Terminology

Alkyl Benzene Oil（AB） - A synthetic refrigeration oil commonly known as Zerol.

Alternative Refrigerant - any of a number of refrigerants or refrigerant mixtures designed to replace the current CFC or HCFC refrigerants.

ASHARE – the abbreviation of Amevican Society of Heating Refrigerating and Air -conditioning Engineers 

Azeotrope - A mixture made up of two or more refrigerants with similar boiling points that act as a single fluid. The components of azeotropic mixtures will not separate under normal operating conditions and can be charged as a vapor or liquid. 

CFC Refrigerant - CFC refers to the chemical composition of the refrigerant. ChloroFluoroCarbon indicates that the refrigerant is comprised of Chlorine, Fluorine, and Carbon. Common CFC refrigerants are R11, 12,13,113,114, and 115.

Drop-In Replacement - An alternative refrigerant that can be installed directly into an existing system with minor equipment changes. Most interim alternatives fall into this category.

Global Warming Potential (GWP) - Global warming occurs when solar energy penetrates the atmosphere and the resultant infrared energy from the earth's surface is absorbed by certain gases and not allowed to leave. This process is commonly known as the greenhouse effect. Refrigerants are normally rated on a scale from 1 to 10. 

HCFC Refrigerant - HCFC refers to the chemical composition of the refrigerant. HydroChloro-Fluoro-Carbon indicates that the refrigerant is comprised of Hydrogen, Chlorine, Fluorine, and Carbon. Common HCFC refrigerants are R22.

HFC Refrigerant - HFC refers to the chemical composition of the refrigerant. HydroFluoroCarbon indicates that the refrigerant is comprised of Hydrogen, Fluorine, and Carbon. Common HFC refrigerants are R134a.

High Pressure Refrigerants (HP) - A term used for some alternative refrigerants designed to operate in the low temperature (-35° F to 0° F) range.

Hygroscopic - A tendency for refrigeration oils to absorb moisture from the atmosphere. 

Interim Replacements (SHORT TERM) - Any of a number of refrigerants intended to serve as an intermediate solution during the transition from CFC to HFC refrigerants. Most interim replacements contain HCFC refrigerants like R22.

Long Term Replacements - Alternative refrigerants that are considered to have no adverse affect on the stratospheric ozone layer. Most long term replacements are HFC compounds. 

Medium Pressure Refrigerant (MP) - A term used for some alternative refrigerants designed to operate in the medium temperature (0° F to 4° F) range. 

Mineral Oil (MO) - Refrigeration oil currently in use but is not compatible with most of the alternative refrigerants. Refrigerant conversions often require. a procedure for the removal of existing mineral oil because of the incompatibility with alternative refrigerants.

Near Azeotrope - A mixture made up of two or more refrigerants with different boiling points that, when in a totally liquid or vapor state, act as one component. However, when changing from vapor to liquid or liquid to vapor, the individual refrigerants -evaporate or condense at different temperatures. Near-azeotropic mixtures have a temperature glide (see below) of less than 10° F and should be charged in the liquid state to assure proper mixture (non-azeotropic) composition.

Ozone Depletion Potential (ODP) - This is a relative indication of the effect of the chlorine in CFC's on breaking down the ozone layer. It is measured on a scale from 0 to 1 with 0 being non-depleting and 1 being the highest depleting. 

P.A.G. Oil （PAG）- A general term that applies to a family of synthetic oils based on the chemistry of Polyalkyline Glycols. The primary application of P.A.G. oils will be for automotive air conditioning. 

Polyol Ester Oil (POE) - A general term that applies to a family of synthetic refrigeration oils based on the chemistry of polyol esters. Ester oils are generally regarded as the oil to use with most of the alternative refrigerants. Ester oils are generally compatible with existing mineral oils, and system components. Ester oils are slightly hygroscopic and should be in non-porous containers. 

Temperature Glide - the temperature difference that occurs between the vapor state and liquid state during evaporation or condensation at constant pressure, i.e. the temperature in the evaporator and condenser is not constant. Temperature glide occurs in near-azeotropic and zeotropic mixtures. 

Zeotrope - A mixture made up of two or more refrigerants with different boiling points. Zeotropic mixtures are similar to near-azeotropic mixtures with the exception of having a temperature glide greater than 10° F. Zeotropic mixtures should be charged in the liquid state.