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Anonymous Poster

Wanted: Large Parabolic dish solar collector

02/16/2008 12:43 PM

Anyone out there a manufacturer capable of building large [24ft], low-cost parabolic dish reflective solar collectors, either in aluminum, fiberglass or other, or know of one?--prefer manufacturer in TX, but will take what I can get.

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Guru
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#1

Re: Wanted: Large Parabolic dish solar collector

02/16/2008 2:37 PM

Why not use lots of smaller much cheaper reflectors focussed at the point of interest?

It would also be much more portable and easy to get to site etc...

Don't forget the humble umbrella - they are remarkably good parabolic shapes and can easily be lined with reflective foil...?

There you go.... my consultation fee invoice is in the post to you!!

John.

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Anonymous Poster
#11
In reply to #1

Re: Wanted: Large Parabolic dish solar collector

02/26/2008 1:04 PM

thanks--my imaginary check is in the mail! I've thought of all those things--umberellas, satellite dishes, wedgewood ashtrays, but I'm not building a tower for a target--and I'd like to minimize flyover hazzard as well

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Associate

Join Date: Aug 2007
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#2

Re: Wanted: Large Parabolic dish solar collector

02/17/2008 8:05 PM

The latest way of making a large parabolic mirror is to spin a bowl of water, with silver nano particles floating on top. For such a large collector I would suggest using something a little more viscous to stop waves and vibrations, eg oil as a base liquid. reflectivity would be up to 80%. Sounds like a crass idea, but it is seriously being looked at for zenith telescopes, the surface is that exact

Admittedly the mirror axis has to be vertical, and it really only focuses the sun directly over head, but for heating purposes one could collect from the sun off axis for a couple of hours before and after midday, using a moveable off axis focal heat absorber.

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Anonymous Poster
#5
In reply to #2

Re: Wanted: Large Parabolic dish solar collector

02/18/2008 9:39 AM

A simelar idea was shown in an issue of popular science a number of years ago, for building your own low cost telescope. The idea was to build a mold (essentially a cylinder), stick it on a record turntable and use a thin epoxy. By changing the speed, you could change the shape of the reflector. Once the epoxy set, you could then clean up the surface and have it coated with a reflective material (mylar comes to mind). Granted you probably arent going to turn a 24 foot dia. mold with a record player, but I'm sure you could find something more appropriate. But, if all you're interested in is solar collection and not optical quality, then I might agree with whats already been suggested - gluing a bunch of mirrors to a frame - as probably the most cost effective means.

Avery Montembeault

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Participant

Join Date: Dec 2007
Location: albany oregon
Posts: 4
#3

Re: Wanted: Large Parabolic dish solar collector

02/17/2008 8:09 PM

Have you considered fiber-reinforced light weight concrete "skins"? Manufacturing location to suit market! Would be happy to discuss more details.Gulmodena

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Anonymous Poster
#10
In reply to #3

Re: Wanted: Large Parabolic dish solar collector

02/26/2008 12:49 PM

That sounds very interesting--would you recommend a website?

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Power-User

Join Date: Oct 2007
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#4

Re: Wanted: Large Parabolic dish solar collector

02/18/2008 1:38 AM

hi,

no idea. am curious how you specked this. what are you wanting to use it for?

depending upon what you are trying to accomplish, there are somethings that are much smaller and give equal performance.

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Anonymous Poster
#14
In reply to #4

Re: Wanted: Large Parabolic dish solar collector

03/01/2008 2:00 AM

need two 24ft. diameter collectors minimum to run 275kW thermalelectric generator--goal is for distributed utility grid support--four generators + eight to ten collectors = one megawatt for WalMart, HEB, ETC.--or community amenities for Centex, Lennar, ETC.

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Anonymous Poster
#34
In reply to #14

Re: Wanted: Large Parabolic dish solar collector

11/27/2009 7:41 PM

Hi dear,

Unfortunately, you can not get 275 kW with Stirling engine from 24 ft dia.(7.3 mt).

If you are lucky you can get max 20 kW with that size of dish. You need another technology which is not invented yet. Check Tessera Solar farm with 1080 dishes totallaing up 27 mW.

Good luck

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Power-User

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#6

Re: Wanted: Large Parabolic dish solar collector

02/18/2008 10:34 AM

Do you need round to focus to a point or sheet formed to focus light on a pipe?

Anyway here's a link to an interesting method. It's called a stretched membrane.

http://query.nytimes.com/gst/fullpage.html?res=9E0CE6D81230F935A15757C0A964958260

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Anonymous Poster
#9
In reply to #6

Re: Wanted: Large Parabolic dish solar collector

02/26/2008 12:31 PM

http://www.osti.gov/energycitations/product.biblio.jsp?osti_id=5494221

yes, this right up my alley--problem is they appear to no longer be in business

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Power-User
Popular Science - Weaponology - New Member

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#7

Re: Wanted: Large Parabolic dish solar collector

02/19/2008 9:21 AM

Help the environment recycle those old obsolete satellite dishes.

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Anonymous Poster
#8
In reply to #7

Re: Wanted: Large Parabolic dish solar collector

02/26/2008 12:28 PM

Been doing that--too small, even at 8' diameter, plus too heavy

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Guru
United Kingdom - Member - Indeterminate Engineering Fields - Control Engineering - New Member

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#12

Re: Wanted: Large Parabolic dish solar collector

02/28/2008 5:31 AM

Er, for home-brew, how about sticking smaller pieces of mirror glass, or even aluminium foil shiny-side outwards, onto a parabolic 'something else'? Is there a parabolic satellite dish luring somewhere on eBay? Can the local amateur radio community provide some guidance as to sources of them, perhaps?

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Anonymous Poster
#13
In reply to #12

Re: Wanted: Large Parabolic dish solar collector

03/01/2008 1:52 AM

Thanks--as a matter of fact I have a reflective film I can use--problem is finding a "low cost" means to fabricate a large dish--they need to be individual dishes with individual targets--"Dish Network" dishes, first-generation satellite dishes are too small and/or too heavy--upper-end needs to be 24 ft. diameter, lower-end needs to be 12+ft.--my "example" dish is 8ft. and I'm thinking of trying to adapt it to create a larger mold, but I'd prefer to find something already available

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Participant

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#15

Re: Wanted: Large Parabolic dish solar collector

03/01/2008 12:57 PM

Is seems you are still "fishing" for a source for a 24 foof parapoloc solar collector. I would like to encourage you to investigate the potential application of advanced "inorganice materials" i.e. cement. We prototyped this material concept - eight foot reflector - eight years ago, when the material science for this material system was in its infancy. Current refinement suggest this material concept for low cost, rugged, solar cells.

Food for thought or action?

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Anonymous Poster
#16
In reply to #15

Re: Wanted: Large Parabolic dish solar collector

03/02/2008 1:39 AM

Is this the sort of thing you're suggesting?

http://www.freepatentsonline.com/4268332.html

"An improved method of making a high precision trough shaped parabolic reflector apparatus is described. A smooth surfaced sheet of flexible material is bent and formed over a convex mold comprising a number of precision shaped parabolic arcs mounted to a base. Means are provided for clamping the flexible sheet of material and drawing it into close conformity with the convex mold. The backside or convex side of the sheet of material is then cemented to a support framework comprising a number of approximately parabolic, but not necessarily precision formed web or rib members which are joined together by a torsion tube or similar structural stiffening means. The type of cement utilized accurately fills any discontinuities and/or inaccuracies in the arcuate shape of the approximately parabolic ribs so that the ribs and the flexible sheet are bonded rigidly together as a unit without distortion or strain on the sheet. The approximately parabolic, but non-precision ribs and stiffening means thereafter serve to maitain the sheet of flexible material in a highly accurate and precision parabolic contour produced by the precision parabolic mold."

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Participant

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#17
In reply to #16

Re: Wanted: Large Parabolic dish solar collector

03/03/2008 1:13 PM

You have to dig deeper. Your findings are generally on the right track but fail to indicate the "optimization" potential of the material properties and processing through available science and know how. I would like to cite just on example of advanced processing and application of "cementitious" materials - Green, disposable fast food packaging! Demonstrating a Green, low cost solution for a demanding and competitive market.

The determination of the validity and suitability of this technology for parabolic dishes depends on a realistic market assessment, which has to include an effective distribution net work.

The elevator is ready to go to the next level!

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Anonymous Poster
#18
In reply to #17

Re: Wanted: Large Parabolic dish solar collector

03/06/2008 1:26 AM

Well Scotty, the doubletalk generators are on overload! Seriously, I'm looking into "foaming" biological, plant-based epoxy insulation, such as used in the "green" building industry, and scrap wood or metal for structural support--now I need to work out my "wedge" form so I can make squared-off "dishes" of the correct parabola, and just add or remove to get the size(s) I need.

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Active Contributor

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Posts: 14
#19

Re: Wanted: Large Parabolic dish solar collector

03/11/2008 6:18 PM

Sounds to me like you may have trouble finding an off the shelf design ... With that said, our company can possibly help you out. Our design group has experience designing and building telescopes among other equipment, and may be interested in breaking into the alternative energy industry.

We have design facilities in Vancouver Canada and have a manufacturing facility in Texas.

please contact me at 604-986-5600 if you are interested in pursuing further.

Regards,

Hans.

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Anonymous Poster
#20
In reply to #19

Re: Wanted: Large Parabolic dish solar collector

03/12/2008 11:56 PM

You wouldn't by any chance be Oceanworks.com, would you? If so, I see there is a Houston office--perhaps it would be better to contact them? In any event I will seek to contact you this week.

Or you may contact me at clamrod2001@hotmail.com

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Active Contributor

Join Date: Mar 2008
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#21
In reply to #20

Re: Wanted: Large Parabolic dish solar collector

03/13/2008 1:20 PM

Indeed, it is OceanWorks. Our Vancouver office is the primary design center where we have about 30 designers and a core group of about engineers. Our engineering manager and one other fellow both have many years of experience with telescope design and fabrication.

please do contact me.

Regards,

Hans.

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Guru
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#22

Re: Wanted: Large Parabolic dish solar collector

03/13/2008 2:35 PM

Try google on "heliostat". There are multiple examples of such instalations around the world.

Benefits: Single (fixed) focal point, portions of mirror can be replaced without taking whole unit out of service, can be "expanded" to provide the various sizes that you require with a common (interchangeable) controller, lightweght (relative to a single large dish and necessary support mechanism) able to track the sun across the sky, able to clean individual mirror portions without taking whole unit out of service.

Disadvantages: Cannot perform as well as "full tracking single mirror" near horizon, multiple devices to "aim" each small mirror.

There's one located in Newcastle (Australia) being used for energy research at CSIRO centre for energy technology.

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Anonymous Poster
#23
In reply to #22

Re: Wanted: Large Parabolic dish solar collector

04/02/2008 11:51 AM

Great suggestion, mate!

Found this site http://www.heliotrack.com/Parabolic.html

It has heliostats, parabolics, lots of goodies.

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Power-User

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#24
In reply to #23

Re: Wanted: Large Parabolic dish solar collector

06/07/2008 8:45 AM

Did you ever find what you were looking for? If so do you have any success stories to share because it seems like I am embarking on the same road as you, and the fact the information is so scarce and the idea is such a good one, you have to wonder why info is so scarce. I live up in maine, and we use the most oil to heat our houses, and thought these would be a great "alternative" to cut back on some of the bills. Feel free to email me, and thanks for starting this topic. sbruel@yahoo.com

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Anonymous Poster
#25

Re: Wanted: Large Parabolic dish solar collector

08/04/2008 11:56 AM

did you ever find the dish source ?

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Power-User

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#27
In reply to #25

Re: Wanted: Large Parabolic dish solar collector

10/21/2008 9:14 AM

Never did find dish source, I created one from an 8 foot satellite dish, used acrylic mirrors 4x8 feet, and cut in to triangular pieces, and used locktight in 1 pound tubes from home depot to secure the mirrors in place: 2 problems: something cheap and accurate to track the sun (wanted software, not light diodes, and the wind will destroy this monstrosity now, think of it as an eight foot umbrella in the wind.

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Anonymous Poster
#26

Re: Wanted: Large Parabolic dish solar collector

10/21/2008 4:42 AM

hi from downunder,

was looking at same type of collectors as your self but have found some or heaps of results from solar 1 in nevada desert:www.nrel.gov/csp/troughnet made from german aurospace technology.is trough parabola in about 4meter sections the flat trough mirrors are cheaper to make than a complete parabolic reflector(the only cheap way to make that is by sectioning -like an old reflector from a flashgun.)hope this might help but you have the tech people there should have already thought of this anyway.

cheers peter hawkes.

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Guru

Join Date: Sep 2006
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#28

Re: Wanted: Large Parabolic dish solar collector

01/14/2009 1:00 PM

What is going to be at the focus of this reflector? You're concentrating sunlight, to be sure, but what's the target? A heat exchanger? Too much sunlight focussed at your target and you'll destroy it.

Others have mentioned various means including distributed collectors, segmented mirrors or collector arrays. Must your "dish" be a single, monolithic mirror?

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Guru
Engineering Fields - Control Engineering - New Member China - Member - New Member

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#29

Re: Wanted: Large Parabolic dish solar collector

01/14/2009 11:07 PM

It s too big, the problem is how you will controll its direction to point to the sun? it will need a large motor and complex control system.

or you fit it as a side of wall, like a building somewhere in USA, use it for fusion reaction.

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Anonymous Poster
#30
In reply to #29

Re: Wanted: Large Parabolic dish solar collector

03/20/2009 7:20 AM

Check out Acro Solar Lasers. They have 8 foot solar dishes and 14 foot dishes, as well as a 44 inch dish. All are one piece lightweight fiberglass. They use a reflective mirror film on them. They also sell the tracking and management system. Tiny Low mili amprage motors are used to move them on 2- axis very efficiently. They use optics to track the sun very accurately which is something you will have to do when using a parabolic dish or the reflection won't hit on target. Lots of power to be had there. Simple structural balanced design with a tracking computer that will controll tracking motors, pumps and monitor temperatues. Completely automated. Its the only system of its kind I've seen available to the public and average Joes.

http://www.acrosolarlasers.com/

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Anonymous Poster
#31
In reply to #30

Re: Wanted: Large Parabolic dish solar collector

06/19/2009 11:47 AM

Don't get the acrosolarlasers dish. They are poorly constructed. The welds on the tracker look like my kid was playing with the welding machine again. The tracker gets off course eaisly when any clouds are present. It is worth looking at though for ideas.

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Anonymous Poster
#32

Re: Wanted: Large Parabolic dish solar collector

08/06/2009 5:10 PM

www.tmeink.com will build most custom anything

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Anonymous Poster
#33

Re: Wanted: Large Parabolic dish solar collector

09/14/2009 9:05 PM

try www.tmeink.com they will build most anything

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Participant

Join Date: Jul 2010
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#35

Re: Wanted: Large Parabolic dish solar collector

07/22/2010 4:29 PM

We represent a manufacturer of a composite solar parabolic trough and is capable of building them in these large lengths. Our focus now is water heating however we can discuss other opportunities.

Can you tell me more about what you are looking for?

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Anonymous Poster
#36

Re: Wanted: Large Parabolic dish solar collector

07/23/2010 6:16 PM

You could use a Fresnel lense instead of a dish. You can get them on Ebay.

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