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Technology - How does energy from wastewater work

In both municipal and commercial construction, environmental goals and energy efficiency are now at the top of the list of criteria. Around 73% of the energy consumption in the building sector is used for heating, cooling and hot water preparation. To date, CO2-critical energy sources have been used almost exclusively for this purpose. It is therefore important to switch quickly to renewable energy sources.

Duct waste heat heats and cools buildings

If office and residential buildings, hospitals or shopping centers are located near sewers with a waste water volume of at least 10 liters per second, these buildings can be heated and cooled with the energy from the waste water in a particularly economical and environmentally friendly way. Here, innovative heat exchanger systems and efficient heat pumps are used, which significantly reduce energy costs and CO2 emissions for systems with an output of 100 kW or more.

With our proven technologies, we provide you with a solution that meets your requirements:

Channel heat exchanger with dry weather channel

  • Suitable for all duct shapes, quick assembly
  • Optimum use of heat, since the entire surface is flooded even in dry weather
  • Supply and return lines are routed below the heat exchanger to ensure easy maintenance of the channel by the operator

External heat exchangers

  • For large projects from approx. 500 kW output
  • Waste water is pumped out of the sewer via a shaft and pre-cleaned using a mechanical filter
  • Extremely high efficiencies (COP 7 to 8) can be achieved using externally mounted heat exchanger bundles and heat pumps

You can find more information about using energy from wastewater to heat and cool buildings here.

Home technology of the future - with hot water treatment

A significant amount of waste water is generated in buildings every day. With innovative, self-cleaning heat exchangers, it is possible to recover up to two thirds of the heat from the waste water and use it efficiently for hot water preparation. The result: less energy consumption, lower costs, less CO2 emissions. Rabmer supplies innovative heat exchanger systems for this!

Plate heat exchanger – once-through system

  • The pre-cleaned waste water flows through the countercurrent heat exchanger and heats the incoming fresh water.
  • A cleaning scraper removes dirt from the heat exchanger surface every day, which ensures optimal heat transfer.

Basic requirements

  • Amount of waste water: at least 2 m3 per day
  • Residential buildings: gray water pipeline separate from faecal sewage; central water heating available
  • Spatial proximity of the sewage pipe to the central water heating system


  • baths, sports facilities
  • Hotels, wellness parks
  • Canteen kitchens, hospitals
  • food processing industry
  • laundries
  • residential complexes
  • retirement home
  • and much more …

More info

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