Pointless solar panel question

Pants

Pants

Pants

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I have two solar panels. One is connected to nothing and the energy is going nowhere, the other is connected to an electric heater.

Would there be any difference in the temperature or any other aspect of the panels? Surely there has to be some kind of difference as the energy has to come from somewhere?

Random thought inspired by building this little robot thing with my daughter...

upload imagem
 
Your qeustions/random staements.rambling are a little incoherrent, but I'll respond anyway.

Pants said:
One is connected to nothing and the energy is going nowhere,
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If it's not connected to anything - the energy isn't "going nowhere". The energy isn't being collected in the first instance - t remains in it's original form (insolation).

Would there be any difference in the temperature or any other aspect of the panels?
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Solar energy is converted to electrical energy, not heat, therefore both panels will be the same temp. There may be a small amount of heat generate as a by product of collecting the solar energy and transferring it to a controller, but it will be negligable.

Surely there has to be some kind of difference as the energy has to come from somewhere?
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The energy comes from the sun.
 
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I get his point - two panels receiving the same amount of solar radiation, one is connected the other isn't.

The panel that is connected is converting some of the solar energy to electrical energy. The disconnected panel isn't converting any energy into electricity - given it receives the same amount of energy - what happens to equivalent energy the other panel converts? It is either reflected back or absorbed and turned into heat.

Therefore the disconnected solar panel either is more reflective or gets hotter.

Found the same question on Reddit:

https://m.reddit.com/r/askscience/comments/ye346/when_you_complete_a_circuit_with_a_solar_panel_it/

Seems to be an agreement that the disconnected panel is hotter.
 
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sorry off topic : What kit is that ? I'd like to play around with solar panels , but need something light (inexpensive) to try out a few projects.
 
both panels will be the same temperature, the one connected may be slightly lower temp, but not by much, heat is generated by different energy's as to what is being used to generate electricity.

UVA and UVB etc.
 
OP Has come across with a very convoluted question.

If energy is used it will generate heat, so the connected panel will be hotter than the unconnected panel.
 
itchy said:
OP Has come across with a very convoluted question.

If energy is used it will generate heat, so the connected panel will be hotter than the unconnected panel.
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Physics says you're wrong - conservation of energy. Both situations have the same input energy and both have to have the same output. So the one where light is converted into electrical energy will be cooler than the one that isn't.
 
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Minstadave said:
I get his point - two panels receiving the same amount of solar radiation, one is connected the other isn't.

The panel that is connected is converting some of the solar energy to electrical energy. The disconnected panel isn't converting any energy into electricity - given it receives the same amount of energy - what happens to equivalent energy the other panel converts? It is either reflected back or absorbed and turned into heat.

Therefore the disconnected solar panel either is more reflective or gets hotter.

Found the same question on Reddit:

https://m.reddit.com/r/askscience/comments/ye346/when_you_complete_a_circuit_with_a_solar_panel_it/

Seems to be an agreement that the disconnected panel is hotter.
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Thanks, that thread seems to mirror what I thought, that the same amount of enrgy is going into each panel, but more coming out of the connected panel, therefore the connected panel being cooler.
 
itchy said:
Solar panels do not generate energy from heat? :rolleyes:

So how am I wrong? :confused:
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Solar panels generate electricity from visible light, visible light causes heating.

The panel that is converting light to electrical energy can't also be hotter than the disconnected panel. Conservation of energy means this can't happen.
 
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Minstadave said:
Solar panels generate electricity from visible light, visible light causes heating.

That's where you're wrong.
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Its far to late to go into the complexities of this but, a solar panel is not a heat sink.

Its Photovoltaic and uses light not heat to generate electricity.

A un used solar panel will get the same amount of infrared radiation as a used one. But the used one will be generating heat as its energy is expelled.
 
itchy said:
Its far to late to go into the complexities of this but, a solar panel is not a heat sink.

Its Photovoltaic and uses light not heat to generate electricity.

A un used solar panel will get the same amount of infrared radiation as a used one. But the used one will be generating heat as its energy is expelled.
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and what happens to photons it doesn't convert into electricity, this is why solar panels, like any material heats up under lights. materials only reflect a certain percentage, the rest is mainly absorbed as heat then radiated back out.

solar cell efficiency also drops with heat, which is why water cooled ones are a lot more efficient and why nearly all solar panels have a aluminium backing that acts as a heats ink.

no one is saying it uses heat however they still get hot as its unavoidable.
 
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itchy said:
Its far to late to go into the complexities of this but, a solar panel is not a heat sink.

Its Photovoltaic and uses light not heat to generate electricity.

A un used solar panel will get the same amount of infrared radiation as a used one. But the used one will be generating heat as its energy is expelled.
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I understand how a solar panel works, I think you need to revisit the principle of conservation of energy. Forget infra-red radiation from the sun - it is irrelevant.

Both panels get the same amount of visible light, visible light causes heating. The connected panel converts some visible light into electricity, so that light does not cause heating, the rest is reflected or turned into heat.

The unconnected one can not convert visible light into energy, therefore more is reflected or converted into heat - so it is warmer.

The connected panel can not be generating electricity as well as outputting more heat. That is impossible.
 
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Both panels will have the same reflectivity/absorption properties. Therefore the one being used will have a slightly lower temperature than the one not being used, because some of its input energy is converted into electricity.

The one not being used will reach an equilibrium at a slightly hotter temperature. As solar panels don't generate much energy per unit area, the difference will be quite small.

IMO.
 
danlightbulb said:
Both panels will have the same reflectivity/absorption properties. Therefore the one being used will have a slightly lower temperature than the one not being used, because some of its input energy is converted into electricity.

The one not being used will reach an equilibrium at a slightly hotter temperature. As solar panels don't generate much energy per unit area, the difference will be quite small.

IMO.
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This. He has lightbulb in his name. He understands light.
 
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