In an indirect refrigeration system, which would not be used as a cooling medium for the building spaces?

• A. R22 Refrigerant
• B. Water
• C. Glycol Solution
• D. Chilled Water

Answer: (A)

In an indirect refrigeration system, cooling to the building spaces comes from a secondary loop of a liquid (usually water or a glycol solution) that circulates through coils in air handling units. The primary refrigerant stays inside the chiller’s refrigerant circuit and transfers heat to that secondary medium through a heat exchanger.

The best choice is the refrigerant itself, since R22 is used inside the chiller's primary circuit and does not circulate through the building spaces as the cooling medium. Water, glycol solution, and chilled water are all suitable secondary media that carry cooling from the chiller to the space coils in indirect systems.