Which of the following is NOT considered a secondary coolant?

In industrial ammonia refrigeration systems, secondary coolants are fluids that absorb heat from a primary coolant (like ammonia) and then transfer that heat elsewhere. They are typically used to lower the temperature of substances or environments without exposing them directly to the primary refrigerant.

Sodium Chloride, Calcium Chloride, and Glycol are all examples of secondary coolants. They can absorb and transport heat effectively, allowing for efficient operation in refrigeration systems. These substances are chosen for their properties, which facilitate heat transfer and cooling.

R-134a, however, is not classified as a secondary coolant in this context. R-134a is a refrigerant, which serves as a primary cooling agent. It participates directly in the refrigeration cycle by undergoing phase changes to absorb and release heat. As a refrigerant, R-134a operates in a closed system, while secondary coolants work to enhance the efficiency of heat transfer within or outside the system.

Understanding the distinction between refrigerants and secondary coolants is vital in industrial refrigeration applications, particularly when considering system design and operational efficiency.