This energy source can be used via ground collector or ground probes. The required area of the collectors is determined according to the soil conditions and heating requirements of the building. The ground collector consists of pipes, which are laid with a brine / water mixture just under the frost line in approx. 1.2 m. The rule of thumb is approximately 1.5 times the heated area as a collector surface. Ground probes uses the stored heat in a depth of several meters up to over 100 m. Ground probes are also filled with a brine / water mixture, thereby absorbing the stored heat of the soil and deliver it to the heat pump.
If ground water is available in the required quantity and quality, the HERZ water / water systems can achieve the highest coefficient of performance. The water is transported from the extraction well to the heat pump . There the heat is extracted and the water is returned to an injection well to the nature. One kilowatt of heating capacity requires about 220 l / h of water. A water / water heat pump system requires a water license according to territorial regulations.