In the SFOE project "Efficient Air-to-Water Heat Pumps through Continuous Capacity Control"
(2008-2011), valuable knowledge regarding the improved efficiency of air-to-water heat pumps through continuous capacity control was gained. These findings shall be used now for brine-to-water and water-to-water heat pumps. Various studies show that the implementation of continuous capacity control could increase the efficiency of brine-to-water heat pumps as well. The aim of the project is the development of an optimized control system for capacity controlled brine-to-water heat pumps. The control system will regulate the rotational speed of the brine circulating pump and the compressor, dependent on the state of the heat source and the heat sink, in such a way that the efficiency of the heat pump is always at a maximum.
In order to verify the potential and quantify the increased efficiency, a prototype with a capacity controlled brine-to-water heat pump will be realized and tested. Different control strategies will be investigated regarding the efficiency (e.g. control of just the compressor and simultaneous control of the compressor and brine circulation pump). The results will be compared with the efficiency of an on-off-controlled brine-to-water heat pump.
All obtained knowledge and relationships regarding the development and control system of the capacity controlled brine-to-water and water-to-water heat pumps will be described, according to the individual needs of the target groups, in the design priciples.