Originally Posted by
sunnyday
on the subject of solar panels...I see 2 main ways of increasing their outputs without increasing total surface areas they take up :
1. new technologys that make the solar cells more powerful/efficient without increasing their size..
OR
2. technologys that allow solar panels to be transparent and allow light to pass thru them and reach other transparent solar panels that are stacked tightly behind them...while still harnessing the rays of the sun to make electrical current. This is the technology I saw on the special program about the cube solar panels...
so technology #2 would now allow people to harness 200 watts of solar energy , in a 12 " x 12" sqaure cube ....instead of having to place SEVERAL 12"x12" solar panels in a flat formation , all of which have to be angles properly to recieve the suns light...which is also less aeroydynamically beneficial then the 12" x 12" square solar cube...
What you're ignoring is the data that was provided previously on the total amount of power that's available in the incoming sunlight. This is a little under 1 W/sq.in. So even if the solar cells were 100% efficient and aimed perfectly perpendicular to the incoming light, this is the most power you could ever hope to get out of them.
Currently even the best solar cells are way under 100% efficiency - and the only way that you gain anything by stacking them is if they remain very inefficient. That is, if you have one panel that only extracts energy from the highest energy photons (violet to near UV) and lets the rest of the light through, then that panel is rather inefficient but the remaining energy in the lower energy photons can still be extracted by panels lower in the stack with each panel designed for a particular range of photon energy. But if you ever achieved a single solar panel with high efficiency then it would make no sense to stack them since the top panel would already have extracted all the available energy and the lower panels would not be adding any value.
So the most power you could ever hope to get out of a 12" x 12" panel is about 120 W assuming perfect efficiency, a clear sky, sun high overhead, etc. Making a stack of panels doesn't let you get any more power than this out of a square foot of collector, but it might be a practical way to improve the efficiency that we can currently get from a single panel.