Water Droplets from the sky

[cereal tiller]

Am playing with new Solar Panels assessing performance and ideal positioning.

 

If Rainwater is allowed to remain on the panels will it lower input?

 

CT

[Beaker]

I don't think it makes much difference.

 

Snow, however, is a different matter!

[bizzard]

Improve it I'd say. Water globules are like lenses and will magnify the suns rays. Its what used to happen with mainly red cellulose paint on cars, pale scorch spots.

[Supertramp]

I find it's the best time to clean the panels, when they have the early morning mist on them, or after a shower.

A quick swipe with a rubber window cleaner (like a car windscreen wiper) removes the dirt and leaves them dry as well.

[Machpoint005]

Improve it I'd say. Water globules are like lenses and will magnify the suns rays. Its what used to happen with mainly red cellulose paint on cars, pale scorch spots.

 

You'd be wrong, Bizz. Rain droplets on the panels don't affect the total area on which the sunlight falls, so no difference overall in electrical output.

 

ETA: It's the average amount of energy on the surface that matters, whereas your paint scorching is a localised increase.

Edited May 7, 2014 by Machpoint005

[Clifford]

If you use a lens to focus the sun onto a spot, that spot will get very bright and very hot. But the area around is now very dim. The lens hasn't created any new light and infra red, it's just moved it so instead of falling on the dim area, it's fallen on the bright area.

 

I guess that a solar panel with raindrops is LESS effective, because the bright spots will exceed the cells' ability to make full use of incoming light, and the other areas will be dimmer than normal. It may be that polycrystalline will cope better than mono. Or not. Anyway, the raindrops will scatter light away from the panel.

 

Hang on! Or will the drops catch grazing light that would have missed the panel and deflect it downwards?

 

Theory fails! Someone shouild test this instantly!

 

 

I am confident thgat Bizzard will now come up with a way of moving sunlight from a neigbour's solar panel to one's own.

[RLWP]

I am confident thgat Bizzard will now come up with a way of moving sunlight from a neigbour's solar panel to one's own.

 

If he does, I'll bet it will be all smoke and mirrors

 

Richard

[dor]

My flat mounted panel produces the same output whether it has water droplets on it or not.

 

What will affect output is shadows from other objects on the roof or ropes left across the panel. Also if the panels get dirty. The cells on the panels are basically wired in series and go to a much higher resistance if they are shaded.

[Ex- Member]

If you use a lens to focus the sun onto a spot, that spot will get very bright and very hot. But the area around is now very dim.

 

 

I can't get my head around that. If I shine a torch or indeed a sunlight from a lens on anything, how does that dim the surrounding light? It will of course be dimmer than the beam but no dimmer than before the beam was applied surely?

[RLWP]

 

I can't get my head around that. If I shine a torch or indeed a sunlight from a lens on anything, how does that dim the surrounding light? It will of course be dimmer than the beam but no dimmer than before the beam was applied surely?

 

The lens and the torch both cast a shadow. In the case of the lens, the focused light will appear as a bright spot in the shadow. In the case of the torch, the light generated by the batteries and bulb override the shadow

 

Richard

[Ex- Member]

 

The lens and the torch both cast a shadow. In the case of the lens, the focused light will appear as a bright spot in the shadow. In the case of the torch, the light generated by the batteries and bulb override the shadow

 

Richard

 

Still don't get it. You don't need to cast a shadow, I can easily direct light on to a panel at an angle that doesn't cause a shadow. If the panel is receiving natural light as for example at factor of 10 and I shine a torch on the panel at a factor of 20 casting no shadow from the torch, the light on the remaining panel remains at a factor of ten surely, how can some additional light in one spot/area diminish the natural light in the other areas.

Edited May 7, 2014 by Julynian

[RLWP]

 

I can't get my head around that. If I shine a torch or indeed a sunlight from a lens on anything, how does that dim the surrounding light?

 

 

 

Still don't get it. You don't need to cast a shadow, I can easily direct light on to a panel at an angle that doesn't cause a shadow. If the panel is receiving natural light as for example at factor of 10 and I shine a torch on the panel at a factor of 20 casting no shadow from the torch, the light on the remaining panel remains at a factor of ten surely, how can some additional light in one spot/area diminish the natural light in the other areas.

 

You have changed the question

 

Richard

[Ex- Member]

 

 

 

You have changed the question

 

Richard

 

Where exactly?

[RLWP]

 

I can't get my head around that. If I shine a torch or indeed a sunlight from a lens on anything, how does that dim the surrounding light?

 

There is a uniform field of light. The lens casts a shadow, making it dimmer, and the light is focused into a bright spot

 

The torch is different, it generates it's own light, and as you say doesn't change the brightness of the uniform field around the light spot

 

The point raised by Bizzard earlier was that the panels would work better because of the intense light spot. As was pointed out, it doesn't because the intense, focused spot is surrounded by the shadow of the drop. It would damage paint in the focused spot, it won't change how a solar panel works as there is no additional energy

 

Richard

[Ex- Member]

 

There is a uniform field of light. The lens casts a shadow, making it dimmer, and the light is focused into a bright spot

 

The torch is different, it generates it's own light, and as you say doesn't change the brightness of the uniform field around the light spot

 

The point raised by Bizzard earlier was that the panels would work better because of the intense light spot. As was pointed out, it doesn't because the intense, focused spot is surrounded by the shadow of the drop. It would damage paint in the focused spot, it won't change how a solar panel works as there is no additional energy

 

Richard

 

Ok I see the shadow from an individual water droplet. I didn't think a water droplet would cause a shadow though, although possibly it does, never really thought about it LOL

[RLWP]

never really thought about it LOL

 

It's funny how often this forum throws up things like that. I have found out loads of things from random stuff started here

 

Thinking about it, raindrops on a glass roof look dark, presumably because of their shadow

 

Richard

[Ex- Member]

 

It's funny how often this forum throws up things like that. I have found out loads of things from random stuff started here

 

Thinking about it, raindrops on a glass roof look dark, presumably because of their shadow

 

Richard

 

Yeah I was just thinking that running water from a hose might also cause a shadow. I'll test that out when we top up LOL

[matty40s]

 

Yeah I was just thinking that running water from a hose might also cause a shadow. I'll test that out when we top up LOL

 

 

 

I tried to find out, does this answer your question, taken in Nottingham.

 

[Ex- Member]

Pretty conclusive Matty

[Clifford]

Like I said, a magnifying glass burning a hole in something doesn't create new light and heat , it just moves it around. So areas around the hot, bright spot are cooler and darker than they were before the lens arrived.

[bizzard]

The size and shape of raindrops are governed by the size and shape of the holes in the clouds where the rain leaks through, just like a colander does when your draining your veg.

You can also boil kettles in the beams of powerful search lights. Shielded you could heat up a late night cup of cocoa in the beam of your boats headlamp but it mightn't be ready before breakfast time.

[RLWP]

The size and shape of raindrops are governed by the size and shape of the holes in the clouds where the rain leaks through

 

Wow, Bizz! I didn't know you were a Metrologist!

 

Richard

[bizzard]

 

Wow, Bizz! I didn't know you were a Metrologist!

 

Richard

Well ahem meteorology is just one of my studies.

[RLWP]

Oh . Who measured all them holes then?

 

Richard

[bizzard]

Oh . Who measured all them holes then?

 

Richard

You don't have to. The size of the clouds rain holes can be determine by presenting various sized washers between your fingers to the rain drops as they fall and watch carefully as they pass through the holes. Or lie on your back on the lawn in the rain pointing a Spotmatic camera at a cumulus rain cloud. When a rain drop approaches within an inch or so of the lens quickly click the shutter. You will then have a magnificent raindrop photo which can be compared with objects of known sizes like 5p pieces, marbles or beads so as to gauge the raindrops true size and the size of the holes from whence they came.

Edited May 9, 2014 by bizzard