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How to Reduce Power Consumption with Cooling Towers

Cooling towers are an important component in providing comfort in commercial facility and process of cooling systems. Their working is simple and are expected to be efficient and reliable, even though they are installed in the outdoor that makes them vulnerable to wind, rain, temperature extremes, organic contamination, dust, dirt, etc.

Now, there are two types of systems, air cooled and water cooled, the water-cooled systems being more energy efficient than air-cooled alternatives. Initially, the very first water-cooled systems used water directly from the ground, i.e., potable water in the condenser to reject heat with the cooling water outlet to a drain. Cooling towers were basically developed to recycle more than 98% of this wasted water, which resulted in the reduction of the consumption of water and energy use in these systems and thus their popularity increased immensely.

Ways of reducing energy consumption:

§  Designers have found that lessening the cooling tower energy, eventually reduces overall system energy at several conditions. Hence, the cooling tower fans and the condenser pumps functioning at full design speed becomes a bigger portion of the energy use of the system, especially when multiple speed chillers are being used. Reducing the fan speed of the cooling tower repairing can reduce the associated fan power significantly thereby increasing the chiller power slightly. The key is thus, to balance the performance of the components of the system so as to optimize the overall performance.

§  Another way of reducing the energy in the system is, choosing a cooling tower by the use of an approach that might be typical for a particular region. The tower approach is basically the difference between the water temperatures between the water that enters the wet-bulb temperature and that leaves the cooling tower. When you choose the approach of closer design, the cooling tower that results, gives water to the chiller condenser which is much cold, which thereby reduces the compressor energy.

§  There are specific methods to optimize the energy use of a cooling tower. This method can be achieved in different ways that include using technology of variable speed drive or two-speed motors. In case of cooling towers of multiple cells, all the fans should be functioning simultaneously at a uniform fan speed, thus maximizing the surface area of the heat transfer, used in the evaporative cooling process, for reduced energy use. This is opposed to the conventional manner of fan cycling (on/off) that furnishes step control. This operating sequence has become even easier to apply nowadays with the extensive use of VSD or variable speed drives that are cost-effective, although pony or multi-speed motors can also utilized. Nonetheless, by running all fans concurrently at the lower speed, energy of the fan is reduced by more than 60% as compared to step control. Along with the significant energy savings, this control sequence has even more advantages, namely:

   All motors for fans are frequently utilized without requiring any lead/lag preparation
         Fan system maintenance is reduced to the minimum due to the lower average fan speed and reduced starts and stops
         The cooling tower has a low sound profile, thanks to the average fan speed which is low along with starts and stops of the soft fan
         Remarkably improved condenser water temperature control

This easy energy-saving technique can be effectively applied on both new and existing installations. But both the minimum fan speed as well as the flow requirements for the particular cooling tower design must be followed as per the recommendations of the manufacturer.
How to Reduce Power Consumption with Cooling Towers How to Reduce Power Consumption with Cooling Towers Reviewed by Lokesh kumar on 10:05 AM Rating: 5