Encapsulation. Is EVA the only way to build panels?

[riff42]

Ok, I've been looking around on this site for a bit, and my head is hurting. I've seen various things people use. EVA (vacuum method the best, I can do that easily), a liquid version (Sylgard) is also listed. I also just saw something saying that silicone caulk is not good. Why? If I am sealing the cell array between two glass panels, and use the caulk to seal around the cell array, AND tabbing wires coming out, and seal the back with another plate of glass, or plastic (as long as it doesn't degrade structurally, who cares about transparency)....why is silicone bad? It stays flexible, outside versions I hope are UV stable. This way, I can leave 2 holes, and inject dry N2 which I have laying around, into the cell array cavity, and seal it up after that. Frame it, and go.

I have looked for EVA film, and it seems VERY expensive, and I would think the Sylgard is nearly the same.

I need glass anyway, I have N2, and silicone is cheap. Sooooo....what's the deal?

[Naptown]

If the silicone you have smells like vinegar it will cause corrosion on the cells and wires.
double glass will also tend to hold more heat at the cells reducing performance on hot days.

[green]

I can confirm the double glass thing for you. I made one panel like that and it retained so much heat that the panel only produced about 50% power once it heated up. It was reaching temperatures in the 150-170 range.

With the silicone I've found that you don't want to use it inside the panel like some people do. Using it to seal up the edges is fine. That's just my experience and my opinion though, you need to find what works for you.

[inetdog]

like some people do. Using it to seal up the edges is fine. That's just my experience and my opinion though, you need to find what works for you.

+1
The non-acetic-acid-curing silicone will still produce solvent vapors which can be trapped inside the panel unless it is completely cured before you close the panel.
When you use it to seal edges with small or no visible separation, the solvent will usually not go into the panel.

[tjames]

So best to just laminate Glass / EVA / PV Cells / EVA / Tedlar

[green]

So best to just laminate Glass / EVA / PV Cells / EVA / Tedlar

That is the ideal sandwich. The problem becomes heating it all and doing it in a vacuum while applying pressure. It can be done though.

[tjames]

Thanks for that-

I have the oven and silicone vac-bag all figured out. Fortunately, the temps just need to get to ~220F. Simple heating elements in a foam-lined box with metal fans circulating air for even fusion. I have Johnson temp controllers and would use one to maintain the temp.

I'll use an air pump also, not a shop vac. More complete vacuum possible. Fresh EVA, also. It has volatile plasticizers, so stale is not as good as fresh.