Ideal physical properties of refrigerants
1. Evaporation pressure should be high
If the evaporation pressure of the refrigerant is lower than the atmospheric pressure, air will easily invade the system, making it more difficult to handle the system. Therefore, it is hoped that the evaporation pressure of the refrigerant can be higher than the atmospheric pressure when it evaporates at low temperature.
2. Latent heat of evaporation should be large
The latent heat of evaporation of the refrigerant is large, which means that a large amount of heat can be absorbed by using less refrigerant.
3. Critical temperature should be high
A high critical temperature means that the condensation temperature of the refrigerant is high, so the refrigerant can be cooled by air or water at room temperature to achieve the effect of condensation and liquefaction.
4. Condensation pressure should be low
A low condensation pressure means that the refrigerant can be liquefied at a lower pressure, and the compression ratio of the compressor is small, which can save the horsepower of the compressor.
5. Solidification temperature should be low
The solidification point of the refrigerant should be low, otherwise the refrigerant will freeze in the evaporator and cannot circulate.
6. Smaller specific volume of gaseous refrigerant
The smaller the specific volume of gaseous refrigerant, the better. The volume of the compressor can be reduced to reduce costs, and the suction and exhaust pipes can use smaller refrigerant pipes.
7. High density of liquid refrigerant
The higher the density of liquid refrigerant, the smaller the liquid pipe can be.
8. Soluble in refrigeration oil, the system does not need to be equipped with an oil separator.
Ideal chemical properties of refrigerant
1. Stable chemical properties
The evaporation temperature will change with the application temperature. For example, the evaporation temperature of the chiller is about 0~5℃. In the refrigeration cycle system, the refrigerant only undergoes physical changes, but no chemical changes, and does not decompose.
2. Non-corrosive
It is non-corrosive to steel and metals. Ammonia is corrosive to copper, so copper pipes shall not be used in ammonia refrigeration systems; the insulation should be good, otherwise it will damage the insulation of the compressor motor, so ammonia shall not be used in closed compressors to avoid direct contact with copper coils. Ehvacr
3. No environmental pollution
No harm to the natural environment, no damage to the ozone layer, low greenhouse effect.
4. Non-toxic.
5. Non-explosive and non-flammable.
