The companies Bosch Thermotechnology and Bosch CHP have been working closely with Stadtwerke Gießen (SWG) for many years. Thanks to their many positive experiences, the heating experts from Lahnstrasse use products from the Bosch Group in their projects whenever possible. This renowned group of companies also includes the long-established company Buderus, whose subsidiary Buderus Immobilien maintains 182 flats in Lollar. The 38 buildings have been receiving efficient district heating from Stadtwerke Gießen since November 2018.
"Connecting the buildings to the existing district heating network proved to be the most sensible option," says Thimo Rieger, SWG customer advisor, summarising the previous discussions. Because Buderus Immobilien had to act. "The heating systems were due for renewal," explains Sabine Olbrich, Managing Director of Buderus Immobilien. However, district heating was not only a cost-effective solution that could be implemented quickly. It also opens up a really exciting option for the future. This is because the plants in Lollar produce a lot of waste heat that could potentially be used to heat flats. "Nobody can say for sure today whether this approach will actually become reality. But the conditions are in place," summarises Thimo Rieger.
Everything up to date
The conversion of the 38 buildings to district heating took a good six months. SWG first had the necessary connecting pipes laid between the individual buildings and the existing heating network. The old boiler systems were then replaced by ???ANZAHL??? transfer stations. The district heating reaches the individual buildings via these stations. The compact, weather-controlled appliances and the hydraulic balancing carried out in all flats ensure optimum utilisation of the heat energy supplied. After all, a heating system can only work optimally if the same pressure is applied to all radiators, i.e. the same amount of water flows through each unit of time. "To achieve this, it was necessary to replace around 900 conventional thermostatic valves with pre-settable ones," explains SWG project manager Christian Spratte. Naturally, models from Buderus were used for this. It goes without saying that the setting values of each individual valve were meticulously documented. Christian Spratte also ensured that the now superfluous chimneys were professionally sealed.
Buderus Immobilien not only offers its tenants maximum efficiency for heating and hot water. State-of-the-art technology also makes billing more transparent: Heat meters transmit the consumption values via a so-called M-Bus system. "It couldn't be more precise and easier to understand," says Thimo Rieger.
Even more plus points
Switching to district heating has even more advantages. For example, the primary energy requirement and therefore CO2 emissions are reduced. In addition, Buderus Immobilien saves massively on maintenance costs. This is because district heating systems usually require no inspection and work reliably for many years. The company also saves the costs for the chimney sweep.
Incidentally, the heat energy required for the 29 properties comes from the heating centre in the Lumdaniederungen development area. Here, a modern combined heat and power plant from Bosch KWK converts environmentally friendly natural gas into heat and electricity. This dual utilisation of the primary energy used is what makes district heating so efficient. To generate one kilowatt hour of heat, SWG only has to use 0.6 kilowatt hours of natural gas primary energy - i.e. natural gas or heating oil. And should the idea materialise and the waste heat from the two Bosch plants actually provide pleasant temperatures and hot water in the Buderus homes in the future, this would significantly improve this balance even further.