Refrigerant is the lifeblood of any refrigerator. Many people are surprised to learn that a refrigerator doesn't use refrigerant to add coldness to the inside of the appliance. Because cold is simply a state of absence of heat, refrigerants work by extracting heat, not generating cold. Over the years, commercially available refrigerants used for cooling have gone through evolutions in chemical composition. The most well-known refrigerant is trademarked Freon. The term has become generic over decades of usage, and it's still frequently applied to almost any kind of refrigerant. Not all refrigerant in refrigerators is Freon anymore, however, and Freon will soon no longer be used as a refrigerant in any refrigerators.
The Freon Era
Freon is Dupont's registered patent name for dichlorodifluoromethane (CFC) and hydrochlorofluorocarbon (HCFC) refrigerants. These all-purpose refrigerants were the staple of cooling systems in heating, ventilation and air conditioning as well as appliance and automotive applications for the last 50 years. Interestingly, one reason Freon was so widely adopted during that time span was because of its perceived safety. It was a welcome alternative to more hazardous, toxic refrigerants in use before its development. (As an early demonstration of Freon's safety, the scientist credited with its discovery would actually fill his lungs with the gas, then use it to blow out a candle.) Unfortunately, Freon's benign reputation would eventually turn out to be too good to be true.
The Silent Threat
Ozone is produced by the natural reaction between oxygen and sunlight. A thin concentration of ozone surrounds the Earth at an altitude of approximately 18 miles. The ozone layer has the beneficial effect of blocking ultraviolet radiation from the sun. UV rays in large amounts are harmful to life on Earth and responsible for development of cancers and other illnesses as well as destruction of plants. CFCs and HCFCs like those present in Freon are highly stable and inert. These properties allow refrigerants released on Earth to rise very high in the atmosphere before they are broken down by sunlight. As CFCs and HCFCs decompose, free radicals are generated that destroy ozone.
A Worldwide Effort
Damage to the ozone layer was first verified in the early 1970s and linked to use of CFCs and HCFCs as refrigerants and propellants in spray cans. Release of Freon R-12 and R-22 into the atmosphere from air conditioners and refrigerators was isolated as a major cause of ozone depletion. In 1989, the Montreal Protocol formalized a progressive international reduction of CFC and HCFC use, including all types of Freon. This process is scheduled to culminate in a total ban before 2030.
Fortunately, you won't have to have blocks of ice delivered to your home to have an efficient refrigerator in your kitchen to keep perishables. Replacements for CFC and HCFC refrigerants are now used in refrigerators engineered to accept these new substances. While none of them is totally environmentally neutral, refrigerants such as HFC-134A contain only fluorine and not the chlorine that depletes the ozone layer. These new refrigerants are made by various manufacturers and are not marketed under the trademark name Freon. In addition, no new refrigerators are being manufactured that use Freon. Older refrigerators that use Freon cannot be retrofitted to accept the new refrigerants. When these units reach the end of their service life, the Freon must be recovered in accordance with strict Environmental Protection Agency guidelines before the units are recycled or sent to a landfill.