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 R134a for air conditioner is mainly used as a substitute for Refrigerant R12 and is widely used in refrigeration and air conditioning systems such as automobile air conditioners, refrigerators, central air conditioners, and commercial refrigeration. The standard boiling point of R134a is -26.5°C. R134a has a large latent heat of vaporization, a larger heat capacity than constant pressure, and a better cooling capacity; the volume of saturated gas is large, the mass flow rate of the refrigerant of the same displacement compressor is small, and the ODP ozone layer has no destructive effect, but the GWP of R134a changes globally The warm potential value is 1600.
HFC-134a has a smaller capacity than FREON R22 and a lower pressure than R22. Refrigerant Gas R134a has strong water absorption, which is 20 times that of R22. Therefore, the requirements of the dryer in the unit system are higher to avoid ice blocking.
The R134a system requires a special compressor and a special grease lubricant. Due to the high water absorption, high foaming and high diffusivity, the grease lubricant is inferior to the mineral oil used in the R22 system in terms of the stability of the system performance.