Sodium chloride brines, freezing point

Freezing point of sodium chloride brines Compiled in collaboration with C. D. Looker, Ph.D., International Salt Co., Inc. 

Sodium chloride, an ordinaiy salt (NaCT), is the least expensive per volume of any brine available. It can be used in contact with food and in open systems because of its low toxicity. Heat transfer coefficients are relatively high. However, its drawbacks are it has a relatively high freezing point and is highly corrosive (requires inhibitors thus must Be checked on a regular schedule). 

Calcium Chloride Aqueous solutions of calcium chloride find wide use as a circulating brine. Similar to sodium chloride solution, it is nonflammable and nontoxic. It has a lower freezing point than sodium chloride solution and can be used down to -37°C. The main disadvantages are that 1) it is highly corrosive 2) it has a reduced heat transfer coefficient below —20°C and 3) it cannot be used in direct contact with foods. 

The name "brine" refers to a liquid used in a refrigeration system, which is usually an aqueous solution of calcium chloride or sodium chloride, that is externally cooled by an evaporating refrigerant (Figure 1.31). The addition of salt lowers the freezing point of the solution. The lowest temperature which can be reached by a solution of sodium chloride is about -21 °C (-7°F). That for calcium chloride is -52°C (-52°F). 

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