Desirable Properties of Marine Refrigerants
When selecting refrigerants for shipboard use, the following properties are considered ideal:
- Low Specific Volume: Reduces the size requirements for compressors and piping.
- High Critical Temperature: Allows condensation at higher temperatures, which is beneficial in varying marine climate.
- High Latent Heat of Vaporization: Ensures efficient heat absorption during the evaporation process.
- Chemical Stability: Resists decomposition under operating conditions.
- Environmental Friendliness: Low ODP and GWP values are preferred to minimize ecological impact.
- Non-Corrosive: Prevents damage to system components.
- Non-Flammable and Non-Explosive: Enhances safety aboard ships.
- Compatibility with Lubricants and Materials: Ensures smooth operation and longevity of the system.
- Easy Leak Detection: Facilitates maintenance and prevents environmental harm.
Key Refrigerant Properties Comparison
| Refrigerant | ODP | GWP | Pressure Level | Flammability | Typical Use |
|---|---|---|---|---|---|
| R-134a | 0 | 1,430 | Medium | Non-flammable | Marine AC |
| R-404A | 0 | 3,922 | High | Non-flammable | Freezers |
| R-407C | 0 | 1,774 | Medium-High | Non-flammable | AC/Refrigeration |
| R-410A | 0 | 2,088 | Very High | Non-flammable | High-efficiency AC |
| -744 (CO2) | 0 | 1 | Extremely High | Non-flammable | Eco-friendly systems |
Note: The critical temperature of a substance is the highest temperature at which it can exist as a liquid, regardless of the pressure applied. Above this temperature, the substance cannot be liquefied by pressure alone and will exhibit properties of both gases and liquids.