Interesting Observation...

[FB.]

Not being "one of the trade", I said that I would stop posting on here - but I found this observation to be too interesting to not mention:

Two adjacent solar PV arrays, mounted on near-identical houses, facing near-identical direction (SouthEast) and neither with shade issues, taken at 9.45am (mostly bright and clear since daybreak), today (10th February 2012), after a couple of cm snowfall overnight.
Very interesting to see that one of the arrays has cleared the snow much better than the other.

One array is 15x250W panels, the other is 18x190/200W panels (I think).

 

[synergy power]

Looks like someone has got the polish out on the left house so the snow slides straight off!

 

[dansk]

interesting, i wonder if one has a special coating.

 

[ruston]

More likely one house has better insulation than the other.

 

[grandfortune]

a few factors could solve this, if the house on the left has a new born baby in, the people will be running the heating on alot more and higher, that could cause alot more heat, also depends on the insulation in the loft, and just one small slip of the snow at the top is all it would take for the whole column to come sliding down.

just my thoughts

 

[mogga]

one might have an attic room ? you get "Selfcleaning" Glass coating could it be applied to panels?

 

[FB.]

Panels have not had special coating (other than anything applied by the manufacturer). Both arrays of very similar age (a few months).
Neither house has any major changes in the loft such as an attic room to affect heat exchange - and the amount of snow remaining on the tiles beside the panels is very similar for both houses; suggesting comparable heat loss through the roof.

 

[wstevew]

Has the clear one got a tl inverter and the other not?

 

[Earthstore]

Maybe, due to orientation, as the sun came up it hit the roof on one house just a little before the other. because of shading from neighboring houses,
The sun is still very low in the sky, just a thought..
Have a look early tomorrow if the sun is shinning.

 

[SolarCity]

Not being "one of the trade", I said that I would stop posting on here

That's no reason not to post. Don't let disagreements worry you - we all have them.

 

[SolarCity]

More likely one house has better insulation than the other.

That was my immediate thought. I'm not sure it would affect the solar panels so much though.

Judging by the amount of snow in the gutter it would appear that the snow if falling off rather than thawing - although a mild thawing could be causing the fall.

 

[Earthstore]

It is good on here to get feedback from customers, if we like it or not we can all learn from them, at the end of the day, we work on there behalf, and without them we would not have an industry..
Please carry on with your posting.

 

[ruston]

That was my immediate thought. I'm not sure it would affect the solar panels so much though.

Judging by the amount of snow in the gutter it would appear that the snow if falling off rather than thawing - although a mild thawing could be causing the fall.

Yes, It's amazing how much heat is lost through a badly insulated roof though, they could have insulation removed to accommodate the fashion for down lighters, coupled with the heating being on full tilt in the cold weather. The edge of the house may not be affected by down light holes Could speculate all day lol.

 

[FB.]

Maybe, due to orientation, as the sun came up it hit the roof on one house just a little before the other. because of shading from neighboring houses,
The sun is still very low in the sky, just a thought..
Have a look early tomorrow if the sun is shinning.

Both houses are identical twins, side-by-side in the same orientation. There's no shading at all - just a big open field to the SouthEast; nothing between the PV arrays and the sun. No buildings, no telephone wires.

 

[Earthstore]

In pic 3 there is a house next to it, as the sun rises in the east and is low in the sky maybe a little shade early on.
Sorry, it was just a thought.
Guess it is just a mystery of life, like why did kamikaze pilots where crash helmets?

 

[FB.]

Panels all clear of snow now - here's how they look without their blanket:

 

[whinmoor]

Can you tell the panel brands or if they are monos or polys?

 

[FB.]

Can you tell the panel brands or if they are monos or polys?

In the next several days I will try to get all the details (panel type, schematics, inverter etc) and add them to this topic. I haven't had much chance to speak to the neighbours for a few months. I strongly suspect that the neighbours' 18x200W(ish) array is "rent-a-roof".

The 15x250W panels are Chinese-built mono.
The 18x200W (ish) panels look like mono (there's no "cracked" look to the cells) but the light is fading now and they might be poly; the 18x200W panels are noticably blue-tinted in comparison to the 15x250W array, as you can see in the pictures above.

Sorry that I can't provide more details at the moment, but nevertheless, there might be something going on which others can look out for on other arrays around the country - and it could turn out to be of value in areas where snow is a problem.

At the moment, I have several wild guesses in my head:
1. The bigger panels cause the snow to lay in a more fragile way (like a long piece of plywood gives way more easily than a smaller piece).
2. The bigger panels might have a smaller rim around the edge, so snow slides off easier.
3. The bigger panels might have slightly wider "ventilation" spacing which helps snow fall off.
4. The layout of the string(s) and/or bypass diodes could be affecting heat accumulation/disipation.
5. The panels have different coatings on the glass.
6. A flock of birds landed on the 15x250 array and dislodged the snow. Given the way the snow remains on the middle panels though, I can't see this as being the cause but you never know.

 

[Yanman]

I have an observation...... Oh the joy to to have such straightforward roofs to install pv as those!!!!!!

 

[SolarCity]

I have an observation...... Oh the joy to to have such straightforward roofs to install pv as those!!!!!!

I know! The easiest to survey, the easiest to install. So very rare over the last few weeks.