|
|
Parabolic troughs:
Above - Parabolic troughs at Murdoch University, Rockingham Campus.
Parabolic troughs focus sunlight onto a line rather than onto a point. These systems are parabolic only in one dimension and form a long parabolic shaped trough. Although the trough arrangement is mechanically simpler than two-dimensional systems, which require more complex tracking systems, the concentrating factor is lower. Tracking systems are required in these systems to ensure that the maximum amount of sunlight enters the concentrating system.
Renewable energy scientists have discovered that parabolic troughs have the potential to produce electricity at less cost than flat plate collectors. Trough systems can either be orientated horizontally, in long rows, like the Luz system in California or vertically, like the demonstration systems by the Australian National University (ANU) –
click here to view the photographs at:
 http://solar.anu.edu.au/level_1/gallery/gallery.php?gal=8
Horizontally orientated systems are usually positioned in an east-west direction to reduce the amount of tracking required, and hence the cost. Alternatively, vertically mounted systems follow the motion of the sun throughout the day, by rotating the direction of the trough.
In 1998, Western Power Corporation and Solahart Industries joined forces to install a small demonstration PV/Trough system (400W) at World of Energy in Fremantle.
Above -The demonstration solar trough located at World of Energy in Fremantle
The solar cells in the Fremantle system were initially water cooled. Each mirror is 1.6m x 1.2m with a total collection area of 154m2. The focal length for the parabolic mirror troughs is approximately 710mm. The mirrors are made from a laminated glass structure with a silver mirror film between the glass layers. A microprocessor positions the troughs pointing towards the sun, even during cloudy weather. The troughs “roll” from east to west each day and the long central support tilts the troughs to adjust for seasonal variation. This is called “two-axis” tracking.
While the World of Energy system is no longer operating, it was an important forerunner to an innovative project in Rockingham. The Rockingham Photovoltaic Trough Concentrator System was installed at the Rockingham Campus of Murdoch University in 1999. The project was a joint effort by the Australian National University, Solahart and Verve Energy, which owns and operates the Rockingham system. There are 40 pairs of mirrors (80 in total). Each PV receiver is rated at 250W and is air cooled. There are three inverters which take the DC power and convert it to AC. The AC (grid quality) power is fed into the SWIS power grid.
For more information, go to the Verve Energy website and follow the links:
http://www.verveenergy.com.au
 Next Section >> Thermal blankets.
^ back to top ^
|
 |
|
