In indirect low-temperature refrigerant systems, using glycol as the intermediate cooling medium instead of salt brine provides which main advantage?

• A. Lower cost
• B. The elimination of corrosion
• C. Higher energy efficiency
• D. Simpler maintenance

Answer: (B)

Corrosion control in the secondary cooling loop is the main reason glycol is preferred over salt brine in indirect low-temperature refrigerant systems. Salt brine brings chlorides and other ions into contact with metals, which accelerates corrosion, leading to rust, pitting, and potential leaks in pipes and heat exchangers. Glycol-based cooling fluids, when formulated with corrosion inhibitors and used at proper concentrations, are much less aggressive toward common metals and often stay non-conductive, which further reduces corrosion risk. In practice, this means the system experiences far less metal degradation over time, extending equipment life and reducing maintenance related to corrosion. The other potential benefits—cost, energy efficiency, or maintenance simplicity—depend on many variables, but the reduction or elimination of corrosion is the most direct and reliable advantage of using glycol.