Fa. Carpe Diem Solar 72348 Brittheim, SchwarzwaldstraRe 11

Solar heat Power stations using Parabolic Trough collectors have been in commercial use in the U. S.A. for over 15 years. With an output of 354 MW they have, to date, delivered 11.400 GWh of electrical power to the net and represent the most successful technique for converting solar radiation into electrical power.

However, because of sinking prices for fossil fuels since 1991, no new solar heat Power stations have been built.

Photo 4

Detail view of the Eurotrough structure

Because of changes in the Spanish energy provision policy in 2002, important conditions have been created for the building of 2 new Parabolic trough power stations in Guadix, each with 50 MW output.

In Guadix a part of the days output will be stored in salt heat stores so that the turbines will be able to run during the night.

Demand profile for Parabolic trough collector structures

• High torsional rigidity against wind last

• Optical precision for the focussing mirror

• Compact transportability

• Low manufacturing costs in materials and assembly

• Flexibility in size and shape

• Suitability for erection in deserts and areas of high salinity e. g. coastal areas

• High long term reflectivity

Concept

We are developing a structure for Parabolic trough power stations that offers clear advantages compared with the current versions shown above.

• The support frame comprises the fewest possible components.

• The closed profile has very high rigidity, which is indispensable for this application.

• The closed profile structures make corrosion protection easier to achieve.

• The completed structures should be simple to construct and easy to assemble.

• As much as possible of the functional geometry i. e. the parabolic form should be contained within the construction process.

• Reduction of handlings technique

o The simplest possible on site assembly, which can be performed by a semi­skilled workforce, without expensive building cradles. o Simple positioning of the mirrors is made possible

• Use of more cost effective thin profile reflector surface allows flexible size and shape.

• Circa 25% cost saving compared with present structures.

• The completely enclosed skeleton structure offers high rigidity with a low use of materials.

• Through the low number of components (about 12 stabilising ribs and the covers) a short, problem free, on site assembly process is possible.

SHAPE * MERGEFORMAT

As the structured components can be transported separately, the necessary transport volume per structure is very low. The top cover of the parabolic surface consists of 3x12m long and 2.20m wide trapezoidal profile metal sheets. For transport these can be stacked on top of each other so that containers of several hundred can be carried up to the maximum load capacity of the vehicle. Similarly the lower cover sheets and the sickle shaped forming ribs can be stacked for transportation.

The metal pressing and shaping techniques used allow cost effective manufacturing of the stabilising ribs and increased accuracy.

The parabolic shaped hull structure combines the two essential demands of a parabolic trough (Mirror geometry and support structure). Because of this mirror panels need not be used. Thin surface reflectors offer the same quality, are considerably cheaper and can be glued directly onto the given form. This results in significant cost reductions. Alternatively, reflector foil could be used. The ALANOD company offer appropriate surface treated aluminium sheets for solar applications.

• Through the integrated construction of Reflector and support structure, storm damage and glass breakage can be considerably reduced.

• The very high glass insurance costs of the mirror panels used up to now are well known. The previous point shows that these costs could also be reduced.

Environmental Relevance

The planned production process promises a noticeably lower electricity and overall energy use in the manufacture of the structure.

• An important savings factor is the use of thin sheet reflectors (e. g. 1mm thick glass mirror replaces the 4mm thick mirror panels used at the moment).

• Energy consuming welding technology is replaces by simple glue and rivelting techniques.

Protection of Fossil resources

Through a more cost effective and simpler manufacturing process, the competitiveness of environmentally friendly, solar heat power stations enhanced. Because of this the adoption of renewable energy technology in the general market would be increased. This would proportionally reduce the operation of conventional power stations. Fossil fuel recourses would be conserved and CO2 emissions would be avoided.

SHAPE * MERGEFORMAT