Since its invention in 1902, the air conditioning unit has become a staple piece of equipment in businesses, institutions and homes around the world. Air conditioners come in many sizes and 
configurations, from large central chiller systems to small window units. But what do they have in common? Air conditioners all use refrigerants to transfer heat to the outdoors.
THE DEVELOPMENT OF REFRIGERANTS
In the early days of air conditioning, the options for refrigerants were ammonia, methyl chloride and Sulphur dioxide. Methly chloride and Sulphur dioxide are both toxic and were replaced with chlorofluorocarbons (CFCs) in the 1920’s. We used these for decades before discovering the drawbacks.
A HOLE IN THE OZONE LAYER
In the 1970’s, scientists discovered that the ozone layer had been experiencing an overall reduction in concentration by about 4% per decade and a severe annual springtime depletion over the polar regions. In the 1985, the British Antarctic Survey thought that their instrumentation was faulty because the levels of ozone had dropped so dramatically. The main cause of this depletion was traced back to the rampant use of man-made substances containing chlorofluorocarbons (CFCs), which were released into the atmosphere from aerosols and refrigerants. CFCs break down in sunlight to release chlorine and bromine, which destroy ozone molecules. The Polar Regions are more susceptible to ozone depletion because of the formation of “polar stratospheric clouds” caused by cold temperatures in these regions. These clouds provide the ideal conditions for the chemical reactions that break down ozone molecules. Hence their ozone levels drop to lower levels than the rest of the globe, creating “holes”.
THE MONTREAL PROTOCOL
On September 1987, the Montreal Protocol treaty was introduced to outline the phasing out of ozone-depleting refrigerants. This treaty defined the timeline for introducing alternatives that would not affect the ozone layer. A total of 197 states signed it, making it the most successful international treaty to date.
Since then, we have moved away from refrigerants containing ozone depleting substances and, more recently, refrigerants that contribute to global warming.
NEW REFRIGERANTS
Many older residential air conditioners used a refrigerant called chlorodifluoromethane (R-22), which has a high ozone depleting potential (ODP) and global warming potential (GWP). Multiple alternatives are available but R-410A has high GWP, so other alternatives may become more common in the future.
If you still have a unit using refrigerants that are destructive to the ozone layer, give us a call to talk about a system upgrade.
