Design of a vertical earth heat pump system. Results from system simulations.

In the paper technical and economical aspects of introducing a vertical pipe heat storage with natural convection heat collector and heat pump in an existing building are discussed. The technical influence of the design parameters is studied with a big computer program which is briefly presented. The general influence of the design parameters is presented with special interest in the occurrence of freezing in the vicinity of the storage pipes. Some examples are given which show that an economical optimum storage/collector combination can be found. In this optimum storage freezing will occur. The reduction of total annual cost can be considerable compared to a non-freezing storage.