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 R22 :
Refrigerant R22 also belongs to Freon refrigerant, the chemical name is difluorochloromethane, and the chemical formula is CHF2Cl. It is a medium-pressure and medium-temperature refrigerant with a boiling point temperature of -40.8℃, a freezing point of -160℃, a critical temperature of 96℃, and a critical pressure of 4.974MPa. HCFC gas R22 is non-flammable and non-explosive, and has low toxicity, but it has a strong penetration ability and is difficult to detect.
The unit volume of HCFC-R22 is similar to that of ammonia refrigerant. Freon R22 can be obtained through a two-stage compression or air-conditioning refrigeration system, the lowest temperature can reach -80 ℃, but it is not economical.
Refrigerant R22 temperature and pressure comparison table