Is really necesary the Tedlar?

[pablinho]

Hi, i'm a begimer in solar panel construction. I'm doing two large solar panels 150x130cm each, with 2x6inch solar cells. I speak about this in a blog (spanish) http://renovableselicork.wordpress.c...-fotovoltaica/

Now that i've made a few tests with EVA film. I have all ready to encapsulate it with only EVA (front and back). I have a homemade vacum machine.

I have questions before encapsulate the cells.

• First, is really necesary Tedlar sheet to protect EVA film from the outside?
• Exists some sustitute of tedlar, like vinile or similar. (The shipping cost it from the USA to Spain is my main reason to look for an alternative)
• In case to be absolutely necesary the Tedlar sheet. Is better to encapsulate it at once or in two steeps (first EVA and then Tedlar)

Thanks!

[Mike90250]

The Tedlar provides the moisture resistance to the backside, and a little more protection the cells.

There are VERY FEW (rare) materials, that provide the water vapor resistance needed for the panels. Most plastics and paints, allow moisture through them. Tedlar does not.

EVA is "hot melt glue" and is used to stick the cells to the front glass, and hold the Tedlar to the backside to make it vapor tight. Doing the glue and seal in one operation reduces thermal stress issues, as you have to heat the entire panel, under vacuum, above the EVA melting point, for some time, and then slowly cool it so as to not crack your cells.

[pablinho]

Thanks for answer

I've seen that in this post http://www.fieldlines.com/board/inde...topic=145004.0 They are using a backpanel of Tyvek (Dupont).
I'm thinking that coul be a good alternative, because is a material easy to get and it could be cheap too.

What do you think about this material?

For the encapsulation of large panel, i don't have an autoclave, but i have a heat gun and two home air heaters. Do you think that i could make a decent panel heating it only with this and an vacum pump?

[TnAndy]

Tyvek is used in the construction industry as an air infiltration barrier (house wrap).....it is designed to wick moisture thru the fabric to prevent trapping it on the warm side of the home, and thus, if you're wanting something to keep moisture OUT, Tyvek would be a REALLY REALLY bad choice.

[pablinho]

Ok, i discard tyvek as backpanel. I'll try to buy cheap pieces of Tedlar

[pablinho]

Finaly, i bougth a 6m x 1m of Tedlar. 72

[Thierry]

Tedlar

You can find Tedlar (TPT) here :
The shipping is free !

http://www.aliexpress.com/store/400691/200408635-317346971/Solar-Back-Sheet-PV-back-sheet-TPT-for-encapsulation-solar-panel-with-TUV-UL-certification-810mm.html

Hi, i'm a begimer in solar panel construction. I'm doing two large solar panels 150x130cm each, with 2x6inch solar cells. I speak about this in a blog (spanish) http://renovableselicork.wordpress.c...-fotovoltaica/

Now that i've made a few tests with EVA film. I have all ready to encapsulate it with only EVA (front and back). I have a homemade vacum machine.

I have questions before encapsulate the cells.

• First, is really necesary Tedlar sheet to protect EVA film from the outside?
• Exists some sustitute of tedlar, like vinile or similar. (The shipping cost it from the USA to Spain is my main reason to look for an alternative)
• In case to be absolutely necesary the Tedlar sheet. Is better to encapsulate it at once or in two steeps (first EVA and then Tedlar)

Thanks!

[pablinho]

Thanks Thierry, very usefull link.

I've finished my first panel, here you can see photo of result https://plus.google.com/photos/11836...79887619391346

I cured the eva in a homemade autoclave, but i have a problem just in last moment i had to stop and a corner is just melted but not cured.

I don't know if i'll have problems if i try to make the autoclave process again to cure the corner. Is this dangerous for the cured EVA?

Thanks!

[Thierry]

I really don't know ! I'm making my first panel.
For encapsulation, I don't know yet if I will choose :
-Sylgard or PV 6010 or
EVA, cells, EVA, Tedlar

Thanks Thierry, very usefull link.

I've finished my first panel, here you can see photo of result https://plus.google.com/photos/11836...79887619391346

I cured the eva in a homemade autoclave, but i have a problem just in last moment i had to stop and a corner is just melted but not cured.

I don't know if i'll have problems if i try to make the autoclave process again to cure the corner. Is this dangerous for the cured EVA?

Thanks!

[Mike90250]

remember, Glass and Tedlar are your water vapor moisture barriers, EVA is not a vapor barrier.

[pablinho]

Mike90250 I know, but... my question is if i can warn EVA a second time to finish the cure process in one corner. Is melted but not cured.

I don't know if i can damage EVA in the process

[Mike90250]

Mike90250 I know, but... my question is if i can warn EVA a second time to finish the cure process in one corner. Is melted but not cured.

I don't know if i can damage EVA in the process

EVA s a hot melt glue. I think you can melt & remelt it several times. Be sure to reheat the whole panel, if you do only a corner, the glass expands differently, and may break.

[pablinho]

Thanks Mike!