Refrigerants

Chlorofluorocarbons (CFCs) are widely used as refrigerants, aerosols and solvents. We know that CFCs damaged the ozone layer and that as a result of the Montreal Convention this damage is slowly being repaired. The LEED rating system advocates Zero use of CFC based refrigerants for heating, ventilating, air-conditioning and refrigeration (HVAC&R) systems.

The CFCs were replaced with mostly HCFCs (hydrochlorofluorocarbon) over the last couple of decades. However, HCFCs are just marginally better than CFCs as they contain chlorine, which is harmful for the environment and needs to be phased out as well.

The goodness of a refrigerant is measured by its Ozone Depletion Potential (OWP) and Global Warming Potential (GWP).
HFCs (or Hydro Fluro Carbons) are the next generation refrigerants which is void of chlorine. Although they also have the potential for global warming, they are better than HCFCs as they do not deplete the ozone layer. The most common HFC used in air conditioners today is R-410A.

Global Warming Potential and Ozone Depletion Potential of popular refrigerants used today:

Source: http://www.linde-gas.com/internet.global.lindegas.global/en/images/Refrigerants%20environmental%20GWPs17_111483.pdf

Natural refrigerants that are not man-made are hydrocarbons, ammonia, carbon dioxide and water. Hydrocarbons (HC) just have a Global Warming Potential of 1 owing to the presence of carbon dioxide but is the most environment friendly option that should be commercially adopted as early as possible.

The air-conditioning system at the eFACiLiTY® Building uses R-410A owing the lack of commercial availability of the next generation refrigerants like R-32 (65% better GWP compared to R-410A) at the time of ordering.

The refrigerator at the eFACiLiTY® Building users R-600A which is the most environmental friendly refrigerant available today.