Development of unglazed solar absorbers resorting to coloured selective coatings on steel for building facades and integration into heating system

Project duration: January 2003 – June 2006
Contacts: Christian Roecker, Maria-Cristina Munari Probst

This project was part of the 5th Framework Programme of the European Commission, specific programme “Energy, environment and sustainable development (EESD)”.

photo of coloured unglazed solar collectors used as building elements on a demonstration module


The main objectives of SOLABS were:

  • Development of an innovative solar system featuring a significant decrease of the capital costs and unit cost of the delivered heat (target: 0.025-0.03 €/kWh).
  • Development of weather-resistant, coloured selective solar absorbers made of steel. To reduce the costs, the collectors were to be unglazed and designed for integration in the building, particularly in facades.
  • Major improvement of the public acceptability (non technical barrier) thanks to colours.
  • Simplified implementation in large office, residential or industrial buildings for new or retrofit applications.

The LESO-PB Renewables Integration Group was responsible for

  • Specifications for the architectural integration of the absorbers
  • Architectural design
  • Dissemination of results


To evaluate the aesthetic requirements for a widespread use of solar thermal technology, a major survey was conducted among European architects and engineers on the architectural integration quality of several systems. Design and development decisions were based on this survey. > Survey Results

Project participants

LESO-PB Project participants: Maria-Cristina Munari-Probst (PhD Student), Christian Roecker (Group leader)

Project coordinator: Fraunhofer Institut Solare Energiesysteme (Germany)

Project participants: Clipsol (France), Dortmunder Oberflächencentrum GmbH (Germany), Ecole Polytechnique Fédérale de Lausanne (Switzerland), Institut für Solartechnik SPF (Switzerland), Interpane Solar Beschichtungs GmbH (Germany), National Institute of Chemistry (Slovenia), Planair SA (Switzerland), Thyssen Krupp Stahl AG (Germany), Universidad de Málaga (Spain)

Main Publications

  • Munari Probst M.C.; Roecker C. Towards an improved architectural quality of building integrated solar thermal systems (BIST) In Solar Energy, vol. 81, num. 9, 2007, p. 1104-1116 (2007)
  • Munari Probst M.C.; Kosoric V.; Schüler A.; De Chambrier E. and al. Facade Integration of Solar Thermal Collectors: Present and Future In CISBAT 2007, p. 171-176, Lausanne, EPFL, 4-5 September (2007)
  • Munari Probst M.C.; Roecker C. From Thermal Collectors Integration to Active Façade Systems In PLEA 2007 – The 24th Conference on Passive and Low Energy Architecture, Singapore, 22-24 November (2007)
  • Roecker C.; Munari Probst M.C.; De Chambrier E.; Schüler A. Facade Integration of Solar Thermal Collectors:A Breakthrough? In ISES Solar World Congress 2007, Beijing, 3-6 September (2007)
  • Munari Probst M.-C.; Roecker C. SOLABS: Development of a Novel Solar Thermal Façade Cladding System Presented at EUROSUN 2006, Glasgow, United Kingdom, June 27-30 (2006)
  • Integration and formal development of solar thermal collectors / Munari Probst, M.-C.; Roecker, C. – Presented at PLEA 2005, Beirut, Lebanon, November 13-16. BEST PAPER AWARD!
  • Architectural integration of solar thermal collectors: results of a European survey / Munari Probst, M.-C.; Roecker, C.; Schueler, A. – Presented at ISES 2005 Solar World Congress, Orlando, USA, August, 6-12.
  • Specifications, criteria and user’s wishes for architectural integration of solar collectors / Munari-Probst M.C., Roecker C. Final report. Deliverable D1.1 EU SOLABS project, August (2004)
  • Impact of new developments of the integration into facades of solar thermal collectors / Munari Probst, M.-C.; Roecker, C.; Schueler, A.; Scartezzini, J.-L. – In EUROSUN 2004 Proceedings, Freiburg in Brisgau, vol. 2 (2004), p. 351-357.