The need for refrigeration is expanding, and it is expected to grow steadily for most of this century. This issue is well-known, and we don’t have a solution. In fact, we aren’t even close to one. The National Institute of Standards and Technology (NIST) just tested 138 of the most promising substances we have identified for the next generation of refrigeration, and none of them was suitable.
They found 27 chemicals that would be ok from the perspective of acting as an effective refrigerant, and also are less harmful that the current technology. There is just one small problem; they are all flammable. Some more than others, but all of the best candidates for a new refrigerant will make your air conditioner a potential fire-ball.
Under US law a refrigerant can’t be flammable, so it would seem that we are at something of an impasse. The study started by analyzing more than 60 million possible substances, and that makes this result all the more frustrating.
At the moment we use hydrofluorocarbons (HFCs) as refrigerants, and regrettably they are greenhouse gases that probably contribute to climate change. Their present contribution is small, but with the advance of air-conditioning and refrigeration in developing countries that will change rapidly.
Originally The Montreal Protocol encouraged countries to restrict the use of HFCs, but in the absence of a viable alternative there was no choice but to use them. Now we realize just how difficult it will be to engineer the next generation of refrigeration technology.
While I am usually very adamant about getting pollutants out of the environment, this situation is extremely unique. If we move to use refrigerants that are flammable, there will be fires and loss of life. But if we continue to use HFCs, we will be stuck with refrigeration that encourages global warming.
Thankfully there is being research done, and the NIST team did suggest that blending some of the chemicals may yield positive developments. It is good to see that a “steady as she goes” attitude isn’t being embraced, and everyone sees the need for a change.
With time and effort, we will find a balanced way forward.