What medium is commonly used as a coolant in water-cooled condensers?

Water is commonly used as a coolant in water-cooled condensers due to its high specific heat capacity, availability, and cost-effectiveness. It can efficiently absorb heat from the refrigerant vapor that has condensed, allowing for effective heat exchange. In a water-cooled condenser, water circulates and removes heat from the condenser, facilitating the cooling process and maintaining the system's efficiency.

Other options, while relevant to refrigeration, serve different roles. Freon is a refrigerant rather than a coolant, generally used within the refrigeration cycle itself. Ammonia also serves as a refrigerant and may be used in certain industrial applications but is not typically used as a coolant in standard condenser setups. Glycol is often used in chilled water systems as an antifreeze agent, but it is not the primary medium used for cooling in water-cooled condensers. Thus, water remains the best choice for this application.