The power of cool
You like power, right? No, not the kind thrown around by emperors and presidents. The kind that turns on lights after a simple flick of a switch — the exhilarating kind of power.
Well, there’s been a recent breakthrough that can make power plants even more powerful — or at least more environmentally friendly and efficient.
In 2015, the U.S. Department of Energy’s Advanced Research Projects Agency-Energy gave the University of Colorado Boulder a $3 million grant spanning three years to develop an efficient, low-cost supplementary cooling system for thermoelectric power plants. “Wow, uh, how exciting,” you say with more than a hint of sarcasm. No, it really is! Researcher Ronggui Yang explains why:
What is this cutting-edge technology?
Yang and other researchers created a film that reflects incoming solar rays while simultaneously allowing the object it covers to release heat, effectively cooling the object by up to 25 degrees in a lab setting. It’s basically a super-thin air conditioner.
Give us the tech specs.
The “metamaterial,” another way of saying engineered material with properties not found in nature, consists of two layers. The bottom layer is a silver lining that reflects sunlight. The top layer has scattered glass microspheres that are infrared radiant. Both layers together are only slightly thicker than aluminum foil.
What makes this so freakin’ cool?
It drastically cools objects without expelling any energy or consuming any water. How is that possible? Science!
Your science basics:
“No, really, how is that possible?” you ask. It’s due to a little thing called passive radiative cooling, the process by which objects naturally shed heat without consuming energy. Objects do this when they cool at night. The problem has been that solar energy negates the cooling process. By reflecting sunlight, this film allows the radiative cooling process to occur during the day.
How efficient is it?
So, you’re probably thinking it would be great to throw a sheet over your house or car, and cut down on those air-conditioning bills. Hold your horses, people. That might work fine and dandy in summer, but Yang nixed the idea for winter.
Houses have too many elements to contend with, including gaps where air leaks out and, well, doors that open and close. If someone were truly committed to the cause, Yang said they would need to install a thermal water system to regulate the temperature inside the house.
Why should energy enthusiasts care?
The Sparknotes version is that the film acts as a supplementary product that makes existing energy generation sources more productive.
In basic terms:
To generate thermoelectric power, you have to heat water to a vapor and send it through a turbine, then cool it to condense the water again.
This process uses two cooling systems: wet and dry. A majority of power plants use wet cooling systems because they are the more efficient of the two. But they have another cost — they use a boatload of fresh water (about 139 billion gallons per day, if we’re being specific). Wet cooling systems are responsible for 41 percent of freshwater withdrawals from sources such as rivers, lakes and oceans, according to CU Boulder.
Dry cooling systems have the potential to significantly reduce water consumption, CU Boulder says. Right now, they’re expensive and not particularly efficient — they cool water to the ambient temperature. But if a handy-dandy film were to lower a building’s temperature relatively cheaply … I think you know where I’m going with this.
Yang said current technology would improve efficiency by 1 to 2 percent. That may not sound like much, but when you’re talking about a billion-dollar business, the savings add up quickly. The technology could be used with solar panels, which can overheat and lose their efficiency.
What does the future hold?
Because of its thinness, the film can be manufactured in rolls, giving it the potential for large-scale residential and commercial applications.
Yang said the researchers have been approached by several interested companies after their work was published in the journal Science. For now, research and testing continue.