Flammable refrigerants: focus on hydrocarbons

The damage caused by chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs) to the ozone layer and the fact that their synthetic alternatives, hydrofluorocarbons (HFCs), contribute to global warming, have focused attention on “green” alternative refrigerants that both are ozone-friendly and have limited or, possibly, null effect on global warming.
Among the various green possibilities (CO₂, water, ammonia), hydrocarbons are one possible way forward, with both advantages and disadvantages. 
This document examines the current panorama regarding the use of hydrocarbons as refrigerants and the standards affecting their wider use.