Behind the historic brick walls of OTTO Textil GmbH’s woolen mills – which opened in 1861 – workers were still producing specialty yarns until 2020. Largely protected structures, the buildings are now being renovated and new contemporary buildings added to transform the area into a lively mixed-use neighborhood with a highly efficient energy design by 2027. The consulting company Drees & Sommer with headquarters in Stuttgart is supporting the property developer, HOS Group, with the implementation of a smart heat network for the entire site using an internet-based technology platform. Another member of the consortium for the purposes of the N5GEH BOOSTER research project is RWTH Aachen University.
Everyone wants to use green heat, but too few people know how to – whether for heating, hot showers or the manufacturing of industrial products. Eighty percent of German houses and apartments still obtain their heat from fossil fuels. This is seriously slowing down the energy transition. In the development of the Neckarspinnerei neighborhood in Wendlingen, near Stuttgart, HOS Group is demonstrating a different approach. The developer is implementing a fourth-generation heat network for the carbon-neutral running of the future urban quarter. ‘The Neckarspinnerei is one of the first projects of this kind in Germany. When it is completed, the neighborhood will produce and use only renewable heat, cooling and electricity. This will not only make Neckarspinnerei completely climate-neutral despite its special historic architecture, but also overcompensate for CO2 emissions of up to 300 metric tons per year. That makes our project a model for the transition of existing buildings to green heating,‘ explains Andreas Decker, Managing Director of HOS Group.
The highly efficient heat and energy design is based on a smart supply mix. One exciting element of the design is a run-of-river power station, which has supplied the site situated on the Neckar river with energy since the factory opened. Also, climate-friendly electricity will soon be provided by photovoltaic panels on the roofs. Together they will produce around 4.5 gigawatt-hours of green electricity per year. Around two-thirds of the energy produced – of which about 62 percent will come from hydroelectric power stations and 38 percent from PV systems – will be used by the neighborhood itself with the help of an electricity storage system, and the rest will be fed into the electricity grid. Neckarspinnerei will obtain its renewable heat from the surface water of the Neckar river by means of heat pumps and a large ice storage unit. Wastewater heat will also be put to use.
Practical Know-How Combined with Top-Level Research
The development of green and intelligent heat networks depends not only on sophisticated energy infrastructure, but also on digital networking. In the Neckarspinnerei neighborhood, the Internet of Things (IoT) is being used to optimize energy systems and try out solutions for carbon reduction. Drees & Sommer’s energy consulting and IT expertise is a core part of this project. The team of experts from the company is working with researchers from RWTH Aachen University to develop an IoT platform specially for the Neckarspinnerei neighborhood as part of the Booster research project. Dr. Thomas Schild, expert in energy and sustainability design at Drees & Sommer SE, explained: ‘Up to now, IoT applications have concentrated only on special interfaces and data formats, or services such as optimum heating system operation. The interdependencies between these and other building facilities are often neglected. This may result in an efficient heating system, but there will be unused potential in the ventilation or air conditioning systems. The new platform ensures that every individual system in Neckarspinnerei – from heating to water, to ventilation – is digitally networked end to end, coordinated, and continuously optimized over its entire operation. The solutions tested and the knowledge gained in this way will later serve as a blueprint for IoT-based enhancement of the operation of future neighborhoods and groups of buildings. The development of the innovative heat network in Neckarspinnerei also received funding in the form of a grant for efficient buildings (BEG) from the German Federal Office for Economic Affairs and Export Control (BAFA).
A Green Heat Network Is only Possible for Existing Buildings that Are Green.
An important element of the design of the heat network is the renovation of the existing buildings. For Drees & Sommer’s team of experts, this meant a thorough examination of each of the historic buildings, including the spinning mill building, various workshops and the former owner’s mansion. The team found that for climate-neutral operation, all existing buildings had to be renovated in a way that enabled them to be supplied by heat pumps. This necessitates insulation and surface heating and cooling systems compatible with the protected status of the buildings, and a ventilation design that uses a maximum of natural ventilation. To meet the conditions for an energy supply from exclusively renewable sources, all this renovation work has to be carried out on the existing buildings, and the new buildings have to be constructed to plus-energy standard. Another element, invisible but crucial, is a predictive operating strategy. This helps to coordinate the use of the storage capacity so that climate-positive operation can be maintained over the whole year.
When finished, the site will have a total floor area of around 50,000 square meters, divided between residential, work, retail and culture spaces. A mobility plan will provide good connections between the neighborhood and local public transport, as well as cycle and pedestrian routes. By 2027, Neckarspinnerei will be developed into an attractive, sustainable neighborhood for families, young entrepreneurs and creatives.
The competitive tendering process for the development area was run jointly with IBA’27 and the city of Wendlingen. The winning design was from architecture firm Rustler Schriever and landscape architects gornik denkel. The NQ Festival, which will be held at the site on July 8, 2023, will provide a glimpse into the future of the Neckarspinnerei neighborhood. A variety of artists, technical experts, young people and pioneers will come together at the event, galvanized by the festival’s name, Remix. For further details, please see the program.