Over 100 years of Carbon Dioxide as a Refrigerant?

CO2 was the refrigerant of choice during the early 20th century but was later replaced with man-made chemicals. In light of environmental concerns carbon dioxide is making a return appearance. Thanks to technological advances that include the manufacture of extremely thin yet strong aluminum tubing carbon dioxide is now a more practical and affordable choice when selecting a refrigerant. The Linde Group says that Carbon Dioxide marketed and sold as, R744, “is environmentally friendly, having zero ODP (Ozone Depletion Potential) and minimal GWP (Global Warming Potential).”  Since scientists have been able to develop a safe and stable way to use CO2 as a refrigerant, we now have a GREEN option to replace R22 which is being phased out worldwide, due to its production of Greenhouse gases.

The use of CO₂ as a refrigerant dates back more than a hundred years; however, it fell out of favor in the air conditioning and refrigeration industry with the development of the more economical chlorofluorocarbons (CFCs) in the 1930s. Later, hydrochlorofluorocarbons (HCFCs) such as R22 were introduced as the most economical and readily available refrigerant. R22 became the primary refrigerant of choice for many years, until recent concerns about the depletion of the ozone layer emerged. After much research, The Montreal Protocol international treaty was enacted in 1989 to phase out any use of CFCs and HCFCs that would further deplete the ozone layer. By 2010 CFCs and HCFCs have been reduced by 75%. By 2030 they will be completely phased out and banned on a global level.

Carbon dioxide is non-flammable and non-toxic in contrast to the other natural refrigerants known as hydrocarbons (flammable) and ammonia (flammable and toxic). CO2 is also inexpensive and widely available worldwide, which makes it an ideal candidate to replace R22 Freon refrigerant. The high operating pressures of CO₂ also afford the opportunity to downsize refrigeration systems themselves, allowing for more storage space in units.

Greenhouse Gases?

While CO2 is can be a contributor to the greenhouse effect, when used as a refrigerant it has been placed under strict control and observation. A mandatory reporting system has been put in place by the EPA (Environmental Protection Agency) as a result of The Kyoto Protocol and The Montreal Protocol. According to greenhouse gas (GHG) regulations, all users of refrigerant gases are required, as of 2010 to comply with mandatory carbon emissions reporting. There are six chemical compounds that must be reported to the agency: greenhouse gases: carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), sulphur hexafluoride (SF6), and refrigerant gases: hydrofluorocarbons (HFCs) and perfluorocarbons (PFC.)

Harvard announced on March 24^th, 2011 that its award for Environmental Partnership, The Roy Family Award, will be given to Refrigerants, Naturally! This group is an alliance of corporations making the move to using more “ozone-friendly” gasses that exist in nature, such as, ammonia, carbon dioxide, and hydrocarbons, rather than CFCs and HCFCs. Refrigerants, Naturally! has brought four major companies into the environmental awareness movement and are helping them solve their commercial refrigeration needs in a safer, cleaner method. The companies on board are: Coca-Cola Company, McDonald’s, Unilever, and PepsiCo. Together with Greenpeace and United Nations Environment Programme they are committed to fighting climate change and ozone depletion currently and in the future.