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Closing the last Energy “Leak”

das-letzte-energieleckThe heat contained in wastewater is one of the last major untapped resources in the field of renewable energies, despite the fact that it may some day provide some 20% of the heating energy we need. This huge potential has been addressed by a Swiss engineering company, Rabtherm AG, which now supplies patented technology for generating energy from wastewater, used for heating or cooling buildings. Rabtherm is the original technology for waste water heat recovery.

The brainchild of Urs Studer, an expert in building technology, Rabtherm AG was established in Zurich, Switzerland, in March 2000. Although the concept was warmly welcomed in the energy technology market from the very beginning, Rabtherm’s entry into this field of business was sluggish, especially with oil and gas prices still being very low at the time. This changed dramatically in 2007 as the price of oil started to soar. The company employs eight members of staff, as well as sixteen freelancers. All components are manufactured by licensees in Germany, Switzerland, Canada and South Korea.

The Rabtherm concept is both simple and ingenious: when wastewater is emitted from buildings, it has a temperature of around 25°C, and even in extremely cold winters, temperatures in the sewers seldom fall below 12°C. This heat can be extracted using patented heat exchangers installed in the sewers - a very environmentally friendly type of energy recovery system indeed. Depending on the system of electricity generation used to power the heat pump, the carbon footprint could be reduced by 30% to 85%. Over and above the patented technology, Rabtherm provides customers with the initial analyses, location, potential and feasibility studies, and other profound advice.

The advantages of the technology are obvious: it is economic and environmentally friendly, emits no particulate matter, reduces annual energy costs by 20% to 30%, is independent from fossil energy, and the return-on-investment is less than six years. Rabtherm technology is primarily aimed at customers with a high demand for heating or cooling energy, such as in municipal buildings, schools, sport venues, swimming baths, industrial and commercial buildings, housing estates and so on. The company exports its product around the world with a ninety-two-percent export rate - our single biggest market at this point is Germany. Other important export destinations are the United States, China, Canada, France, Korea, the Netherlands, Austria and Great Britain. One of our current customers is Harvard University in Boston.

Rabtherm builds total energy systems with guarantees of power in kW and temperature for the need of the customer. The system includes sewer pipe, heat exchanger, connecting pipes, any type of heat pumps (electric, gas motor, absorption), peak boiler, all installations in the energy plant, control systems. We designed and installed the first absorption heat pump 20 years ago.

Rabtherm is always ahead in research and development, having invented an anti-fouling system to prevent the formation of an insulating biofilm and a new heat exchanger material with a 80 % better heat conductivity. The two inventions brought Rabtherm 40 % ahead of the present market solutions. A new overruling control system brings 15 – 20 % less operating cost, controlling waste water flow, operation of the heat pump and the peak energy system. Our experience in building technology is 40 years, in waste water technology 20 years.