As with any complex mechanical system, maintenance is the key to performance. Cooling towers are more intricate than most systems, representing the careful coordination of fluid, electrical, and mechanical systems. As a result, there are many maintenance tasks that affect performance:
1. The concentration of solids in the water is a critical parameter that can foul parts of the entire cooling circuit and cause substantial problems in sensitive and expensive equipment. Even if the system is automated, it should be checked regularly for acceptable performance.
2. The clearance at the overflow pipe indicates the water level in the basin. This level must be maintained within narrow limits if the full cooling capacity of the tower is to be available.
3. The fan and its motor- and drive-chain need regular attention. This includes swift diagnosis of any unusual noise, tensioning of the fan belt, and proper alignment of the fan and motor, as applicable.
4. A clean tower will have a minimal air- and water-pressure drop. Both of these require the input of energy to overcome—fan and pump horsepower, respectively.
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5. The intake strainer is a sieve that extracts larger solid particles from the fluid loop. When it’s clogged, the pump horsepower increases, fluid flow drops, and performance suffers. It’s important to keep the strainer clean and also to be wary of the type and quantity of solids that are trapped there as potential symptoms of problems elsewhere in the condenser-water loop.
6. A gravity-distributed tower depends on the static pressure of standing water to distribute water consistently into the fill. The water depth should be consistent throughout.
7. The working component of spray-filled or distributed towers is the nozzles. They should be kept clean and in good repair.
8. Any tower can have air bypass, given certain circumstances. This is when air is discharged from the tower, only to be drawn back in and recirculated. Air that leaves the tower is hot and humid, so when it goes back through the tower, it does more harm than good for the system. This bypass can be prevented, though, by the addition of baffles or by increasing the height of the discharge stacks.