Modification of standard cooling circuits in heat pumps for the optimized integration of several environmental heat sources and the management of the heat source and heat sink


Optimization of heat pump systems by controlling the heat sink

  MoSKWa-Logo Copyright: EBC

The aim of the research project MOSKWA is the development of an energy and cost efficient multi-source heat pump system by optimizing the heat source and the heat sink. The lower the temperature difference between the heat source and sink, the higher will be the theoretical performance factor of the heat pump process. The project work is in cooperation with Vaillant GmbH and Fraunhofer Institute for solar energy systems.

To maximize the temperature at the source side, the combination of the heat sources has to be exploited and the temperature level of each heat source has to be considered inside the evaporating process. The studies about the management of the heat sources is made at the Fraunhofer ISE in cooperation with Vaillant GmbH.

At the Institute of Energy Efficient Buildings and Indoor Climate (EBC) the optimization measures at the sink side of a heating system are considered. The management of the sink side requires the lowest possible temperatures. This can be done by adapting the heat emission in the rooms to the necessary heat demand. For this purpose, the knowledge about the rooms or areas with different use of space is mandatory. The approach is an adapting control algorithm, which uses electrical thermostatic valves for the single room heating control. Within the scope of this project, the information of the adapting control algorithm of each room is merged as input for the control of the heat pump system. This enables a needs-based inlet temperature for the heating systems and consequential an improved efficiency. First simplified simulation studies at the EBC demonstrates a potential for primary energy savings up to 7 % by adapting the inlet temperature of the heating system. Even a higher saving potential at the side of the heat source can be expected with detailed investigation in the scope of this project and an exact adjustment of the heating system.

The project starts with a separated examination of the interactions at the heat source and the heat sink. Each side of the heating system is initially optimized independently. After that, both sections are merged in an overall system to investigate a total optimum. For this purpose, the system in different versions is analyzed with simulation studies and experiments using the hardware-in-the-loop technology. Finally, the new developed system is implemented at a demonstration object.

The project is supported by the Federal Ministry of Economics and Energy (BMWi) with the promotional reference 03ET1169C. The projected started in January 2014 and has a duration of 36 months.