Air vent for solar panel

[Mike90250]

What area ? What's your relative humidity? In Arizona, I'd expect it to last at least 5 years, in Florida, maybe 2 years. It all depends on how fast the silica saturates and becomes useless. Humid areas = shorter life

If you bake it daytimes, and bring in under cover so dew and rain don't get on it, it'll last longer. The hot innards bleed vapor off, and when it hits the cool glass, you get the fogging condensation dropletts on the glass

[philpaine]

I live on the south coast of England - I suspect we get a little more precipitation than Arizona!

But lets work with Florida - after 2 years would you expect it to just stop working? Or does the current start to fall off year on year?

I am trying to understand the impact of water vapour on a homemade solar panel. Are there any links to suitable sites that you can post?

Thanks

Phil

[Mike90250]

Failure modes:

http://pvcdrom.pveducation.org/MODULE/Failure.htm

http://www.nrel.gov/pv/performance_reliability/pdfs/failure_references.pdf

http://www.sciencedirect.com/science...62060afa54c1ab
http://www.sciencedirect.com/science...dbaa3363bd8ee3

[scheek]

Doublesided Butyl mastic

This may be an alternative to silicone to seal glass.

I've used this in the environmental industry for years. It works well when sandwiched between SS batten to waterproof. Not sure of the affect it may have on cells. Maybe a moderator has an answer to that one. It comes in various thicknesses.

Ok. Let's solve this problem.

[scheek]

Encapsulating cells with epoxy

Mike what do you think of the idea of building a retainer around the edge of the glass that supports the cells with 1/2" weather stripping and then pouring epoxy into the newly formed reservoir.

It would be important to tape off the cells first to prevent the epoxy from migrating under the cells.

I've read about silicone, acrylics, polyurethane, and epoxy, and it seems that epoxy rates the highest from transitivity into the enclosed area. All do, however. As you said.

That's why I thought about just covering the solar cells completely and then seal the panel too.

It seems from what I read ALL fail at some point due to moisture. Maybe a capped drain hole is necessary.

[Mike90250]

I can't recomend anything. You also have thermal expansion effects, and from -10C to 50C, that can be a lot. Try and report back.

[philpaine]

From what I read, Mike, you are saying that a home made solar panel is not going to keep water vapour at bay for more than a coule of years, regardless of what one does.

OK - so if we accept that, what about encapsulation. Is that the way forward?

[Mike90250]

From what I read, Mike, you are saying that a home made solar panel is not going to keep water vapour at bay for more than a coule of years, regardless of what one does.

OK - so if we accept that, what about encapsulation. Is that the way forward?

Could be, the encapsulant needs to have a thermal expansion coefficient of about the same as the panel wafers, otherwise, it will crack them up.

On home built PV solar panels, I've full of NOs and no yess. Sorry. Just a lot to go wrong there.

[philpaine]

Has anyone got any experience of encapsulation? I would Love to hear about it!

[philpaine]

Mike

Will silicone keep water vapour out for years?

Phil - still looking for ways of sealing solar panels effectively

[Anttistaatti]

I think that if the panel is made of plywood or something not so moisturetight material it is better to use ventholes. If panel is made only with metal, glass and plastic parts and there is no moisture left in it then it could be better to seal it tight. Maybe ventholes need to be in bottom and top of panel so the air will flow through the panel. When there is air movement and heat the moisture should dry quickly. Of course humidity will go in at nights when the sun is not there heating and drying it.

[BuzzBuds]

I live on the south coast of England - I suspect we get a little more precipitation than Arizona!

But lets work with Florida - after 2 years would you expect it to just stop working? Or does the current start to fall off year on year?

I am trying to understand the impact of water vapour on a homemade solar panel. Are there any links to suitable sites that you can post?

Thanks

Phil

South coast of england Hmm ok very little humidity and and very little heat compaired to what we get over here in the states.

South coast? Portmouth hampshire somewhere?

Have you looked into the vacuming thing like using it with a heat gun and some clear sheats of thick heat shrink type plastic to sanwich the cells themselves and then work on incapsulate them with a durable glass as your winds and debree dont damage the casing you could use the vented casign this way. I am not sure though as I have not tried it yet but am working on the calculations of one design before I get there.

[BuzzBuds]

Lived in portsmouth for 3 to 4 years with my wife and kids
The sun there could be real good if you are right on the sea front highrise.
You would have dawn and sunset on ocean if possitioned right.
but then if your in that possition I would be more inclined to go with wind power with a little turbine if I am not mistaken here when I think of the sun vs wind being only day light with solar turbine could be running when you are not 24/7 very seldom do you have no wind at all in that location. But being that this is a solar solution board I am not sure if I can mention that in here or not but I will try as it is still green

[Pennguy]

I have another method that just might take care of your moisture infiltration.


1. What I would use to sandwich in the cells would be 1/4 inch low iron 2x4 tempered glass for the front view of the panel and 1/4 inch 2x4 of plexi glass to what will be the back view of the panel and do not use anything less then 1/4 inch if you desire to have your panels last for a long time. Next will be important: leave an inch and a half of space all around your glass panels. So make sure you arrange your cells to fit inside these measurments. Why an inch and a half? Good question, we'll get back to this in just a sec but just keep it in mind for now.

2. Make a hole 2 1/4 inches from the bottom of the Plexi-glass. Meaning the"back panel" Try not to misunderstand this part now, ok! The hole will not be 2 1/4 inches NO! What I want you to do is measure from the bottom of the panel 2 1/4 inches upward to drill your hole, get it? But make it look nice by making the hole towards the middle of the panel unless good looks in your work doesn't matter to you. Now, make sure that the hole is just big enough for the rubber molding to clamp into the plexi glasss. DO NOT HAVE GAPS BETWEEN THE OUTSIDE OF THE MOLDING AND THE PLEXI-GLASS PANEL. Remember to put plenty of silicone inside the rubber molding "after the whole assembly of the panels are completed", do not worry about that now. The type of rubber molding I would use would be like one of an electric drill which is long and the wires could swivel all around. This molding is used to protect the wires from being dammaged and also for insulation purposes. So remember, the reason I stated have no gaps between the glass an the rubber molding it is so that the external elements created by seasonal changes do not affect your panel.

3. Next, place the cells as they should on the "glass" for the front view. Which means, you'll have the negative side of the cells looking up. Now, the back panel will NOT be placed yet, it will be placed later, so leave it aside for now.

4. Now I will give you the answer to the number 1 question. The reason I told you to leave an inch and a half around the whole panel is, so that you can place an inch of weather proof molding. This molding has sticky applications on both sides which will stick to the front panel as well as the back panel. Place this molding tightly ON THE GLASS by the sides of the cells [without touching the cells] all around the cell configuration. So this means you will need to cut 4 strips to fit it squarely all around the cell configuration. MAKE SURE THEY ARE CUT NEATLY WITH SISSORS AND REMEMBER, LEAVE NO GAPS!

IMPORTANT NOTE: When you buy the weather proof molding make sure it's thick enough to pass the cells hight so that when you lay your back panel down it will not damage the cells. The thickness of the weather proof molding will also act as a shock absorbing mechanism for the panel.

Now as I was saying, when sticking your mold to the glass if the bus wire configuration sticks out to where it interferes with your wether molding & the 1 1/2 inches you need to stay behind just tuck your bus wire in a bit.

5. Next, pour a small quantity of clear epoxy resin [SYLGARD-184] which you can find in EBAY. Pour the epoxy in and around all the cells to fasten the cells down to the glass so that it could keep it from moving around inside the panel and damaging it. Don't worry if you get the epoxy on your bus wire application as this epoxy is to cover all your cells. You should keep any diodes out side of the panel though, just incase you will need to replace it later. Remember, use enough quantity of the epoxy for holding down your cells to the glass If you need more to cover your entire work, do so! NOTE: Pour enough of the sylgard-184 to be seen just above the cells but keep it just below the wetherproof molding. The reason you also have the weatherproof molding all around the cells is to keep the epoxy from running all over the place to. After this is completed you must let it dry before continuing to the next step.

6. Next, run the wires thru the back panel 1st and then place the back panel down on to the wether proof molding. Make sure your back panel is flush with front panel and no wires are getting kinked. Now that you have completed this step you should still have a half inch of gap all around your panel. This is good, so continue to step number seven.

7. In this half inch gap get your clear silicone or silicia gel [I prefer the clear epoxy resin but to explain to you so that it will not run all over the place it would just take to long] but anyways silicone is good too. Fill the gap with silicone till it's flush with both glass. Do this all around the panel and you're done!

8. Now you can build your self an aluminum frame for your work and hang it on the wall LOL!!! But seriously, as you see we did this work without the frame work first the frame is last in the way I sceem up things. First you take a picture than you go looking for the frame, that's how I look at it anyways.

Now that you are completed did you remember to put silicone inside the rubber molding that your wires run thru? Do this now, let it dry and you have just made yourself a waterproof panel. Nothing should ever get inside!

[old pipefitr]

old pipfitr

This is my last question before I get one answer to the others.

I am sandwiching my cells between glass panels. I've seen on several diy panels the builder says to leave air vents in the bottom to prevent fogging. On another,(which I really like and copied) shows using silicone between the sandwich glass panels. He has made his air tight.

Before enclosing, which method should I use?

Could you drill 2 ports at the the top on either end and use 1 port to purge the panels with nitrogen and when most all the air has been replaced with nitrogen, plug the ports. It would appear the nitrogen would displace all air and moisture making the panel interior inert. Just a thought...............