Production of the R-500 refrigerant halted on January 1, 2006 because of its environmentally harmful chemical makeup. Used in heating, chilling, air conditioning and ventilation applications, the R-500 was replaced by eco-friendly refrigerants, such as the R-410A. Still used in systems from the 1970s through 2005, the R-500 is a legal refrigerant in systems pre-dating 2006, but it is expensive, due a lack of supply and demand.
The R-500 is scientifically known as Dichlorodifluoromethane/Difluoroethane. Categorized as an azeotropic blend, 74 percent of its makeup comes from Dichlorodifluoromethane. R-12 and R-152a refrigerant gases make up the remaining 26 percent of the mixture, according to environmentalchemistry.com. With a Hazard Class of 2.2, R-500 is non-flammable and non-poisonous. It has a molecular mass of 99.31. Its boiling point at atmospheric pressure is negative 28 degrees Fahrenheit, and its freezing point at atmospheric pressure is negative 107.9 degrees Fahrenheit. It has a critical temperature of 222 degrees Fahrenheit, a critical pressure of 642 per square inch and a critical specific volume (Cu.Ft/lb) of .0323.
Primarily used in air conditioning systems for both commercial and residential systems, the R-500 is an outdated refrigerant developed by Carrier in attempt to sell both HVAC systems and the refrigerant to go with them. Chillers and low-temperature units also used R-500 prior to 2006. Military and government buildings also used R-500 systems.
As of January 1, 2006, the Federal Clean Air Act made illegal production of the R-500 because of its physical properties, which are harmful to the ozone layer and the environment, when exposed to the air. Exposure can occur from leaky refrigerant lines (due to age or if installed improperly), or if the gas is spilled from its container. It is legal to service and recharge old R-500 systems with stockpiled R-500 created prior to 2006. As of 2010, refrigerant systems are no longer made to support the R-500.
R-500 is non-flammable by itself, but under compression, it can become combustible. The refrigerant can separate in larger systems: Known as “pooling,” which occurs when the high pressure portions of the R-500 becomes stuck in the condenser unit of the system, it can lead to temperature and head pressure problems. The chlorine included in R-500 can irritate the skin, so avoid contact with it.
As of 2010, the EPA phased out the use of any environmental harmful refrigerants in new heating, ventilation and air conditioning systems, to make room for the chlorine-free R-410a refrigerant. R-22 is the primary refrigerant named in the EPA phase-out; R-22 is chlorine-based, and used in commercial and residential applications throughout America.
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