In the south of the city of Chemnitz, the energy supplier "eins energie in sachsen GmbH & Co. KG" operates the Altchemnitz heating plant. After 40 years of operation, the plant had to be completely modernised. Viessmann Industrial Boiler Solutions GmbH, a company of the Viessmann Industrial Systems Division, was awarded the contract for the complete conversion.

Viessmann installed a completely new heating system in an existing building. The basis for this is formed by special shell boilers. Three identical models, each with 33.3 MWth, contribute to supplying around 40 percent of households in the region with hot water and heating water. Viessmann supplied not only the boilers, but also the burners, chimneys, flue gas system, electrical wiring, piping and insulation.

Viessmann Industrial Boiler Solutions was responsible for project management from plant engineering to installation and commissioning. Boilers of this size are manufactured at the Viessmann subsidiary HKB in the Netherlands. The boilers were specially designed so that they could be transported by road.

A particular challenge was the installation of the boilers, each weighing 70 tonnes, in the narrow boiler house. Crane and transport devices were installed especially for this application in order to bring the boilers to their final locations.

Since commissioning at the end of 2018, the three double-tube boilers have been feeding up to 100,000 kilowatts into the district heating network as required. The emission values are below the legal requirements.

With two power plants, one with a total length of approx. 300 kilometres operates one of the largest district heating networks in Germany. Altchemnitz is only used as a peak heating plant when required, for example during a particularly cold or long winter period or during maintenance work at the main plant. Thanks to the modular design, the three boilers can be switched on flexibly.

Not least for the operators was the fact that they were able to operate the boilers without any need for operation or monitoring, which was an important criterion in awarding the contract to Viessmann. The power station is controlled from a central control room. For Silvia Trümper, head of the heating and power generation department at one, replacing the old hot water generators fulfilled a great wish: "I am delighted that a good system has been created and that we were able to complete the project successfully together with Viessmann.