Solar energy in building renovation - results and experience of international demonstration buildings

If the use of solar energy is to mean that significantly less fossil fuel will be consumed, solar systems must be readily adaptable to existing buildings as well as new buildings. Under the Solar Heating and Cooling Programme of the International Energy Agency (IEA), Task 20 "Solar Energy in Building Renovation", a number of the most promising solar concepts and systems for building renovation were explored. The first activity was a performance analysis of existing solar renovation projects [J.-O. Dalenback, Solar Energy in Building Renovation, Energy in Buildings, 24 (1996) 39-50.]. Drawing on the information gained from these case studies, promising concepts with respect to energy savings and replication potential were identified and investigated by simulation studies [A. De Herde, Improved Solar Concepts, Technical Report, 1997, Centre de Recherche en Architecture, Universite Catholique de Louvain, Belgian.]. Strategies for incorporating these concepts into the renovation process were developed [O.B. Jorgensen, Solar Renovation Demonstration Projects, Technical Report, 1998, Esbensen Consulting Engineers, Copenhagen, Denmark.]. Fourteen demonstration projects mostly focusing on multifamily dwellings featuring solar concepts were initiated, implemented, and evaluated. This article summarises the cross-analysis of the demonstration projects, evaluated between 1995 and 1998. The analysis covers technical, economic, and building physic issues of solar collectors, glazed balconies, and solar walls. The aim of a renovation design process is generally not to find the cheapest solution to maintain a proper building function. Renovation deals with a balance of maintenance, improvement, and architectural topics within a given budget. The analysis of the demonstration projects proves that solar technologies have their place - financially, technically and architecturally - as part of integrated renovation concepts. Many of the demonstration projects evaluated tend to be "solar dominated" as the analysis of the technology is a main topic. A wider market penetration of solar concepts needs compromises in the size of the solar systems with respect to the investment. The first and primary requirement for future projects is improved cost competitiveness of solar concepts compared to the regular renovation measures. (C) 2000 Elsevier Science S.A. All rights reserved.