The digging has already begun in Aznalcòllar, Spain, even if the official ground-breaking ceremony is scheduled for July. The timetable for the construction project is ambitious: By the spring of 2008, receivers for solar thermal power plants with a total annual output of 150 to 200 MW will be manufactured on the factory’s 18,000 m² premises. In doing so, SCHOTT will effectively double its current manufacturing capacity of 150 MW that the company has been manufacturing at its site in Mitterteich, Germany, since August of 2006.
“Andalusia lies close to the earth’s sunbelt. This is why many solar thermal power plants will be built here in the years to come,” explains Dr. Martin Heming, member of the Corporate Management of SCHOTT AG and Managing Director of SCHOTT Solar GmbH, in explaining why the site was chosen. “We are a technological leader and the close proximity to excellent sites for solar thermal power plants in Europe and North Africa will strengthen our market position quite considerably,” he adds.
Solar thermal power plants generate electrical power in an environmentally friendly and efficient manner. Parabolic mirrors bundle the incident sunlight along the caustic line. This is where the receivers, specially coated, vacuum-insulated absorber tubes made of borosilicate glass, are found. Up to 80 times the concentrated solar radiation heats up the heat transfer fluid that flows through the receivers. The resulting temperatures of up to 400 degrees Celsius generate steam inside a downstream heat exchanger that drives the turbines inside a steam power plant.
SCHOTT receivers offer higher efficiency
The receiver is regarded to be the key component for ensuring the efficiency of solar thermal power plants. Light is converted into heat inside the heart of the evacuated tube. Comparative measurements conducted by the German Aerospace Center (DLR) revealed that the efficiency level of receivers from SCHOTT is approximately two percent higher than that of competitive products.
A novel anti-reflective coating on the outside of the glass cover ensures that more than 96 percent of the sun’s rays are actually converted into heat, rather than reflecting the light at the expense of precious energy. The task of the steel absorber tube that lies inside, on the other hand, is to absorb as much solar radiation as possible. To achieve this, SCHOTT developed a coating that exhibits an absorption rate of 95 percent and emits a maximum of 14 percent of the heat when temperatures reach around 400 degrees Celsius.
The sensitive part of the receiver is the junction between the absorber tube and the glass cladding that seals the vacuum. To create the bond between glass and metal, SCHOTT developed a new borosilicate glass that displays the same coefficient of expansion as the metal used. This means the joint stands up reliably to the extreme temperature shifts between cool nights and heat during the day.
The “SCHOTT Memorandum on Solar Thermal Power Plant Technology” offers a comprehensive overview of the technology, the market and the chances that solar thermal power plants offer. It can be downloaded from:
http://www.schott.com/...
Download-link to ZIP-file containing the picture in printable quality: http://www.schott-pictures.net/...
Image caption no.: 118479
An employee checks the quality of solar receivers during the inauguration of the most modern production plant for solar receivers worldwide of the international technology company Schott in Mitterteich, southern Germany, Tuesday, Sept. 26, 2006. Receivers are a key component of the solar thermal parabolic trough power plants, which will become an important source of power in the future. Schott has already received orders to supply receivers for the solar power plants "Nevada Solar One" in the U.S. state of Nevada and in Andalusia (Spain) that are currently under construction. The project in Andalusia represents the first commercially operated solar thermal power plant in Europe.
Image caption no. 118463:
An employee checks the quality of solar receivers during the inauguration of the most modern production plant for solar receivers worldwide of the international technology company Schott in Mitterteich, southern Germany, Tuesday, Sept. 26, 2006. Receivers are a key component of the solar thermal parabolic trough power plants, which will become an important source of power in the future. Schott has already received orders to supply receivers for the solar power plants "Nevada Solar One" in the U.S. state of Nevada and in Andalusia (Spain) that are currently under construction. The project in Andalusia represents the first commercially operated solar thermal power plant in Europe.
More press pictures can be downloaded at http://www.schott-pictures.net