R134a and R404A are common refrigerants in refrigeration systems, so what is the difference between them? How should you choose?

Chemical stability

R134a has better component stability. Why? Because R134a has a simple structure and is composed of pure substances, while R404A is a mixture of R125/R143a/R134a in different proportions. These three refrigerants have different boiling points and different volatilization rates. If the system leaks, they will change the component ratio and affect the refrigeration effect. Therefore, when the refrigerant leaks, the equipment using R404A must be evacuated and refilled with new refrigerant, while the equipment using R134a only needs to be replenished.

Refrigeration oil compatibility

Refrigeration oil is used to lubricate the compressor, and it needs to be compatible with the refrigerant. R404A usually uses POE oil, but it is highly hygroscopic and will generate acidic substances when wet. Therefore, if the R404A system is not well sealed, the service life of the oil will be shortened. R134a is compatible with many types of refrigeration oil, and you have many choices.

Thermal stability

At high temperatures, R134a has better thermal stability. However, when the temperature exceeds the standard, both R134a and R404A may decompose and generate highly corrosive hydrofluoric acid. Therefore, it is necessary to use appropriate refrigeration oil to reduce this risk.

Operation stability

R404A has a higher operating pressure. If you want to achieve high temperature control accuracy, you need to use a high-performance controller and expansion valve. R134a has a low operating pressure and can still maintain good temperature control accuracy and refrigeration efficiency under partial load and load fluctuations.

Kapazität der Kältemaschine

Under medium and low temperature conditions, the cooling capacity of R404A is higher than that of R134a. It has a higher gas density and a higher evaporation pressure. Therefore, it can take away more heat when the compressor speed is the same. R134a has a lower gas density. If you want to avoid excessive compression ratio of the compressor, you have to choose a compressor with a larger displacement.

Coefficient of performance

The coefficient of performance of the R134a chiller is higher than that of the R404A system, and the energy consumption is lower. However, R404A sacrifices energy efficiency at low temperatures and provides stronger cooling capacity.

Environmental protection

Both R134a and R404A do not contain chloride ions and will not directly damage the ozone layer. However, both have high global warming potentials, and the GWP of R404A is nearly 3 times that of R134a. The EU F-Gas regulations stipulate that from 2020, the use of refrigerants with GWP > 2500 in new systems will be prohibited, and R404A has been gradually phased out in many countries and regions. The US SNAP policy also restricts the use of R134a to specific areas, which means that R134a is slowly being replaced by HFO or natural refrigerants with lower GWP.

Anmeldung

Purchase cost

The preparation process of R404A is more complicated, so the price is usually higher than R134a. Although some countries restrict the use of R404A, some old equipment is still in demand, so its price has risen significantly in recent years.

Schlussfolgerung

To avoid the risk of elimination of high GWP refrigerants, you should consider using more environmentally friendly refrigerants when purchasing a chiller system. Not sure which refrigerant is suitable for your cooling system? Our chiller team can provide you with professional guidance and quick quotes based on your application. Ask us!