Bau-DNS – Holistic Process for Sustainable, Modular and Circular Building Refurbishment

The majority of the building stock in Germany is in need of energy-efficient refurbishment - the annual refurbishment rate is less than 1%. In order to achieve the climate policy targets in the construction sector, an energy renovation rate of well over 2% per year and a rapid switch to renewable energy sources in building operation are required. In addition, considerable increases in efficiency in production are necessary.

The Fraunhofer lead project "Bau-DNS" aims to significantly increase productivity in the construction industry, particularly in building refurbishment, and at the same time create the conditions for cost reductions. Three parallel process strands are being pursued, which are highly interdependent and must therefore be optimized simultaneously: the consistent use of data, the design of sustainable processes and the systemic production of components.

The increase in the rate of energy-efficient refurbishment has so far failed due to two main problems: On the one hand, there are foreseeably not enough craftsmen and skilled personnel to increase the refurbishment rate. On the other hand, many owners are not prepared to invest in comprehensive building refurbishment, as the costs have so far only been amortized over a very long period of time through the energy costs saved.

As part of the project, an integral construction process is being developed and implemented as a prototype to ensure the consistent use of data. Optimized and simplified digitization of the building stock will create the basis for a digital twin, which will serve as a data management tool and information model. In addition to the data already mentioned, a material database will be set up to enable the selection of materials that are ecologically and economically sensible and therefore sustainable. The material data contained will also be used to develop a modular system to support the circular economy and CO2 reduction. Through this process, individual components can be qualified and automatically provided as individual modules for systemic production. At the same time, this enables the industrial production of precisely fitting components for building renovation, including adapted logistics, optimized for this process.

“Bau-DNS” examines the planning process on the basis of the usual description of planning and construction phases to the German HOAI. The aim is to show how productivity increases can be achieved with a consistent integral workflow and how the agility of the processes can be increased through newly developed structures. Construction and refurbishment processes can thus be thought of completely from the end - i.e. from dismantling and recycling - and the building survey, planning, component development and factory design can be organized and improved accordingly.

Fraunhofer ISE's focus within the project is on the development of digital process descriptions and optimizations that map the entire construction process and simplify the planning and installation of BIPV products on façades. Innovative, easy-to-install and easy-to-dismantle BIPV modules with an insulating function are also being developed and demonstrated.