Definition: Refrigerants occurring naturally (not synthetic), typically with very low or zero GWP and zero ODP (Ozone Depletion Potential).
Common Natural Refrigerants:
CO₂ (R744):
- GWP = 1, non-toxic, non-flammable
- Works well for cascade systems and low-temperature applications
- Requires high operating pressures (special equipment)
- Excellent for cold storage, challenging for high-ambient transport
Ammonia (R717):
- GWP = 0, excellent thermodynamic properties
- Toxic (requires safety systems)
- Primarily industrial cold storage
- Not suitable for transport (safety concerns)
Hydrocarbons (Propane R290, Butane R600a):
- GWP < 5, excellent efficiency
- Flammable (charge size restrictions)
- Increasingly common in commercial refrigeration
- Growing use in transport refrigeration
Why They Matter:
- Refrigerant phase-out driving transition from high-GWP refrigerants
- Long-term availability assured (not subject to phase-out)
- Often more energy efficient
- Future-proof equipment investment
Related Terms: GWP, Refrigerant, Sustainability, Environmental Impact