Usually according to the standard evaporation temperature of refrigerant, it is divided into high, medium and low temperature. The standard evaporation temperature refers to the evaporation temperature under standard atmospheric pressure, that is, the boiling point.
Low-pressure high-temperature refrigerant: the evaporation temperature is higher than 0℃, and the condensing pressure is lower than 29.41995×104Pa. This type of refrigerant is suitable for centrifugal refrigeration compressors in air conditioning systems.
Medium pressure medium temperature refrigerant: Evaporation temperature -50 ~ 0 ℃, condensing pressure (196.113 ~ 29.41995) × 104Pa. This type of refrigerant is generally used in ordinary single-stage compression and two-stage compression piston refrigeration systems.
High-pressure low-temperature refrigerant: the evaporation temperature is lower than -50℃, and the condensing pressure is higher than 196.133×104Pa. This type of refrigerant is suitable for the low temperature part of the cascade refrigeration device or the low temperature device below -70 ℃.
REFRIGERANT R32 FOR AIR CONDITIONER
Trade name: difluoromethane; molecular formula: CH2F2, R32 colorless, odorless, slightly burning (A2 level), boiling point (oC, normal pressure): -51.6. The combustion limit in air is 14% to 31% (volume ratio). The structure of HFC-32 is stable at room temperature and is not easy to decompose, but it decomposes into HF and carbonyl fluoride when exposed to open flames and high temperatures. The ignition temperature is 647.8 ℃. Here, the refrigeration encyclopedia is long-winded, R32 refrigerant equipment must be evacuated, and open flames must be banned!
R32 refrigerant is easily soluble in oil and hardly soluble in water. The ozone destruction potential ODP is 0, and the global warming coefficient value GWP is 670. The pressure is about 60% higher than R22. Products need to withstand high pressure, and tools and equipment used for maintenance also need to withstand high pressure. The pressure is equivalent to R410A, and the thermal performance of R32 and R410A is very close.
In fact, we have published many trainings on R32 refrigerants on the Refrigeration Encyclopedia platform, many friends are asking me, R32 refrigerants are flammable and explosive, why do many manufacturers use R32 refrigerants? Compared with R22, R32 refrigerant has a CO2 (carbon dioxide) emission reduction ratio of up to 77.6%, while R410A has a CO2 (carbon dioxide) emission reduction of 2.5%.
Temperature and Pressure Comparision Table