Author Topic: Home Rooftop Solar Power System Update - Shattered Panel!  (Read 40812 times)

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Offline thm_w

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Re: Home Rooftop Solar Power System Update - Shattered Panel!
« Reply #150 on: December 15, 2015, 12:27:24 am »
In volume most glasses are cheap, multilayer wideband antireflective coatings for the glass would be the expensive part (while being cheap to put on the silicon its self). There are even cheaper plastic films you can use instead of glass but they have comparatively poor impact protection. Losses in the protective layers/coatings are a very small part of the efficiency of the assembled panel so there is lots of wiggle room to use less than ideal parts.

We used a plastic/epoxy coated panel for a while at work and it was horrific. The coating is soft so scratched easily, and dirt would stick or embed itself in the surface.
I'm sure there are better parts out there, but I can't think of where you'd ever want to use the cheap panels we got.
 

Offline rs20

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Re: Home Rooftop Solar Power System Update - Shattered Panel!
« Reply #151 on: December 15, 2015, 02:05:54 am »
They use Physical Vapor Deposition (PVD) using a hard vacuum to put the silly decorative metallic finish on plastic kitchen blenders; it becomes economic with large quantities. And very nice antireflective coatings are commonplace in camera lenses.

With that in mind, I'd be very surprised if the glass used in solar panels wasn't coated (at least on the underside) -- it seems like a very easy efficiency win for a very low recurring cost?  I know the glass panels are larger than camera lens elements, but still.

Also, regarding antireflective coatings being delicate: yeah, making a coating that is both durable, not overly sticky, and antireflective is a difficult compromise. But don't forget that the underside of the glass is a potential reflection point. Even if they only coated the underside of the glass, that still halves your reflection losses, and the side of the glass that sees the outside environment is dead-standard uncoated glass (or differently coated).
 

Online blueskull

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Re: Home Rooftop Solar Power System Update - Shattered Panel!
« Reply #152 on: December 15, 2015, 05:14:11 am »
PV panels are very cost sensitive. From the perspective of a utility company, to make this cost effective (forget about the California rubbish renewable energy regulations, we only talk money), at large scale, only the cheapest and most robust ones can be used. Efficiency does not matter, unless it is too low.

Utility companies run on very low margin with very high initial capital, and are regulated heavily by regulatory bodies.

I did a case study on Alabama Power, it reveals if we do not use existing infrastructure, and build a new grid in Alabama, we have to sell energy for >10cents per kWh to make acceptable profit to get invested.
 

Offline LabSpokane

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Re: Home Rooftop Solar Power System Update - Shattered Panel!
« Reply #153 on: December 15, 2015, 06:30:49 am »
PV panels are very cost sensitive. From the perspective of a utility company, to make this cost effective (forget about the California rubbish renewable energy regulations, we only talk money), at large scale, only the cheapest and most robust ones can be used. Efficiency does not matter, unless it is too low.

Utility companies run on very low margin with very high initial capital, and are regulated heavily by regulatory bodies.

I did a case study on Alabama Power, it reveals if we do not use existing infrastructure, and build a new grid in Alabama, we have to sell energy for >10cents per kWh to make acceptable profit to get invested.

You need to keep in mind that Dave is not a utility trying to repurpose a brownfield site. Dave bought the LG panels due to their quality and efficiency.  Trying to optimize the output from a fixed size rooftop is a slightly different value proposition than utility-scale solar. Dave knowingly paid a premium and got great service when he had a problem.
 

Online blueskull

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Re: Home Rooftop Solar Power System Update - Shattered Panel!
« Reply #154 on: December 15, 2015, 06:39:36 am »
You need to keep in mind that Dave is not a utility trying to repurpose a brownfield site. Dave bought the LG panels due to their quality and efficiency.  Trying to optimize the output from a fixed size rooftop is a slightly different value proposition than utility-scale solar. Dave knowingly paid a premium and got great service when he had a problem.

I think most of the premium goes into minor improves and better material as well better service.

For the process (PVD, CVD, whatever), I don't think it makes economical sense for LG to build a new premium product line for small amount of premium customers.
 

Offline Chris Jones

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Re: Home Rooftop Solar Power System Update - Shattered Panel!
« Reply #155 on: December 16, 2015, 01:45:46 pm »
They use Physical Vapor Deposition (PVD) using a hard vacuum to put the silly decorative metallic finish on plastic kitchen blenders; it becomes economic with large quantities. And very nice antireflective coatings are commonplace in camera lenses.

With that in mind, I'd be very surprised if the glass used in solar panels wasn't coated (at least on the underside) -- it seems like a very easy efficiency win for a very low recurring cost?  I know the glass panels are larger than camera lens elements, but still.

Also, regarding antireflective coatings being delicate: yeah, making a coating that is both durable, not overly sticky, and antireflective is a difficult compromise. But don't forget that the underside of the glass is a potential reflection point. Even if they only coated the underside of the glass, that still halves your reflection losses, and the side of the glass that sees the outside environment is dead-standard uncoated glass (or differently coated).

The encapsulant ("glue") between the glass and the cells is usually EVA or sometimes silicone, but in any case it has a similar refractive index to glass so there is not much reflection from the interface between the glass and the encapsulant and not much point in applying anti-reflective coatings on the underside of the glass.
 

Online Ian.M

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Re: Home Rooftop Solar Power System Update - Shattered Panel!
« Reply #156 on: December 16, 2015, 03:55:56 pm »
What can be done with a shattered solar panel?  Once the new panel is up and working, maybe a teardown?   Can the shattered glass be effectively re-bonded by resins like the one in the video near the start of the topic? Can the glass be removed and the panel hacked up and re-glazed to power small low voltage projects?
 

Online blueskull

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Re: Home Rooftop Solar Power System Update - Shattered Panel!
« Reply #157 on: December 22, 2015, 09:15:41 am »
What can be done with a shattered solar panel?  Once the new panel is up and working, maybe a teardown?   Can the shattered glass be effectively re-bonded by resins like the one in the video near the start of the topic? Can the glass be removed and the panel hacked up and re-glazed to power small low voltage projects?

 

Offline gildasd

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Re: Home Rooftop Solar Power System Update - Shattered Panel!
« Reply #158 on: December 22, 2015, 04:09:48 pm »
What can be done with a shattered solar panel?  Once the new panel is up and working, maybe a teardown?   Can the shattered glass be effectively re-bonded by resins like the one in the video near the start of the topic? Can the glass be removed and the panel hacked up and re-glazed to power small low voltage projects?


UV Resistant epoxy, no filler, slow reactant, very thin layer.
I'm electronically illiterate
 

Offline Seekonk

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Re: Home Rooftop Solar Power System Update - Shattered Panel!
« Reply #159 on: December 22, 2015, 04:49:05 pm »
Free panels!  I can see people sticking on those shattered glass decals and taking a picture.
 

Online Kleinstein

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Re: Home Rooftop Solar Power System Update - Shattered Panel!
« Reply #160 on: December 22, 2015, 05:40:57 pm »
A simple AR coating (just 1 or 2 layers) is not expensive. You can get this on windows at a rather low extra costs. Coating window panes is standard (at least in Europe) - in small quatities you may have to pay extra for an uncoated gals.

Even if its only some 3 % of more energy gained, the cost of the coating is likely less than 3% of the panel, and higher efficiency panels also need less area and mounting.

Sould not be a golf ball, as the panels should withstand hail of comparable size and weight und thus therminal speed.  This one looks like not just shatterd but way over the design limit.
 

Offline gildasd

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Re: Home Rooftop Solar Power System Update - Shattered Panel!
« Reply #161 on: December 22, 2015, 06:50:38 pm »
I found proof of what happened...
I'm electronically illiterate
 


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