Exhaust air heat pumps in Sweden. Developments and experiences.

Exhaust-air heat pump technology has proven to be the most efficient way of recovering heat from a ventilation system. In Sweden this technology is now playing an important role in the heating market, particularly in new singly-family homes. However, larger exhaust-air heat pump systems are also being installed here, the largest unit, with a heat output of 3.4 MW, serves 2,500 flats. This article describes some of the projects that have contributed to the development of exhaust-air heat pumps in Sweden. Details are also given on the latest technology trends including an integrated exhaust-air heat pump and gas boiler.