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Climate protection with the energy potential from the "underground

Environmental technology specialist Rabmer uses wastewater energy to heat and cool buildings.

Washing hands, showering, kitchen water, washing clothes and much more. – Enormous amounts of warm wastewater accumulate everywhere throughout the day and flow unused into the sewage system. But “clean” energy can be easily and efficiently obtained from this “dirty” wastewater. The environmental technology specialist Rabmer has been dealing with this issue for many years and offers its customers innovative solutions based on state-of-the-art heat exchanger and heat pump systems.

(Altenberg, 30.10.2020.) When the keyword renewable energies comes up, one reflexively thinks of photovoltaics and wind energy. This is hardly surprising, as sun and wind are also omnipresent as sustainable energy sources. However, they are primarily used to generate electricity, while CO2-critical energy sources such as oil and gas are still mainly used to generate heat. Now there is an innovative and climate-friendly alternative. The renewable energy source wastewater is available all year round at an almost constant temperature and can thus be used for heating and cooling buildings by means of state-of-the-art technologies. “This environmentally friendly method of energy generation is becoming increasingly important – finally also in our home market of Austria. Energy from wastewater’ has enormous potential and can, above all, make a significant contribution to climate protection. After all, up to 12 percent of buildings in Austria could be heated and cooled in an environmentally friendly way with this technology,” says Ulrike Rabmer-Koller. The managing partner of the Upper Austrian environmental technology pioneer speaks from experience, as the Rabmer Group and its technology partners have already accompanied many wastewater energy projects from planning to implementation.

One energy source, different technologies and areas of application

For the layman, the most unusual and at the same time most spectacular use of wastewater energy is that which starts directly in the municipal sewer system. This requires a sewer up to a maximum of 300 metres away with a wastewater flow rate of at least 10 litres per second. With the help of innovative heat exchanger systems installed directly in the existing sewer and efficient heat pumps, nearby office and residential buildings, but also shopping centres, hospitals and other public facilities can be heated and cooled in a particularly economical and environmentally friendly way. External solutions are also used for large properties with an output of more than 1 MW. In this case, the wastewater is extracted via a shaft and passed through specially developed heat exchangers placed in a plant room. The energy obtained in this way is then either used for heating on site or can also be fed into the district heating system. For cooling, heat is extracted from the building and released into the duct.

But heating and cooling are not the only issues here; preheating fresh water can also be done with energy recovery from wastewater. Within the framework of “in-house projects”, the Rabmer Group relies on innovative heat exchanger systems that use wastewater heat for the energy-intensive preheating of fresh water. “With these individually tailored solutions, we support companies from the beverage industry, large-scale catering establishments, laundries and wellness and bathing facilities, for example, in saving energy and thus reducing their CO2 emissions,” reports Rabmer-Koller and adds with regard to investment costs: “Our solutions, whether for in-house or sewer solutions, usually pay for themselves after only a few years and thus in many cases have a clear advantage over conventional approaches. Using energy from wastewater means a win-win situation for our customers and the environment!”

About the Rabmer Group

The Rabmer Group is an Upper Austrian family business based in Altenberg near Linz. The company is managed by Ulrike Rabmer-Koller in the second generation and combines tradition with innovation and regional roots with international activities. The main focus is on construction & real estate as well as environmental technology with a focus on water & wastewater technology and renewable energy. For more than 30 years, the Rabmer Group has been providing solutions for climate protection with a wide range of innovative environmental technologies and is considered, among other things, a European pioneer in the field of “excavation-free pipe rehabilitation”. As a Climate Alliance company and bearer of the Austrian Federal Eco-label, great importance is also attached to the topic of sustainability and environmental protection in our own company. Innovative technologies and well-trained skilled workers form the basis for the company’s success – which is why there is also a strong focus on in-house apprentice training. The Rabmer Group currently employs 110 people and generated a turnover of 17.9 million euros in 2019.

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Heat Exchanger In The Canal © Rabmer Group