Just a quick question about glass

[Photonfanatic]

So we have to get any and ALL moisture out? A dehumidifier on one panel; yes it would take up more power than the panel produced. But what about that same dehumidifier, on a bank of 8 panels? Keep in mind they're made to suck moisture out of a whole room. A bank of panels would contain airspace far less than a 10'x10' room. It would be way more dehumidifying power would be require for that amount of airspace. You could use one dehumidifier for 20 panels if you needed to and it would still not be half of the dehumidifier's capabilities.

[russ]

Why not just buy a quality factory made panel - cheaper, easier and better quality.

[Mike90250]

Once you see a few drops of condensation inside a wristwatch - it will not last very long afterwards. Solar panels are even more demanding 0% humidity allowed. Except for glass, some metals, and a few specially engineered plastics, water vapor, in damaging quantities, zooms right through most materials. It only takes a few months to start building up to fatal levels.

Glass for light & vapor
EVA for UV resistant adhesive
Tedlar for backside seal
There are few substitutes for these materials.

[Sunking]

Once you see a few drops of condensation inside a wristwatch - it will not last very long afterwards. Solar panels are even more demanding 0% humidity allowed. Except for glass, some metals, and a few specially engineered plastics, water vapor, in damaging quantities, zooms right through most materials. It only takes a few months to start building up to fatal levels.

Glass for light & vapor
EVA for UV resistant adhesive
Tedlar for backside seal
There are few substitutes for these materials.

And a heated 0% humidity vacuum chamber to seal the panels up.

[green]

So we have to get any and ALL moisture out? A dehumidifier on one panel; yes it would take up more power than the panel produced. But what about that same dehumidifier, on a bank of 8 panels? Keep in mind they're made to suck moisture out of a whole room. A bank of panels would contain airspace far less than a 10'x10' room. It would be way more dehumidifying power would be require for that amount of airspace. You could use one dehumidifier for 20 panels if you needed to and it would still not be half of the dehumidifier's capabilities.

The problem I see with this solution (there are many actually) is that you propose pumping air through this system. For one thing if the dehumidifier fails you have your system which should be sealed off to the elements is now open and exposed. Another problem is the pipes to move the air will wind up getting very cold, which will actually create condensation. If the system isn't 100% sealed you may wind up introducing moisture into the system through leaks where the pipes penetrate the panel.

I could go on and on, but I'll just say I don't think it's a good idea.

[inetdog]

And a heated 0% humidity vacuum chamber to seal the panels up.

And a space suit to wear inside the chamber while you are working on the panels.
(Think big....)

[Photonfanatic]

So there is no clear, plastic goop that could be poured over the PV wafers? And then polished to a shine? I swear I recall some kind of... I don't know.... acrylic or something that you could buy wet, mix with a hardener or something, and it would dry rock hard and clear. And then, if its not quite clear enough to allow the photons to pass through freely, you'd break out the polishing compound and polish it until it was. Then you put your sheet of glass over that, and wam bam cheap water tight home made solar panels. I swear there is some kind of goop like that... I know I've seen it in some other hobby. Perhaps it was autobody, or plastic art.

Nobody has tried this? Nobody has done a solid state panel?? I thought I would see some innovation around here! If we're ever going to defeat the awful power companies, we're going to have to come up with something good.

[Mike90250]

So there is no clear, plastic goop that could be poured over the PV wafers? And then polished to a shine? I swear I recall some kind of... I don't know.... acrylic or something that you could buy wet, mix with a hardener or something, and it would dry rock hard and clear. And then, if its not quite clear enough to allow the photons to pass through freely, you'd break out the polishing compound and polish it until it was. Then you put your sheet of glass over that, and wam bam cheap water tight home made solar panels. I swear there is some kind of goop like that... I know I've seen it in some other hobby. Perhaps it was autobody, or plastic art.

Nobody has tried this? Nobody has done a solid state panel?? I thought I would see some innovation around here! If we're ever going to defeat the awful power companies, we're going to have to come up with something good.

If you could keep that from ever changing it's temperature, it might work. Otherwise the thermal stress from the different expansion rates, will tear it apart (microcracks) in a few weeks. It will look good, and work as well as a brick. Daily thermal swings from 40F to 160F are the norm, and few materials will hold up properly. I'm not meaning to rain on your parade, but that's the facts.

[Photonfanatic]

Alright well thanks for the reply. So it would have to be some real tough stuff which can take a beating. I'll look into it further. What temperature can the PV wafers take, before they break? If they can stand up to some higher temps just once, then the idea may have merit. Cause there are some plastics that can do it, but they have to be poured on and they're damn hot when you pour 'em. So I'd need to know what kind of temps those bare wafers can take.

[inetdog]

Alright well thanks for the reply. So it would have to be some real tough stuff which can take a beating. I'll look into it further. What temperature can the PV wafers take, before they break? If they can stand up to some higher temps just once, then the idea may have merit. Cause there are some plastics that can do it, but they have to be poured on and they're damn hot when you pour 'em. So I'd need to know what kind of temps those bare wafers can take.

Regardless of how you get it there, you need to have the coefficient of expansion of the "encapsulant" match that of the silicon unless the encapsulant is very flexible.

[Photonfanatic]

Do you happen to have that number for the silicon? On the off chance that its just common knowledge on this forum. Or is it pretty much the same for all silicon?

[Mike90250]

do a search for "thermal coefficient of expansion"

https://en.wikipedia.org/wiki/Thermal_expansion#Thermal_expansion_coefficients_for_various_materials

Quartz is very stable, copper is not so stable. Glass and silicon can be pretty close to each other when you look in the big tables. What is way off, are the plastics and metals. Casting plastic will hold the brittle cells very rigidly - and pull them apart. So the EVA bonding material, is thick enough, and flexible enough to absorb all the expansion differences, saving the cells. The copper tabbing wires, generally have a small Z stress relief wrinkle formed into them to allow some flex there too.

[Photonfanatic]

So basically what you guys are saying, is there is no (inexpensive) material to do this with. What if you had a little help? Farm out the vacuum service to some company that has a vacuum pump, sort of like they use to vacuum out air condition systems. For example: I can purchase a cheap tire somewhere, for much less than I can buy it from the tire store. But then, I have to get it mounted and balanced on the rim. I certainly don't want to put forth all the effort to mount it, and I can't balance it myself. So I take my cheap tire, to the tire shop, and pay them $10 to mount and balance it. In this way, I've saved a good amount of cash.

So maybe, I can build the panel, ready to be air tight. But its not. Not yet, anyway. I then take it to a company somewhere, who would provide a service. They have a strong vacuum pump, and they pump out all the air from the little orifice that I've installed. Now, I've got a sealed, airless panel? Is that somehow within the realm of possibility? I don't think you need some kind of giant, super expensive apparatus just to get all the air out of something and keep it out. As one member suggested. Or perhaps pressurize it with nitrogen.

[Naptown]

For as much as you will use it you could buy a vacuum pump from horrible fright for $90.00 or rent one from a tool rental place.
check with the local pawn shop there. Many times they have them too and cheap (hint offer half what they want for it)

[Photonfanatic]

Well you're an admin here... has anyone suggested this before? According to all you've read, would you say that its something that might work? Seems like you'd be the right person to ask. Did have one other idea though, but its probably kind of obscure. I don't remember the name of the part. But back in the day I used to work a job where we would break down those old computer monitors. Those big CRT dinosaur ones. Well, there was one part in there, that you had to be careful with. It was a small cylinder looking thing, and it was capable of holding a full charge for a whopping 15 years or more. And it held so much, that it could send you to meet the lord. I can't for the life of me remember what it was called. I want to say capacitor, but that's not right.

Anyway, we knew how long they could hold electricity because many of the monitors had the date they came in, labeled on them, for company use. Some had been there over 15 years, just sitting on the shelf. And still, that little thing would be full of power and could seriously hurt you. It was not any kind of battery. If I could figure out what that was, perhaps larger ones could be purchased, and used in lieu of batteries?

Also, I'd love to know where you got the horrible fright nickname for Harbor Freight.