Energy from wastewater: New building complex in Bremen uses HUBER ThermWin for heating and cooling

A new future quarter for business, living, work, culture and leisure is currently being built in Bremen – with a sustainable energy supply from wastewater: Europe's once largest tobacco factory is being revitalised into the “Tobacco Quarter” building complex. The quarter has reinvented itself, turning an outdated industrial site into a prime example of urban development with its finger on the pulse of the times. It is one of the largest urban development areas in northern Germany.

The new Tobacco Quarter will utilise energy from wastewater for heating and cooling with the help of the HUBER ThermWin system. On average, 1 MW of thermal energy will be used for heating and around 0.4 MW for cooling building sections of the new urban quarter. The sustainable overall concept of the Tobacco Quarter was awarded the DGNB Gold pre-certificate by the German Sustainable Building Council (DGNB) in 2023.

Technical solution together with swb and hanseWasser

At an initial meeting in 2021, an inspection of an existing pumping station took place in order to assess the extraction situation. This took place with the parties involved in the project, hanseWasser Bremen GmbH and swb Services AG & Co. KG. Based on the wastewater volumes and temperatures, numerous potential analyses were carried out as part of a feasibility study. hanseWasser Bremen GmbH was able to provide extensive measurement data and it soon became clear that wastewater as a resource could make a major contribution to a sustainable energy supply for the new urban quarter.

Experience utilised from existing HUBER system in Bremen

swb Services AG & Co. KG, the sales company for technical services of Stadtwerke Bremen, the Bremen municipal utilities, contacted HUBER SE: One of the reasons for this was that HUBER had already supplied a plant for energy recovery from wastewater to hanseWasser Bremen GmbH about ten years ago. A HUBER Heat Exchanger RoWin size 4 reliably operates at the pumping station in Bremen.

”Exclusively positive feedback“

According to Frank Estler, Project Manager at swb Services, the reasons in favour of the HUBER ThermWin system were obvious: ”When looking for a suitable heat transfer system, two points were particularly important to us. The system had to have proven its efficiency in practice and the maintenance effort on the wastewater side had to be minimised. We received exclusively positive feedback from hanseWasser from the project in Findorff on both points and on the cooperation with HUBER.“

The HUBER ThermWin system

The HUBER ThermWin system enables the heating and cooling of buildings by utilising the wastewater in the sewerage system as a regenerative energy source. The temperature of wastewater in the sewerage system is usually between 12 and 20 °C and hardly drops below 10 °C even in winter, which is why wastewater is an ideal energy source for operating a heat pump. All larger buildings and local heating networks are suitable consumers of the heating energy obtained in this way.

Part of the wastewater flowing through the sewer is first passed through a HUBER water pre-screening solution (e.g. usually a screen such as the HUBER Pumping Stations Screen ROTAMAT® RoK4), which removes the coarse material from the wastewater. In the Bremen Tobacco Quarter project, the raw wastewater is pre-screened by a HUBER Rotary Drum Fine Screen ROTAMAT® RPPS 1400. The wastewater is then distributed into three HUBER Heat Exchangers RoWin, which are installed above ground and specially developed for wastewater, and then flows back into the sewer. Inside the heat exchanger, the heat is exchanged with the secondary circuit, which is coupled with the heat pump.

Federal funding for efficient heating networks

The HUBER ThermWin process utilises wastewater as a long-term secured and constantly renewing energy source to enable an environmentally friendly and sustainable process for heating and cooling buildings. Fossil fuels such as gas, oil or coal can be saved and CO₂ emissions minimised. In future, the Tobacco Quarter will save around 245 tonnes of CO₂ per year. This is why this project is subsidised by the Federal Ministry of Economics and Climate Protection (BMWK) under the Federal Funding Scheme for Efficient Heating Networks (BEW). With this funding measure, the BMWK supports the construction of new heating networks with a high proportion of renewable energies as well as the decarbonisation of existing networks.

1 MW for heating, 0.4 MW for cooling the Tobacco Quarter

The plant for energy recovery from wastewater is expected to supply energy to the city quarter in October 2024. Three HUBER Heat Exchanger RoWin units will then utilise an average of 1 MW of thermal energy for heating and around 0.4 MW for cooling sections of the building. Another important contribution to sustainable and environmentally friendly building and urban planning with exemplary character – and a lighthouse project for HUBER.