Encapsulation doesn't have to suck

[fingolfin]

Doesn't sound like you are grasping the physics of Fluid Mechanics and the sub discipline of Fluid Dynamics. If you were you would clearly understand you can lift a car with nothing more than the air in your lungs as the power source.

No no I get fluid mechanics. If you have a thin pipe and apply a little pressure to a piston while moving it a very large amount, you can get a larger piston in a larger pipe to move a much shorter amount with much greater force.

My question is why one needs to apply 60psi to the cells being encapsulated. I know it's done in the industry, and that they know what they're doing. I'm just curious why.
Because it seems to me like if you have all of the air out of the panel and you're encapsulating, and there's enough pressure to generate a good bond between the EVA, glass, and cells, there might not be a need for 60psi.
Rephrased, as long as you have a good bond without airbubbles between your cells, glass, backing, and encapsulant, what's the need for extra pressure?

Again, just pondering.

[Sunking]

Doesn't sound like you are grasping the physics of Fluid Mechanics and the sub discipline of Fluid Dynamics. If you were you would clearly understand you can lift a car with nothing more than the air in your lungs as the power source.

[fingolfin]

Okay so I get sucking out the air to remove the airbubbles and moisture while getting the atmosphere to apply its 14.6psi, but why the extra pressure on the outside?
I've been mulling this over all day and can't make heads or tails of it...
Additionally does any of the EVA encapsulant (I'm just assuming film encapsulant for now) ever get squeezed out of the edges?

[Sunking]

But the vast majority of what you breathe is nitrogen

So true but Nitrogen is a inert gas.

[Naptown]

But the vast majority of what you breathe is nitrogen

[Sunking]

I am personally very fond of Oxygen.
In its place....

Yeah so am I like any air breathing organic life form. But oxygen is extremely poisonous or destructive to just about everything else. Water even more so.

[green]

Like these guys say, there is no way you can duplicate what the manufacturers are doing. But on the other hand the manufacturers can't duplicate your methods either.

Keep experimenting untill you find what works for you. For me the fun is in the experimenting.

Green

[inetdog]

.. and most important no nasty Oxygen.

I am personally very fond of Oxygen.
In its place....

[Sunking]

I suppose that's what the professional encapsulating machines do in a nutshell?

Yep plus they purge the chamber of all outside air and replace it with Nitrogen which has 0% moisture and most important no nasty Oxygen.

[inetdog]

I suppose that's what the professional encapsulating machines do in a nutshell?

Pretty much, yes.

[fingolfin]

Keep on bouncing, just remember to duck if they bounce back too hard.
Moisture in the encapsulant is far more of a concern than just air, as it can lead to damage to the cells or wiring eventually. The combination of vacuum and heat deals with that too. Pressure and heat will not necessarily do as well.

Interesting. I get it now. You need to pull out all the air you can because with it comes moisture.
How about this as an alternative: You need a vacuum on the panel, you need pressure outside the panel, and you need heat somewhere in the mix.
Perhaps a sealed chamber, with a vacuum pulling on the panel. Outside of the panel, but inside the chamber is heated air. The ideal gas law will help a little, in that heating up a gas while maintaining volume and amount of gas will raise the pressure. However from the back-of-the-envelope calculations I ran, it seems that bringing the temperature from 20C to 200C, and starting at 1atm, would only raise the pressure to 1.5atm, so you'd definitely need to pump in more.
I suppose that's what the professional encapsulating machines do in a nutshell?

[inetdog]

Very interesting. I figured it wouldn't be that easy. However leaving air dissolved in the encapsulant isn't too much of a bad thing, unless it changes an optical property of the encapsulant, or it condences back into gas after the pressure is removed from the solar panel. I realize that there is a reason the professionals do what they do. I just like bouncing ideas around.

Keep on bouncing, just remember to duck if they bounce back too hard.
Moisture in the encapsulant is far more of a concern than just air, as it can lead to damage to the cells or wiring eventually. The combination of vacuum and heat deals with that too. Pressure and heat will not necessarily do as well.

[fingolfin]

Quick answer: NO.
It could put the same amount of pressure on the surface of the panel, but it would leave air dissolved in the encapsulant or present as air bubbles which will try to expand when the pressure is released. A good vacuum pump will result in almost no air remaining and any bubbles would try to shrink when the vacuum is released.

Very interesting. I figured it wouldn't be that easy. However leaving air dissolved in the encapsulant isn't too much of a bad thing, unless it changes an optical property of the encapsulant, or it condences back into gas after the pressure is removed from the solar panel. I realize that there is a reason the professionals do what they do. I just like bouncing ideas around.

[inetdog]

So that begs the question if one were to roll their own machine to encapsulate solar panels, would it produce a similar result to raise the pressure on the container to 4atm, while forgetting about the vacuum entirely and having the internals of the solar panel vent to the outer atmosphere?

Quick answer: NO.
It could put the same amount of pressure on the surface of the panel, but it would leave air dissolved in the encapsulant or present as air bubbles which will try to expand when the pressure is released. A good vacuum pump will result in almost no air remaining and any bubbles would try to shrink when the vacuum is released.

[fingolfin]

Atmosphere Unit is an international standard of air pressure at sea level of approx 14.7 psi, so 3 Atmospheres is approx 44.1 psi. So when you use a vacuum pump which removes all down to 0 psi, then add 3 atmospheres of pressure outside the vacuum area the effective pressure differential is roughly 58.8 psi. The best vacuum cleaners out there can only lower the pressure about 20% or just less than 3 psi at sea level. You cannot even remotely duplicate what a manufactures do.

So that begs the question if one were to roll their own machine to encapsulate solar panels, would it produce a similar result to raise the pressure on the container to 4atm, while forgetting about the vacuum entirely and having the internals of the solar panel vent to the outer atmosphere?
This would maintain the 3atm differential between the pressurized container and the inside of the to-be-laminated solar panel, while dropping the requirement for a vacuum pump.
This is advantageous because, in general, a vacuum pump better than that of the household vacuum cleaner is less likely to be lying around at home than something that can bring pressure up to 60psi (air compressor, bike pump, etc.)

That said, what seems to be the big drawback is that a container which can contain 60psi, big enough for a solar panel, and able to hold whatever kind of heating element one would be using would probably be expensive.