What's that silly song from the 1980s say?
"The night is gonna come here anyway"
So, to Save The Earth, is a square foot of solar panel better than a square foot of white plywood?
-- John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
Radiation cooling can kill you on a summer night in the desert.
I was telling the kids, in my noise lecture, that an antenna aimed at the sky can look like a very cold resistor.
-- John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
Yeah a couple of guys got a noble prize for measuring how cold. (well really how hot it was... 'cause it wasn't 0 K. :^)
Un-related, but a nice article in favor of nuclear energy by an ex- greenie.
It's a nice example of sloppy thinking, but correspondingly unpersuasive.
"France shows that moving from mostly nuclear electricity to a mix of nuclear and renewables results in more carbon emissions, due to using more natural gas, and higher prices, to the unreliability of solar and wind."
If you rely on fast start gas turbine-powered generators to cover for the intermittent nature of solar and wind power, you will up your carbon emissions.
If France had invested in energy storage - pumped hydro, pumped compressed air and batteries - it wouldn't have. The guy may claim to be an ex-greenie, but he indulges in exactly the same kind of specious arguments as regular greenies.
-- Bill Sloman, Sydney
If the square foot of solar panel supplies energy that would otherwise have been generated by burning fossil carbon, it saves the earth for rather longer - roughly 800 years - than a square foot of white plywood.
John Larkin is unconvinced of the deleterious effects of extra atmospheric CO2 - or rather has been unconvinced by heap of denialist propaganda - so he may not buy the argument.
-- Bill Sloman, Sydney
The windshield is an interesting one as is the roof of a car with thin supports. They are effectively thermally isolated and cool faster by radiation than the heat can be replaced by conduction.
Making ice in the desert is something of an art. A thin shallow blacked metal bowl with cold water in it on a straw bale on a night with a cool evening breeze is the classic way to demonstrate it. Even then it only works some of the time. It all depends on just how low the humidity is.
And you require both the cooling effect of the breeze and further radiative losses to bring it about. Too much breeze stops a frost forming but not enough breeze in the early stages prevents the water getting cool enough by evaporative cooling to actually freeze.
Only if you are naked and/or regularly sprayed in cold water. Wearing clothing pretty much stops radiative heat loss except from exposed skin.
I have observed in deserts at night in shirt sleeves without any problems at all. It does get a bit chilly near dawn. In the UK you really do need to dress warmly in winter as night frosts are common.
Deserts exist in Antarctica where you might easily die of hypothermia but that has nothing to do with radiative cooling.
Depending on the wavelength something like 80K for near to intermediate IR and the cosmic 4K microwave background at microwaves and radio where the atmosphere is properly transparent again. Penzias and Wilson got the Nobel prize for establishing that their excess noise was cosmic in original and not related to pigeon dielectric material in the horn. BTW It did not end well for the pigeons.
One advantage of modern cassegrain radio telescope dishes is that the sidelobes of the receiver are pointing skywards rather that at the hot noisy ground (like they do at Arecibo and Jodrell Bank for example). The latest generation dishes are designed to distort to a parabola under the influence of gravity irrespective of where they are pointed in the sky.
-- Regards, Martin Brown
That would be an interesting calculation to see.
Does the solar panel reduce CO2 by an amount greater than the carbon captured in the plywood? (I would guess yes.) How long does it take the solar panel to 'save' the amount of CO2 that was generated during it's creation? Several years I think.
George H.
That conjecture started all this nonsense.
OK, use natural wood. Or woven palm leaves. Or natural gravel.
I've seen it argued "never." Depends on how long it lasts, and whether that beats the coming ice age.
-- John Larkin Highland Technology, Inc lunatic fringe electronics
OK this has some numbers
and links therein. But it ignores CO2 needed to make solar panel.
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Only on denialist web sites.
The amount of CO2 we've already got in the atmosphere guarantees that we ca n't flip into an ice age. If we wanted one we'd have to get the CO2 levels back to preindustrial levels at precisely the right phase of the Milankovit ch (and that won't come up for quite a while - this would have been a long interglacial even if we hadn't gone in for digging up fossil carbon and bur ning it for fuel on an industrial scale).
John Larkin is either amazingly ignorant or amazingly persistent in insisti ng that he wasn't hoodwinked by the denialists into posting total nonsense.
-- Bill Sloman, Sydney
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You don't need to generate CO2 when you make a solar panel. At the moment a lot of the electricity used in the process does come from burning fossil c arbon, but the standard solar panel seems to generate some seven times more energy over its operational life-time than it took to make it.
I've seen an idiot denialist piece claiming that this made solar cells impr actical as a main energy source - the fact that this came to be published i n the Royal Australian Chemical Institutes monthly newsletter probably says something about the political influence of Australia's Lavoisier group
as well as speaking volumes about their poor grasp of reality.
-- Bill Sloman, Sydney
whether that beats the coming ice age.
Citation? 'Seen it argued' means you didn't see a calculation, i suspect. Insist on the calculation, you'll see the error without the time delay of waiting for an ice age.
It depends where you install it and what lifetime you assume it has in service but the lifetime energy yield is something like 4x that used to make it in Northern Europe and a more useful 7x in sunnier climes like Australia. See for example David MacKay's analysis:
Bottom paragraph and following page.
-- Regards, Martin Brown
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