Heat and efficiency of solar cells

[Kingfisher]

Hello everbody,

This is my first post on this form. I have a question on my mind and thought this is the right spot to place it.

I am a newbie on solar energy and solar cells but the technology and the possibility to transfer sunlight into useful energy interest me. It’s general knowledge that the efficiency of a solar cell goes down when the heat goes up. So to increase the efficiency of the solar cell you have to cool it down or you have to ensure that the cell does not become to hot.

After searching the internet if found that there is not yet a good solution to solve this problem for solar cells in hot dry environments with a lot of sun.

I was wondering if it’s maybe possible to mix a light colour pigment with the semiconductor (without modifying its properties) so that the solar cell adsorbs less heat? Or what are the most common solutions in a hot dry environment with a lot of sun?

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Kingfisher

[Sunking]

You cannot have your cake and eat it too. The only solution to your problem is to move to a cooler climate. But if you do that you will have to have even more panels to generate the same amount of energy due to the shorter amount Sun Hours available in the cooler climate.

Example here in the USA Phoenix AZ is one of the warmest regions, and Seattle WS is one of the coolest regions. It would take a 300 watt panel in Seattle WS to generate the same amount of energy as a 100 watt panel in Phoenix in a day.

[PNjunction]

Don't forget to look at the other end of the system - the charge controller.

I can tell you first hand that a very big mistake in a hot environment is to run with a cheap charge controller that does not even have ambient temperature-compensation. (this is different from temperature protection). The worst would be the simple on/off controllers that have a fixed setpoint window. Controllers that have ambient compensation are a bit better, and a controller with actual battery-temp monitoring via an attachable probe are best.

It hurts me when I see a relatively expensive hobbiest solar system baking batteries with the cheap controllers in the hot desert. I guess they just like buying batteries sooner than necessary.

[Kingfisher]

Thank you for the responses so far.

Regarding the cake; I believe that within now and a few years people will have cake and eat it to There are solutions, we simply did not find them yet… And most probably the solutions will come form people who surf forms like these.

Maybe we can turn this topic into a brainstorm to generate new and list existing theories (regardless of they work or not) so we can build on each other idea’s and theories.

Objective: increase the efficiency of the solar cell in a hot dry environments with a lot of sun.

Theory 1: Create white solar cells so that the solar cell adsorbs less heat
Theory 2:…..

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Kingfisher

[Naptown]

Thank you for the responses so far.

Regarding the cake; I believe that within now and a few years people will have cake and eat it to There are solutions, we simply did not find them yet… And most probably the solutions will come form people who surf forms like these.

Maybe we can turn this topic into a brainstorm to generate new and list existing theories (regardless of they work or not) so we can build on each other idea’s and theories.

Objective: increase the efficiency of the solar cell in a hot dry environments with a lot of sun.

Theory 1: Create white solar cells so that the solar cell adsorbs less heat
Theory 2:…..

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Kingfisher

Downside to the white solar cell is that a white cell would reflect the light back as opposed to absorbing the light which is the object of the exercise thereby decreasing it's efficiency. There have been some products that claim to increase efficiency by installing a water heat exchanger on the back of the panels to harvest the heat. There have been very mixed reviews on this product.

[Kingfisher]

There have been some products that claim to increase efficiency by installing a water heat exchanger on the back of the panels to harvest the heat. There have been very mixed reviews on this product.

Interesting theory that can increase the efficiency (in theory) if you have a purpose for the heat (and a supply of cold water).

In a very hot climate the challenge could be the supply of cold water.

Brainstorm idea: could it be possible to pump the hot water from the heat exchanger through cupper tubes into the ground to cool it down and feed it back to the heat exchanger?

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Kingfisher

[Sunking]

You will use more power circulating the water than what you will gain.

[inetdog]

Objective: increase the efficiency of the solar cell in a hot dry environments with a lot of sun.

Theory 1: Create white solar cells so that the solar cell adsorbs less heat
Theory 2:…..

The very best way to reduce the temperature of the cells would be to increase their PV efficiency. Any sunlight that is converted successfully to electrical energy will not contribute directly to heating the panel in the way that absorbed photons would. If you could go from 20% efficient to 80% efficient, you would reduce the solar heating of the panel by a factor of four at the same time.

[Sunking]

If you could go from 20% efficient to 80% efficient, you would reduce the solar heating of the panel by a factor of four at the same time.

Well in about 100 years you might see a 30% panel.

[inetdog]

Well in about 100 years you might see a 30% panel.

Not quite enough reduction in heating to allow Hell to freeze over, but....

[MidOhioValleySolar]

V3

Hello!

If you have not seen the V3 solar concentrator, then check it out. V3solar.com

It is a moving conical shaped solar collector that increases effeciency while addressing

the heat issue.

Lance

[russ]

The V3 site is 100% either 1) loony or 2) shyster.

Let them be around 10 years before jumping in - I doubt they see 2015

[inetdog]

The V3 site is 100% either 1) loony or 2) shyster.

Let them be around 10 years before jumping in - I doubt they see 2015

There is at least one other thread about the V3, which debunks it pretty thoroughly.
It looks pretty, and sounds good on the surface, but makes absolutely no sense if you look at it too hard.

On the other hand, it should appeal strongly to Dr. Who fans, just by its appearance.