Daytime radiative cooling
http://nanotechnologytoday.blogspot.com/2013/03/ultrabroadband-photonic-structures-to.html
Ultrabroadband Photonic Structures To Achieve High-Performance
Daytime Radiative Cooling. A Stanford team has designed an entirely new
form of cooling panel that works even when the sun is shining. Such a
panel could vastly improve the daylight cooling of buildings, cars and
other structures by radiating sunlight back into the chilly vacuum of
space.
Homes and buildings chilled without air conditioners. Car interiors that
don't heat up in the summer sun. Tapping the frigid expanses of outer
space to cool the planet. Science fiction, you say? Well, maybe not any
more.
A team of researchers at Stanford has designed an entirely new form of
cooling structure that cools even when the sun is shining. Such a
structure could vastly improve the daylight cooling of buildings, cars
and other structures by reflecting sunlight back into the chilly vacuum
of space.
“People usually see space as a source of heat from the sun, but away
from the sun outer space is really a cold, cold place,” explained
Shanhui Fan, professor of electrical engineering and the paper’s senior
author. “We’ve developed a new type of structure that reflects the vast
majority of sunlight, while at the same time it sends heat into that
coldness, which cools manmade structures even in the day time.”
The trick, from an engineering standpoint, is two-fold. First, the
reflector has to reflect as much of the sunlight as possible. Poor
reflectors absorb too much sunlight, heating up in the process and
defeating the purpose of cooling.
The second challenge is that the structure must efficiently radiate heat
back into space. Thus, the structure must emit thermal radiation very
efficiently within a specific wavelength range in which the atmosphere
is nearly transparent. Outside this range, Earth’s atmosphere simply
reflects the light back down. Most people are familiar with this
phenomenon. It’s better known as the greenhouse effect—the cause of
global climate change.
Tuesday, July 22, 2014
Cooling solar cells
I found this, which is a follow-on to my previous post on radiative cooling
http://www.osa-opn.org/home/newsroom/2014/july/self-cooling_solar_cells/
http://www.osa-opn.org/home/newsroom/2014/july/self-cooling_solar_cells/
By adding a specially patterned
layer of silica glass to the surface of ordinary solar cells, a team of
researchers led by Shanhui Fan, an electrical engineering professor at Stanford
University in California has found a way to let solar cells cool themselves by
shepherding away unwanted thermal radiation. The researchers describe their
innovative design in the premiere issue of The Optical Society's (OSA) new
open-access journal Optica.
Solar cells are among the most
promising and widely used renewable energy technologies on the market
today. Though readily available and easily manufactured, even the best designs
convert only a fraction of the energy they receive from the Sun into usable
electricity.
Part of this loss is the unavoidable
consequence of converting sunlight into electricity. A surprisingly vexing
amount, however, is due to solar cells overheating.
Under normal operating conditions,
solar cells can easily reach temperatures of 130 degrees Fahrenheit (55 degrees
Celsius) or more. These harsh conditions quickly sap efficiency and can
markedly shorten the lifespan of a solar cell. Actively cooling solar cells,
however—either by ventilation or coolants—would be prohibitively expensive and
at odds with the need to optimize exposure to the Sun.
The newly proposed design avoids
these problems by taking a more elegant, passive approach to cooling. By
embedding tiny pyramid- and cone-shaped structures on an incredibly thin layer
of silica
glass, the researchers found a way of redirecting unwanted heat—in
the form of infrared radiation—from the surface of solar cells, through the
atmosphere, and back into space.
"Our new approach can lower the
operating temperature of solar cells passively, improving energy conversion efficiency significantly and
increasing the life expectancy of solar cells," said Linxiao Zhu, a
physicist at Stanford and lead author on the Optica paper. "These
two benefits should enable the continued success and adoption of solar
cell technology."
By adding a
specially patterned layer of silica glass to the surface of ordinary
solar cells, a team of researchers led by Shanhui Fan, an electrical
engineering professor at Stanford University in California has found a
way to let solar cells cool themselves by shepherding away unwanted
thermal radiation. The researchers describe their innovative design in
the premiere issue of The Optical Society's (OSA) new open-access
journal Optica.
Solar cells are among the most promising and widely used renewable energy technologies on the market today. Though readily available and easily manufactured, even the best designs convert only a fraction of the energy they receive from the Sun into usable electricity.
Part of this loss is the unavoidable consequence of converting sunlight into electricity. A surprisingly vexing amount, however, is due to solar cells overheating.
Under normal operating conditions, solar cells can easily reach temperatures of 130 degrees Fahrenheit (55 degrees Celsius) or more. These harsh conditions quickly sap efficiency and can markedly shorten the lifespan of a solar cell. Actively cooling solar cells, however—either by ventilation or coolants—would be prohibitively expensive and at odds with the need to optimize exposure to the Sun.
The newly proposed design avoids these problems by taking a more elegant, passive approach to cooling. By embedding tiny pyramid- and cone-shaped structures on an incredibly thin layer of silica glass, the researchers found a way of redirecting unwanted heat—in the form of infrared radiation—from the surface of solar cells, through the atmosphere, and back into space.
"Our new approach can lower the operating temperature of solar cells passively, improving energy conversion efficiency significantly and increasing the life expectancy of solar cells," said Linxiao Zhu, a physicist at Stanford and lead author on the Optica paper. "These two benefits should enable the continued success and adoption of solar cell technology."
Read more at: http://phys.org/news/2014-07-self-cooling-solar-cells-boost-power.html#jCp
Solar cells are among the most promising and widely used renewable energy technologies on the market today. Though readily available and easily manufactured, even the best designs convert only a fraction of the energy they receive from the Sun into usable electricity.
Part of this loss is the unavoidable consequence of converting sunlight into electricity. A surprisingly vexing amount, however, is due to solar cells overheating.
Under normal operating conditions, solar cells can easily reach temperatures of 130 degrees Fahrenheit (55 degrees Celsius) or more. These harsh conditions quickly sap efficiency and can markedly shorten the lifespan of a solar cell. Actively cooling solar cells, however—either by ventilation or coolants—would be prohibitively expensive and at odds with the need to optimize exposure to the Sun.
The newly proposed design avoids these problems by taking a more elegant, passive approach to cooling. By embedding tiny pyramid- and cone-shaped structures on an incredibly thin layer of silica glass, the researchers found a way of redirecting unwanted heat—in the form of infrared radiation—from the surface of solar cells, through the atmosphere, and back into space.
"Our new approach can lower the operating temperature of solar cells passively, improving energy conversion efficiency significantly and increasing the life expectancy of solar cells," said Linxiao Zhu, a physicist at Stanford and lead author on the Optica paper. "These two benefits should enable the continued success and adoption of solar cell technology."
Read more at: http://phys.org/news/2014-07-self-cooling-solar-cells-boost-power.html#jCp
Scientists may have
overcome one of the major hurdles in developing high-efficiency,
long-lasting solar cells—keeping them cool, even in the blistering heat
of the noonday Sun.
By adding a specially patterned layer of silica glass to the
surface of ordinary solar cells, a team of researchers led by Shanhui
Fan, an electrical engineering professor at Stanford University in
California has found a way to let solar cells cool themselves by
shepherding away unwanted thermal radiation. The researchers describe
their innovative design in the premiere issue of The Optical Society's
(OSA) new open-access journal Optica.
Solar cells are among the most promising and widely used renewable energy technologies on the market today. Though readily available and easily manufactured, even the best designs convert only a fraction of the energy they receive from the Sun into usable electricity.
Part of this loss is the unavoidable consequence of converting sunlight into electricity. A surprisingly vexing amount, however, is due to solar cells overheating.
Under normal operating conditions, solar cells can easily reach temperatures of 130 degrees Fahrenheit (55 degrees Celsius) or more. These harsh conditions quickly sap efficiency and can markedly shorten the lifespan of a solar cell. Actively cooling solar cells, however—either by ventilation or coolants—would be prohibitively expensive and at odds with the need to optimize exposure to the Sun.
The newly proposed design avoids these problems by taking a more elegant, passive approach to cooling. By embedding tiny pyramid- and cone-shaped structures on an incredibly thin layer of silica glass, the researchers found a way of redirecting unwanted heat—in the form of infrared radiation—from the surface of solar cells, through the atmosphere, and back into space.
"Our new approach can lower the operating temperature of solar cells passively, improving energy conversion efficiency significantly and increasing the life expectancy of solar cells," said Linxiao Zhu, a physicist at Stanford and lead author on the Optica paper. "These two benefits should enable the continued success and adoption of solar cell technology."
Read more at: http://phys.org/news/2014-07-self-cooling-solar-cells-boost-power.html#jCp
Solar cells are among the most promising and widely used renewable energy technologies on the market today. Though readily available and easily manufactured, even the best designs convert only a fraction of the energy they receive from the Sun into usable electricity.
Part of this loss is the unavoidable consequence of converting sunlight into electricity. A surprisingly vexing amount, however, is due to solar cells overheating.
Under normal operating conditions, solar cells can easily reach temperatures of 130 degrees Fahrenheit (55 degrees Celsius) or more. These harsh conditions quickly sap efficiency and can markedly shorten the lifespan of a solar cell. Actively cooling solar cells, however—either by ventilation or coolants—would be prohibitively expensive and at odds with the need to optimize exposure to the Sun.
The newly proposed design avoids these problems by taking a more elegant, passive approach to cooling. By embedding tiny pyramid- and cone-shaped structures on an incredibly thin layer of silica glass, the researchers found a way of redirecting unwanted heat—in the form of infrared radiation—from the surface of solar cells, through the atmosphere, and back into space.
"Our new approach can lower the operating temperature of solar cells passively, improving energy conversion efficiency significantly and increasing the life expectancy of solar cells," said Linxiao Zhu, a physicist at Stanford and lead author on the Optica paper. "These two benefits should enable the continued success and adoption of solar cell technology."
Read more at: http://phys.org/news/2014-07-self-cooling-solar-cells-boost-power.html#jCp
Scientists may have
overcome one of the major hurdles in developing high-efficiency,
long-lasting solar cells—keeping them cool, even in the blistering heat
of the noonday Sun.
By adding a specially patterned layer of silica glass to the
surface of ordinary solar cells, a team of researchers led by Shanhui
Fan, an electrical engineering professor at Stanford University in
California has found a way to let solar cells cool themselves by
shepherding away unwanted thermal radiation. The researchers describe
their innovative design in the premiere issue of The Optical Society's
(OSA) new open-access journal Optica.
Solar cells are among the most promising and widely used renewable energy technologies on the market today. Though readily available and easily manufactured, even the best designs convert only a fraction of the energy they receive from the Sun into usable electricity.
Part of this loss is the unavoidable consequence of converting sunlight into electricity. A surprisingly vexing amount, however, is due to solar cells overheating.
Under normal operating conditions, solar cells can easily reach temperatures of 130 degrees Fahrenheit (55 degrees Celsius) or more. These harsh conditions quickly sap efficiency and can markedly shorten the lifespan of a solar cell. Actively cooling solar cells, however—either by ventilation or coolants—would be prohibitively expensive and at odds with the need to optimize exposure to the Sun.
The newly proposed design avoids these problems by taking a more elegant, passive approach to cooling. By embedding tiny pyramid- and cone-shaped structures on an incredibly thin layer of silica glass, the researchers found a way of redirecting unwanted heat—in the form of infrared radiation—from the surface of solar cells, through the atmosphere, and back into space.
"Our new approach can lower the operating temperature of solar cells passively, improving energy conversion efficiency significantly and increasing the life expectancy of solar cells," said Linxiao Zhu, a physicist at Stanford and lead author on the Optica paper. "These two benefits should enable the continued success and adoption of solar cell technology."
Read more at: http://phys.org/news/2014-07-self-cooling-solar-cells-boost-power.html#jCp
Solar cells are among the most promising and widely used renewable energy technologies on the market today. Though readily available and easily manufactured, even the best designs convert only a fraction of the energy they receive from the Sun into usable electricity.
Part of this loss is the unavoidable consequence of converting sunlight into electricity. A surprisingly vexing amount, however, is due to solar cells overheating.
Under normal operating conditions, solar cells can easily reach temperatures of 130 degrees Fahrenheit (55 degrees Celsius) or more. These harsh conditions quickly sap efficiency and can markedly shorten the lifespan of a solar cell. Actively cooling solar cells, however—either by ventilation or coolants—would be prohibitively expensive and at odds with the need to optimize exposure to the Sun.
The newly proposed design avoids these problems by taking a more elegant, passive approach to cooling. By embedding tiny pyramid- and cone-shaped structures on an incredibly thin layer of silica glass, the researchers found a way of redirecting unwanted heat—in the form of infrared radiation—from the surface of solar cells, through the atmosphere, and back into space.
"Our new approach can lower the operating temperature of solar cells passively, improving energy conversion efficiency significantly and increasing the life expectancy of solar cells," said Linxiao Zhu, a physicist at Stanford and lead author on the Optica paper. "These two benefits should enable the continued success and adoption of solar cell technology."
Read more at: http://phys.org/news/2014-07-self-cooling-solar-cells-boost-power.html#jCp
Scientists may have
overcome one of the major hurdles in developing high-efficiency,
long-lasting solar cells—keeping them cool, even in the blistering heat
of the noonday Sun.
By adding a specially patterned layer of silica glass to the
surface of ordinary solar cells, a team of researchers led by Shanhui
Fan, an electrical engineering professor at Stanford University in
California has found a way to let solar cells cool themselves by
shepherding away unwanted thermal radiation. The researchers describe
their innovative design in the premiere issue of The Optical Society's
(OSA) new open-access journal Optica.
Solar cells are among the most promising and widely used renewable energy technologies on the market today. Though readily available and easily manufactured, even the best designs convert only a fraction of the energy they receive from the Sun into usable electricity.
Part of this loss is the unavoidable consequence of converting sunlight into electricity. A surprisingly vexing amount, however, is due to solar cells overheating.
Under normal operating conditions, solar cells can easily reach temperatures of 130 degrees Fahrenheit (55 degrees Celsius) or more. These harsh conditions quickly sap efficiency and can markedly shorten the lifespan of a solar cell. Actively cooling solar cells, however—either by ventilation or coolants—would be prohibitively expensive and at odds with the need to optimize exposure to the Sun.
The newly proposed design avoids these problems by taking a more elegant, passive approach to cooling. By embedding tiny pyramid- and cone-shaped structures on an incredibly thin layer of silica glass, the researchers found a way of redirecting unwanted heat—in the form of infrared radiation—from the surface of solar cells, through the atmosphere, and back into space.
"Our new approach can lower the operating temperature of solar cells passively, improving energy conversion efficiency significantly and increasing the life expectancy of solar cells," said Linxiao Zhu, a physicist at Stanford and lead author on the Optica paper. "These two benefits should enable the continued success and adoption of solar cell technology."
Read more at: http://phys.org/news/2014-07-self-cooling-solar-cells-boost-power.html#jCp
Solar cells are among the most promising and widely used renewable energy technologies on the market today. Though readily available and easily manufactured, even the best designs convert only a fraction of the energy they receive from the Sun into usable electricity.
Part of this loss is the unavoidable consequence of converting sunlight into electricity. A surprisingly vexing amount, however, is due to solar cells overheating.
Under normal operating conditions, solar cells can easily reach temperatures of 130 degrees Fahrenheit (55 degrees Celsius) or more. These harsh conditions quickly sap efficiency and can markedly shorten the lifespan of a solar cell. Actively cooling solar cells, however—either by ventilation or coolants—would be prohibitively expensive and at odds with the need to optimize exposure to the Sun.
The newly proposed design avoids these problems by taking a more elegant, passive approach to cooling. By embedding tiny pyramid- and cone-shaped structures on an incredibly thin layer of silica glass, the researchers found a way of redirecting unwanted heat—in the form of infrared radiation—from the surface of solar cells, through the atmosphere, and back into space.
"Our new approach can lower the operating temperature of solar cells passively, improving energy conversion efficiency significantly and increasing the life expectancy of solar cells," said Linxiao Zhu, a physicist at Stanford and lead author on the Optica paper. "These two benefits should enable the continued success and adoption of solar cell technology."
Read more at: http://phys.org/news/2014-07-self-cooling-solar-cells-boost-power.html#jCp
Thursday, May 15, 2014
Thursday, February 13, 2014
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