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Best reflective materials

04/24/2008 6:42 PM

Does anyone knows what is the best and cheapest reflective material? Silver coated glass mirrors have 92% reflectivity, any material better then this? Could you polish stainless steel or aluminium to achieve such reflections? I'm interested in full spectrum of natural day light.

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#1

Re: Best reflective materials

04/24/2008 8:20 PM

oh, today people use aluminum coat to instead of silver.

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#16
In reply to #1

Re: Best reflective materials

04/26/2008 8:40 AM

Aluminum is only 88 % reflective and it alters (diminishes) the spectrum. "Enhanced" aluminum coatings are coated with SiO2. These coatings are not applied to very large mirrors or lenses. Silver's problem is the black tarnish as it rapidly oxidizes.

There's a shop in Chicago that has a proprietary coating material called...???

Reflection is imperfect as some absorption occurs.

Bobguz

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#44
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Re: Best reflective materials

04/28/2008 8:24 PM

Silver mirror reaction is very familiar by us from our middle school expirement classes. But its been insteaded by coating aluminum for half centruy, not only for its expensive, but from the reason you said.. this sis we all known.

I dont know howmany reflective quantity is the coating al, but I know if you hope to increase the quantity you can coat several lays film just like camera lense. the more layers you coat, the more reflction you get. this is very opposite to lense situation.

one is absorb, whereas others is reflect. or they are in different layer thichness of film. but this will increase cost largely.

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#2

Re: Best reflective materials

04/25/2008 8:33 AM

Surface coatings of aluminium and then stabilised can give much better reflection.

Its used for telescope primary mirrors so I guess its about the best you can get?

John.

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#3
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Re: Best reflective materials

04/25/2008 8:46 AM

Do you know how robust this surface is. I'm looking for suitable surface for large mirrors/heliostats in open spaces (deserts, send storms etc).

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#4
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Re: Best reflective materials

04/25/2008 10:30 AM

Ohhhh if you want to work in that sort of environment then no, surface coatings will not stand up to being sand blasted, in fact not much else will either...

John

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#7
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Re: Best reflective materials

04/26/2008 3:15 AM

I do not think a standard mirror can be beaten easily both in reflection and especially in surface hardness due to the toughness of glass against most metals.

However, sand particles in storm act like a grinder and nothing can withstand that.

And if the shape is important then stainless is maybe your best choice but, how do you wanna clean it after a storm to keep its reflection efficient?

Forget the wiping method, it won't be good.

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#27
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Re: Best reflective materials

04/27/2008 10:36 AM

Why use locations in which such prohibitive conditions exist? Are there not great expanses of the earths surface where the abrasive conditions are minimal? And these great expanses are not used at all, why is that?

After all a warm or temperate area is not needed for reflective quality.

Interesting is the effect of desertification and the attempt to reverse those effects being attempted by China.

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#30
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Re: Best reflective materials

04/27/2008 12:46 PM

It is not just light that should be reflected, and point is that light (together with infrared light) ought to be concentrated to make heat.... In colder areas lot of heat would be wasted as atmosphere would tend to cool focal point, and if there is not hot air it means also less infrared light. Too cold climate preclude growth of plants, or at least agriculturall plants..........

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#41
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Re: Best reflective materials

04/28/2008 10:59 AM

The answer to your question is simple. areas that are not desert are more productive for things like food production. The reason deserts are constantly considered for solar power generation are that there is little cloud cover (dry climate) and the area is not much good for anything but gambling, solar power, and testing nukes. And only two of those make any economic sense. Take a guess which two.

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#43
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Re: Best reflective materials

04/28/2008 3:52 PM

Uh-uh deserts are very suitable for food production; the soils are loose by comparison and allow roots rapid growth rates.

I'd consider the fresh water flood plain areas as more attractive for solar power development; even using the surface of fresh water lakes.

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#5

Re: Best reflective materials

04/25/2008 11:19 PM

You want a highly reflective mirror that will work in a sand storm?

Stainless steel may probably withstand the winds, and yes it can be polished til it reflects but it isn't cheap.

What application is this for anyway? Mirror in desert, solar power?

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#6

Re: Best reflective materials

04/26/2008 1:12 AM

The heliostat itself (I assume a dish) will not get too hot for the use of polymers. There are plastics familiar as reflective birthday balloons called Mylar. Google it; I don't think it is as reflective as mirrors. However it can be purchased in sheets and applied to the parabola by vacuum as needed after a sandstorm or after the elements have reduced the efficiency of flux reflection.

Another option is clear aircraft (or automotive) finishes. They are designed for exposure to the elements and may be used to coat the surface of the Mylar to protect it and recoated as needed, a finish like DuPont Enron. Heavy elements may require rebuffing or recoating.

I agree, however, with another post that states nothing much will survive sandblasting. Consider also that, because of its shape the parabolic dish acts as a sail and is subject to high stress under winds. Under those conditions a trough or power tower might be a better choice.

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#10
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Re: Best reflective materials

04/26/2008 4:40 AM

IF IT IS REFLECTING - IT IS REFLECTING BOTH VISIBLE AND INFRA RED SO WILL NOT GET TOO HOT FROM DIRECT RADIATION. MYLAR MIGHT BE AN ANSWER BUT IT WOULD PROBABLY NEED TO BE VACUUM METALISED ONTO PREFORMED SHEETS. I DOUBT THAT A THIN FILM COULD BE MADE SMOOTH ENOUGH! I WOULD GUESS THAT GLASS IS THE BEST OPTION BUT DON'T KNOW IF THE COATINGS THEY PUT ONTO SPECTACLES COULD BE APPLIED TO A LARGE SURFACE. AS YOU ARE NOT GOING TO SEE MUCH IN A SANDSTORM ANYWAY - A GOOD COVER SHOULD SUFICE.

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#8

Re: Best reflective materials

04/26/2008 3:44 AM

What about 3M's reflective stripes on roadmenders jackets etc. Is that truly reflective or does it just give that impression?

Simon

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#9
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Re: Best reflective materials

04/26/2008 4:16 AM

Gentlemen, the important part of exercise is reflectivity factor, cost of material and length of usage. I'm sure that there are many "exotic" material that have great reflectivity factor, however they are most probably very expensive and not suitable for outdoor use. Currently heliostats are cleaned with high pressure water. Lifetime of a heliostats is 20 years.

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#11
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Re: Best reflective materials

04/26/2008 4:59 AM

silver is better than aluminum, however aluminum endures the elements better than silver

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#15
In reply to #9

Re: Best reflective materials

04/26/2008 6:00 AM

Mike, please put the important part of the exercise in the opening question. Implying we are wasting your time with "exotic" materials not suitable for outdoor use is fine if the original question had stated your parameters. And the Mylar reflective surface on balloons may not work but it is hardly exotic since they are sold on street corners, an outdoor environment. If you want a standard off the shelf answer, CR4 is the wrong place, but if you think there might be a miracle solution, you are as likely to find it here as anywhere. This is an open discussion, and we are responding to the original question.

And we might still get to the answer you need, but not necessarily the one you expect.

Simon

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#25
In reply to #9

Re: Best reflective materials

04/27/2008 7:24 AM

You should worry less about reflectivity factor then about loss of it because of sandstorms that would bruise that reflective surfaces and render them unreflective. If cost is not prohibitive factor, then Your reflecting surfaces could be coated with diamond film like I have seen in newest news about making computer chips. More practical solution would be that You make possible to turn mirrors away from wind/sandstorm direction, or use curtain of water sprays to protect mirrors during sandstorm, but then also sand particles in water could do same damage over time, and water is rather scarce resource in deserts, right? Next solution could be to have iris doors that could be closed in front of mirror during sandstorm, or You have to make mirors foldable, or mirror should be put ON iris doors which would be closed when in use and open during sandstorm when iris frame would protect lamels from damage. I would actually use this last solution, and since I have similar project, perhaps we should cooperate, or You should pay some money to person giving You sucessfull design solution :-)) As for most reflective surface, best telescopes use rotating bowl of mercury to get perfect parabolic mirror. Only mecury is high environmental hazard material and should be avoided in big projects, regardless of practicall problems of use in such conditions.

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#26
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Re: Best reflective materials

04/27/2008 7:36 AM

As the reflectors must track the sun to be effective, in a sand storm disengage drive and deploy wind vane to keep them back to the wind. You will have dust problems, not grit blast problems. Your doors are still necessary Henrik but this might reduce the load on them.

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#12
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Re: Best reflective materials

04/26/2008 5:11 AM

No ways!!! These are small spheres and only reflect light back to source. no real mirror effect.

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#13

Re: Best reflective materials

04/26/2008 5:28 AM

As previously stated, vacuum deposited metal is "the best" (used for telescope mirrors and such.) but if you put it on the BACK surface of your glass, then you get the film protected by the glass in front.

Good deposited vacuum aluminium (or silver or gold) are able to be given a protective surface coating during the vacuum metalising process and have extremely good reliability. (We make automotive lamp reflectors that way and they have to withstand humidity, heat cycle, cold cycle and such)

From your description of the environment, plastics are "out" since they will be abraded by the sand. (Otherwise you could use polycarb coated on the rear.)

Once you find a vacuum metalising supplier/processor, the coating is relatively cheap and reproducable. (Unless you're going to do "heaps, the equipment is quite expensive and is really a specialist process.)

Careful on your selection of glass. Specular reflection from the surface could be an issue and some glass has "funny" characteristics regarding portions of the visible spectrum (Like absorbing portion of the blue spectrum where your high energy photon are).

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#14

Re: Best reflective materials

04/26/2008 5:42 AM

You don't mention if you need a first surface mirror, or whether second surface is okay. Aluminum coating is cost effective in either case. Assuming a second surface mirror will suffice, you might consider covering the exposed glass surface with miltilayer tranparent sheets of plastic like they do for racing windscreens. When optical transmission becomes degraded by the elements, you peel away the top layer to expose a fresh window.

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#17

Re: Best reflective materials

04/26/2008 8:44 AM

Contact, The Mirror Lab, at the University of Arizona in Tucson, AZ.

Bobguz

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#18

Re: Best reflective materials

04/26/2008 8:59 AM

Take a look at Edmond Optics http://www.edmundoptics.com/us/

They have lots of great info and products. Also can give advice from their technical staff. There are loads of specialty coatings suppliers, try Google.

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#19

Re: Best reflective materials

04/26/2008 9:19 AM

You mentioned Stainless Steel.

You can get stainless with mirror finish or you can get Stainless Steel T430 Brite which is also just a mirrir finish.

Both look nice when brand new but it scratches easy. I think you've seen examples of this in public restrooms at rest areas, that scratched up metal sheet hanging above the sink, it started out as reflective as a mirror and look at what just wiping it with a rag has eventually done to it.

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#20

Re: Best reflective materials

04/26/2008 9:45 AM

Check out this guy in Florida.

http://www.spectrum-coatings.com/

Bobguz

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#21

Re: Best reflective materials

04/26/2008 1:02 PM

Hi,

silver gives best reflection and can be deposited by simple chemical reaction but is slightly "yellowish" as reflectance in the blue goes down.

Aluminum has to be vacuum deposited, good, expensive and is protected by its own oxide-hydroxide layer or by other layers also deposited in vacuum coating.

Most companies that are familiar with vacuum coating will offer reflectivity enhanced coatings up to 98% in the visible or as high as you want at a single wavelength.

These layers are made from transparent oxides and fluorides and have very definite thickness (quarter and half wavelength).

The theory you will find in the books from McLoed (and many others).

Protecting against the sandblast in desert seems to be impossible but most desert storms let the bigger particles down in a layer of a few meters, so put your mirror on an elevated tower.

RHABE

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#22

Re: Best reflective materials

04/26/2008 6:03 PM

water

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#23

Re: Best reflective materials

04/26/2008 7:07 PM

Just had another thought....

It's not as good as AL but you might consider either

Nickle or Chrome. Both are good reflectors and are quite ruggade

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#38
In reply to #23

Re: Best reflective materials

04/28/2008 9:18 AM

I think you have found a good compromise between reflective quality and durability. A quality three step chroming process applied to steel should yield good reflective quality and good resistance to the sand effects. Not as hard as diamond. Not as reflective as the best mirror. But a reasonable compromise.

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#24

Re: Best reflective materials

04/27/2008 12:26 AM

In your out door setting could you use opposing charges to reduce wear of reflective surfaces?

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#28

Re: Best reflective materials

04/27/2008 10:38 AM

Does anyone knows what is the best and cheapest reflective material?

It may be that I am totally misunderstanding this, but do you want to reflect light?

If so, Go to Phillips, Holland, in lighting for glasshouses.

Remembering from a project I did years ago, I seem to remember that flat white reflects more light than does any polished, reflective surface.

Yes, I thought that they were crazy too, but I wasn't prepared to argue with them!

(Holland does, or did, lead the world in the indoor growing of flowers. Phillips was providing the lighting knowhow.)

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#29

Re: Best reflective materials

04/27/2008 12:30 PM

Hi Henrik, I'm originally from Croatia and it is nice to here from some countryman. Heliostats are moved in horizontal position during night time and in high winds, not so much to protect glass mirrors from scratching, but to prevent them from breaking up under the wind forces. It is important to reflect as much solar power as possible with minimal losses. Focus on particular spectrum of sunlight that consist of the highest energy photons is interesting idea, best reflecting materials for that particular spectrum (presumably blue/ultraviolet) are, most probably commercialised, however, here we are substituting wide spectrum mirrors against narrow spectrum mirrors, benefits should be measured in overall amount of energy reflected.

Cost factor is unfortunately very important, especially because standard silvered mirror reflects 92% of energy received, any other percentage of improvement in reflection will carry much higher price tag. Standard silvered mirror is not as standard as indicated, glass used is a actually low iron glass.

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#33
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Re: Best reflective materials

04/27/2008 3:16 PM

Hi, countrymen!

Do You know this joke about best tea in Chinatown NY? There were lot of tea drinking parlors in Chinatown, but people liked best tea made by old Ching Lao and his place was allways full of customers. For years has other teamakers tried to learn secret of success of Chin Lao tea, but without results.... So finaly when they heard that old Chin Lao is at his deathbed, they all assembled around his bed and asked him to reveal his secret. With his last strenght he whispered: Put.... in the... water........ ( What? What? cried everybody) little.........( What? What? cried everybody again) and with his last breath, allmost inaudible, Ching Lao whispered: more tea........

So, instead of chasing elusive reflection percentage and exotic materials, enlarge Your project 20 or more % in size of heliostats, can You? In regard to puting heliostats in horizontall position during the night, I think it is waste of energy as only protection from sandstorms and wind maters.........

Now, since we are countrymen, how about some cooperative effort, since I have also similar project in mind? You should also check allready registered patents in that field as there are many and they would not expire soon, so someone can ask that You pay royalty on this person invention.........

Bog i Hrvati! (ili skraceno: Bok!)

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#34
In reply to #29

Re: Best reflective materials

04/27/2008 7:32 PM

Sounds like you should be focusing on wind turbines instead of solar

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#31

Re: Best reflective materials

04/27/2008 1:53 PM

Hi,

there is a magnificent book by Salomon Musicant: Optical Materials.

In this book you will find a lot of reflection and tarnsmission curves over wavelength. All useful metals and many other ceramics, glasses and plastics.

You will not find the thin film coatings in there as these are not basic optical data but a function of (complex) refractive index and thickness of all layers laid upon each other.

There is a wealth of information on the SPIE.org website and their conference proceedings and milestone series. Look also to OSA.org.

RHABE

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#32

Re: Best reflective materials

04/27/2008 3:07 PM

I read your question again but my most profound conclusion is pretty much the same as before.

No material can withstand the abrasion of sand in high-wind conditions as it'll give you a sandblaster effect, not even glass can.

Which is why I thought a mirror is the best choice, also with the best reflection factor in its price range and the toughness of glass compared to most other protective materials for the reflective layer.

However, if you need any bowl shape to it then perhapse stainless steel mirror is your best and cheap choice by making it collapsible like an umbrella as the storm nears.

And could remote clean it with pressurized blust of air through the middle as it starts to open up again for its next task.

This isn't gonna be the cheapest but perhapse one way getting around your problem at a reasonable cost, especially if you wanna make it unmanned.

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#35

Re: Best reflective materials

04/27/2008 10:50 PM

Just yesterday, I was at the Global Green Fair in Liberty Park, NJ, where over 100 venders were showing off their "green" technology. One was promoting "Solatube" skylights "500% brighter than ordinary skylights" because they are made of a patented reflective coated aluminum material, "Spectralight Infinity".

"Spectralight Infinity is a revolutionary new material developed by Solatube International designed specifically for tubular skylights. ... [It] has the highest reflectivity of any material in the world - 99.7% - for the brightest, purest light and unmatched color rendition." <http://www.skytube.net/faq_components.asp> sorry, link no longer available

So that answers one of your questions. Of course, it is not made for outdoor use. In the skylights, the reflectors are protected by windows, both above and below.

The Solatube company has a very interesting history. See http://www.solatube.com/corporate/about_history.php - sorry, link no longer available

Is it "cheap"? I doubt it. "Cheap" and "best" seldom appear in the same sentence. You'll need to contact them about cost.

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#36
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Re: Best reflective materials

04/28/2008 1:55 AM

Hi hparker,

this is not a material but a sophisticated multilayer coating.

The users of astronomical telescopes know these pretty well, there it is most important to get the very last % of light as the main mirror area of a scope is very expensive.

But for "only" getting some sunlight?

Look to "Schott Solar" they coat their light and heat gathering tubes with a very black inner surface to catch most of the light and convert it to heat.

As long as the original post is not clear what purpose is intended all we can do is speculate.

RHABE

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#37
In reply to #36

Re: Best reflective materials

04/28/2008 2:50 AM

Spot on Rhabe. As long as the original post is not clear what purpose is intended all we can do is speculate.But that speculation can lead in fascinating directions.

Simon

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#39

Re: Best reflective materials

04/28/2008 10:09 AM

What about Mylar?

It is used by NASSA on satelllites, clowns on party ballons and food companys on packaging, you know the really shinny 'tin foil' or silver stuff found in food packaging, etc. It is also a great insulator and reflects over 99% of light and much of the infrared spectrum. Also, called boFET film.

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#40
In reply to #39

Re: Best reflective materials

04/28/2008 10:41 AM

Now there is a marketing first. Solar collectors with big red clown noses. Take my deposit now.

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#42

Re: Best reflective materials

04/28/2008 2:40 PM

There is a material by Saint-Gobain Quartz called rigid silica. very good reflectivity. it is a diffuse reflection, much better than Al.

it is under the heading Quartzel at www.quartz.saint-gobain.com

it is also a fantastic insulator, very low thermal conductivity. It is not cheap though. if you need high performance and very high (99.99%) purity, this is the material.

Fiber Optic manufacturing, and RHB blowmolding industry feed back is 15-20% energy savings due to properties of the mateiral.

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#45

Re: Best reflective materials

04/29/2008 2:42 AM

Hello MikeSpike,

As it seems you have alot of reflective suggestions, I thought of perhaps 1 way to guard your mirrors. Could some blower system be designed to deflect the sand from the sunny side of your mirror.

I have a simular process to cool my Movie Projector Lamphouse Reflector Mirrors and it long came to me, that if a proper wind flow could keep things cool, then perhaps why could wind not keep my mirrors clean too ?

When we clean them , even with the best tissue for the job, some wear happens, so after a while we have to replace them ( Many Years) . If a wind shear curtain could be configured on the non protected side your new mirror, the sand might not effect them and they might last longer without much cost to protect it.

Hope that made some since, Damn its 2:42 , Goodnight

Best Regards,

Joe Woodall, Managing Partner

Georgia Adobe Rammed Earth & Renewable Energy

2395 Bowman Hwy. NW.

Dewy Rose GA 30634

www.georgiaadobe.com

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#46
In reply to #45

Re: Best reflective materials

04/29/2008 4:13 AM

Hi all,

I do not think this topic is all that much worth to talk about anymore.

The poster of this question is not responding all that well and his quiery was/is less than clear.

It seems he wants a 100% reflector at the price of a standard mirror and resistant to sand storms.

To be honest he could have clarified his question but he failed even after the others complained.

All the suggestions and ideas have been put forward to him already yet he doesn't even care to respond, at least once in a while.

I am not whinging but still if somebody raises a question and the others trying to help then he/she surely could have the decency to clear up things.

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#47
In reply to #46

Re: Best reflective materials

04/29/2008 5:01 AM

Dear Isti80,

I have responded once a day for the last 4 days that question has been public, There is no definite/final design for this idea and this forum is a place for throwing idea around (brainstorming). Sorry to take your limelight. Nobody is forcing you to participate in this forum.

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#48
In reply to #47

Re: Best reflective materials

04/29/2008 6:19 AM

Hi,

I am beginning to like you because it seems you can make a quick responce if want to.

This was your 3rd reply since you raised your Question but you have never reacted appropriately to anyone's comment, least of all when they said your question isn't clear enough.

Lets be honest this is a little less than satisfactory for starters.

Your first response, as I can see, was about a type of reflector that can be water cleaned and lasts upto 20 years.

If you knew already about this reflector than why did you bother to raise this question on the first place?

However, you have to be more convincing to me about any reflector that can last that long especially in a desert enviroment.

Finally, no offence but if people raise a question they should respond accordingly when it comes to clarifying it, don't you think?

cheers,

steph

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#49
In reply to #48

Re: Best reflective materials

04/29/2008 7:57 AM

Stephen, I think if you hang around here long enough you will be surprised when the original poster DOES return, most post a question and are never seen again.

So be thankful this one has returned more than once

John.

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#51
In reply to #49

Re: Best reflective materials

04/29/2008 10:16 AM

John, You're right.

I was more astonished to see that somebody raises a question an then the others even respond to it but also saying would be easier to give better answers had he tried to make his points clearer as we went along.

Instead, he made a point in his first response as he had the answer to it all along here:

"Gentlemen, the important part of exercise is reflectivity factor, cost of material and length of usage. I'm sure that there are many "exotic" material that have great reflectivity factor, however they are most probably very expensive and not suitable for outdoor use. Currently heliostats are cleaned with high pressure water. Lifetime of a heliostats is 20 years."

Can anyone explain to me what is this all about? I did not make any more of this other than a conundrum as he seemed to have the all the answer to it already.

Making his point clearer for those of us who were fasinated by his question to respond to it can help to carry on and maybe learn even.

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#50
In reply to #46

Re: Best reflective materials

04/29/2008 10:13 AM

Don't just fall after tripping turn the rock over there may be an unexpected or unsolicited prize waiting to be discovered or not.

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#52
In reply to #50

Re: Best reflective materials

04/29/2008 10:23 AM

Hi bwise,

It feels I've just made a fool of myself 'cos now I am the one who is copping it.

I did not try to attack the guy this harhs but somehow it came out and now I have to answer questions, maybe you all right.

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#53

Re: Best reflective materials

04/29/2008 1:01 PM

In another thread currently running in C4, a man asks, and I paraphrase, that engineers are specialized with little interdisciplinary coordination. And he asks can't we get together to solve the energy crisis?

It is an incredibly perceptive point. Of course there is a perception that inquisitors are vague and irresponsive frustrating the engineer's naturally inquisitive mind. But it is understandable given the reward of intellectual property.

Perhaps the answer to what this man poses is taking place right here, right now. And within it C4 demonstrates the power of the internet in bringing brilliance together. We should marvel. There is incredible potential in it.

I submit that this discussion we are having will stand documented in history as inspiration to all those guys in back yard and garage experimenting with concentrated solar. One of them will come up with the right formula.

Sure the best minds in the country are employed by big business and follow their own lead but discoveries like Faraday's happen in small laboratories. It is the miracle of capitalist America, inspiring creativity by the incentive of its reward.

I personally think he exaggerates about sandblasting to stimulate the farthest reaches of our collective imagination by stating a worst case scenario. Brainstorming should be free wheeling. we must be willing to take a chance of being wrong or criticized; hell who is perfect. We all are made a fool of often. Do not feel bad. I remember pasting aluminum foil on an abandoned satellite dish and for nothing got 400 F. That energy can be harnessed.

Alternative Energy:

http://www.alternative-energy-news.info/why-solar-is-the-best-energy-solution/

reports that CSP has the greatest potential to solve the energy crisis. Here we discuss just a small part of the art.

I say in the interest of the energy crisis and to inspire all those garage mechanics, let us exhaust the subject to the best of our collective ability.

My advice to inventors: Use inexpensive materials in prototypes or use Mylar and overbuild. Or, just use cheap mirror tiles, leaving room to tune with high tech (big money) like low iron or stainless later.

Experimentation is essential; and it could be the unseen fruit of our effort here. Nevertheless in demonstration of our giving spirit we make these offerings. However to settle our frustration, we all would enjoy hearing about any results or failures inspired by our input.

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#54
In reply to #53

Re: Best reflective materials

04/29/2008 3:12 PM

Wise words Cornelius,

If anything (design, prototype or commercial application) does come out of this discussion I will be more then happy to publish it on this site. At this point in this is just an idea based on existing R&D.

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#55
In reply to #53

Re: Best reflective materials

04/29/2008 4:10 PM

Hi,

I only had a go at the guy 'cos he wasn't responsive enough after many of us tried to give him hints about the ups & downs of turning his idea into a reality, if he had any.

I once saw at an exhibition, June 2002 in Munich, where a parabola shaped reflector about 3 meters in diameter was setup on the ground in an angle and in its focal point there was a Vat (without the 69) on a tripod with a few liters of water in it. By the time I got there to see it, the water was bubbling on the bottom ready to just about to boil and I was told it had an oven also.

This was a truely marvelous stuff, almost ancient in its concept yet modern in every aspect.

The men who staged this show told me they designed it for remote locations in many parts of Africa where there's no energy available. They themselves spent sometimes over there and saw the need for it.

The important part here is that the reflector was the same type of flimsy material they use in fluorescent light boxes as a reflector.

I was told the reflector needs to be treated with care during transportation as it was foldable in a circular fashion, like those hand held fans women used to have in the old days.

Hope this'll enlighten some on this forum including our friend, who raised this reflective material issue, and realise that going for a few extra % in reflextion may not be worth such a high cost when you can achive good results with cheaper and readily available materials!

Unless he is gonna be more specific what he is trying to achive with all this so that we could help him better next time.

Have a very good hight to you all on this side of the world and a very good day or afternoon in the other parts!

cheers,

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#56
In reply to #53

Re: Best reflective materials

04/29/2008 4:51 PM

Well, I proposed something of kind in other forums, because for one thing there is need for good program for designing devices, wether opticall, thermal, magnetic, electric, mechanic or fluid dynamic (i.e. windmills) that would enable inventors to try any idea and then test resulting device to see if it works and if it work, what results of this work would be. Program should apply all that is aplicable in use of such device in any aspect that would influence real device, i.e. gravity, mass, inertia, heating, cooling, mechanicall movement, power generation or heating, vibration, centrifugal and centripetal forces and so on, based on materials used and their properties and geometry (like wing profile in fluid dynamic) and simulate any condition that in reality could happen (i.e. strong wind with rain, hail, sandstorm, buffeting wind, waves on water changing, wind direction and so on) and see animated result on computer screen together with results of device work on some simulated analog metering device. THEN any inventor, would be inventor, engineer or designer could see results of his work before prototype is built, which would release creativity in all >>garage inventors<<......... I have plan for such a program, but there is classic problem Nr. 2 and it is MONEY. For this I proposed that fund would be instituted where engineers any anybody else could invest the money, be it 100$ or 100 milions. Then, there would be commision made of engineers that would rewiev any proposal for new device production (once results of computer simulation show this device can work and be good for our civilisation in generall) and finance patenting and production of such device by giving loan, but instead of interes, collect 25% of pure profit from this production, in addition to returning originall loan.....

Most important role there would be of engineering and scientific comunity in making before mentioned program as perfect as possible, as many kind of experts can work together, but each in his specialized branch of engineering or science. Then, such program could be given FREE OF CHARGE to anybody capable of inventing or designing anything, provided they sign contract that they would pay 25% of profit from device production and sales to before mentioned fund, who could be sole owner of such program. Anybody who could contribute to development of such program would get paid either from fund in one time payment, or could earn equivalent % of shares in fund, and shares would be virtuall: one share equall to one Euro (so there would be no loss of walue of shares possible, nor could somebody buy existing shares to get control of fund). Profit collected would be distributed to shareholders according to total number of shares in fund and proportionally to % of fund owned by shareholder. Whoever would need money need not sell shares on the market, he can just withdraw that much money from his investment, and so diminish his share in future profit collected, but anybody's money would be SAFE as value of shares could not drop to zero :-))

It is right time for such project to be commenced as there is internet for fast comunication and informing everybody, so everything would be open for inspection by any investor in real time and no bad transactions are possible as money would be invested into projects approwed by board of engineers and scientists, which would be responsible for asesment of impact any device would have on our planet and human civilization.

Do You agree with me?

Now for concrete problem at hand, impact of sandblasting is NOT overrated but very serious problem indeed. I remember case if truck factory from my country that was bidding for big order from Libia (it were 40-50 years ago, dont get upset) and they were surprised how other factories have asked high prices for their vehicles, as they could ofer 1/10 of their price and earn good profit too... Being cheapest supplier, they won that bid and started producing and sending trucks to Libia, but very soon they started geting their trucks back with paint totaly removed by blasts of sandstorms, windows and lamps of truck made opaque and broken by gravel that fly near ground in extreme sandstorms, not to mention destroyed ventilators and motors by sand entering air intake of internall combustion engines..........

They simply did not take sandstorms into consideration. Mylar baloons would not withstand such weather, nor anything open to flying quartz sand. So it is FIRST problem to solve for ANY device in desert conditions! My countrymen is concerned with reflection percentage, but I would use just BIGGER reflecting surface to offset less effective reflection, as in the end, it is end result that count, and nothing else.

Dear coleagues, it is true that first post was incomplete, but it is explained in next posting of my countrymen: he want to make Heliostats, from which I conclude it is necesary to concentrate sunlight for production of heating in some focal point, and this would be used to heat water and generate electricity (my conclusion) which process is not so much effective in energy conversion, so any percentage lost at start would be multiplied in later stages of generating mechanicall and electric energy. Of course that if reflection would be smaller, simply enlarging area for it would bring problems with mass of heliostat, larger motors to turn it, bigger area to act as sail in the wind and so on, which make project more expensive........and therefore electricity produced would be too expensive compared to other systems.

Here program for simulation would also help, and once program could controll output results from simulation, it could try to modify basic design in search for optimall device which would produce cheapest electricity in long run.........

Would You help me to start project for making such program and to organize inovation fund for all engineers that cannot finance their own projects on their own?

Marijan Pollak,

IT SE/SA 1st. Class,

Instructor and team Leader

(retired)

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#57
In reply to #56

Re: Best reflective materials

04/30/2008 12:39 AM

Fabulous post Marijan,

Yes, I do agree. I have my own ideas similar but not quite like yours. I will help however I can; address any correspondence to: Corneliusvansant@aol.com.

*****

Of course you are thinking on the utility scale, Marijan. Your knowledge is impressive.

However there is another scale of CSP invention some of us are working in, and that is residential. And that translates into much smaller equipment. In such a case it is feasible to overbuild a CSP trough and rather than have the reflective surfaces exposed, have them contained within a glass enclosure like a flat plate collector. The results are protection from the elements as well as low tech greenhouse effect. A little less efficient than vacuum tubes but a whole lot less expense.

If CSP can bring us a device to realize net zero energy homes, then homeowners would pay for the property rights, manufacturing, marketing and maintenance for each machine. A viable device would put many to work with marketing, distribution, installation and maintenance of non polluting free energy.

If affordable, it could electrify the world. It would make homeowners independent of utilities. Marketers should well note the fierce independence of Americans who abhor the coercive force of dependence on the grid. The inefficient, incomplete and vulnerable to sabotage and blackout grid would become obsolete.

I would expect the inventor of a viable device to consummate the net zero energy home to be bought out for a handsome retirement by big utility interests, stopping deployment in its tracks. Creating a public company in advance would prevent that.

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#58
In reply to #56

Re: Best reflective materials

04/30/2008 9:58 AM

Henrik14, consider this for a moment however. while a mylar reflector would not be terribly sturdy during sandstorms, it would be REALLY cheap to replace. If you have a sturdy frame to attach it to and designed the mylar reflector for quick changeout and replacement, the economics might not be as bad as you might think.

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#60
In reply to #58

Re: Best reflective materials

05/01/2008 2:33 AM

Yes, I agree! Specialy if surface could be made soft so sand could bounce instead making hard hit and scratch it..... Also, if position would be high above ground (in case it is a baloon anchored to ground with light and strong nylon ropes), its bigger surface can make up for not so perfect reflection. Perhaps it could also be turned to follow the Sun by computer control of winding and unwinding anchoring ropes........

Such baloon could be made internaly into compartments where each could receive separate light nylon pipe feeding it hydrogen, which is (I believe) cheapest and least harmfull gas used for balones. But then in sandstorm is generated lot of static electricity, and this could cause accidents, or whole baloon would be one big target for lightning strokes, which is fortunately rear above deserts :-))

If we would have program about which I was writting recently, then we would be able to design and test such baloon virtualy under any imaginable condition that could be really going on in such location where it would be positioned, and then some worse, just to be safe........ I really hope all of you would realize value of such program, by which any idea could be tested in matter of days if not hours, and then optimized to perfection.

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#64
In reply to #53

Re: Best reflective materials

05/01/2008 4:21 PM

BRAVO!!!

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#59

Re: Best reflective materials

04/30/2008 8:16 PM

Yes, in many ways I think that the only answer is cheap to build and cheap to maintain.

There once was a time when craftsmen were proud to sign their name to their work; now throw-away and built in obsolescence has won the day. Here in the USA we call that the American way.

But any device must have intrinsic market viability or it will fail. There is plenty of venture capital for the inventor who can build a working prototype that can power a home to net zero energy. Sustainable is a hot item right now; politicians can never be depended on like the market. If a device has value it will advance, if not it will languish.

I am convinced that there is nothing wrong with novel use of existing technology. That is what most new patents are. Consider the revived interest in the external combustion engines, the Stirling and the steam or the ancient turbine. We now reconsider their use as the internal combustion engine becomes politically incorrect and we can run them with solar energy.

It would be wonderful if one could invent new thermodynamic phenomena. But there are so many existing ways to move heat to point X then extract the energy from that heat already. We have more than enough to work with – let there be light.

Enough of Philosophy, back to our brainstorming:

If the heliostat is forced to be in a vulnerable environment, then the system must be protected by some fluid force field like air or water, turn away from the elements or collapse. All these have been suggested by colleagues above. I also like the idea of chrome.

A refinement I might suggest is to have the parabola collapse like an Asian fan or poker hand into a recessed protective cover.

If this proves impractical, reflective replacement must be quick, easy and inexpensive. With precise engineering, and a proper substrate, replacement should be designed as a simple inexpensive and rapid matter.

Vacuum installed Mylar is the best answer we have so far to a destructive environment where the parabola face must be exposed to sandstorm damage.

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#61
In reply to #59

Re: Best reflective materials

05/01/2008 4:15 AM

Dear Cornelius, unfortunately, what is true for America is impossible to find elsewhere :-(( so if I need loan to start some business, I have to prove that I have property at least ten times more valuable which I can then give as guarantee for this loan, and that make it simply mortgage credit.........

Solution to this would be to partner with someone from America like You, so are You ready to become business partner with me? All my ideas are marketable, specially now when price of energy goes skyward...... I am also ecconomist, so I know all that is necesary about production and profit making from that angle. Unfortunately my government has robbed its citizens of their posesions at least three times, and even if I have company for 15 years now which has survived where over 100 000 others have perished, I have nothing to show for all my efforts..... I have survived bankrupcy of my business Bank where they took my money that has had nothing to do with loan of 100 milion $ this bank has taken from our state Bank and not returned, And two three customers that has not paid for goods or services delivered that has declared insolvency and liquidated their companies just because it is cheaper to open new company for 5 000 $ then to pay 500 000 $ of debt. Recently again I suffered loss because my traveling representatives wanted to save few thousands of Euro by not paying insurance on package worth over 100 000 Euro and misdeclaring value to be ridiculously small in order to save on postage, too...... When feriboat that was carrying package over the river sunk with 138 passengers aboard, I lost all I have and also 35 000 Euro worth of goods that were paid by AMEX Company Card, so I am also in debt as well :-(( Because of debt, AMEX blocked my company account and I cannot do any business so I lost 200 000 Euro of profit I could have made in the meantime. I warned AMEX that this is contraproductive to block my company as then I would be unable to pay, but they told me they just follow rules of company :-(( If I were in America, I would be able to raise loan based on previous performance of my company, but here it is not the case............

In regard to throaway production, unfortunately it is ecconomic necesity, even if nowadays it is really became rather grotesque. If car factory would build cars that would last 100 years with little cheap maintenance, then who would buy new car once everyone has a car? Something could be gained if they produce nicer models or more economic or less poluting environment, but not much. So they would gave to close factory and fire workers, and without work, how would they feed their families? It is paradoxicall that those workers that were supposed to be protected by such policy have allready lost their jobs because of robotization of car factories...... Perhaps nowadays car industry should turn to individuation of cars, making unique cars on order, since they have allready robotic factory that could be programmed for such work, or they should make small serials of one distinct model, with better materials and more expensive, but lasting longer also.

Anyway, if someone suceed to replicate gravity energy converter that Mr. Tesla has built, then every wehicle would have inexhaustible source of free energy at disposal, which would make flying cars cheap and practicall, therefore there would be no need for roads nor for airports, and we would have something akin to cities depicted by movie >>5th Element<<. Then also there would be no need for Solar Power plants, windmills nor anything else :-)) producing electricity, and all transport would be using electromotors for driving or flying..... Just that would not be so easy and we have to use Solar and wind energy for some time jet.

In previous answer I suggested solution to problem posted, so for now I would like to close this discusion, since we summed all possible inside parameters posted for problem of my countrymen......

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#62
In reply to #61

Re: Best reflective materials

05/01/2008 11:36 AM

Would a material like Mylar reflect at the right wave? how will it stand to UV/Photo degredation.

Wouldn't the sand be abrasive to the surface as opposed to "bouncing" off?

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#63
In reply to #61

Re: Best reflective materials

05/01/2008 1:16 PM

Dear Marijan,

Please let us continue this discussion off-line as it is a digression.

I would be honored to partner with you. But you may have the wrong impression about me - and my country. I am not a wealthy man. I have spent all my life as an educator and have recently retired with a small pension. Thermodynamics is an avocation with me.

I have graduate work in Administration and that gave me the insight to create a telecommunication business 25 years ago that still exists (AMSties.com). So I have entrepreneurial skills. I have a modest supplemental income from my sale of that business. But in 1989 I also had a rough patch that required federal bankruptcy protection for a while but I recovered and the business prospered. The point, cheer up - everyone has troubles in life.

We all have witness your country ripped apart by religious fanatics. And I am empathetic about your misfortune; the ferry story is heart wrenching. I am grateful to have been born in a country that is so rewarding for people with talent. Nevertheless, few are rich.

Regardless of the excitement over sustainable energy, it is not easy to raise money for a new business. One must have a working prototype before one can attract venture capitalists money or even a small bank's money. In affect it leaves development expenses imposed on the inventor.

Money to propel a company to national/international affect comes from investment bankers who are agents of investors. These investors are generally average people and the bankers have a fiduciary responsibility to these folks who have their life savings at risk. They are very wary of startups like you suggest. One needs more than ideas even in America. Ideas are as cheap as opinions.

There is another route to funding: applying for a Grant from a state government that has such grants, or from the US department of Energy. These are very competitive and are reviewed by competent experts. They generally require active co-funding 50-50 by the applicant with increasing funding participation as time goes by.

Please direct any response to my email corneliusvansant@aol.com

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#65
In reply to #59

Re: Best reflective materials

05/01/2008 4:51 PM

If this proves impractical, reflective replacement must be quick, easy and inexpensive. With precise engineering, and a proper substrate, replacement should be designed as a simple inexpensive and rapid matter.

This you said reminds me of when we motocross raced years ago. As the racer went through mud the crud would stick to the visor, trying to wipe off was tantamount to catastrophe; crash. So someone started stapling layers of plastic film over the visor to simply tear off when needed.

The same principle could be used with Mylar reflective sheeting as well. May be better than covering with water for protection or not.

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