22 May 2008

RECENT AND HISTORICAL ADVANCES IN HEAT PUMP TECHNOLOGY AND MARKET IN SWEDEN


The ground source heat pump has reached a mature level in terms of technology
and market penetration in Sweden. Typical figures for the seasonal performance factor has
been steadily increasing from 2,5 to 3,5 and the energy coverage factor has been increasing
up to 95-98%, thus minimizing the need for peak heating to a minimum in many installations.
This does however not mean that the full technical (thermodynamic) potential is realized,
rather that the market, i.e. customers and manufacturers, have found a temporal equilibrium
relation between cost and performance (reliability, efficiency, design, noise etc). Ongoing
development efforts are the elimination of peak electric heating and easy to install distribution
systems for direct electric houses. A strive for higher seasonal performance is needed to
clearly demonstrate the benefit of heat pumps in the energy system to all stakeholders.
Several development efforts are ongoing at universities and manufacturers, often in close
cooperation, including more efficient control, variable capacity, and better utilization of bore
holes and so on. Other development efforts are increased use of natural refrigerants and
charge minimization through new types of heat exchangers. Large scale heating only heat
pumps in district heating remain an efficient alterative but new system are not likely due to a
strong focus on cogeneration of heat and electricity. On the other hand development of
district cooling systems may open up new possibilities.