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[LordBucket]

Anyway, solar irradiance is calculated over the entire electromagnetic spectrum, so there are no real gains to be made there.
There's a nice advantage in that you can recollect energy absorbed/reflected by clouds though.

I'm unsure how those number are caculated, but if so...then presumably the super expensive 40%+ efficiency panels do already collect from both frequency ranges and therefore would probably work in heavy cloud cover just fine right now. Probably.

Anyway, as you say...yes, nice advantage. Solar might take longer to be practical in some regions, but it's probably only years longer rather than "it will never work in the following states and countries."

[10ebbor10]

Solar irradiance is measured by a satellite in Earth's orbit, and IIRC, it's over the entire energy spectrum. How much of that energy reaches the Earth, and in which form, is a different thing, but on average it's something of 180W/m².

Anyway, gathering infrared isn't that beneficial, as the energy per lumen is significantly lower than energy from the higher end UV spectrum.

[LordBucket]

Solar irradiance is measured by a satellite in Earth's orbit, and IIRC, it's over the entire energy spectrum. How much of that energy reaches the Earth, and in which form, is a different thing, but on average it's something of 180W/m².

I was referring to the solar efficiency percentages on solar panels. I assumed they were a measure of the percent energy collected from the portion of the spectrum they were designed to collect from. You appear to be asserting they're a measure of the percent collected of total solar radiation that reaches them. I've been unable to find corroboration for either interpretation.

Anyway, gathering infrared isn't that beneficial, as the energy per lumen is significantly lower than energy from the higher end UV spectrum.

I'm not sure that's true.

http://en.wikipedia.org/wiki/Sunlight#Composition_and_power



The yellow is what the sun emits. The red is what makes it through the atmosphere to sea level. Not a lot of UV.


As for IR, it's my understanding that residential solar panels collect exclusively from the range between the dotted lines. If the solar efficiency numbers are they way you say...a measure of total possible energy collected...that vastly reduces the upward potential for improvements. It's the difference of whether a 20% panel collects 20% of the red between the dotted lines, or 20% of all the red on the entire chart.

That's a big difference.

[Leafsnail]

Efficiency is always going to be a percentage of the total incident energy, not sure why you'd think otherwise.  In any case I'm not sure that using vastly more expensive materials to squeeze a little bit of extra energy out of the IR spectrum is the way to go.  Might as well just get twice as many cheaper solar cells.

[alway]

Efficiency doesn't really matter. It's all about the cost of mass production.
There's all sorts of efficiency charts, like this one: http://www.solardave.com/images/efficiency-chart.gif
which show the rise in efficiency over the past several decades... But most of the gains are relatively modest. Thin film are actually some of the most promising, despite being some of the least efficient, simply because they are much cheaper to produce, and thus have a lower cost/watt. We've got enough surface area on a typical house to power probably half their block, even with current tech; so efficiency per square meter is unimportant.

And here's an interesting one: http://physics.ucsd.edu/do-the-math/2011/09/dont-be-a-pv-efficiency-snob/
It has a pretty good look at a variety of efficiency related bits. Basically, it works out that you will never really be able to get above 35% or so with a silicon PV cell; requiring a much more complex & expensive multi-material panel to get above that (those are the Multijunction ones mentioned in many of those efficiency charts). So yeah, not only has efficiency been unimportant for widescale adoption we are currently seeing, but it will also continue being unimportant into the future, since it can only offer modest gains without hitting the physical limitations of the material science behind it.

[forsaken1111]

So bottom line is that once costs drop, solar films may become viable? I want a PV paint that I paint my house with.

[XXSockXX]

Relevant to the topic. (Just saw that on Silicon Valley, which is pretty funny.)

[Glloyd]

Who still uses a pager? A VCR?

I'd like to note that I still use a VCR almost daily. In a non-ironic way.

[Sheb]

Let me guess: you're a security guard and your CCTV register on tape?

[Glloyd]

Let me guess: you're a security guard and your CCTV register on tape?

Nope. I live out in the country, and therefore have terrible internet. So, T.V shows that I want to watch, I tape them on V.H.S. When everyone started selling them, I picked up a ton of blank tapes and a couple extra VCR's for dirt cheap. It's great, because I can skip through the commercials that would normally appear on T.V. Also, I can tape good movies that come on and whatnot. They're actually surprisingly useful still. The only downside is putting up with the odd stares and comments I get when I mention that I still use VHS, hahaha.

[LordBucket]

http://thehigherlearning.com/2014/05/28/google-reveals-their-new-robo-taxi-with-no-pedals-or-steering-wheel-video/
http://www.electronics-eetimes.com/en/google-robot-car-targets-urban-services.html?cmp_id=7&news_id=222921260&vID=44
http://thenextweb.com/google/2014/05/28/googles-self-driving-car-project-destroy-taxis-uber-lyft-knows-everything/

Looks like this might be moving ahead faster than anticipated. 100 prototypes are being built now to be tested this summer.

 * Fully electric
 * Two seats, one compartment
 * No pedals or steering wheel
 * 100 mile range
 * 40km/hr max speed (24 mph? really?)
 *  "the vehicle comes with a plastic windshield and offers ample legroom. A large screen in the cockpit displays time, air temperature and estimated time of arrival at the destination. To start the ride, the user just enters the destination into the computer and pushes a start button."

[Mech#4]

That cars all "0_o_0".

[alway]

* 40km/hr max speed (24 mph? really?)

So far as I could tell, they suggested that was an artificial limitation simply to prevent all but very minor injuries that could result from something going horribly awry. After all, the last thing they want their early prototypes doing is ending up in a bad accident and dismembering someone. And unlike their previous self driving prototypes, there won't be a Google employee sitting behind the wheel, able to take control if something goes wrong.

[Helgoland]

Can you kill someone at 24 mph?

(Reminds me of that Borat scene: 'How fast do I need to go with this vehicle to reliably kill a Jew?')

[tryrar]

So, how long until google becomes out new overlords?

Seriously though, this is actually pretty cool. I'd use it(though I live out in the boonies, so I doubt I'd get service)