22 May 2008


The ground is a heat sink/heat source, which is, similar to outside air, almost not
limited by availability. Limitations can be the ground temperature in very hot regions and the
composition of the ground. In cold regions with mainly heating demand ground-source
systems are dominating the market, but the share of systems for cooling is also increasing. A
completely different use of the ground happens in the case of large systems with both
cooling and heating demand. In such a case natural recharging of the ground no longer
works; an excellent solution is to use heat removal from cooling operation. The ground
becomes a store, and the temperature changes in this store are the result of heat
extraction/heat removal over the year. Using this excellent heat sink/heat source, it is
necessary to consider the system including the building, the heat source and the heat sink
system, the heat pump unit and the system control. Taking all these aspects as a whole
highly efficient systems can be realised.