Before delving into the differences between R134a and R404A, it is important to emphasize that these are distinct gases and should not be considered substitutes for each other.
Composition of R134a vs R404A
- R134a: It is a pure gas, not composed of a mixture of various gases.
- R404A: It is a blend of several refrigerants, including R125, R143a, and R134a itself.
Properties:
- R134a, being a single-component gas, does not have glide (temperature change in the evaporator while boiling) and can be charged in either liquid or gas phase.
- R404A, as a blend, must always be charged in the liquid phase and has a small amount of glide.
Working pressures of R134a vs R404A
The working pressures of R134a are significantly lower than those of R404A:
| Temperature (°C) | R134a (psig) | R404A (psig) |
|---|---|---|
| -20°C | 4.7 | 29.54 |
| -10°C | 14.7 | 48.8 |
| 5°C | 36.6 | 88.64 |
Applications of R134a vs R404A
- R134a:
- Used in automotive air conditioning systems.
- Used in medium and low-temperature refrigeration equipment with medium and small capacities.
- Widely used in water chillers.
- R404A:
- Used in refrigeration systems of any capacity.
- Not used in air conditioning systems.
- Exclusively employed in special low-temperature chillers.
Environmental restrictions of R134a vs R404A
- Neither of these gases damages the ozone layer.
- R134a:
- Has a Global Warming Potential (GWP) of 1430.
- Subject to restrictions in new vehicles but continues to be used in new refrigeration equipment with limitations in certain countries.
- R404A:
- Has a much higher GWP, with a value of 3940.
- Subject to stricter ecological restrictions due to its environmental impact.
Oil compatibility R134a vs R404A
- R134a:
- Uses POE (polyester) oil in refrigeration systems.
- Uses PAG (polyalkylene glycol) oil in automotive air conditioning systems.
- R404A:
- Always works with POE oil.
