Development of a cost-effective heat pump system for family dwellings

Since the 1970s TNO MEP has played an important role in heat pump research, focused on perfonnance improvement, implementation, testing and development. In 1996/1997 a heat pump competition was organised. The main conclusion was, that the capital cost was too high and system performance was not sufficient to create a break-through in the implementation of heat pumps for family dwellings. A study to the production costs of a single heat pump led to a cost price of DFL 2.900 (about US$ 1.500), whereas the consumer has to pay DFL 8.000 to DFL 12.000 for a commercially available heat pump. It triggered TNO MEP to develop a heat pump that can compete in the Dutch situation. About the same time the same idea arose at the management of Itho bv., a leading company in the field of refrigeration and air-conditioning equipment and member of the Danfoss-Group. As both parties are rather complementary, they decided in December 1997 to start - together with some suppliers - a joint development of an advanced cost-effective heat pump system for family dwellings. The first six months of 1998 were spent to make a system design. Starting-points were a Seasonal Perfonnance Factor (SPF) of 5 and application of a low temperature heat delivery system. Within a team of 8 to 15 experts extensive discussions were held with respect to the system design, heat exchanger designs, control algorithm et cetera. As a result, important features of the system are a solar collector, an advanced control system and the possibility of free cooling. May 1999 the heat pump will be tested in the Development and Test Centre for Heat Pumps of TNO MEP, including simulations of the total system, followed by a field test in 1999.