Energy from wastewater: a children daycare in Munich uses HUBER ThermWin
As part of Munich's Education Construction Initiative, Germany's largest municipal education construction programme, it was decided in 2020 to build a new daycare centre with three nursery groups in the Freimann/Kleinlappen district. The chosen location was an undeveloped plot of land on Josef-Wirth-Weg. A special feature of the building site is a sewer that runs slightly elevated in a dam to the north of the property. This sewer is not just a simple collection channel, but one of the main inflows to Munich's Gut Großlappen sewage treatment plant.
Sustainability was a guiding principle in planning and construction
From the outset, sustainability was a key consideration in the planning of the daycare centre. The centre was designed as a passive house using timber construction. The building was also designed to be 100% renewable. The engineering firm Eder was commissioned to develop and plan an energy concept that met the client's sustainability requirements.
Focus on alternative energy sources
However, as the location was outside the urban district heating network, alternative energy generation options had to be explored. As well as near-surface geothermal energy, the possibility of utilising the heat from the sewage in the channel flowing directly past was considered.
HUBER as a partner for innovative energy use
At the end of 2021, HUBER received a request from the engineering firm for a feasibility study of the HUBER ThermWin system for this project. Initial energy designs by HUBER showed that the conditions for wastewater heat recovery were excellent. An on-site meeting with HUBER, the engineering firm and Munich's municipal drainage authorities also showed that the location of the sewer and its height in relation to the construction site were favourable for such an application. The city of Munich now pushed ahead with plans to heat the daycare centre with a wastewater heat recovery system, and the engineering firm Eder was awarded the planning contract.
Unique installation arrangement of the HUBER machines
Throughout the planning phase, HUBER was always available to answer questions and provided plans for the shaft and plant technology free of charge via its in-house plant planning department. In collaboration with the building authority, the architect and the engineering firm, a plan was developed to implement the ThermWin system into the open-group concept of the daycare centre. This resulted in a unique arrangement for installing the plant system. It was planned that the HUBER RoWin wastewater heat exchanger and heat pump would be installed on the first floor, while the shaft for the pumping station screen would be located in an annex beneath the pram parking area.
Delivery and commissioning
In mid-2023, a tender was issued for the heating system, which also included the HUBER Pumping Stations Screen ROTAMAT® RoK4 300 and the RoWin 4 wastewater heat exchanger. The contract was awarded to a Munich-based heating system manufacturer, which placed its order with HUBER at the end of 2023. In autumn 2024, the HUBER system was delivered to the construction site and installed by the service team.. The heating plant was commissioned in December.
