IEA HPP Annex 29 - Ground Source Heat Pumps - Overcoming Market and Technical Barriers

Ground source heat pumps have a great potential to provide highly efficient heating and cooling. However, different systems are in operation or under development, and the SPFs achieved with the various systems are different again, depending on the operating conditions. The operation mode with the highest SPF values is heating-only; the design of the heat pump unit can then be kept very simple. The most successful system is the horizontally installed system connected to low-temperature floor heating systems. If the maximum supply temperature required is being 35C or lower, SPFs of 4 to 5 can be achieved. In newly constructed buildings, monovalent heat pump systems are cost-effective compared with oil-fired boilers; the initial cost of both systems is about the same, the running costs of the heat pump are lower. Effective utilization of ground source systems is the heating and cooling operation. Heating and cooling operation, as required in North America and Japan, but also in Austria in the case of large commercial buildings. But the main concern is again cost-effectiveness, which is much more recognized in North America and Japan (pay-back times required are shorter than in Europe). Therefore, it is necessary to reduce first cost of such systems by developing new systems and types of ground coils; additionally, new financing models are required, by governments, by utilities, and by contracting companies.