How we keep ourselves and our stuff (like food) cool is a lesson in ingenuity, innovation and a little like Whack-A-Mole. Every time scientists developed the next best thing, it caused problems somewhere else.
When the scientists started looking at ways to get air colder than a fan, they focused on vapor compression systems. Essentially, this is the air conditioner you have now in your car and in your house. It uses circulating liquid refrigerant to remove heat from a space.
The first refrigerants were things like ammonia and carbon dioxide, which were effective but, you know, toxic.
In 1928, Freon was developed. Freon was the trade name for a type of coolant called a chlorofluorocarbon. . This worked well — it wasn’t toxic, for one thing — but eventually proved to have a nasty habit of destroying the planet’s ozone layer.
In the 1970s, the scientists created hydrofluorocarbon (aka HFCs), which proved to work well and didn’t damage the ozone layer. But it was a significant cause of global warming: Its contribution is 12,000 times more damaging than carbon dioxide.
With countries all over the world now getting on the ban wagon to get rid of HFCs, the question is: What is next, and what problems will it cause?
The folks at the National Renewable Energy Laboratories in Golden are looking at that exact problem. Chuck Booten is one of the authors of a recent report from NREL about market trends in refrigerants.
“What we found is there is no one-size-fits-all approach,” Booten said. “But there are a lot of really smart people doing their best to make this work.”
The next thing on the horizon is hydrofluoroolefin (and no, we aren’t making up), which does not hurt the ozone layer and reduces the impact on global warming by a factor of 10. The problem? “Well, it is flammable … which can be a bad thing,” Booten said in typical engineer speak. It’s also less efficient which means the machinery tends to be bigger.
So, the fix seems to be different versions of blends of HFO and HFC. These are already being used in most vehicles coming from Europe and expected to be in the U.S. when companies begin the transition to non-HFC units, expected to be in model years by 2023. Home and commercial production will follow a similar timeline.
“I would be shocked if we aren’t still using vapor compression for most of my lifetime,” Booten said. “But maybe when I am old and gray, I could see a solid-state system with no liquid or something else to change it up.”