RS-51 (R470B)
Non-flammable replacement for R404A & R507 with GWP below 750
RS-51 is a non-flammable drop-in replacement for R404A and R507 with a Global Warming Potential (GWP) less than 80% of R404A with similar thermodynamic performance.
RS-51 (R470B) provides an easy and straightforward retrofit option to replace R404A and R507 in existing equipment at low cost. No changes to lubricant and minimal modifications to hardware are necessary so that the overall costs of conversions are kept to a minimum, and purchase of new equipment is avoided. RS-51 (R470B) has similar properties to R404A including Coefficient of Performance, cooling capacity, discharge pressure, discharge temperature and others. The much lower direct GWP of RS-51 (R4707B) means that users will achieve a lower carbon footprint which is a major benefit under the European Union’s F Gas regulations.
Global Warming Potential
The European Union F Gas regulations focus on the direct GWPs of refrigerants so that the lower the GWP of a refrigerant the more of that refrigerant can be sold & used. RS-51 (R470B) has been developed as a very low GWP replacement for R404A and R507 with the lowest GWP of any non-flammable alternative to R404A on the market. The GWP of RS-51 (R470B) is approximately 45% less than R448A and R449A
Performance Characteristics
- Global Warming Potential less than 80% of R404A
- GWP less than 45% of R448A and R449A
- Higher efficiency than R448A & R449A
- Non-flammable & low toxicity
- Suitable in OEM & retrofit applications
- Similar cooling capacity
- Similar discharge temperature to R404A
- Minimal changes to hardware
- Compatible with lubricants used with R404A and R507
- Similar cooling capacity and energy efficiency to R404A
- Mass flow equivalent to R448A & R449A
- Zero Ozone Depletion Potential
Applications
RS-51 (R470B) can replace R404A and R507 in many of the applications where these refrigerants are found including supermarkets, cold stores, freezers, ice machines, refrigerated transport, beer cellars, freezer cabinets, transportation of foodstuffs, freeze dryers, environmental test chambers & others.
Lubricants
RS-51 (R470B) is compatible with the same (POE) lubricants which are commonly used with R404A and R507, so that there is no need to change the oil when converting from R404A and R507 to RS-51 (R470B).
Safety
RS-51 (R470B) is non-flammable under all conditions of fractionation as per ASHRAE Standard 34. The components of RS-51 (R470B) have been subjected to toxicity tests carried out by Alternative Fluorocarbons Environmental Acceptability Study (AFEAS), and have been declared to be of low toxicity.
Servicing
Because RS-51 (R470B) is a blend, it should be charged into the system in the liquid as opposed to vapour form. When converting from R404A or R507 to RS-51 (R470B), minimal hardware changes are needed. RS-51 (R470B) has a lower flow rate than R404A and R507, so there is may be a need to adjust or change the expansion device during a retrofit.
Physical Properties
| Property | RS-51 (2) | R404A (2) | |
|---|---|---|---|
| Molecular Mass | 89.73 | 97.60 | |
| Boiling point (1 atm) (1) | °C | -61.45 | -46.23 |
| °F | -78.6 | -51.2 | |
| Temperature Glide | K | 4.1 (4) | 0.5 |
| Critical Temperature | °C | 94.29 | 72.12 |
| °F | 201.7 | 161.8 | |
| Critical Pressure | bara | 54.66 | 37.35 |
| psia | 792.8 | 541.7 | |
| Liquid Density (25°C) (1) | kg/m3 | 1107 | 1044 |
| Density of saturated vapour (25°C) (1) | kg/m3 | 56.74 | 66.41 |
| Latent Heat of Vaporisation at boiling point (3) | kJ/kg | 259.9 | 200.9 |
| Heat capacity constant volume Cv (25°C & 1bara) | kJ/kg.K | 0.762 | 0.784 |
| Heat capacity constant pressure Cp (25°C & 1bara) | kJ/kg.K | 0.862 | 0.877 |
| Cp/Cv (25°C & 1 bara) | 1.131 | 1.118 | |
| Vapour Pressure (25°C) (1) | bara | 17.07 | 12.55 |
| psia | 247.7 | 182.0 | |
| Vapour Viscosity (25°C & 1 bara) | cP | 0.0129 | 0.0121 |
| Liquid Viscosity (25°C) (1) | cP | 0.143 | 0.128 |
| Liquid Thermal Conductivity (25°C) | W/m.K | 0.0812 | 0.0627 |
| Surface Tension (25°C) (1) | N/m | 0.00642 | 0.00446 |
| Specific heat of liquid (25°C) (1) | kJ/kg.K | 1.54 | 1.54 |
| Ozone Depletion Potential | ODP | 0 | 0 |
| Global Warming Potential AR5 | GWP | 717 | 3943 |
| Flammability limit in air (1 atm) | vol% | none | none |
| Inhalation exposure (8 hour day & 40 hour week) | ppm | 1000 | 1000 |
(1) Bubble point
(2) RS-51 refrigerant properties obtained from NIST's REFPROP v10 program.
(3) Difference between bubble point liquid enthalpy and dew point vapour enthalpy at 1 atm.
(4) Pressure drop in the evaporator of 0.5 bar.