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How to control the temperature of the outlet water of the low-temperature chiller?
Nov 05, 2021
The structure of low-temperature chillers
is similar to that of piston chillers. Low-temperature chillers generally refer
to chillers whose outlet temperature is less than or equal to 5°C. They are
mainly used for process cooling in food processing, chemical, pharmaceutical
and other industries. Low-temperature chillers are usually used for
low-temperature requirements on certain special production lines in the
industry. Low-temperature chillers can generally reach about -40°C.
Low-temperature chillers are quite
different from conventional chillers in terms of unit design due to the lower
temperature of the outlet water. The most basic difference is that on the
chilled water side, the cryogenic unit needs to be added with the appropriate
type and concentration of antifreeze. Low-temperature chillers include low-temperature
air-cooled chillers, low-temperature water-cooled chillers, low-temperature
screw chillers, and low-temperature piston chillers. So how to control the
temperature of the outlet water of the low-temperature chiller?
The main refrigerants used in low-temperature
chillers are ethylene glycol solution, sodium chloride solution and calcium
chloride solution. Their operating temperatures are as follows: ethylene glycol
solution 4~-20℃, sodium chloride solution -15~-25 ℃, calcium chloride solution -20~-45℃.
The chiller that has used glycol as the refrigerant is also called glycol
chiller. The water supply temperature of the low-temperature chiller is
determined according to user needs. However, it should be noted that the
condensation point of brine is related to the concentration of brine.
Therefore, the brine concentration of the equipment must ensure that it freezes
inside the evaporator of the chiller. The actual operating temperature should
be 5~8℃ higher than the freezing point of brine.
Secondly, it should be noted that the concentration of sodium chloride solution
and calcium chloride solution must not exceed their eutectic concentration.
In addition, sodium chloride solution and
calcium chloride solution have a corrosive effect on metal materials. Corrosion
inhibitors should be added during use to adjust the pH of the solution to
7.0-8.5. Add sodium dichromate as a corrosion inhibitor, the addition amount
is: add 3.2kg sodium dichromate per 1 cubic meter of sodium chloride solution,
and add 2kg sodium dichromate per 1 cubic meter of calcium chloride solution.
Controlling the outlet temperature of
low-temperature chillers can not only increase the cooling capacity of
low-temperature chillers, but also help companies increase production. Omar
Refrigeration provides customized production of low-temperature chillers.
According to the customer's water temperature, water tank size, compressor
type, and type of refrigerant, it provides customized chillers. For the price
of low-temperature chillers, please contact us for the most detailed solution.