Natural refrigerant

Natural refrigerants are natural substances that serve as refrigerants in refrigeration systems (including refrigerators, HVAC, and air conditioning). They are alternatives to hydrofluorocarbon (HFC), hydrochlorofluorocarbon (HCFC) and chlorofluorocarbon (CFC) based refrigerants. Unlike other refrigerants, they are not synthetic chemicals and can sometimes be found in nature. They are not only used due to environmental sustainability as some applications are better suited to a particular natural refrigerant.

HFC, HCFC, CFC classes of chemicals are all potent greenhouse gases. HCFC and CFC classes of chemicals are damaging to the ozone layer, with CFCs being a primary culprit. Natural refrigerants do not deplete the ozone layer and have a much lower impact on the environment. Though the chemicals may exist in nature, they are not entirely harmless or nontoxic. Most are highly flammable but aside from ammonia they are generally less harmful in the event of refrigerant release.

Natural refrigerants

• Carbon dioxide (CO₂) [R-744] used in the automotive industry and in some commercial refigeration systems,[1] an asphixiative gas that has to operate at the highest pressure of all commonly used refrigerants
• Ammonia (NH₃) [R-717] the refrigerant most used in industrial refrigeration and absorption refrigerators, formerly the primary refrigerant in home refrigerators, a highly toxic gas
• Petroleum-derived hydrocarbon (HC) refrigerants, all are flammable
  • Methane (CH₄) [R-50]
  • Ethane (CH₃CH₃) [R-170]
  • Propane (CH₃CH₂CH₃) [R-290]
  • Ethylene (CH₂CH₂) [R-1150]
  • n-butane (CH₃(CH₂)₂CH₃) [R-600]
  • Isobutane (CH₃CH(CH₃)₂) [R-600a]
  • Propylene (CH₃CHCH₂) [R-1270]
  • Pentane (CH₃CH₂CH₂CH₂CH₃) [R-601]
  • Isopentane (CH(CH₃)₂CH₂CH₃) [R-601a]
  • Cyclopentane ((CH₂)₅)
• Oxygen compounds
  • Diethyl ether / ethyl ether ("ether") (CH₃CH₂OCH₂CH₃) [R-610] (from dehydrogenation of ethanol; extremely flammable)
  • Methyl formate (HCOOCH₃) [R-611] (from carbonylation of methanol, which usually both come from syngas; or by condensation of methanol; highly flammable).
  • Dimethyl ether (CH₃OCH₃) [R-E170] (From dehydration of methanol which comes from syngas, natural gas or from some biofuels; highly flammable, medium toxicity)
• Nitrogen compounds (extremely rarely used in refrigeration systems)
  • Methylamine (CH₃NH₂) [R-630] (from reaction of ammonia and methanol; medium toxicity; controlled substance).
  • Ethylamine (CH₃CH₂(NH₂)) [R-631] (from reaction of ammonia and ethanol; very toxic).
• Elemental gases (mostly for ultra low temperature uses, mostly in laboratories or some superconductive devices)
  • Noble gases (also for ultra low temperature use, or for use as gases itself)

References

1. "New Automotive Refrigerants". www.aa1car.com. Retrieved 2016-10-18.

External links

• Greenpeace, Natural Refrigerants: The Solutions

See also

• List of refrigerants
• Sustainable automotive air conditioning, also covering the Alliance for CO₂ Solutions
• eurammon, a European non-profit initiative for natural refrigerants