Heat is the largest energy end-use, accounting for 50 % of global final energy consumption in 2018 and contributing to 40 % of global carbon dioxide emissions. Of the total heat produced, about 46 % was consumed in buildings for space and water heating at relatively low temperatures. Regarding the heat supply of buildings, district heating systems play an important role and are well-established in many countries since they typically enable efficient resource utilization.

However, most district heating networks in Europe and worldwide still operate with supply temperatures over 80 to 120°C (medium-high temperature), which is still typically produced by caloric power plants. Currently available solar district heating (SDH) systems are mainly operated with flat-plate collectors providing either heat at lower temperatures or with lower efficiency in case of higher temperatures.

To increase the efficiency of SDH systems, the purpose of the Task is to investigate how:

  • to provide the heat most efficiently at the desired temperature level either directly by solar (e.g., combining flat-plate collectors with other solar collectors) or indirectly by solar by combining solar collectors with other technologies (e.g., solar collectors with heat pumps) focusing on the system aspect instead of single technologies.
  • to take a next step regarding digitalization measures in order to allow for more efficient data preparation (e.g., regarding the gathering, storing, validation, and visualizing of data) and data utilization (e.g., regarding control strategies, automatic fault detection, predictive maintenance aspects, open data) 
  • to make SDH systems more competitive and business appealing by exploring new business models and finding ways how to reduce costs
  • to raise awareness for solar technologies and disseminate the knowledge regarding SDH systems, especially for medium-high temperature heat, by collecting and providing best practice examples, country reports, and data and insights from real installations.

The objectives of the Task are to:

  • Continue the work on Solar District Heating systems from Task55 and former Tasks.
  • Provide an overview on the present state-of-the-art of solar collector technologies for providing medium-high temperature heat (80 – 120°C).
  • Provide an overview on possible SDH system configurations (combination of technologies) in order to efficiently provide medium-high temperature heat either directly by solar or by combining solar with other technologies. 
  • Give an overview and examples of present state-of-the-art digitalization measures regarding data preparation, i.e., how data can be gathered, stored, distributed, validated.
  • Give an overview and examples of present state-of-the-art of digitalization measures regarding data utilization, i.e., advanced control strategies, automatic monitoring. 
  • Explore and propose possible new business models for SDH systems in general but also considering medium-high temperature heat as well as digitalization measures.
  • Investigate ways of cost reductions in the balance of systems (BOS) for SDH systems in general but also considering medium-high temperature systems. In particular, to investigate possibilities for cost reduction based on the insights from measurement data analysis.
  • Gather results and operating experience from SDH systems in general, in particular, systems efficiently providing medium-high temperature heat by solar (directly or indirectly).
  • Provide scenarios how to decarbonize the district heating sector and investigate, collect and compare EU wide grant mechanisms for SDH systems.