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Re: New high end Solar Cell claims 42.8 % efficiency

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> Team sets solar cell record > Using a novel technology that adds multiple innovations to a very > high-performance crystalline silicon solar cell platform, a consortium led > by the University of Delaware has achieved a record-breaking combined > solar cell efficiency of 42.8 percent from sunlight at standard > terrestrial conditions. > > [snip] > > Robert H. > > >

So what are the long term effects? If ~50%? of the solar energy that normally be reflected back out into space is used to create electricity which ultimately will end up as heat, doesn't this mean that global warming will become a reality very quickly?

Ok, I know the 50% figure above is wrong as most of the energy is reflected back before it reaches ground. But what would be a good estimate? 1%? Now if everyone replaced there energy consumption with solar cells then what would be the equivilent ambient temperature increase? Isn't it the same increase one would have with current methods?

i.e., it seems we can easily estimate the world's current energy consumptions on global warming? We might not know how much fossil fuel consumption plays a part but surely we know with solar cells? and we can make an equivilence between the two. Knowing how much extra solar energy that is not going to be absorbed should give an easy estimate on the increase in temperature.

I'm just rambling here but seems to me if everyone used solar cells, not even taking into account all the energy and materials required to manufacture them, just the amount of solar energy being absorbed by them would increase global temperature quite easily? Now if thats the case then obviously thats whats happening with fossil fuels because its just a different method. (while its not a direct equivilence I would imagine its not to far off)

Seems like an easy way to estimate if global warming is actually happening or not and I've not read an argument along those lines. Although I suppose one could estimate the amount of energy used per capita and convert that into heat and compare it to the energy from the sun. i.e., the real issue in global warming is just how much energy we used compared to what the sun "gives" us. The first one we can control while the second we cannot. (so, if its 1/10^6, say, then chances are there is no global warming... or if it is, then its out of our control)

Anyways, I'm sure theres been some research along those lines, anyone know of the results?

Jon

Reply to
Jon Slaughter
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So called global warming is caused by changes in the composition of the atmosphere that slow the escape or infrared radiation into space. Right now, 100% of the radiation that reaches the surface is either bounced back as visible or raises the temperature of the surface. that energy must convect away, or radiate away as long wave IR radiation. Swapping the natural surface for solar cells bounces little back as visible radiation, because the cells are generally pretty dark.

But about half of the radiation that penetrates their surfaces is converted to electrical energy and half raises the temperature of the cells, just like what happens to dirt. The 50% converted to electricity actually lowers the temperature rise of the cells, but that doesn't lower the total IR radiation, because it is just transported elsewhere and radiated away, there.

The net effect with or without solar cells is a wash, except that people get to run appliances off the energy before it leaves into space. If instead, those appliances are run off fossil fuel, their heat is added to what the dirt in sunlight produces, except that the burnt fuel gets added to the atmosphere, getting in the way of the natural and waste heat escaping into space. Either way, solar energy overwhelms any addition from fuel consumption, as far as the amount of heat to be radiated. The big difference is in the composition of the atmosphere that heat has to pass through, to escape.

For the last few decades, we have been pumping several million barrels of oil out of the Earth, every day, and setting fire to it. That is a lot of carbon added to the atmosphere, and carbon dioxide in the atmosphere in the form of carbon dioxide, is very absorbent in the long wave IR part of the spectrum, where all that natural and wast heat is being radiated. As the CO2 builds up it raises the temperature of the atmosphere which raises the equilibrium water vapor content in the atmosphere. Water vapor is another IR absorbing gas, positive feedback takes over at some point and the system swings rapidly to a very much hotter equilibrium temperature, world wide. That is the so called global warming process (originally called global thermal run away, before the oil companies renamed it), in a nut shell.

Reply to
John Popelish

I'm looking forward to climate change... can you imagine Arizona

10-15° cooler ?:-)

...Jim Thompson

--
|  James E.Thompson, P.E.                           |    mens     |
|  Analog Innovations, Inc.                         |     et      |
|  Analog/Mixed-Signal ASIC\'s and Discrete Systems  |    manus    |
|  Phoenix, Arizona            Voice:(480)460-2350  |             |
|  E-mail Address at Website     Fax:(480)460-2142  |  Brass Rat  |
|       http://www.analog-innovations.com           |    1962     |
             
         America: Land of the Free, Because of the Brave
Reply to
Jim Thompson

If water-vapor positive feedback were sufficient for the loop to run away, it would have run away anyhow, CO2 or not. The water vapor loop must be net *negative* feedback, probably because of clouds.

CO2 absorption is so small that the only way the GW enthusiasts can get worked up is to apply a *lot* of conjectured "helper" positive feedback mechanisms. And clearly (clearly to me, anyhow) if those mechanisms existed 1000 years ago, they would have snapped then.

Earth is currently something like 20 degrees C below the temperature of an equivalent spherical black body.

I read that, on average, water vapor absorbs as much reflected IR in the first 30 feet as does all the CO2 from the ground to space.

John

Reply to
John Larkin

That is like saying that if a Schmitt trigger is capable of snapping on a positive input, varying less positive signals would have already have snapped it. The CO2 level is the threshold setting. As long as it is below some limiting concentration, the net feedback is negative, as you say. Above some limiting concentration, the positive feed feedback gets bigger than the negative feedback and the system flips. That is the concept, anyway.

Reply to
John Popelish

The key point everybody has yet to pick up on is that the VARIABILITY will also get a lot worse. Much worse.

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Reply to
Don Lancaster

But the feedback is continuous, analog, not a sharp threshold. And Earth has been a lot warmer in the past, with much higher CO2 levels. If there were positive feedback, we'd still be in the latched-warm state. If you look at the graphs of temp versus time over the last million years, there are periodic hot spikes caused by solar influx, but nothing that snaps or sticks.

GW is about political control; it the long-sought killer app of the anticapitalist "environmental" movement.

John

Reply to
John Larkin

Where can I find data that shows CO2 levels higher anytime in the last million years higher than it is now (and rising)? The system may be analog, but it is not linear. A couple degrees more, and Antarctic ice slides into the ocean and sea levels pop up in a season. It has happened several times in the past and it will happen again. It is not a question of if, but only when. Our fossil fuel use is just pulling the trigger sooner. If I had my choice, I would rather we delay the snap.

It has latches in the past, but that raises water levels so much that, eventually, the reflectivity of sea water swings the system back through the snap.

Right, it lasts only a few 1`0s of thousands of years. A moment in geologic time.

Freeing ourselves from fossil fuel consumption will be the biggest boost to capitalism since the locomotive.

The question is whether we will do it before or after the south pole melts. I have little hope left that we will get their first. I expect to see it go within a decade... two at most.

Reply to
John Popelish

There are negative feedback loops too but they are much slower, AIUI. For example the carbon in CO2 eventually ends up converted to calcium carbonate by marine organisms, or into fossil fuels by forests, but this takes thousands (or millions) of years. In the mean time you can get melting of the icecaps & extinction events.

--

John Devereux
Reply to
John Devereux

I'm rather looking forward to it - who knows, we might enjoy the ride! ;-)

Right. So it equilibrates. And it's going to happen anyway. What we really need to do is prepare for it and learn how to live through it and get on with our lives.

Actually, getting rid of income taxes would be the biggest boost to capitalism since, well, since capitalism itself. ;-)

If you're truly addicted to taxes, just replace it with a sales tax. You buy a $3.00 toothbrush, you pay $0.30 tax. Well, maybe not health care stuff, like not for grocery store food. But you get my point. Buy a $3,000,000.00 boat, you pay $300,000.00 tax. There is no more fairly distributed tax, if it's even possible to rationalize taxation as "fair" at all.

The truth is, taxation is theft. It's just that simple. If you don't believe me, try not paying your "voluntary" tax. They will take it by force, which is pretty much the definition of theft.

Thanks, Rich

Reply to
Richard The Dreaded Libertaria

On Sat, 28 Jul 2007 00:57:48 -0400, John Popelish wrote: ...

This just goes to show that Al Gore and his disciples are quite insane. They seem to believe that it's possible to stop the inevitable by preaching from a soapbox.

Oh, well.

Thanks, Rich

Reply to
Richard The Dreaded Libertaria

On Sat, 28 Jul 2007 12:46:38 +0100, John Devereux wrote: ...

Everyone seems to be totally sidestepping the fact that green plants inhale CO2, and turn it into food. Ergo, the more CO2 in the air, and the warmer it is, which translates to "longer growing season", means more food for everyone!

So, global warming is a GOOD thing.

And, so what if the icecaps melt and our coasts are swamped? Who needs New York, Miami, or LA anyway? >:->

Cheers! Rich

Reply to
Richard The Dreaded Libertaria

You can get the CO2 out of the atmosphere by just weathering and erosion. That's what happened in the Snowball Earth era back 750 million years ago.

Back then, all the continents were around the Equator and the high rate of weathering took so much CO2 out of the air that the global climate flipped to "cold" and the oceans froze over. That stopped the oceanic CO2 sink, and the climate flipped to "warm" when volcanic CO2 built up enough to get enough greenhouse warming to melt it.

Happened several times, a planetary sized relaxation oscillator.

Mark Zenier snipped-for-privacy@eskimo.com Googleproofaddress(account:mzenier provider:eskimo domain:com)

Reply to
Mark Zenier

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