FlexKaelte: Making cooling supply systems more flexible

How to improve the integration of renewable energies by linking the electricity and cooling sectors

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Cooling supply systems

Making cooling supply systems more flexible and improving the integration of renewable energies by coupling the electricity and refrigeration sectors – this is the objective of FlexKaelte

Project aims

The project FlexKaelte focuses on the question, which contribution cooling supply can make to the transition of energy systems. The UMSICHT researchers are working out the potential that cold supply systems in combination with cooling storage systems have for electrical energy balancing. In this context, they develop energy models for the technical-economic evaluation of flexible cooling supply systems. At the end of the project, a web app will be developed, which processes the results for different target groups from practice and science and with which companies can calculate and evaluate FlexKaelte-options.


One of the major challenges of energy system transition is to adapt existing energy supply systems. In the future, they will have to feed and distribute decentralized renewable energies that fluctuate over time. This requires both an expansion of the energy networks and the use of energy storage or load management to balance generation and consumption. In addition to classic energy storage systems such as batteries, heating and cooling supply systems can also be used in combination with thermal energy storage systems.

The cooling sector has a high potential for load shifting

So far, however, research and practice in load management have concentrated almost exclusively on making heating supply systems more flexible – for example in the form of heating pumps, resistance heating systems or flexibly controllable combined heating and power units. With regard to cooling supply, however, there are a large number of research gaps both at the methodological and application level. Moreover, this is despite the fact that the cooling sector also has a high potential for load shifting.

Among other things, cooling can be used to convert excess electricity from photovoltaic systems into cold and store it in the summer. In this case, the load would only have to be shifted over a short time horizon. However, production processes such as those in the food and chemical industries also require cooling in spring, autumn and winter, as do computer centers and hospitals. In concrete terms, the final energy requirement for cooling in Germany is between 80 and 90 TWh/a. Since a large proportion of this is covered by electricity, a total of 14 percent of total electricity consumption in Germany is used for cooling.

Next steps

The UMSICHT researchers are first preparing a meta-study on the extent and type of cooling applications in Germany. Among other things, they will shed light on the technical and economic framework conditions for a possible flexibilization of the cooling supply. Based on their results, they then describe the state of the art in specific cooling applications and categorize them.

This is followed by the development of scenarios for system coupling as well as of models that depict the dynamic behavior of the cooling supply systems and enable an assessment of the flexibilization of cooling plant operation. In parallel, the researchers are looking at real cooling supply systems at ten sample sites. Finally, they evaluate the flexibilization of cooling supply in Germany and disseminate their results – both in the form of a web app and various workshop formats.

Duration: May 2019 to November 2022
Funding code: 03EI1007
Website: www.bmwi.de