Tips for improving energy efficiency

This section lists the most important options to improve energy efficiency of cooling towers.

• Follow manufacturer’s recommended clearances around cooling towers and relocate or modify structures that interfere with the 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.
• In old counter-flow cooling towers, replace old spray type nozzles with new square spray nozzles that do not clog.
• Replace splash bars with self-extinguishing PVC cellular film fill.
• Install nozzles that spray in a more uniform water pattern.
• Clean plugged cooling tower distribution nozzles regularly.
• Balance flow to cooling tower hot water basins.
• Cover hot water basins to minimize algae growth that contributes to fouling.
• Optimize the blow down flow rate, taking into account the cycles of concentration (COC) limit.
• Replace slat type drift eliminators with low-pressure drop, self-extinguishing PVC cellular units.
• Restrict flows through large loads to design values.
• Keep the cooling water temperature to a minimum level by (a) segregating high heat loads like furnaces, air compressors, DG sets and (b) isolating cooling towers from sensitive applications like A/C plants, condensers of captive power plant etc. Note: A 1oC cooling water temperature increase may increase the A/C compressor electricity consumption by 2.7%. A 1oC drop in cooling water temperature can give a heat rate saving of 5 kCal/kWh in a thermal power plant.
• Monitor approach, effectiveness and cooling capacity to continuously optimize the cooling tower performance, but consider seasonal variations and side variations.
• Monitor liquid to gas ratio and cooling water flow rates and amend these depending on the design values and seasonal variations. For example: increase water loads during summer and times when approach is high and increase air flow during monsoon times and when approach is low.
• Consider COC improvement measures for water savings.
• Consider energy efficient fibre reinforced plastic blade adoption for fan energy savings.
• Control cooling tower fans based on exit water temperatures especially in small units.
• Check cooling water pumps regularly to maximize their efficiency.