In 1987,《The Montreal Protocol》was signed. In order to protect the ozone layer hole, countries all over the world have carried out the research on the replacement of HCFCs refrigerant R22, and developed a variety of HFCS alternative refrigerants, among which R410A and R407C have been widely used. 《The Kyoto Protocol》signed in 1997 and the Copenhagen climate conference held in 2009 not only required that the ODP of alternative refrigerants should be 0, but also the GWP should be as low as possible. HFCS refrigerant R32 has been widely used in recent years because of its low GWP value, good cycle performance, low charge and low cost.
R32 as a kind of HFCS refrigerant, its ODP = 0, GWP = 675, compared with R22 (ODP = 0.055, GWP = 1810) and R410A (ODP = 0, GWP = 2100), is more in line with the international environmental protection standards, and its system charge is only 60% of R22, compared with R22, the emission reduction ratio can reach 62.7%
Under different working conditions, the operating pressure ratio of R32 and R410A is equivalent, and the cop is about 0-5% higher than R410A. which is equivalent to R22. It is feasible to use R32 as an alternative refrigerant. R32 is one of the components of R410A, its evaporation and condensation pressure is close to R410A, so it is almost unnecessary to replace refrigeration components when replacing refrigerant. Thus, R32 has a great application prospect in air conditioning system.
R32 has low flammability (A2L, moderate flammability), and its combustion explosion limit, ignition point and combustion speed are relatively safe.
In terms of flammability, compared with R290, the ignition energy of R32 is much greater than R290. The ignition energy of R32 is about 30 to 100 mJ, while the ignition energy of R290 is about zero. Thus, compared with R290, R32 is safer and further reduces the possibility of combustion.
