Energy Savings in Water Treatment – Cooling Towers

With rising energy and production costs, managing energy consumption has never been more important. Businesses today are paying closer attention to their operational expenses, aiming to pinpoint areas where energy is being wasted and implement strategies to reduce costs wherever possible.

However, when it comes to facility or building management, water treatment is often overlooked. Many do not realise how critical sustainable water management can be. Not only for environmental reasons but also for achieving significant energy savings within their operations.

Cooling Towers

Over time, a poorly maintained cooling tower will experience a rise in leaving water temperature, increasing energy consumption by up to 6% for every 2°F rise. In contrast, a properly maintained cooling tower will continue to operate efficiently, keeping energy costs to a minimum.

Cooling towers play a vital role in many industrial and commercial systems. There are several ways to improve their energy efficiency—starting with ensuring the tower is properly sized, upgrading to high-performance fans, integrating variable-frequency drives (VFDs), or replacing outdated fill and nozzles for better water distribution.

Let’s break this down further.

Tower Sizing

Having the correctly sized cooling tower from the outset is crucial. Proper sizing ensures the tower can meet the system’s cooling demands while maintaining efficiency and reliability.

Since HVAC systems depend on cooling towers to regulate temperature, an undersized tower may fail to dissipate enough heat, potentially leading to system inefficiency or even equipment failure.

Fan Control and Efficiency: Fans, Fill, and Nozzles

If the tower is not optimally sized, it’s worth maximising the potential of the existing system, which may involve refurbishment or upgrades.

Fans

Fans are typically the largest energy consumers in a cooling tower, making them the first place to look for savings. Consider using two-speed motors, which can operate on just one-sixth of the power at low speed.

Alternatively, installing VFD controllers on fans and pumps allows you to reduce power consumption during periods of low heat load. This works effectively because fan power usage varies with the cube of airflow (CFM), while thermal performance is directly proportional to airflow.

Fill

The fill media also plays a role in energy efficiency. Many older towers still use splash-type fill, which is less effective. When conditions allow—meaning low risk of scaling, algae, or fouling—switching to film-type fill can enhance performance. However, film fill can clog more easily if the water quality is poor, so it’s essential to evaluate compatibility with your fan and nozzle systems before making the change.

Nozzles

In crossflow towers, nozzles must provide uniform water distribution over the fill to maintain efficient cooling. Improved distribution can be achieved by adding distribution decks below the nozzles.

For counterflow towers, nozzles can influence up to 25% of the cooling capacity, so upgrading them can significantly impact performance—positively or negatively—depending on system design.

Maintenance for Optimal Efficiency

Routine maintenance ensures your cooling tower operates efficiently, saves energy, conserves water, and prolongs the equipment’s lifespan. Here are some essential checks:

• Inspect overall system performance and listen for unusual noises that may indicate problems.
• Follow all lock-out/tag-out procedures before starting any maintenance work.
• Clean debris from strainers to maintain proper water flow.
• Examine the water distribution system for dry spots; clogged or cracked nozzles can reduce cooling efficiency.
• Keep the make-up water supply at the correct level to prevent air entrainment and water waste.
• Adjust the bleed rate based on local water-quality conditions to prevent solids buildup.
• For gear-driven systems, check oil levels, oil condition, and shaft alignment regularly, following manufacturer guidelines.
• Lubricate fan shaft bearings at least every three months—or install automatic greasers to reduce manual maintenance needs.

Developing strong maintenance habits helps prevent breakdowns, optimise performance, and extend the life of your cooling system.

Interested in Further Energy Savings?

Want to learn more about how your cooling towers can be optimised for energy efficiency? Get in touch with us today to discover practical solutions that can reduce costs and enhance performance.