Refrigerant R744 Physical And Chemical Characteristics
WARNING: This page is about a different car, the 2022 Volkswagen ID.4 and 2021 Volkswagen ID.4. However, it is still accessible from the selected car via links, so may be relevant.
The most important characteristics and safety precautions for refrigerant R744 are listed below. All specifications can be found in the respective safety data sheets in compliance with regulation (EC) (No. 1907/2006, for example) for the respective gas distributors.
| Chemical formula | CO2 |
| Chemical designation | Carbon dioxide |
| Boiling point at 1 bar (14.5 psi) (absolute pressure) | - 78.7 °C (-109.7 °F) |
| Solidification point | - 56.6 °C (-69.9 °F) |
| Triple point | - 56.6 °C (-69.9 °F) at 5.18 bar (75.13 psi) (absolute) |
| Critical temperature | 31.1 °C (88 °F) |
| Critical pressure | 73.8 bar (1, 070.38 psi) (absolute) |
| Purity for the refrigerant circuit | Refer to REFRIGERANT R744 |
| Flammability | Non-combustible |
| Shape | Compressed liquid gas |
| Color | Colorless |
| Smell | No inherent smell |
- At temperatures below -56.6 °C (-69.9 °F), carbon dioxide can be in either a solid or liquid state, depending on the pressure.
- At temperatures between -56.6 °C and +31.1 °C (-69.9 °F and 88 °F), carbon dioxide can be a liquid and a gas, depending on the pressure.
- At a temperature of -56.6 °C (-69.9 °F) and a pressure of approximately 5.2 bar (75.42 psi) (triple point), carbon dioxide can be a solid, a liquid, and a gas.
- At ambient pressure, solid carbon dioxide (dry ice) changes directly from a solid state to a gaseous state at a temperature of -78.7 °C (-109.7 °F) (sublimation point).
- The vapor pressure curves of refrigerant R744 and other refrigerants are sometimes very similar, therefore it is not always possible to make a clear distinction solely based on pressure. Refer to REFRIGERANT PRESSURE AND BOILING POINT and Refer to REFRIGERANT VAPOR PRESSURE TABLE .
- Refrigerant R744 has a critical temperature of 31.1 °C (88 °F). When this temperature is exceeded, the density also strongly influences the refrigerant circuit pressure, which makes identifying the type or amount of refrigerant in the circuit impossible when only considering the refrigerant circuit pressure. Refer to REFRIGERANT VAPOR PRESSURE TABLE .