Air conditioning has a climate problem. New technology could help.
There are a lot of ways to make existing AC technology more efficient. Some newer AC units use different refrigerants, such as one known as R-32, which has less planet-warming potential than other hydrofluorocarbons and also takes less energy to compress, thus saving electricity. Other units use technology known as “variable speed compressors,” that allow the unit to run on different settings. The compressor can speed up if it’s 100 degrees Fahrenheit and sweltering, or slow down if it’s only 85 degrees. That can help save on electricity and utility bills.
And more advanced models are just around the corner. Kalanki was one of the leaders of an initiative at RMI known as the Global Cooling Prize, which rewarded manufacturers who could produce affordable AC prototypes that would be at least five times better for the climate than existing models. Two companies received the prize in tandem: Gree Electric Appliances and Daikin Industries. Both used traditional vapor compression technology but with improved refrigerants and clever designs that could change settings in response to outdoor temperatures.
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Other companies, start-ups, and researchers are investigating whether they can ditch vapor compression entirely. A start-up called Blue Frontier uses a liquid that sucks moisture from the air and stores it in a tank to control the temperature. According to the company, this approach could save up to 60 percent of the electricity required to run an AC year-round. And a group of researchers at Harvard University has developed an air conditioning prototype that they call coldSNAP. The prototype doesn’t use a refrigerant, but uses a special coating on a ceramic frame to evaporate water to cool the indoor space without adding moisture to the air. “Because we don’t have the vapor compression system and the energy of trying to release and compress the refrigerants, the energy consumption of these systems is far, far lower,” said Jonathan Grinham, one of the researchers on the project.