The paper treats the development of the first industrially produced water/water heat pump in Denmark during the period 1973–1975. It describes the problems that have been encountered and makes recomendations for their correction.
Thereafter it deals with the development and testing of an improved, second generation water/water heat pump. The total increase of the heat output exceeded 50%, and the
... [Show full abstract] production costs was lowered by more than 30%.