Parabolic trough

Parabolic trough

A parabolic trough is a type of solar thermal energy collector. It is constructed as a long parabolic mirror (usually coated silver or polished aluminum) with a Dewar tube running its length at the focal point. Sunlight is reflected by the mirror and concentrated on the Dewar tube. The trough is usually aligned on a north-south axis, and rotated to track the sun as it moves across the sky each day. Alternatively the trough can be aligned on an east-west axis, this reduces the overall efficiency of the collector but only requires the trough to be aligned with the change in seasons, avoiding the need for tracking motors. Heat transfer fluid (usually oil) runs through the tube to absorb the concentrated sunlight. The heat transfer fluid is then used to heat steam in a standard turbine generator. The process is economical and, for heating the pipe, thermal efficiency ranges from 60-80%.The overall efficiency from collector to grid, i.e. (Electrical Output Power)/(Total Impinging Solar Power) is about 15%, similar to PV(Photovoltaic Cells) and less than Stirling dish concentrators. [ Patel99 Ch.9 ]

Current commercial plants utilizing parabolic troughs are hybrids; fossil fuels are used during night hours, but the amount of fossil fuel used is limited to a maximum 27% of electricity production, allowing the plant to qualify as a renewable energy source. Because they are hybrids and include cooling stations, condensers, accumulators and other things besides the actual solar collectors, the power generated per square meter of space ranges enormously.

Energy storage

As this renewable source of energy is inconstant by nature, methods for energy storage have been studied, for instance the single-tank (thermocline) storage technology for large-scalesolar thermal power plants. The thermocline tank approach uses a mixture of silica sand andquartzite rock to displace a significant portion of the volume in the tank. Then it is filledwith the heat transfer fluid, typically a molten nitrate salt.

Existing plants

The largest operational solar power system at present is one of the SEGS plants and is located at Kramer Junction in California, USA, with five fields of 33 MW generation capacity each. [Cite web | title = Kramer Junction SEGS III, IV, V, VI,VII. | publisher = Solel | url =]

The 64 MW Nevada Solar One also uses this technology. In the new Spanish plant, Andasol 1 solar power station, the 'Eurotrough'-collector is used. This plant is scheduled to go online in summer 2008 [Cite web | title = The Construction of the Andasol Power Plants | publisher = Solar Millennium AG | url =,lang2,109,155.html] and has a nominal output of 49.9 MW.

Popular Culture

A parabolic trough solar plant appears in the movie Gattaca.

Notes and References


External links

* [,+ca&layer=&ie=UTF8&om=1&z=14&ll=35.012986,-117.554998&spn=0.030157,0.086517&t=k&iwloc=addr Kramer Junction Solar Power Plants] - satellite image, Google Map.
* [ Picture Perfect Parabolic Solar Collector Systems]

Wikimedia Foundation. 2010.

Look at other dictionaries:

  • Parabolic Trough —   A solar energy conversion device that uses a trough covered with a highly reflective surface to focus sunlight onto a linear absorber containing a working fluid that can be used for medium temperature space or process heat or to operate a steam …   Energy terms

  • Parabolic trough —   A high temperature (above 180 degrees Fahrenheit) solar thermal concentrator with the capacity for tracking the sun using one axis of rotation.   U.S. Dept. of Energy, Energy Information Administration s Energy Glossary …   Energy terms

  • Parabolic reflector — Parallel waves coming in to a parabolic mirror are focused at a point F A parabolic reflector (or dish or mirror) is a reflective device used to collect or project energy such as light, sound, or radio waves. Its shape is that of a circular… …   Wikipedia

  • Solar trough —   or solar parabolic trough   See Parabolic trough …   Energy terms

  • Solar Trough Systems — (see also Parabolic Trough)   A type of solar thermal system where sunlight is concentrated by a curved reflector onto a pipe containing a working fluid that can be used for process heat or to produce electricity. The world s largest solar… …   Energy terms

  • List of solar thermal power stations — This is a list of power stations that are based on solar thermal energy technology. Since 2004 there has been renewed interest in solar thermal power stations and two plants were completed during 2006/2007: the 64 MW Nevada Solar One and the 11… …   Wikipedia

  • Solar thermal energy — Solar thermal system for water heating in Santorini, Greece …   Wikipedia

  • Concentrated solar power — The PS10 Solar Power Plant concentrates sunlight from a field of heliostats onto a central solar power tower. Concentrated solar power (CSP) systems use mirrors or lenses to concentrate a large area of sunlight, or solar thermal energy, onto a… …   Wikipedia

  • Solar energy — is the light and radiant heat from the Sun that powers Earth s climate and weather and sustains life. Since ancient times it has been harnessed for human use through a range of technologies. Solar radiation along with secondary solar resources… …   Wikipedia

  • Solar Energy Generating Systems — (SEGS) is the largest solar energy generating facility in the world. It consists of nine solar power plants in California s Mojave Desert, where insolation is among the best available in the United States. FPL Energy operates and partially owns… …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”

We are using cookies for the best presentation of our site. Continuing to use this site, you agree with this.