Since the 1980’s scientists have been concerned about the effects refrigerants have on the environment. R-11 and R-12 are wonderful refrigerants that provide for efficient cooling systems, but they destroy ozone in the upper atmosphere. With the Montreal Protocols, their use in refrigeration systems have been banned. R-22 and later R-134a were used as substitutes. Though less destructive to the ozone layer, these compounds are potent greenhouse gases. R-22, for example, is 5,160 times better a greenhouse gas than the same amount of CO2. So, the challenge for scientists and engineers has been to develop compounds that are good refrigerants, that don’t destroy the ozone layer or create significant global warming if released.
The answer is to look towards the past, before chemists starting making synthetic refrigerants. Carbon dioxide, ammonia, and other compounds were used in early refrigeration systems. And this is what the Beijing Olympic committee did when tasked with building facilities to create the ice for skating events. The refrigeration systems creating the ice for the Olympic and Paralympic Games use CO2 as the refrigerant, instead of CFC’s or HCFC’s more commonly used today. The International Olympic Committee estimates natural refrigeration systems will save 57 million pounds each year of greenhouse gas emissions, the equivalent CO2 of 3,900 cars taken off the road. – Steve Terry, DTC HVAC & Refrigeration Instructor
