How to choose refrigerant for different types of industrial chillers

How to choose refrigerant for different types of industrial chillers

We all know that the working temperature of medium and high temperature chillers can be controlled between 3°C and 35°C, low temperature chillers can also be controlled between 0°C and -60°C, and ultra-low temperature chillers can even reach -60°C to -120°C. The temperature range is different, their choice of refrigerant is also different.

　　The carrier refrigerant is an indispensable part of the safe operation of industrial chillers. However, the choice of carrier refrigerant is different due to the different working temperature and requirements/features of the chiller. According to the working temperature range of the chiller, the applicable range of various refrigerants and the specific method of selecting refrigerants:

1. If the working temperature of the industrial chiller is above 3°C, the system generally uses water as the refrigerant. This is because the water is the easiest to obtain and the price is low, and the water has good chemical stability, high specific heat, and no Toxic, non-flammable, non-explosive, and less corrosive to metals than salt water. However, the freezing point of water is high (the freezing point is 0°C under atmospheric pressure), which greatly limits the use of water as a refrigerant in the refrigeration system;

　　2. If the working temperature of the industrial chiller is in the range of 3～-60℃, sodium chloride aqueous solution or calcium chloride aqueous solution is generally used as the refrigerant. However, due to the limitation of freezing point, sodium chloride brine is suitable for refrigeration systems at 3 to -16°C, while calcium chloride brine can be used in refrigeration systems at 3 to -50°C. Salt water is also very common as the refrigerant of the chiller refrigeration system. It has a wide temperature range, is affordable, and has a large heat capacity. However, it has a certain corrosive effect on metals, so many users will also choose glycol or The aqueous solution of glycerol is used as the refrigerant (only used in refrigeration systems above -30°C). When the temperature is outside this range, trichloroethylene or methylene chloride can be used instead of calcium chloride.

3. When the working temperature of industrial chillers is lower than -50℃, hydrocarbons with lower freezing points are usually used as refrigerants, such as trichloroethylene, methylene chloride, ethanol, acetone, etc., and their boiling points are also It is very low, so a closed system is generally used to prevent pump cavitation and reduce evaporation loss.