In refrigeration terminology, what is the main role of a secondary coolant?

The main role of a secondary coolant is to transfer heat without being the primary refrigerant. Secondary coolants are fluids that absorb heat from the substance needing to be cooled and then transfer that heat to the primary refrigerant in a refrigeration system.

This process allows for efficient heat exchange while maintaining the primary refrigerant's role in achieving the desired cooling temperature. Secondary coolants are often used in applications where direct contact with the primary refrigerant is impractical or where it is necessary to transport cooling capacity over a distance, such as in larger systems with multiple cooling zones.

The other choices do not accurately describe the function of a secondary coolant in refrigeration systems. For instance, increasing pressure or cooling the refrigerant directly does not characterize the role of secondary coolants, and while barriers to prevent leaks are important in system design, they do not relate to the thermal transfer functions of a secondary coolant.