Star Refrigeration Systems

A chiller (cooling water circulation device) is a general term for a device that controls the temperature by circulating a liquid such as water or heat medium as a cooling liquid whose temperature was adjusted by the refrigerant cycle.

In part because they are closed-loop systems, it can be easy to ignore power plant cooling water systems that support the reliable functioning of everything from stator bars in the generator to critical pump bearings for feed pumps and heat exchangers on air compressors. Proper monitoring and maintenance of these water systems can help you avoid more-costly repairs to the mechanical systems they cool.

There may be multiple closed-loop cooling systems at your power plant. Chances are good that they cool or control temperature on some very critical components. The two that are most likely to exist are the so-called bearing cooling water system (which takes care of more than just bearings) and the stator cooling system, for those plants that have a water-cooled stator. Closed-loop cooling systems can also be found in air coolers on the intakes of combustion turbines.

By its very nature, when a closed-loop system remains closed and operates properly for an extended period of time, it is often forgotten—or at least neglected. Small changes in the chemistry or the flow rates and differential pressures throughout the system may not be noticed. However, once corrosion processes get a foothold in these systems, it can be very difficult to correct them. In the meantime, critical data equipment may be damaged to the point where it affects the ability of the plant to operate.

We begin with some general principles and practices for closed-loop cooling water systems before looking at the stator cooling water system, which is a special case.