22 Sep '15 08:00>6 edits
http://phys.org/news/2015-09-transparent-coating-cools-solar-cells.html
In this case, the purpose of the design feature that reflects the radiation the solar cell doesn't use is to boost its efficiency by reducing how hot it gets in the sun. But I can think of another reason to do that:
I assume no solar panel can ever be exactly 100% energy efficient because that would break the laws of thermodynamics.
But, I have long thought that the 'ideally' solar panel should only absorb the solar radiation that it manages to convert into electricity while reflecting near-enough ~100% of what it fails to convert into electricity upwards where most of it would be radiated to outer space. That way, whatever solar energy the solar energy it fails to convert into useful energy would tend to be reflected upwards and thus contribute towards the albedo of the Earth and thus help counteract global warming.
I personally think one of our long term objectives should be to design solar panels optimized to do that.
I think even at the cost of the solar panel only absorbing, say, half of the solar energy and reflects the other half, I would still imagine it to be easily possible to make it cost effective and, so to minimize global warming, even at that cost, it would be worth so designing it to minimize the proportion of solar radiation it absorbs that it wastes as useless thermal radiation. I would guess it would be better to have a solar panel that converts ~50% of the solar energy into electricity and reflects ~50% of the remaining solar energy than have a solar panel that converts ~90% of the solar energy into electricity but absorbs and thus converts the remaining ~10% of the solar energy into waste heat that contributes to global warming. Well, that is what I think. I don't know if anyone here would disagree.
In this case, the purpose of the design feature that reflects the radiation the solar cell doesn't use is to boost its efficiency by reducing how hot it gets in the sun. But I can think of another reason to do that:
I assume no solar panel can ever be exactly 100% energy efficient because that would break the laws of thermodynamics.
But, I have long thought that the 'ideally' solar panel should only absorb the solar radiation that it manages to convert into electricity while reflecting near-enough ~100% of what it fails to convert into electricity upwards where most of it would be radiated to outer space. That way, whatever solar energy the solar energy it fails to convert into useful energy would tend to be reflected upwards and thus contribute towards the albedo of the Earth and thus help counteract global warming.
I personally think one of our long term objectives should be to design solar panels optimized to do that.
I think even at the cost of the solar panel only absorbing, say, half of the solar energy and reflects the other half, I would still imagine it to be easily possible to make it cost effective and, so to minimize global warming, even at that cost, it would be worth so designing it to minimize the proportion of solar radiation it absorbs that it wastes as useless thermal radiation. I would guess it would be better to have a solar panel that converts ~50% of the solar energy into electricity and reflects ~50% of the remaining solar energy than have a solar panel that converts ~90% of the solar energy into electricity but absorbs and thus converts the remaining ~10% of the solar energy into waste heat that contributes to global warming. Well, that is what I think. I don't know if anyone here would disagree.