Characteristics of R12, R22, R407C refrigerants in cold storage

Characteristics of R12, R22, R407C refrigerants in cold storage

I don’t know if you still remember that okmarts.com wrote "How to Choose Refrigerant for Cold Storage Design" some time ago. Today okmarts.com will introduce several different cold storage refrigerants in detail, namely R12, R22, R407C

R12 refrigerant characteristics

　　R12 refrigerant (molecular formula CFC, code R12) is currently in the restricted use and phase-out list, but there are still a large number of small and medium-sized cold storage refrigeration not in use, so it is necessary to understand its characteristics

　　(1) R12 is a colorless transparent liquid, non-toxic and non-irritating odor. At any concentration, the vapor is non-irritating to humans and respiratory system. When the concentration in the air exceeds 20%, people will feel uncomfortable, and when the concentration in the air exceeds 80%, it will cause breathing.

　　(2) R12 does not burn or explode. But when its element gas temperature reaches 400℃, it will produce toxic phosgene in case of open fire.

　　(3) Although R12 does not corrode metal, it is a strong detergent that can clean the rust layer on the metal surface and block the pipeline.

　　(4) R12 has a corrosive effect on aluminum alloys containing 2% magnesium.

　　(5) R12 is a medium temperature and medium pressure refrigerant. Under standard atmospheric pressure, the boiling point is -29.8°C and the freezing point is -15°C. When condensing with water, the condensing pressure is below 1.0MPa; when condensing with air,

　　The condensing pressure does not exceed 1.2MPa.

　　(6) R12 has strong permeability, which can easily cause system leakage.

　　(7) R12 is corrosive to organic matter.

(8)R2 is insoluble in water, and can be miscible with refrigerated lubricating oil in any ratio. R22 refrigerant characteristics

　　 R22 refrigerant (molecular formula CHF2Cl, code R2) is now the main refrigerant used in small and medium-sized cold storage refrigeration systems. Its characteristics are as follows:

　　R22 is colorless, odorless, non-flammable, non-explosive at room temperature. At standard atmospheric pressure,

　　 R22 has a boiling point of -40.8°C and a freezing point of -160°C.

　　R2 is a medium-temperature and medium-pressure refrigerant with a condensation pressure of about 1.4MPa

　　 The unit volume cooling capacity of R2 is about 50% greater than R12 under air conditioning conditions.

　　 R22 can partially dissolve with the refrigerated lubricating oil, and can fully dissolve with the refrigerated lubricating oil at higher temperature; at lower temperature, there will be delamination.

　　R22 is not miscible with water.

　　 R22 does not corrode metals, and has strong corrosion and permeability to synthetic rubber and enameled wires.

R407C refrigerant characteristics

　　 The chemical formula of R407C: CH2F2/CHF2CF3CF3CH2F, that is, R407C is a mixture of R32 refrigerant and R125 refrigerant plus R134a refrigerant in a certain ratio. It is an environmentally friendly refrigerant that does not damage the oxygen layer. The boiling point is 43.9°C at a standard atmospheric pressure. Under normal temperature and pressure, RAO7C is a non-chlorine-free fluoroalkane non-azeotropic mixture refrigerant. It is a colorless gas and can be easily compressed into a liquid state when stored in a cylinder.

　　 The ODP of R10C is 0, and the GWP is 1,526. Because R407C has very similar characteristics and performance to R22, it is a long-term replacement of R22 refrigerant for cold storage refrigeration systems. R0C can be used in the original R2 system. There is no need to redesign the system, just replace a few parts of the original system, and replace the mineral refrigerating oil in the original system with a lubricating oil (POE oil) that is miscible with RA0C, and then it can be directly filled R407C, realize the environmental protection replacement of the original equipment. Because RA07C is a mixed non-azeotropic working fluid, in order to ensure that its mixed composition does not change, RAO7C must be charged in liquid form. If the refrigerant leaks in the R407C system and the performance of the system changes significantly, the remaining R407C in the system cannot be recovered For recycling, the remaining R407C refrigerant in the system must be emptied and recharged with new R407C refrigerant.