
New houses can benefit from so-called ‘free cooling’, if a ground-coupled heat pump is applied. During the summer, cold brine is simply pumped to the house without operating the heat pump. The heated water is recharging the heat pump’s heat source. This concept has become popular in some countries, stimulating the use of heat pumps.