Americans love their air conditioning—and the rest of the world is catching on fast. The International Energy Agency predicts that the number of cooling units will almost triple by 2050, with most of the growth coming in developing countries with hot climates. As most people know, this is bad for the planet. Air conditioners use chemicals called refrigerants, potent greenhouse gases that can be several hundred times as damaging as carbon dioxide. These units also guzzle electricity—accounting for about 10 percent of all energy consumed globally. And that number is rising.
As global warming accelerates, demand for atmosphere-damaging air conditioners will increase, creating a potentially catastrophic cycle. With this in mind, inventors on opposite sides of the globe are scrambling for less-damaging ways to keep us cool.
Professor Ernest Chua of the National University of Singapore is one of them. Conventional technology is more than a century old, he noted, “yet we have not made breakthroughs in evolving air conditioning that is more environmentally friendly.” Chua’s solution is an air-cooling device that runs exclusively on water. Hot air is sucked into a machine in which a special membrane removes moisture. Then the dried air is blown over a layer of water, cooling it down much in the same way a breeze cools the sweaty skin.
In addition to not using refrigerants, Chua’s unit will be 30 percent more efficient than existing technology, a major benefit to residents of his home country, who spend, on average, 40 percent of their utility bills keeping cool. In the U.S., a startup called SkyCool Systems is taking a more cosmic approach. While all objects emit heat in the form of infrared radiation, much of that is reflected back down by the atmosphere. At certain wavelengths, however, that radiation can escape to space. By coating objects with a special material, Burlingame, Calif.-based SkyCool has found a way to facilitate this escape to coolness.
The idea is to put special panels on the roof of a building and run water pipes beneath them, said co-founder Aaswath Raman. The water cools and is then circulated throughout a building. The SkyCool team estimates that integrating their technology into an existing AC system could cut electricity use by 20 percent, while a building that incorporates it from the ground up could save up to 70 percent.“What excites us about our technology is that it represents a unique and completely different way of handling the cooling problem,” said Raman. “Our hope is that this can eventually become a component of cooling systems everywhere.”
