IEA SHC Task 55: Integrating Large SHC Systems into DHC Networks

Despite the large potential for integrating large solar thermal plants into district heating and cooling networks, the share of solar heat worldwide is below 1%. The aim of this project was to analyse the technical, economic, and regulatory barriers that hinder a faster market development of such systems, and to propose solutions to support the growing heat market. The results (roadmaps, data, information) are available in the form of fact sheets.

Short Description

IEA SHC Task 55 investigated the technical and economic requirements for a significant market expansion of solar district heating and cooling systems in a broad range of countries. A key element of the project was the direct cooperation of SDH experts with associations, companies, and institutions from the DHC community to bridge the gap between the research fields and organizations.

A key innovation of IEA SHC Task 55 is the analysis of systems that have a significant share of solar heat (>5%) and can be cross-linked with hybrid technologies. This required a holistic approach including:

  • Subtask A: Network analysis and integration: analysis of best-practice examples; identification of economically optimal transformation strategies of the entire network toward a maximum share of alternative heat sources (with focus on solar thermal); scenario analyses; SWOT analysis; assessment of seasonal storage and hybrid energy systems; hydraulics analysis of decentral feed-in; development of efficient control and optimization algorithms as well as of strategies for a significant network temperature reduction.
  • Subtask B: Components testing, system monitoring and quality assurance: definition of indicators for performance analysis of different collector types and key components; development of methods for in-situ performance tests; development of automatic fault detection systems of key components; identification of control strategies and self-learning methods for key components.
  • Subtask C: Design of solar thermal systems and of hybrid components: development of new classification standards and certifications and design schemes for solar thermal fields; simulation and design of large collector fields in system operation; development of design guidelines and drafts for large-scale storage systems; elaboration of guidelines for optimized hydraulics and collector systems; proposals for modular construction of large solar thermal systems.
  • Subtask D: Economic aspects and promotion of solar thermal and hybrid technologies: elaboration of guidelines on economic framework conditions and data for optimized connection of hybrid technologies; overview of business models of solar thermal and hybrid systems; investigation of positive and challenging environmental factors in new and existing markets; trend analyses on local and global market developments for large-scale solar thermal heating and cooling systems; preparation of training materials for industry experts and professionals.

The elaboration of trend analyses and guidelines on economic framework conditions are mainly necessary to minimize the investment risks and to evaluate the potential for the expansion of solar district heating in other countries following the Danish success stories or to identify new pathways.

Project Images

Terms of use: The pictures listed underneath the header “Project Pictures” originate from the projects in the frame of the programmes City of Tomorrow, Building of Tomorrow and the IEA Research Cooperation. They may be used credited for non-commercial purposes under the Creative Commons License Attribution-NonCommercial (CC BY-NC).


Publications are available on the website of IEA SHC Task 55.


Austria (Operating Agent), Canada, China, Denmark, Germany, Finland, France, Israel, Italy, Poland, Spain, Sweden, Switzerland, Turkey, United Kingdom

Contact Address

Project lead

Paolo Leoni
AIT Austrian Institute of Technology GmbH
Center for Energy
Giefinggasse 6
1210 Wien

Ralf-Roman Schmidt
AIT Austrian Institute of Technology GmbH
Center for Energy
Giefinggasse 6
1210 Wien

Projekt partners

Sabine Putz
IEA SHC Task 55 Operating Agent
SOLID Solar Energy Systems GmbH
Puchstraße 85
8020 Graz

Markus Gölles, Daniel Muschick
BEST – Bioenergy and Sustainable Technologies GmbH
Inffeldgasse 21b
8010 Graz

Christian Fink, Daniel Tschopp, Philip Ohnewein
AEE – Institut für Nachhaltige Technologien
Feldgasse 19
8200 Gleisdorf

Fabian Ochs
Universität Innsbruck, Institut für Konstruktion und Materialwissenschaften
Technikerstrasse 13
6020 Innsbruck