Air-conditioner Refrigerants and Their Environmental Impact

Air-conditioners use refrigerants to carry heat between the indoor and outdoor units. In the late 1970s, it was discovered that CFC and HCFC fluorocarbon gases, which were the most common refrigerants of that time, impacts the ozone layer if released into the atmosphere. Since then, Daikin, as a manufacturer of fluorocarbon gas, has been working to find refrigerants that exert as little impact as possible on the environment. Let’s look at air-conditioner refrigerants as they relate to global warming and ozone layer depletion.

		Refrigerant Environmental Impact

• Ozone layer depletion
A look at the causes of ozone layer depletion and the ozone depletion potential.
• Global Warming
A look at the causes of global warming, and the major global warming substances and their GWP (global warming potential).

		International Regulations

• About restrictions to protect the ozone layer and prevent global warming
A look at the restrictions in the Montreal Protocol on ozone layer depletion and in the Kyoto Protocol on global warming.
• The effect of the elimination of CFCs on global warming
A look at how the elimination of CFCs is not only effective in protecting the ozone layer but also in preventing global warming.

		Properties of Future Refrigerant Candidates

• Basic refrigerant properties
A look at the properties required of air-conditioner refrigerants.
• Properties of future refrigerant candidates
A look at the properties, benefits, and drawbacks of substances that are candidates for future refrigerants.

Basic Refrigerant Program

Major Substances Used as Refrigerants
CFC
Chemical compounds consist of chlorine, fluorine and carbon. Widely used in the past as refrigerant for air-conditioners. CFCs were found to deplete the ozone layer and developed countries stopped manufacturing them in 1995. CFCs are global warming substances with a global warming potential three to 10 times that of HFCs.

HCFC
Chemical compounds consist of hydrogen, chlorine, fluorine and carbon. Used to substitute for CFCs, HCFCs have an ozone depletion potential just one-twentieth that of CFCs. Developed countries will stop manufacturing HCFCs in 2020. The global warming potential is about the same as HFCs.

HFC
Chemical compounds consist of hydrogen, fluorine and carbon. A CFC substitute (hydro-fluorocarbon). With an ozone depletion potential of zero, HFCs are an the best refrigerant for protecting the ozone layer. HFCs are currently in the process of being substituted for HCFCs. However, HFCs are designated in the Kyoto Protocol as a global warming gas whose emission must be reduced. As well, like CFCs and HCFCs, the release of HFCs into the atmosphere are forbidden under the Fluorocarbons Recovery and Destruction Law(Japan).

Natural Refrigerants
Substances existing in the natural world and having refrigerant characteristics. Examples are ammonia, hydro carbon (propane), and CO₂.