Foundry heat for school pupils and visitors to the spa

BAD WINDSHEIM– Heating with industrial waste heat: the Windsheim public utility company works in this ecologically and economically reasonable manner and is further extending its district heating grid in the north of the spa town. The Heunisch foundry and the school complex will be connected. If everything goes according to plan, construction should be concluded and trial operations should begin at the end of March.

It stews, smoulders and sparks: cast iron with a temperature of up to 1500 degrees flows along the Heunisch foundry's cupola furnace. It has waste heat potential of several million kilowatt hours. On the other hand, it is not only during the bitter cold that the Franken-Therme require a huge amount of energy to heat up their salt baths; and the pupils in the school complex will not have to freeze in their classrooms.
"We're well on the way to implementing a totally ecological and innovative solution," says Rüdiger Wolf, Head of the Public Utility Company. It looks something like this: the Heunisch foundry will be connected to the northern part of the public utility company's long-distance heating supply and feed up to 2.8 million kilowatt hours into the network. The school complex will also pay to connect to the grid, replacing their heating system which, according to Reinhold Ströbel, the public utility company's technical director, is "in need of renewal"
Until now, the northern part of the long-distance heating supply comprised three feed sources and three consumers. The energy comes from the biogas plant owned by Bio-Energie Bad Windsheim, which is located near Galgenbuck and operated by seven farmers from the region. The biomass heating plant between Windsheim and Külsheim and a plant in the KKC [Spa and Congress Centre] also contribute kilowatt hours to the grid. The energy – around 8.3 million kilowatt hours per year – is sent to the Franken-Therme, the KKC and the Hotel Pyramide.
"Being able to use the waste heat is ideal," says Reinhold Ströbel, commenting on the collaboration with Heunisch. The initiative came from the foundry. Part of the waste heat from the cupola furnace is used by Heunisch itself; supplying the drying plant for the paint on the cast parts as well as buildings on the premises. There is more than enough left to supply other companies.

Thermal baths require constant heating

The waste heat is fed into the district heating grid at a transfer station on Bad Windsheimer Straße. "Depending on what's required," says Jürgen Frank, Head of Maintenance at the foundry, "less in summer, more in winter." According to Ströbel, the thermal baths alone need to be constantly heated. A hot water buffer cylinder of 60 cubic metres will be installed at the biomass heating plant in order to have a constant supply of energy. The public utility company is currently waiting for this to happen. "We expect it to be installed no earlier than mid-February," says Ströbel.
The rest of the construction work should be finished by March. The pipes running to the school complex have already been laid in Raiffeisenstraße and Beethovenstraße. The connections between the biogas plant at Galgenbuck, the foundry and the supply network to the thermal baths have been built already, as well as a pump station. The weather will determine when the pipes can be laid under the railway lines between Raiffeisenstraße and Hofmannstraße. According to Wolf, the rail company approved this over Christmas. "If everything goes well, we hope to be able to begin trial operations at the end of March," explains Reinhold Ströbel.
The school complex, thermal baths, the KKC and the hotel can then be supplied with waste heat from the cupola furnace. But for the foundry, the project could still be improved. "We would be pleased if more customers got on board," says Jürgen Frank. "We have not reached our limits yet. And it is a particularly good solution at a time when it is so important to look after the environment."

Report of Windsheimer Zeitung from 06.02.2012
Photo and story: Stefan Blank