Today’s air conditioning and refrigeration systems essentially follow
the same principles that have been around for about hundred years.
If we continue along today’s path then that sets us up for a future where
air conditioning may actually become one of our single largest
sources of greenhouse gas emissions later this century.
Air conditioners have become inescapable part of our cities.
They operate thanks to refrigerants - chemicals which
when released into the atmosphere are potent greenhouse gases.
AC units also require huge amounts of energy.
The U.S. uses more electricity for cooling than Africa does for everything.
As it becomes affordable for millions more people,
the problems that come with AC will only get worse.
Which is why scientists around the world are searching for solutions.
Here at the National University of Singapore professor Chua and his team
are completely rethinking air conditioning.
We need a quantum leap in air conditioning to save energy, secondly to save our environment.
What we have in the lab is next generation of air conditioners
which is extremely environmentally friendly, less energy intensive,
it doesn’t eject heat to the environment and doesn’t need the chemical refrigerant.
It’s a water based air conditioning.
It requires only one litre of water to operate for 20 hours.
And you can use rainwater to power up the system.
But there is a limitation.
The air needs to be dry before you can carry out this process in an efficient way.
And that’s why there are two separate stages in this AC.
First it dries the air, using membranes that filter the moisture.
Then the water inside the unit evaporates taking heat with it.
It’s close to what most of us experience every day - sweating.
This system uses 30% less energy than a traditional air conditioner
and it’s also expected to be 30% cheaper.
Crucially, it uses no refrigerants.
And although it’s not available yet, the government is backing this project,
betting that soon it could be a breath of fresh air for Singapore and beyond.
Across the other side of the world, one start-up in California is looking
towards outer space to revolutionise cooling.
And they’re about to test their breakthrough in the field.
Right now if we measure the temperature of our surface, it’s around 48 degrees Fahrenheit
and the air temperature is 60 Fahrenheit.
We’re not evaporating water and we’re not using any electricity.
You can see we’re in a middle of a field and it is just a thin film coating that enables
this cooling effect and it does this 24 hours a day, 7 days a week.
SkyCool Systems is commercialising a technology that harnesses
the cold of the sky and space to enable electricity-free cooling,
as implausible as that may sound at first glance.
The way it works is it takes advantage of a natural phenomenon
that allows a surface that’s looking up to the sky to essentially send out some of its heat.
Nearly everything on earth gives off heat in the form of infrared radiation.
SkyCool’s panels act as high-tech mirrors reflecting some of that heat
out to the cold expanse of space, allowing a surface to dip below the temperature
of the surrounding air.
SkyCool’s multilayered film means that it’s now possible to achieve even during the day.
The panels could be added onto today’s cooling systems
reducing their energy use by as much as 20 percent.
The energy we use for cooling is expected to grow six fold by the year 2050.
And it’s primarily gonna be driven in warmer countries
where air conditioning use is not prevalent today.
What excites us about our technology is that it represents a unique
and completely different way of handling the cooling problem
by taking use of a resource that's always been there, the fact that space is cold.
It's almost like this has been literally over our heads for centuries, millennia,
but it’s something we’ve not been able to use as a technology.
With the demand for air conditioning skyrocketing, using water and the cold of outer space
may turn out to be the best bet we have for our warming cities.