Refrigerant Knowledge Center
What Is R744 Refrigerant? Properties, Uses and Safety
R744 is refrigerant-grade carbon dioxide, a natural refrigerant with GWP defined as 1 and no ozone depletion, used in transcritical and subcritical systems that operate at distinctly high pressures.
What Is R744?
R744 is refrigerant-grade carbon dioxide, a natural refrigerant with GWP defined as 1 and no ozone depletion, used in transcritical and subcritical systems that operate at distinctly high pressures.
R744 is classified as single component in the natural refrigerant family. Its composition is 100% refrigerant-grade carbon dioxide. Refrigerant choice is never based on designation alone: capacity, pressure, lubricant, controls, heat-exchanger behavior, safety standards and local rules all matter.
R744 Technical Properties
General reference values for comparison; a current product specification and applicable regulatory basis govern a transaction.
| Refrigerant designation | R744 |
|---|---|
| Chemical family | natural refrigerant |
| Composition | 100% refrigerant-grade carbon dioxide |
| Blend type | single component |
| ASHRAE safety class | A1 |
| 100-year GWP | 1 (CO2 reference value, 100-year) |
| Ozone depletion potential | 0 |
| Normal boiling reference | -78.5 (sublimation at 1 atm) °C |
Common R744 Applications
Typical references include supermarket refrigeration, heat pumps, transport refrigeration, and industrial cascade systems.
Use depends on equipment design, operating envelope and applicable local requirements.
Use depends on equipment design, operating envelope and applicable local requirements.
Use depends on equipment design, operating envelope and applicable local requirements.
Use depends on equipment design, operating envelope and applicable local requirements.
Advantages and Limitations
Selection advantages
- Established refrigerant designation with published reference data.
- Application history in supermarket refrigeration.
- ODP reference of 0.
Important limitations
- A1 safety controls must be applied.
- GWP and lifecycle status can affect long-term selection.
- No refrigerant should be treated as a universal drop-in.
Environmental Impact and Regulation
Low direct GWP does not remove pressure-vessel, workplace-safety, efficiency or equipment-certification obligations.
R744 has an ODP reference of 0 and a stated GWP of 1 using CO2 reference value, 100-year. Regulations commonly distinguish between manufacturing or import, new equipment, servicing, recovered material and individual end uses.
Safety, Handling and Storage
Purpose-designed high-pressure equipment, pressure-relief protection, ventilation and oxygen-deficiency controls are essential despite its A1 classification.
The A1 classification describes toxicity and flammability groupings; it does not by itself approve a refrigerant for a particular system. Review the current safety data sheet, cylinder label, transport classification, equipment manual and local code.
R744 Alternatives and Comparisons
Candidate alternatives must be evaluated as system choices, not simple chemical substitutions.
HFC blend; A1 safety class; GWP 3922 on the stated IPCC AR4 100-year basis.
HFC blend; A1 safety class; GWP 3985 on the stated IPCC AR4 100-year basis.
hydrocarbon; A3 safety class; GWP 3 on the stated IPCC AR4 100-year basis.
natural refrigerant; B2L safety class; GWP 0 on the stated commonly reported direct 100-year GWP basis.
R744 Frequently Asked Questions
What is R744 made of?
100% refrigerant-grade carbon dioxide; it is categorized as single component.
What is the safety class of R744?
The published classification used in this guide is A1. Equipment approval and local safety rules still apply.
What is the GWP of R744?
The reference here is 1 on the CO2 reference value, 100-year basis. Other assessment bases may show a different number.
Can R744 replace another refrigerant directly?
No universal drop-in claim is made. Compatibility and conversion requirements must be confirmed for the exact equipment.
Where is R744 commonly used?
Typical applications include supermarket refrigeration, heat pumps, transport refrigeration, and industrial cascade systems, subject to equipment design and local approval.
References and Technical Sources
Source data is summarized for general education. Always use current official documents, standards and supplier-specific safety and technical data for engineering or compliance decisions.
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