SCHOTT solutions no. 1/2010 >Solar Architecture

ertex solar and SCHOTT developed a solar architecture solution for the awning of the REWE Green Building that features efficient polycrystalline cells from SCHOTT Solar Photo: REWE Group

Efficient Energy Management

The REWE supermarket chain is putting the concept of sustainability to practical business use with its ”Green Building”. It can be operated without producing any CO2 and even includes a solar glass architectural solution.

Christine Fuhr

Only shortly after it officially opened in November 2009, the REWE Green Building in Berlin is already becoming a success story. The supermarket designed according to the latest state-of-the-art technology consumes considerably less energy than a normal supermarket and has already received numerous awards for its ”futuristic concept”: a gold prize from the German Sustainable Building Council (DGNB), ”Store of the Year” from Germany’s retail trade association HDE, in addition to being nominated for the EU Commission’s ”Sustainable Energy Award 2010”.

For the REWE Group, sustainability is not a trend, but rather an attitude, and this is reflected in numerous activities and initiatives. In Germany, for instance, REWE is a pioneer in the area of green power and has been offering fair trade food products for more than 15 and bio products for over 20 years.
Photo: REWE Group
With its first Green Building anywhere in Germany, the company has set both national and international standards for sustainable building construction and operation of commercial real estate. The 1,830-square meter sales floor is operated in a CO2 neutral manner. Thanks to the modern heating, ventilation, air-conditioning and refrigeration units that are used in combination with the proper insulation, the company achieves energy savings of nearly 50 percent in comparison to a normal building. Only natural cooling agents are used in the refrigerators and deep-freeze units. SCHOTT Termofrost® freezer doors in the Eco-Clear™ version are being used in the upright freezers. The main advantage that this ”passive” door concept offers is that these doors no longer need to be heated in order to prevent them from fogging up when they are opened, an aspect that saves a lot of energy.
SCHOTT Termofrost® Eco-Clear™ is being used for the doors of the upright freezers. The advantage is that the doors no longer need to be heated, and this saves energy. Photo: REWE Group
The Green Building produces about 40 percent of the energy it needs itself. A photovoltaic system that is nearly 2,000 square meters in size combines the system installed on the roof with a glass-integrated photovoltaic system located in the awning. The architectural solution that was realized by ertex solar GmbH from Amstetten, Austria, uses solar cells from SCHOTT Solar. 99 laminated safety glass elements in an overhead version were used. 8,712 efficient polycrystalline 6-inch cells from SCHOTT Solar were laminated into the modules that are each capable of delivering 311 watt peak (Wp). With a total output of 30.79 kilowatt peak, approx. 27,000 kilowatt hours of electricity can now be produced locally. Transparency of 23 percent was selected in order to allow for a certain amount of daylight to enter into the market.

The concept of daylight architecture is realized in the Green Building using a 280-meter stretch of glass and 18 light domes on the roof that capture daylight. These were then combined with sustainable materials like wood to create a visual symbol for sustainability that can be seen from afar. A geothermal system ensures that no fossil fuels will ever be needed at any time during the year. Additional savings are achieved by using rain water instead of precious drinking water to clean the floors, flush the toilets and irrigate the garden. And those who perhaps drive here to go shopping at Groß-Ziethener Chaussee 37 in Berlin in their electric cars can tank up with ”green” electricity at the service stations that provide certified green electricity from renewable energy.
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