Energy-Optimised Building- Experience and Future Perspectives from a Demonstration Programme in Germany

In 1995, the German Federal Ministry of Economics and Technology launched an intensive research and demonstration programme on energy-optimised construction of new buildings as well as retrofitting the building stock. Beside research on materials and components, approximately 50 demonstration buildings covering various building typologies have been realized and monitored within the programme (www.enob.info). Accompanying research was conducted to systemise the results and lessons learned. The programme led to a set of prominent research results in the fields of e.g. daylighting, passive cooling, energy efficiency and renewable energy use in commercial buildings, user behaviour and user satisfaction. Many of the demonstration projects have reached energy savings of 50% and more compared to current practice in Germany, without exceeding conventional investment costs. A number of these projects have been awarded architectural prizes. This paper summarises key findings and explains the strategies for new projects on the route toward net zero-energy buildings. These strategies are based on a further decrease in energy demand and increased renewable energy utilisation in conjunction with intensified use of building-integrated power generation interacting with the public grid. 1 ENERGY-OPTIMISED BUILDING AS A FOCUS FOR RESEARCH Consumption of fossil fuels and the use of electricity in buildings account for about 37 % of the primary energy consumption and 45 % of the greenhouse gas emissions in Germany [Bundesregierung, 2005]. Apart from the dimensions involved, the main point to be noted is that the reduction potential is extraordinarily large and can already be realised with today’s technology. Against this background, the German Federal Ministry for Economics and Technology (BMWi) already initiated an intensive research and demonstration programme in 1995 to investigate energy-optimised construction types for new buildings, now named “EnBau”. The “EnSan” project, addressing renovation of the existing building stock, followed in 1997. In 2005, the Federal Cabinet decided to draw these projects together within a funding concept with the new title of “Energy-optimised building – EnOB”. Work on integrated energy analysis of nonresidential buildings [Voss, 2006a] was particularly significant in advance of the “Energy Performance of Buildings Directive – EPBD” [EPDB, 2003] and the subsequent adaptation of the new German Building Energy Code (EnEV) and its calculation procedure in 2007 (DIN V 18599). Apart from the demonstration activities, the EnOB programme (Fig. 1) also encompasses technological research to further develop vacuum insulation (ViBau) and to investigate low-exergy systems for buildings (LowEx). It is currently being extended with projects on energy-efficient optimisation of operation management (EnBop), energy efficiency in town planning, local and district heating and energy-efficient school buildings. The joint information platform can be found on the Internet under www.enob.info . Fig. 1: Overview of the BMWi research programme for energy-optimised building, divided into sections on demonstration and R & D. Apart from research conducted on materials and components, to date about 50 demonstration buildings of differing types have been newly constructed or renovated, and the results have been evaluated comparatively. The results and experience were documented and published within the accompanying research programme [Gossauer, 2006, 2008], [Hoffmann, 2005, 2007], [Kalz, 2006], [Pfafferott, 2004, 2006], [Voss, 2006a,b]. Since 2007 this accompanying research is carried out jointly by the Universities of Wuppertal, Karlsruhe and Dresden as well as the Fraunhofer ISE. The University of Wuppertal is co-ordinating the joint project.