Brine is a common fluid used as a secondary refrigerant in large refrigeration installations for the transport of thermal energy from place to place. Being inexpensive, most common refrigerant brines are based on calcium chloride, sodium chloride and glycols It is used because the addition of salt to water lowers the freezing temperature of the solution and the heat transport efficiency can be greatly enhanced for the comparatively low cost of the material. The lowest freezing point obtainable for NaCl brine is −21.1 °C (−6.0 °F) at 23.3wt% NaCl. This is called the eutectic point.
Because of the corrosive properties of salt-based brines, glycols have become common for this purpose.