Cooling towers are readily identified by their ubiquitous presence in large commercial cooling systems. They are an effective means of rejecting heat from a centralized liquid system.
Cooling towers are vital in maintaining optimal temperatures for machinery and processes. By using the principle of evaporative cooling, they also help save energy and reduce operational costs. The applicability of cooling towers is extensive, making them fundamentally useful for industrial operations in power generation, oil refining, petrochemical plants, commercial or industrial HVAC systems, and process cooling. This post discusses the advantages, operating principles and applications of cooling towers.
What Is a Cooling Tower?
A cooling tower helps remove heat from buildings or industrial processes by transferring it to the atmosphere. It uses water to absorb the heat and then release that heat into the air via evaporation. As the warm water comes into contact with cooler air, some of the water evaporates, taking away the heat and cooling the rest of the water. This cooled water can then be recirculated back into the system to absorb more heat.
Cooling towers are commonly seen as large structures with fans on top of them. They are often found in industrial facilities, power plants and commercial buildings.
How Does a Cooling Tower Work?
An evaporative cooling tower involves the movement of a fluid, usually water with some added chemicals, through a series of parts or sections to eventually result in the reduction of its heat content and temperature.
Here are the operating principles of a cooling tower:
Water circulation: Liquid heated by the process operation is pumped through pipes to reach the cooling tower.
Heat exchange: The hot liquid gets sprayed through nozzles or other distribution means onto fill material inside the tower, reducing its velocity to increase the fluid dwell time in the fill area. This maximizes the contact surface area between the water and air.
Evaporation: Electric motor-driven fans force air into the tower and across the fill area. As air passes across the liquid surface, a portion of the water evaporates, transferring heat from the water to the air and reducing the water’s temperature.
Cooling effect: The cooled water is then collected and pumped back to the process-related equipment, allowing for the cooling cycle to repeat.
Heat dissipation: The heat absorbed by the water is released into the atmosphere as the evaporated water vapor rises and disperses, effectively removing heat from the system.
Cooling towers come in various types, each with its own design and functionality:
Evaporative: Evaporative cooling towers rely on outdoor air conditions being such that evaporation will occur at a rate sufficient to transfer the excess heat contained in the water solution. Analysis of the range of outdoor air conditions at the installation site is necessary to assure proper operation of the cooling tower throughout the year. Evaporative cooling towers are of an open loop design, with the fluid exposed to air.
Closed loop: A closed loop cooling tower, sometimes referred to as a fluid cooler, does not directly expose the heat transfer fluid to the air. The heat exchanger can take many forms, but a finned coil is common. A closed loop system will generally be less efficient than an open loop design because only sensible heat is recovered from the fluid in the closed loop system. A closed loop fluid cooler can be advantageous for smaller heat loads, or in facilities without sufficient technical staff to monitor or maintain operation of an evaporative cooling tower.
Crossflow: In crossflow cooling towers, air moves horizontally across the downward flow of water.
Counterflow: Counterflow towers have air moving vertically upwards against the downward flow of water.
Hybrid: Hybrid cooling towers combine features of both crossflow and counterflow designs to optimize performance and energy efficiency, offering a balance between these two traditional types.
What Are the Applications for Cooling Towers?
Some common uses of a cooling tower include:
Heat removal
Air conditioning
Power generation
Environmental control
Thanks to their range of applications, cooling towers vary in size, from the monolithic structures used in industrial areas to small rooftop units. Removing the heat from the water used in cooling systems allows for the recycling of the heat transfer fluid back to the process or equipment that is generating heat. This cycle of heat transfer enables heat-generating processes to remain stable and secure.
The cooling provided by an evaporative tower allows for the amount of supply water to be vastly lower than the amount which would be otherwise needed.
Some industries that use cooling towers include:
Power plant: Cooling towers help cool circulating water used in condensers in power generation facilities.
Industrial: Chemical processing, oil refineries, steel mills and manufacturing plants use cooling towers to maintain optimal temperatures for equipment and processes.
HVAC: Commercial buildings, hospitals, schools and hotels use cooling towers for air conditioning systems to regulate indoor temperatures efficiently.
Data: Cooling towers help dissipate the heat generated by servers and IT equipment in data centers, preventing overheating and ensuring continuous operation.
Food and beverage: Food processing plants use cooling towers to cool equipment, ingredients and products during production processes.
Plastics: Injection molding and extrusion processes in the plastics industry often require cooling towers to maintain consistent temperatures for quality control.
Advantages of a Plastic Cooling Tower
Cooling towers help reduce energy consumption compared to other cooling methods. They are cost-effective in the long run due to lower maintenance and operational costs, plus they aid in water conservation and reduce environmental impact by using evaporative cooling.
In particular, plastic cooling towers offer significant advantages:
Corrosion proof: Cooling towers made of high-density polyethylene (HDPE) are resistant to rust, flaking and peeling, eliminating the need for protective coatings. They offer long-term corrosion protection advantages over metal towers.
Seamless construction:Some manufacturers provide seamless engineered plastic cooling towers with a one-piece shell for better performance and integrity, eliminating the need for fasteners, panels, rivets and seams.
Lighter in weight: Plastic cooling towers tend to be up to 50% lighter than steel towers of similar capacity, thereby reducing installation costs and making them suitable for various placements.
Longer warranty: Unlike metallic cooling towers, those made of HDPE typically come with longer warranties — up to 20 years — ensuring durability and reliability.
Lower maintenance: HDPE cooling towers require less maintenance due to their corrosion-proof construction material.
Find Corrosion-Free Cooling Towers From MSEC
Selecting a cooling tower is an involved process that requires examination and analysis of many facets. Whether customers need small or large cooling towers, the components must function as an integrated system to ensure both adequate performance and longevity. It’s best for customers to share their heat transfer requirements and challenges with cooling tower specialists to find an effective solution.
MSEC is a leading cooling tower product distributor and service provider committed to serving customers with lasting solutions that resolve unique heat transfer equipment challenges. In addition to their portfolio of corrosion-free packaged cooling towers, MSEC also offers customized solutions.
