Wednesday, March 31, 2010

Cooling towers

• Control cooling tower fans based on leaving water temperatures.
• Control to the optimum water temperature as determined from cooling tower and chiller
performance data.
• Use two-speed or variable-speed drives for cooling tower fan control if the fans are few. Stage the cooling tower fans with on-off control if there are many.
• Turn off unnecessary cooling tower fans when loads are reduced.
• Cover hot water basins (to minimize algae growth that contributes to fouling).
• Balance flow to cooling tower hot water basins.
• Periodically clean plugged cooling tower water distribution nozzles.
• Install new nozzles to obtain a more-uniform water pattern.
• Replace splash bars with self-extinguishing PVC cellular-film fill.
• On old counterflow cooling towers, replace old spray-type nozzles with new square-spray ABS
practically-non-clogging nozzles.
• Replace slat-type drift eliminators with high-efficiency, low-pressure-drop, self-extinguishing,
PVC cellular units.
• If possible, follow manufacturer's recommended clearances around cooling towers and relocate or modify structures, signs, fences, dumpsters, etc. that interfere with air intake or exhaust.
• Optimize cooling tower fan blade angle on a seasonal and/or load basis.
• Correct excessive and/or uneven fan blade tip clearance and poor fan balance.
• Use a velocity pressure recovery fan ring.
• Divert clean air-conditioned building exhaust to the cooling tower during hot weather.
• Re-line leaking cooling tower cold water basins.
• Check water overflow pipes for proper operating level.
• Optimize chemical use.
• Consider side stream water treatment.
• Restrict flows through large loads to design values.
• Shut off loads that are not in service.
• Take blowdown water from the return water header.
• Optimize blowdown flow rate.
• Automate blowdown to minimize it.
• Send blowdown to other uses (Remember, the blowdown does not have to be removed at the
cooling tower. It can be removed anywhere in the piping system.)
• Implement a cooling tower winterization plan to minimize ice build-up.
• Install interlocks to prevent fan operation when there is no water flow.
• Establish a cooling tower efficiency-maintenance program. Start with an energy audit and followup, then make a cooling tower efficiency-maintenance program a part of your continuous energy management program.

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