The project consists of two consecutive projects for the thirteen-storey office tower "BS4", which was built in 1975/76 on the inner-city campus of the Technical University of Braunschweig. The office building can no longer meet the functional, structural and technical requirements of today's users.
Thermal comfort in the offices (overheating in summer, draughts) is restricted by the building envelope, which is not rainproof and airtight, and large room depths are the cause of a lack of daylight. The heat and electricity consumption results in high operating costs.
As part of the integral planning process, a refurbishment concept is developed that can be applied to the entire building.
Simulations were used to test the effectiveness of various measures. The results of these studies were incorporated into the planning process, implemented as examples and evaluated in a monitoring phase.
The exemplary implementation was carried out on the tenth floor of the building between May and September 1998, partly funded by the "Deutsche Bundesstiftung Umwelt". The subsequent one-year monitoring phase showed the success of the measures, but also that the necessary weather protection could not be guaranteed with a simple renovation of the existing façade. As a result, the construction of a double façade with integrated photovoltaic elements was proposed, which has been optimized in a pilot project since June 2002 as a demonstration double façade for summer and winter operation.
The refurbishment project focuses mainly on the following areas:
Interaction of floor plan design and improvement of workplace quality
Reduction of heat and electricity consumption by more than 50%
Reduction of summer overheating and night ventilation
Use of building automation systems, e.g. for artificial light or window ventilation
The demonstration façade examines simple and practical solutions:
Possibility of refurbishment during ongoing operation
Summer overheating: parameter study on opening geometry and air exchange
Sound insulation: parameter study to improve immission control
Upgrading the existing façade: reduction of wind-induced pressure peaks and driving rain protection
Investment and operating costs: comparison with conventional façade refurbishment
The gross costs for the overall measure, including the façade refurbishment, amount to €690/m² GFA for cost groups 300+400. The project is intended to show the extent to which a comfortable and energy-efficient refurbishment is possible at minimal cost. Adherence to the cost framework is crucial when transferring the results to similar office buildings.