Consumers held on, and the state’s power grid emerged relatively unscathed from a record-breaking hot day. Still, as temperatures rise around the world, more people will need to install air conditioners. But As currently sold, air conditioning units can make global warming worse: On hot days, they draw tons of electricity from the grid, and their chemical refrigerants can accelerate global warming.
This is why researchers and start-ups are hoping to create new state-of-the-art air conditioning units. AC technology has only seen “incremental improvements over the last 100 years,” said Ankit Kalanki, manager of Third Derivative, a climate technology accelerator co-founded by energy think tank RMI. “There hasn’t been a sea change in innovation.”
The good news is that companies are rushing to develop more efficient ACs. The question is whether they will be ready in time.
Current ACs are not going to be enough
In the coming decades, global demand for air conditioning is expected to skyrocket. According to the International Energy Agency, the number of air conditioning units in buildings worldwide should reach 5.6 billion by 2050, up from 2 billion today.
But unless air conditioning efficiency is revamped, all those air conditioners will put unprecedented pressure on the power grid. Air conditioners and electric fans already account for about 10 percent of electricity consumption worldwide. On extremely hot days, air conditioning efficiency drops as the units have to work harder to move heat from indoors to outdoors. During a heat wave, millions of people come home and turn on their air conditioners at the same time, between 4 p.m. and 9 p.m. When that happens, air conditioning can account for 60 to 70 percent of energy demand. electricity, and shake the grids like the ones in California.
Meanwhile, the key component of modern air conditioners, chemicals known as refrigerants, have been the bane of the atmosphere for decades. Air conditioners work by exposing a liquid refrigerant, a chemical with a low boiling point, to hot indoor air. That heat causes the refrigerant to evaporate into gas, cooling the air. A compressor then turns the refrigerant back into a liquid and repeats the process.
The problem is that refrigerants can leak from air conditioners, both during use and, more commonly, when air conditioners are disposed of. The first ACs were largely made with chlorofluorocarbons, or CFCs, which were responsible for one of the first truly global climate concerns: the hole in the ozone layer. CFCs were phased out by the 1987 Montreal Protocol, an international treaty to counter the depletion of the ozone hole, and were eventually replaced by hydrofluorocarbons, or HFCs.
But HFCs have their own problem: they are greenhouse gases that, in the short term, are thousands of times more potent than carbon dioxide. An amendment to the Montreal Protocol states that HFCs will be drastically phased out by the mid-2040s; in the meantime, however, they continue to contribute to global warming.
There are many ways to make existing AC technology more efficient. Some newer air conditioning units use different refrigerants, such as one known as R-32, which has less global warming potential than other hydrofluorocarbons and also requires less energy to compress, saving electricity. Other units use technology known as “variable speed compressors,” which allow the unit to run in different settings. The compressor can speed up if the temperature is 100 degrees Fahrenheit and sweltering, or slow down if the temperature is only 85 degrees. That can help save on electricity and utility bills.
And the most 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 that could produce affordable AC prototypes that would be at least five times better for the climate than existing models. Two companies received the award on a par: 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 outside temperatures.
Other companies, startups, and researchers are investigating whether they can get rid of vapor compression altogether. A startup called Blue Frontier uses a liquid that absorbs moisture from the air and stores it in a tank to control temperature. According to the company, this approach could save up to 60 percent of the electricity needed to run an air conditioner year-round. And a group of researchers at Harvard University have developed a prototype air conditioner they call coldSNAP. The prototype uses no refrigerant, but uses a special coating on a ceramic frame to evaporate water and cool the interior space without adding moisture to the air. “Because we don’t have the vapor compression system and the energy to try to release and compress the refrigerants, the energy consumption of these systems is much, much less,” said Jonathan Grinham, one of the researchers on the project. .
What to look for when buying
Some of these newer designs can take years to come to market, and when they do, they can still be more expensive than conventional ACs. But in the meantime, Kalanki says, there are still plenty of options for buying a more efficient air conditioning unit. “There are technologies that are two to three times more efficient than the most common air conditioners on the market today,” Kalanki said. “The challenge is that adoption is very low.” Most consumers, she argues, only look at the sticker price of an air conditioning unit and ignore the fact that buying a more expensive unit up front could save them money in the long run.
He recommends that buyers look at three things when considering an air conditioning unit: the type of refrigerant used, the efficiency rating, and whether or not the unit has a variable speed compressor. Those metrics can tell consumers whether their unit is likely to cost them thousands of dollars in electric bills in the future and whether it will unduly add to the climate change problem.
Ultimately, he added, the government must set stricter performance standards for air conditioners so that everybody The ACs on the market, not just the high-end ones, are efficient and safe for the planet. “There are regulations to set the floor for air conditioners,” he said. “But that floor is too low.”
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