Cooling, whether that's air
conditioning or refrigerators is probably one of the
biggest challenges we face with respect to climate change. It's one of the least publicized threats in my view for all the
progress we are making towards decarbonizing a
broader energy system. Global demand for air conditioning is
predicted to triple by 2050. Meeting that demand is a challenge that's at the heart of both the climate and cost of living
crises around the world. I think the problem is very rancid because we see the prices
of electricity going up. I don't think that low
income population can cope with all these increased prices. If everybody started to
use air conditioning, for this we really need
sustainable solutions to really take this forward. So what else can we do to survive extraordinary heat without costing the environment? Turns out some of the solutions already existed centuries ago. Dr. Denia Kolokotsa has been
studying energy efficiency in buildings for the last three decades. When I started doing this research everybody said that I was crazy. You know, what are you going to do? Now, I think everybody speaks about that. So that's the difference. Denia has studied a deceptively simple solution to our cooling problem. Cool roofs. Mainly that can be tiles, paints, shingles whatever it is attached
within a roof that has the ability to reflect
the sunlight and emit the thermal energy that is
absorbed by the surfaces. If it sounds a bit low tech to you that's probably the point. This simple, yet effective solution has been around for centuries. It's rooted in the concept of passive cooling used
in ancient architecture. For example, passive cooling
in Cyclades in Greece is to paint the buildings white to emit the sun back to the sky. Passive cooling in Egypt is to have smaller openings and smaller windows in order not to allow the sun to come in. Madrid is notoriously hot in the summer. That's a problem for Mercamadrid, the world's second biggest fish market. It has the mammoth task
of keeping thousands of workers and fish cool
under its massive roof. The market sells 172,000
tons of fish annually. For example we were told this guy came all the way from Scotland. Thanks to the cooling
system, it's still alive. Temperature inside the
market used to get as high as 40 degrees Celsius, or 104
Fahrenheit, in the summer. With thousands of people and
fish sloshing in and out, keeping everything cold is a top priority. In 2018, the market underwent
a 3 million Euro makeover to do just that. The entire roof was cleaned and repainted with a waterproof and
highly reflective coating. The project also added 68
evaporative cooling units to supply a constant stream
of cold air into the market. Mercamadrid says the new
system saves up to 70% energy and cuts 34 tons of
carbon emissions a year. The temperature is now kept
around 15 degrees Celsius, or about 60 degrees Fahrenheit, even on the hottest of summer days. So cool roofs are helping this market, but in order to make a dent in
the global demand for cooling we need multiple
solutions working at once. In California, a company has come up with a new cooling technology
that is also inspired by ancient wisdom. About 10 years ago, I was
finishing my PhD at Stanford and a labmate and I came
across these references to a capability that apparently
many ancient cultures had, which was the ability to
make ice in the desert even though the air
temperature was above freezing. It turned out they were taking advantage of a natural phenomenon that's
known as radiative cooling. All objects, including you
and I, and the walls around us actually emit our own heat away as a kind of light that we can't see. So this light happens to be in the infrared part of the spectrum. Now, if you go outside and look upwards our atmosphere actually lets out some of this light all the
way out to outer space. This effect was often known as night sky cooling or nocturnal cooling because it's really easy
to observe at night. We asked the question, why can't we make this
passive cooling effect work during the daytime when
we need cooling the most? The co-founders of Skycool then developed a nano material
to achieve this effect. It's a class of materials
that when you put them outside on a hot day, are actually
cool to the touch. It's not getting heated up by the sun but it's continuing to send
that heat out upwards to the sky and space over those infrared wavelengths. We were the first to actually demonstrate that radiative cooling was
possible during the daytime. A common challenge early
on has been to kind of reorient engineers and
people working in this industry from thinking about their
cooling systems as a simple box that they've been used to for decades, and instead to kind of
imagine a new possibility, which is that you might need a
little more area on your roof but in return you get
all this energy savings. In the US, Skycool now works with supermarkets and data centers. They say their clients save
cooling energy by 15-20% but Skycool is also keen to
introduce their technology to emerging economies like India, where demand for cooling
is expected to skyrocket. Recently, they've partnered with industrial equipment maker Trane to help Indian street vendors who have little access to refrigerators. First, we came here, we
studied how they were doing, and immediately found
out they had 30% waste. Anuradha makes $8 a
day selling vegetables. Some days she went home with just about $2 because of the hot weather. They are at the bottom of the society. These people are pushing
the cart through the streets and they don't have
power and other things. Back in the lab, the
engineers have developed a cart to solve the vendor's problem. They're applying Skycool's high-tech film on top so that the fruits and
vegetables will stay cool, even under harsh daylight. As long as it's exposed to the sky, you get the cooling. As you can see, the temperature
of the canopy is low. Inside the cart is also low. And as you come down,
it's more than 35 degrees. But here it is, you know, 25, 22. All kinds of leafy vegetables. They lose water and shrivels very quickly. This technology has
helped them to extend life of this by at least one day. This is a zero energy input, zero water input way of getting cooling, that is unlike any other technology or capability that's out there. Skycool has been collaborating with 3M in their research. Together, they received
$3.5 million of funding from the US Department of
Energy to improve their films, making them cheaper and more durable. So I am most excited about our technology in the context of emerging economies. So places like India,
South America, Africa, these are locations where air conditioning has very low penetration rates today. So there's enormous growth
potential for cooling equipment. We've seen some pretty compelling examples of alternative cooling solutions, but are they enough to really slow our demand for air conditioning? With all these appliances
and facilities that we have, life is becoming easier. So if life is becoming easier you don't think how to solve problems. So the all day solution
should be reminded now. Denia says only having cool materials on our roofs is not enough. We have to combine it with greenery and other technologies
to lower the temperatures of our cities. And every building has to play
a part to make a difference. In Spain, the energy demand
for air conditioners is so high that the government had to
impose a rule last summer to stop people from turning their AC's below 27 degrees Celsius,
or 81 Fahrenheit. Today's buildings are
not really designed to optimally exploit radiative
cooling because architects and engineers didn't know
that it was a possibility. But if these kinds of
materials are available you might imagine entirely
different configurations for next generation, extremely
energy efficient buildings. If we wanna stop the vicious feedback loop between air conditioning
and global warming, the International Energy
Agency says policy action is critical to ensure a sustainable path to the future of cooling. We need more than money to essentially drive these initiatives. We need to have certainly policy changes but we also need to change how
individuals make decisions. Cooling equipment is only as efficient as the policies that governments dictate. There is no solution fits all. But I think that now
that we have the citizens that have raised their
awareness and understand that they cannot continue
consuming electricity the way they used to be, things will change very
dramatically in the near future.
