Improving the Energy Efficiency in Cooling Towers

September 25, 2020 | Blog

The efficiency of the cooling system has a major impact on production in every sector. There is a direct link between the cold water temperature and process efficiency. Only a degree of increase in cooling water temperature can cause a 3% increase in energy usage. But before getting into the importance of energy efficiency in cooling towers, one must properly understand what exactly a water cooling tower is, its function, and the key components involved in its functioning.

The primary task of a water cooling tower is to reject heat into the atmosphere in buildings and large-scale industries to aid cooling systems. They represent a relatively inexpensive and dependable means of removing low-grade heat from cooling water.

Cooling towers help in maintaining temperature for air-conditioning, manufacturing processes, or power generation by utilizing the evaporation of water to transfer heat. Therefore, water cooling towers consume significant amounts of water and the cooling system is often a building’s largest energy consumer.

In general, for water cooling towers, tap water, underground water and river water are the three sources of water used in the cooling process. The make-up water source is used to replenish water lost to evaporation.

In a recirculating cooling system, the concentration of mineral ions in water continuously increases due to water evaporation. For every CoC decrease in temperature across the tower, approximately 1% of the circulation water will be evaporated, thus increasing the dissolved solids content of water in the system. The equation for the water balance in a water cooling tower is below.

Makeup = Evaporation + Blowdown + Drift

Makeup: To maintain the cooling system in proper working order, all water leaving the system must be replaced. This incoming water is referred to as makeup.

Evaporation: Water that evaporates in the cooling tower and is rejected to the atmosphere as vapour. Evaporation provides the necessary cooling for the system.

Blowdown: When water evaporates from the system, the dissolved solids and minerals are left behind. Blowdown is water that is purposefully drained from the system to remove dissolved or suspended solids and prevent scale and corrosion problems in the cooling system.

Drift: A very small amount of water will escape the water cooling tower as mist or water droplets in the air, and is referred to as drift. Compared to evaporation or blowdown, water loss due to drift is insignificant but can be a factor at the highest levels of water conservation efforts.

These factors are the most neglected regimens of cooling systems operation with water cooling towers generally the most neglected component in the mechanical system. That’s why sustainable water treatment is the most important factor in the life and energy-efficient operation of evaporative cooling equipment.

Accumulation of foulants on the tower will inhibit the cooling efficiency of the tower and can reduce the energy efficiency of the overall cooling system by 5% or more. Therefore, water cooling towers should be periodically cleaned to ensure the tower fill media and heat transfer surfaces are free from scale, biological growth, corrosion, and particulate deposits.

There must be regular inspection of the tower on your maintenance log, and if your water treatment is unable to effectively control these issues, consider alternative treatment options that can do these functions automatically like SBR.

SBR is a fully automatic and green technology that continuously cleans the cooling tower water and augments the cooling performance without the use of chemicals. The energy-saving, chemical-free, low maintenance system combats scaling and corrosion using electrolysis.

This process provides a clean, eco-friendly alternative for keeping systems free from harmful fouling. The new generation system delivers an affordable, reliable, and safe alternative to chemical usage when you’re looking to improve the water and energy efficiency in water cooling towers.