Renewable façade retrofit for existing high-rise buildings in Central and South Europe

Contributing to improve the overall efficiency of buildings and encouraging the use of renewable energies as well as reducing the use of fossil resources for building operation, is one major target of the European EPBD from 2010. For existing buildings, this implies to apply retrofit measures that increase the overall building energy efficiency tailored to specific building types or special characteristics which address in the same way building skin and HVAC technology. Within the European project "Cost-Effective" solutions have been developed on how to integrate new renewable energy generating façade components within existing commercial high-rise buildings. As roof surface is rather rare, technical concepts focussing on the façade surface for different types of high-rise buildings in different climates have been set up. These concepts include retrofit measures for the building envelope, the HVAC technology and the building operation. Apart from an evaluation of the cost-effectiveness, Life Cycle Assessment (LCA) studies have been performed to assess also the potential environmental effects of such retrofit measures. Three references have been identified therefor: the building stays non-modernized; the building will be upgraded (e.g. improved insulation and use of efficient HVAC technology) but no renewable components are used and finally the whole retrofit concept (including the renewable components) is applied. Depending on climatic conditions, the building construction and HVAC layout as well as including heat or electricity generation via the new developed components, different break-even points regarding the energetic pay back turn out over a given period of 15 years. These results will be presented and the environmental affordable application of the retrofit measures for commercial high-rise buildings will be discussed.