Wheeler On HVAC: Understanding Ozone Depletion
Depletion of earth's protective ozone layer is the reason given for the phaseout of our industry's most important refrigerants, R-11, R-12, and R-22. This has resulted in a major shakeup of our industry throughout North America and Europe as we have already seen the end of production of R-11 and R-12 (CFCs), and we will soon see the end of production of R-22, and perhaps R-123 (HCFCs). However, this phaseout hasn't been accepted by many of the earth's less-developed countries. In addition, common chlorinated solvents have become almost extinct in all sorts of products (such as house paints), and even plastics are now manufactured using new materials. Is all of this change warranted?
As I mentioned in a previous article in this magazine ("Understanding Global Warming," Supply House Times, July 2002, page 36), I had the opportunity to talk at length to several environmental scientists about this subject in the late 1980s and early 1990s. And as the result of these discussions I was able to accurately predict the coming phaseout of CFCs and the effect this would have on our industry. At the time, my story was pretty unbelievable. However, these discussions have convinced me that global ozone depletion may be real and is the result of refrigerant and solvent releases. Though even here I think the potential has been blown out of proportion in some instances.
It's just a fact that environmentalism is an inexact science, because proving a theory may actually take centuries of observation to prove it true. One theory that I wrote about in 1990, and which was foretold to me by top scientists, was that increased ultraviolet radiation on the earth's surface due to ozone-layer thinning would result in killing huge amounts of oxygen-creating plankton in the seas of the world. Is that really happening? Well, scientists now say the plankton is thriving on the extra radiation. So the scientists and I proved wrong.
So why do I believe that refrigerants (specifically CFCs) are destroying earth's protective ozone layer? It's just simple science. R-12 (diclorodifluromethane) is a man-made substance, which is almost a perfect molecule. You take two chlorine atoms and two fluorine atoms and bond them to a carbon atom. This creates such a tight molecular bond that the only thing that can break it down is burning it with fire (which creates corrosive acids), or allowing it to get up into earth's stratospheric atmosphere where hard ultraviolet radiation from the sun breaks it into its component parts.
Yes, CFCs are heavier than air. However, the molecules are very small and it has been proven that they are eventually carried up into the stratosphere by winds, and that's where they do the damage.
What's so bad about breaking down CFC molecules in the stratosphere? This releases free chlorine atoms in a place where they normally can't reach. Free chlorine gas is very reactive and it either binds with other substances or is washed from the air by rain, fog, and dew closer to the earth. But when it is released in the stratosphere, chlorine atoms remove the charge which binds ozone molecules (which is just O3) together, turning them back into environmental oxygen (O2). And it is this ozone (which is also created by radiation from the sun) that protects the earth from the sun's hard rays. This isn't rocket science. It's pretty easy to understand.
Although there really isn't that much CFC in the atmosphere, almost all of it will break down in the stratosphere. So the average life of a CFC molecule in the atmosphere may be 100 years. In addition, it has been estimated that each chlorine atom will destroy 60,000 ozone molecules in the stratosphere. Thus the effects of CFC releases are cumulative and long lasting.
Of course, the HVACR industry isn't responsible in any way for the greatest release of ozone-destroying gases, since most of what we use was meant to be contained and reused. However, consider the effects of the billions of gallons of solvents which were designed to evaporate. A molecule of carbon tetrachloride, for example, has twice the chlorine of R-12, and it also must get to the stratosphere to be destroyed. Remember, too, that R-12 was the primary propellant in all spray bottles until the 1970s. In addition, CFCs were also the primary ingredient in all plastic foam, which solvent was designed to be released into the atmosphere as the plastic foam expanded and deteriorated.
So, do I think that the phaseout of CFCs could have been avoided in our industry if recovery became mandatory? Yes. There is no valid reason for not recovering it, and small releases aren't necessarily harmful. It was the wholesale releases from spray cans and manufacturing that have put us in the position we're in today.
Then there is the HCFC story. R-22 (an HCFC) is the most important refrigerant in the world today. It is soon scheduled for phaseout since it has been painted with the same environmental-hazard brush as CFCs. Yet the situation here is quite different. The HCFC molecular bond isn't anywhere near as perfect or tight as that of CFCs. For example, R-22 (chlorodifluromethane) has just one chlorine atom and the bond is fragile due to the presence of a tiny hydrogen atom on the molecule. This means that most HCFCs break down in the lower atmosphere and don't deliver a load of chlorine atoms to the stratosphere. Could containment and recovery have been a simple alternative to phasing-out this fine refrigerant? Perhaps, but it looks like we'll never know.
Now our industry is headed into the era of HFC refrigerants. They contain no chlorine so they are said to be safe when it comes to earth's protective ozone layer. That doesn't mean that they don't have global-warming potential - they do. I just wonder what future scientists will say of this change, and whether it really proves to be better for our environment. Again, only time will tell.
Just one final story, something I overheard at a DuPont hospitality suite a few years ago. One scientist was saying to the other: "I'll bet that sometime around 2070 some scientist will come up with an amazing new refrigerant, dichlorodifluromethane (R-12). It will be a scientific breakthrough for the time, but they will recognize the fact that they have to recover it, not dump it into the atmosphere."