Energy efficiency thought further: the energy activated building envelope as part of the process chain

Public discussion on energy system transformation often takes place exclusively in the context of electrical energy. In the industrial sector in particular, thermal energy plays another important role. Rather than following the purely dogmatic approach of 'saving' energy, our intent is to truly comprehend the energy system and to identify the energetic dependencies within it. The guiding principle and the ETA factory concepts derived from it are targeted toward using the necessary quantity (ultimate energy demand) of the appropriate form of energy (primary energy demand) at the right time (flexible energy supply) and the right location (efficient infrastructure). In practice, instead of the previously isolated optimization of individual components (e. g. machine tools, cooling systems, building insulation), the system of a production factory was considered as a whole and a model factory was built on the TU Darmstadt campus, in which building, building services and machinery were synergetically linked to one another through the three level of building automation system. A significant contribution to increase energy efficiency is made by the thermally activated building envelope made from concrete, which includes a water-bearing capillary-like piping network close to the surface. These multifunctional wall and roof elements combine the functions load-bearing, insulating, enclosing and thermally interacting and act as large heating and cooling surfaces. The paper is a continuation of the article from Bautechnik 03/2014 and presents the results achieved in the research project ETA-Fabrik with focus on the constructional implementation. Background and objectives of the project are taken up from the previous article, the research boundary conditions are described and the results of the energy saving potentials are presented. In addition to a brief description of the implemented thermal networking and the building envelope, the thermal performance of facade and roof elements and their contribution to achieve comfort criteria in the production hall are explained. The architectural concept and a critical appraisal of the interdisciplinary cooperation within a networked factory round off this series on the subject of the ETA model factory.