Efficiency of solar panels: Earth vs Space

[pempem]

First of all, if this should have went in the Engineering section, I'm sorry... I wasn't sure where to write this post.

If a solar panel on Earth's surface can gather say 100W/m^2 in full sunlight, how much would the same solar panel be able to gather in space, outside of Earth's atmosphere? In other words, how much energy that could be absorbed by a solar panel on Earth is blocked by the atmosphere?

(Assuming the distance between the space solar panel and the Earth solar panel is small compared to the Earth-Sun distance, so the space panel's being closer or farther away from the sun has no bearing)

Can anyone point me to a source that has this information? I tried finding one, but had no luck.

Thanks!

 

[NobodySpecial]

It depends on the wavelenghts the panel responds to and how well those wavelenghts are blocked by the atmosphere. Over most of the visible the atmosphere is pretty much transparent (<1% absorbtion), as you get into the UV the absorption goes up .

You would have to pick a series of wavelength ranges, multiply them by how much the atmosphere absorbs and the efficency of the panel at that wavelength, then for space you just do the efficency of the panel in that band.

You could also take into account that the panel's efficnency changes with temperature - generally they lose efficency as they are heated but I don't know how efficenct they are at the very low temperatures in space.

 

[pempem]

From a quick search I found that most solar panels absorb light in the visible spectrum, and are not very good at absorbing wavelengths outside of that range. So I guess, with what you said, that would mean that the atmosphere should have little bearing on how much energy a solar panel can gather.

Although what you said makes sense, I found an article on Wikipedia that talks about the power per square meter different planets receive. The amount of power per square meter varies inversely with the square of the distance between the planet and the sun. So, for example, the Earth receives more power per square meter than Mars. The article states: "

"Sunlight on Mars would be more or less like daylight on Earth wearing sunglasses [...] it would give perceptions and "feel" very much like Earth daylight."

This is stated in the context of the presence of an atmosphere. This implies that due to the Earth's atmosphere, the surface of Earth and Mars both receive similar amounts of sunlight in the visible spectrum even though the Earth is closer to the sun. This contradicts the notion that light in the visible spectrum doesn't get absorbed (for the most part) by Earth's atmosphere... or am I not thinking of this right?

I found sources that confirm what you said (that visible light goes through the atmosphere for the most part), so you're right - I'm just confused by what the Wiki article states.

 

[Vagn]

What it means is that Polaroid sunglasses 'cut out' half of the radiation entering the eye at a given time. This is compared to the Amount of radiation received per unit area on Mars, which would be about half of the Earth's at perihilion, so it compares it to wearing sunglasses on Earth, the radiation per unit area is lower on Mars than on Earth, as the table in that article shows.