Heat Pump Cylinders with Two Heat Exchangers

Here the heat pump cylinder has a second heat exchanger, for a second source with its own circuit. Typically one is connected to the heat pump and the other to solar collectors or to a boiler kept as backup, while the electric element is the third source.

It is the solution for hybrid installations: the sun works in summer, the heat pump or boiler in winter, depending on which source is more economical. The large-surface heat exchangers make good use of the low temperatures of both sources.