Comparison of R404A and R507 refrigerants | Differences in refrigeration capacity, exhaust temperature, and pressure under cold storage conditions
R404A and R507 are currently the most popular HFC refrigerants in low-temperature cold storage, and their different compositions result in differences in operating characteristics. They cannot be directly replaced in the system and require adjustment of the expansion valve.
Under the low-temperature freezing conditions of -25 ℃ evaporation and 35 ℃ condensation, the unit cooling capacity of R404A is about 7% higher than that of R507, and the exhaust temperature of R507 is about 8K lower than that of R404A.
The Xitelidou semi closed piston compressor is divided into R404A version and R507 version at the factory. The oil filling amount, expansion valve selection, and protection setting value are calibrated with the refrigerant version.
R507 has minimal temperature slip and belongs to the near azeotropic refrigerant category. After the system leaks fluorine, the components hardly shift, making it easy to replenish and suitable for overseas projects with few supporting spare parts for maintenance.
R404A has slight temperature slip, and after a large amount of leakage, the proportion of internal components changes. Directly adding new refrigerant will cause abnormal operating pressure and a decrease in cooling capacity.
Under the condition of 0 ℃ evaporation under medium high temperature preservation conditions, the difference in refrigeration capacity between the two refrigerants is reduced to within 2%. At this time, the selection should prioritize the local refrigerant procurement price and supply stability.
The overall exhaust pressure of R404A is slightly higher than R507. In high temperature environments in summer, R404A units are more likely to reach the high pressure protection threshold, and a larger condenser margin needs to be reserved.
Many maintenance technicians directly inject R507 into the R404A system without adjusting the expansion valve, which can result in uncontrolled overheating, either due to liquid hammer in the suction or excessive overheating in the return air.
Priority is given to researching the refrigerant supply chain of target countries for foreign trade order selection. R404A is well stocked in many regions of Africa, and R507 is more widely circulated in some South American regions, making spare parts easier to purchase.
Both refrigerants are high GWP refrigerants, and in the long run, control will gradually tighten. Some new EU projects may require alternative low GWP alternatives, and customer needs will be communicated in advance during the quotation stage.
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FAQ
What is the difference in cooling capacity between R404A and R507 under low temperature conditions of -25 ℃? The cooling capacity of R404A is about 7% higher.
Which refrigerant has a lower exhaust temperature? The exhaust temperature of R507 is about 8K lower than that of R404A.
Can R507 be directly replenished after fluoride leakage? Near azeotropic refrigerant, can be directly refilled after leakage.
Can R404A be directly refilled due to a large amount of leakage? Not recommended, component offset, abnormal pressure and cooling capacity.
Can two refrigerants be directly exchanged without adjusting the expansion valve? No, the expansion valve must be readjusted.
Which one is easier to protect against high pressure in high temperature environments? R404A has higher high pressure and is more likely to trigger protection.
What are the trends of these two refrigerants in the new EU project? High GWP, control gradually tightened.
