Cars Simplified: Everything Automotive Explained

Automotive Refrigerant

Refrigerant is a chemical used in air cooling systems, such as the air conditioning system in a vehicle, to reliably change state from a liquid to a gas and back again, moving heat energy efficiently.

Automotive Chemistry Generic ImageThis involves chemical names, terms, and/or reactions, which may be complicated without a basic understanding of chemistry.

R-12 Refrigerant

R12 refrigerant was the first standardized type of refrigerant, developed and first used in the 1930s. It was began being phased out worldwide in 1996, and was banned by most countries in 2010, now only used as a fire supressant in submarines and aircraft.

ASHRAE NumberR12
IUPAC Chemical NameDichlorodifluoromethane
Cylinder ColorWhite
Molecular FormulaCCl2F2

R-134A Refrigerant

The refrigerant R134A was developed as a replacement for R12, due to R12's environmental impact. It is also known as 1,1,1,2-Tetrafluoroethane.

ASHRAE NumberR134
IUPAC Chemical Name1,1,1,2-Tetrafluoroethane
Cylinder ColorLight Sky Blue
Molecular FormulaC2H2F4

R-744 Refrigerant

The refrigerant R744 is just carbon dioxide, but given a designation so that systems and products could be easily identified. CO2 systems need to operate at pressures starting at 60 bar, and of up to 130 bar (1880 psi), so even though CO2 refrigeration systems have been around for decades, they typically haven't been applied to vehicles until recently.

R744 Refrigerant System

ASHRAE NumberR744
IUPAC Chemical NameCarbon Dioxide
Cylinder ColorLight Green
Molecular FormulaCO2

R-1234YF Refrigerant

Chemically known as 2,3,3,3-Tetrafluoropropene, HFO-R1234YF has much less global warming potential than R134A.

A variant called R1234ZE (1,3,3,3-Tetrafluoropropene) is also available.

Handling of R1234YF

This video by Honeywell explains how to properly handle their R1234YF containers. This only shows how the container's gas is transferred into the machine that connects to the vehicle, not adding the refrigerant into the vehicle.

ASHRAE NumberR1234YF
IUPAC Chemical Name2,3,3,3-Tetrafluoropropene
Cylinder ColorWhite with Red
Molecular FormulaC3H2F4

R-451A & R-451B Refrigerants

R451A and R451B are proposed mixes of about 10% R134A and 90% R1234YF, aimed at reducing flammability of the pure R1234YF formulation.

ASHRAE NumberR451A/R451B
IUPAC Chemical NameTBD
Cylinder ColorNot Yet Assigned
Molecular FormulaTBD