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Brewing up Energy-Efficient Beer
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- A brewer checks the tanks at the Hasseröder Brewery in Wernigerode.
- (© picture-alliance/dpa)
For many people a cool, freshly drawn beer is one of life's great pleasures. What most beer drinkers don't realize however, is that they are consuming a drink that requires huge amounts of energy to produce. Luckily though, brewing engineers from the Technical University of Munich (TUM) have put their heads together to improve the energy consumption in the production of Germany's national beverage. Their work will ensure that when we drink beer our conscience is weighed down by traditional health concerns and not environmental dilemmas.
For over 100 years one fundamental technical precept has applied to all breweries: You can't brew beer without a kettle. Only a mighty boil kettle is capable of generating the temperatures of 230 to 320 degrees Fahrenheit required to boil down the malty precursor to beer known as wort. This process consumes substantial amounts of energy: Almost half of the overall energy consumption of a traditional brewery―45 percent, to be exact―goes into wort processing.
Now engineers are combining two areas of German expertise―beer and the environment―to help reduce energy consumption in beer production.
The engineers and scientists are looking into a new process combination that would allow energy savings of up to 20 percent during brewing. One approach is to use combined heat and power (CHP) stations, which are highly energy efficient and environmentally friendly due their cogeneration of power and heat.
Combining two heating systems
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- Zeolite is a highly absorbant material that can store enormous amounts of heat.
- (© Courtesy Birger Klitzing, RWTH Aachen)
Engineers face a significant hurdle in adapting this technology for breweries, however. CHP stations do indeed generate heat in addition to power, but only achieve temperatures up 190 degrees Fahrenheit. Boiling down wort requires at least 230 degrees Fahrenheit. To remedy this deficit, engineers from the Institute for Resource and Energy Technology at the TUM have been brewing up ideas since August 2008. They have combined the CHP station with a so-called "zeolite storage system."
Such storage systems work thermo-chemically with zeolite spheres, 2-3 mm in diameter. These porous pellets are made of silicate minerals and have excellent heat storage properties. One gram of zeolite has an internal surface of about 5,400 square feet. The pores absorb water to full saturation. When zeolite is heated, the spheres dry up, and the storage system is charged. Once water is added again, the zeolite spheres release heat of up to 480 degrees Fahrenheit. The brewing engineers at the TUM want to take advantage of this thermo-chemical principle to close the gap between the heat from the station and the temperatures needed to boil down the wort.
To this end, they intend to use an empty time slot in the production process. "At night a medium-sized brewery needs little energy," says project leader Dr. Winfried Russ. "In this time we can feed unused heat from the CHP station into the zeolite storage system." During the day, when high temperatures are required to boil the wort, additional heat can be fed into the overall system almost instantaneously with the "heat boosting" press of a button. This places resource-efficient, low-energy beer within drinkable reach.
Successful simulations
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- The Technical University of Munich is working with the Weihenstephan brewery to develop a pilot program for energy-saving heat-storage technology.
- (© picture-alliance/dpa)
The newly combined production chain works perfectly already in computer simulations, and practical tests are just getting under way. Researchers from the TUM, in collaboration with colleagues from the RWTH Aachen, have now, for the first time, set up a test station at Weihenstephan that uses the new equipment combination to simulate brewery processes. Winfried Russ is eager to see the results: "We already know that it will work. What we don't know is just how much energy can be saved." The researchers are counting on at least ten percent.
In a second step, the TUM engineers intend to model the energy balance of an entire brewery. The cleaning system, the brewing facilities, the fermenting room and storage cellar, as well as the bottling facilities will all be heated at only 190 degrees Fahrenheit instead of using steam of up to 320 degrees. The researchers are counting on this, taken together with the additional waste heat utilization, to result in energy savings of altogether 20 percent.
"This is more than the total savings from all energy efficiency measures taken in the brewing industry during the last ten years," according to Russ. The experiment will have run its course by mid-2011. Both small and medium-sized breweries are eagerly awaiting the results: Potential takers are already showing interest in the pilot project that will follow.
© Young Germany
