Talk:Parabolic trough

Untitled
The article mentions "Stirling dish concentrators" but the link to "Stirling" is the place in Scotland and nothing to do with this subject. Also Googling brings up nothing that I can see obviously under this title. So this reference should be removed until it can be substantiated. 82.70.14.150 15:18, 21 August 2007 (UTC)

Efficiency Question
What is the efficiency obtained by parabolic throughs, as far as kWh electricity delivered/kWh incoming solar radiation? It'd be nice to know the numbers, including the high temperature/low temperature of the thermal engines used to convert heat to electricity. Ultimately the $invested/kWh delivered is what matters, and parabolic throughs may beat all other solar technologies in this regard. Also, total area required matters too, so if something like a parabolic through is say 0.2% efficient, while a photovoltaic array delivers 15%, unless land area is extremely cheap, if their cost per kWh delivered are within the same order of magnitude, the higher efficiency system may be preferred, for maintenance reasons too. Sillybilly (talk) 15:28, 12 May 2008 (UTC)
 * The answer is already in the article: 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.Sillybilly (talk) 02:13, 20 May 2008 (UTC)

Types
The article writes:"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, due to cosine loss, but only requires the trough to be aligned with the change in seasons, avoiding the need for tracking motors. This tracking method works correctly at the spring and fall equinoxes with errors in the focusing of the light at other times during the year (the magnitude of this error varies throughout the day, taking a minimum value at solar noon). There is also an error introduced due to the daily motion of the sun across the sky, this error also reaches a minimum at solar noon. Due to these sources of error, seasonally adjusted parabolic troughs are generally designed with a lower solar concentration ratio."

Well, what the difference in eficience, between the two types?In a tropical climate, the difference is smaller (or bigger) than in temperate clime?Agre22 (talk) 01:11, 6 December 2008 (UTC)agre22

Operation
The article states that the temperature can be raised to 400C. I was wondering which of two modes were used (or if there was some other mode): 1. Oil enters system at low temperature and is raised to 400C over time (ie there's a strong thermal gradient from the entry of the hot fluid to the cold fluid);  OR 2.  Oil enters from a thermal bath at, say 390C and is raised to 400C.

I can see that option 1 would have the advantage of lower radiation losses, and option 2 would have the advantage of homogeneity. Can someone tell me how it's done, and is it worth including in the article? Grj23 (talk) 04:09, 18 August 2010 (UTC)

Dewar tube
The link to "Dewar tube" links to vaccuum-insulated bottles and containers and it doesn't explain what the application of this would be in the solar trough collector at all.Eregli bob (talk) 07:52, 1 May 2011 (UTC)
 * Elements to adress this point might be found here : . Basically, it is necessary for the tube circulating the liquid to be vaccuum insulated, to prevent all heat from being lost over the length of the plant. --M AURILBERT  (talk)  16:17, 11 July 2011 (UTC)

Clarify the topic
This article is about solar thermal collectors, not generic parabolic troughs. The title does not indicate this specificity (though there is no other usage I am aware of to cause confusion). Recent edits to generalize the topic suggest that we need to clarify this. Solar parabolic trough redirects here - perhaps we should use that for the actual title. Joja lozzo  22:46, 29 December 2012 (UTC).


 * Yes. I would second that motion. However, there are other uses of parabolic troughs. As is mentioned at the top of the article, they are used in some types of solar cookers. They are also, I believe, used in water sterilizers. Sometimes they are used in reverse, e.g. to project heat from a linear electric heating element into a beam or "sheet". So, I think, there should be a general Parabolic trough article that describes the shape of the trough (a parabolic cylinder), together with its property of focusing light onto a line, and other articles about specific uses, cookers, thermal power stations, and so on. DOwenWilliams (talk) 03:23, 30 December 2012 (UTC)

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Nothing on Daniel Lightfoot's "hot-line" collector?
Also a trough, although apparently the curve is a hyperbola instead of a parabola. That one has no moving parts, the hyperbolic curve of its reflector tracks the sun. https://www.motherearthnews.com/renewable-energy/hot-line-solar-collector-zmaz76mjztak (1976) &mdash;Jerome Potts (talk) 10:50, 15 March 2019 (UTC)

combination with agriculture?
is there any principal reason why a parabolic trough field can not be combined with agriculture? if such combinations are known please add them to the article.

the temporary shade delived by the troughs would certainly be beneficial for certain plants, and the plants would reduce sand and dust being blown around blurring the mirrors... HilmarHansWerner (talk) 18:14, 29 February 2020 (UTC)