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| 11/22 |
| 2009/5/27-6/3 [Science/GlobalWarming] UID:53048 Activity:low |
5/27 Paint your roofs white.
http://news.yahoo.com/s/afp/20090526/sc_afp/climatewarmingusbritainchu
"Making roads and roofs a paler colour could have the equivalent
effect of taking every car in the world off the road for 11 years,
Chu said."
\_ Did that already. Already noticed the house is much cooler.
Have not needed cooling even though highs were 90F. --PeterM
\_ I've been telling my wife we should do this, and she thinks I'm
crazy. Now that the energy secretary agress with me, maybe I can
finally do it. What kind of paint do I need for painting roofs?
Is it just the same kind of paints as for exterior walls? -- OP
\_ I actually didn't paint it--I changed roofing materials from
a dark one to a light one. --PeterM
\_ I have a light grey roof and no A/C. With a large shade tree on
the south side of my house I never need A/C. However, won't
this make my house colder in winter. It gets damn cold and I
run the heater constantly. Not sure it's a net win.
\_ Actually, I think it might help even in the winter. A light roof
means you gain less heat from the sun, but you also radiate less
heat away. Even in California, the net heat flow through your
roof in winter is probably outward.
\_ Check your physics crystal ball again. Color does not effect
transmission, only absorbtion. -mrauser
\_ Sorry, he's more correct than you are. Color, or more properly
material properties, can modify
both transmission AND absorbtion. Some, but not all,
white materials have low emissivity as well as high
reflectivity. Some DO have high emissivity and will
radiate heat well.
\_ What is "transmission" in thermal radiation? I know
absorbtion is "going in" and emission is "going out".
-- !PP
\_ Why do you think it is called "black body" radiation?
Black is the most emittive as well as the most absorptive.
\_ Where do you live? Most Bay Area locations don't ever need A/C,
and barely need heat. But A/C is more energy expensive than
heating AND it probably has more of an effect on hot days
than on cold days.
\_ Yeah, I was thinking that I need to heat my house, not cool
it. But it would still help with global warming to paint
my roof white.
\- The computation was done on an ultra 80.
\_ What? |
| 11/22 |
|
| news.yahoo.com/s/afp/20090526/sc_afp/climatewarmingusbritainchu US wants to paint the world white to save energy AFP/Getty Images/File - US Energy Secretary Steven Chu, seen here in April 2009, said Tuesday the Obama administration wanted ... FOXBusiness Tue May 26, 3:45 pm ET LONDON (AFP) - US Energy Secretary Steven Chu said Tuesday the Obama administration wanted to paint roofs an energy-reflecting white, as he took part in a climate change symposium in London. The Nobel laureate in physics called for a "new revolution" in energy generation to cut greenhouse gas emissions. But he warned there was no silver bullet for tackling climate change, and said a range of measures should be introduced, including painting flat roofs white. Making roads and roofs a paler colour could have the equivalent effect of taking every car in the world off the road for 11 years, Chu said. It was a geo-engineering scheme that was "completely benign" and would keep buildings cooler and reduce energy use from air conditioning, as well as reflecting sunlight back away from the Earth. For people who found white hard on the eye, scientists had also developed "cool colours" which looked to the human eye like normal ones, but reflect heat like pale colours even if they are darker shades. And painting cars in cool or light colours could deliver considerable savings on energy use for air conditioning units, he said. Speaking at the start of a symposium on climate change hosted by the Prince of Wales and attended by more than 20 Nobel laureates, Chu said fresh thinking was required to cut the amount of carbon created by power generation. He said: "The industrial revolution was a revolution in the use of energy. It offloaded from human and animal power into using fossil fuels. "We have to go to a different new revolution that can severely decrease the amount of carbon emissions in the generation of energy." The information contained in the AFP News report may not be published, broadcast, rewritten or redistributed without the prior written authority of Agence France Presse. |