30 May 2005


Designing a competitive heat pump system for heating purposes involves thorough economic and
technical considerations. In contrast to other conventional heating systems the performance of a heat
pump system is strongly influenced by the temperature levels in the heat distribution system and the
temperature and the characteristics of the heat source. The use of deep boreholes or horizontal ground
coils as heat source that offer a relatively high and stable temperature level increases the performance in
cold climates but also the investment cost. The high investment cost associated with a heat pump can only
be justified if the running cost and emissions of green house gases are much less than that of a
conventional heating system. This raises the need to evaluate the seasonal performance factor as well as
the design of the heat source. There are a number of different tools and software available on the market
today. Most of which are either looking into the design of the heat pump unit or the heat source. This
paper describes a novel design tool developed in co-operation with the actors on the Swedish heat pump
market. The tool has been developed in order to perform system performance analysis as well as the
design of vertical boreholes.