Aaswath Raman: How we can turn the cold of outer space into a renewable resource
Aaswath Raman is a scientist passionate about harnessing new sources of energy, mitigating climate change and more intelligently understanding the world around us -- by better manipulating light and heat using nanoscale materials. Full bio
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to visit my grandparents,
are pretty mild at best --
or 72 degrees Fahrenheit
and not too hot.
is a hot and humid place
or 90s Fahrenheit.
or sleep in such weather?"
didn't have an air conditioner.
to persuade them to get one.
collectively account for 17 percent
from the air conditioners
during my summer vacations,
that keep our food safe and cold for us
that keep our data centers operational.
account for eight percent
might grow sixfold by the year 2050,
in Asian and African countries.
in and around my grandmother's place
alarming things about climate change
cooling systems --
emitters of greenhouse gas emissions.
to cause a feedback loop,
of greenhouse gases
kilowatt-hours of electricity every year,
to an amazing opportunity.
in the efficiency of every cooling system
on our greenhouse gas emissions,
that worst-case feedback loop.
about light and heat.
allow us to alter the flow
once thought impossible.
the value of cooling
working on this problem
that I came across about six years ago.
able to make ice in desert climates?
located in the southwest of Iran.
of such structures throughout Iran,
throughout the rest of the Middle East
this ice house many centuries ago,
in the pool you see on the left
as the sun set.
might be above freezing,
or 41 degrees Fahrenheit,
in the early morning hours
you see on the right,
something very similar at play
on the ground on a clear night,
is well above freezing.
if the air temperature is above freezing?
cause the water to become ice.
cooling on a window sill.
its heat needs to flow somewhere cooler.
is actually flowing to the cold of space.
like most natural materials,
known as thermal radiation.
as infrared light right now,
with thermal cameras
like the ones I'm showing you right now.
is sending out its heat
that's responsible for climate change.
all of that heat.
on a much warmer planet.
eight and 13 microns,
as a transmission window.
that goes up as infrared light
carrying away that pool's heat.
that is much, much colder.
as minus 270 degrees Celsius,
to send out more heat to the sky
below its surroundings' temperature.
known as night-sky cooling
by climate scientists and meteorologists
of my PhD at Stanford.
simplicity as a cooling method,
had investigated this idea
at least one big problem.
cooling for a reason.
that's doing the cooling,
something cold the most,
you're going to look up to the sun.
this cooling effect.
spend a lot of our time
we can structure materials
new and useful things with light --
than the wavelength of light itself.
or metamaterials research,
to make this possible during the day
a multilayer optical material
than a typical human hair.
two things simultaneously.
lets that heat out the best.
is it avoids getting heated up by the sun.
was on a rooftop in Stanford
and counterintuitive this is:
out of the shade,
from our very first experiment,
more than five degrees Celsius,
than the air temperature,
was shining directly on it.
to actually make this material
do we make something cool,
to do something real and make it useful.
save energy with this idea?
to save energy with this technology
and refrigeration systems.
fluid cooling panels,
to solar water heaters,
they cool the water, passively,
be integrated with a component
called a condenser,
in Davis, California, shown right here.
improve the efficiency
as much as 12 percent in the field.
to its first commercial-scale pilots
and refrigeration space.
to integrate these kinds of panels
building cooling systems
usage by two-thirds.
be able to build a cooling system
below the air temperature
on a hot summer's day.
about all we can do for cooling,
to a more profound opportunity
process here on earth.
I'd like to highlight are solar cells.
the hotter they are.
with deliberate kinds of microstructures
of this cooling effect
at a lower temperature.
to operate more efficiently.
of opportunities further.
we can use the cold of space
generate power with this cold.
between us here on earth
something called a heat engine
amounts of electricity
is being able to manage
that's all around us.
the flows of heat and energy
with the cold darkness of space,
where we, as a civilization,
our thermal energy footprint
this ability in our toolkit
you're walking around outside,
is essential to life on earth itself,
has something to offer us as well.
ABOUT THE SPEAKERAaswath Raman - Applied physicist, engineer
Aaswath Raman is a scientist passionate about harnessing new sources of energy, mitigating climate change and more intelligently understanding the world around us -- by better manipulating light and heat using nanoscale materials.
Why you should listen
Aaswath Raman is an assistant professor of electrical and systems engineering at the University of Pennsylvania. He is also co-founder of a clean energy startup, SkyCool Systems, where he is its chief scientific officer. He initiated and led the development of radiative sky cooling, a technology that he originated as a research associate at Stanford University, beginning in 2012.
Raman is deeply interested in the intersection of science, technology and development work, and he has previously collaborated on projects to redesign refugee camps with UNHCR and to rethink governance in rural Sierra Leone. In recognition of his breakthroughs in developing radiative sky cooling, in 2015 he was named one of MIT Technology Review's "Innovators Under 35."
Aaswath Raman | Speaker | TED.com