Which of the following classifies cooling water systems?

Cooling water systems are primarily classified based on their flow patterns and the methods by which they dissipate or transport heat. The classification of "once through and closed or recirculating" accurately reflects the two main configurations of cooling systems.

Once-through cooling systems involve drawing water from a source, using it to absorb heat, and then discharging it back to the source without recirculating it for reuse. This method is often utilized in power plants or large industrial facilities where there is an abundant source of water.

Closed or recirculating systems, on the other hand, involve a closed loop where water is circulated through the system, carrying heat away and then being cooled through a cooling tower or heat exchanger before re-entering the system. This setup is more efficient in terms of water usage and temperature management, as it allows for continuous reuse of the cooling water without direct discharge into a natural body of water.

By distinguishing between these methods, one can better understand the operational and environmental implications of different cooling systems, making the classification "once through and closed or recirculating" the most comprehensive and informative choice in the context of cooling water systems.