Cooling Tower Classifications
Cooling towers can range in size from fairly modest to extremely large, depending on the cooling loads of a facility. Several types of cooling towers exist, and they’re classified by:
- The direction of the airflow.
- The position of the fans.
- The use of mechanical fans.
Specific classifications include:
Draft Types
Cooling towers use natural or induced draft to provide convection for the system and move air throughout the tower. The most common draft types include:
- Mechanical draft: These towers operate via a fan located at the base or top of the unit. The former is referred to as a forced draft tower, while the latter is known as an induced draft tower. The forced draft version propels air through the water spill area and expels it through the opening at the top. Induced draft towers use the fan to draw air upward as warm condensed air spills downward. Since the air exits the tower at a high velocity, the air is far enough removed to prevent it from recirculating in the system.
- Natural draft: Unlike their mechanical draft counterparts, these cooling towers do not use fans to push air out of the tower. Instead, they rely on the principle of differing densities. The warm air within the tower’s chimney structure rises because its lower density draws the cooler air to the bottom. Natural draft towers tend to be taller and have a hyperbolic shape to produce adequate airflow.
Airflow Types
Airflow in a cooling tower refers to how the air moves through the system. The main airflow types include:
- Counterflow towers: A counterflow tower derives its name from the countering action of air flowing upward and water flowing downward. The result is excellent thermal efficiency due to the coolest air contacting the coolest water in the bottom of the unit and the large surface area of the spray volume produced. These towers typically have a smaller footprint, reduced pump head requirements and greater freeze resistance than crossflow versions.
- Crossflow towers: As the name implies, these towers facilitate horizontal airflow across the water as it falls to the bottom of the unit. The result is lower airflow resistance, which significantly reduces fan horsepower requirements. Other advantages include simple maintenance, smaller and efficient pumps and more variable water flow. Crossflow towers also include gravity-fed water decks with openings to allow water to fall through and spread across the tower fill below.
Air and Water Contact Types
Cooling towers differ in whether they allow contact between air and water. The main types include:
- Open loop: In an open loop design, the same water is used to cool and generate an evaporative cooling effect, which decreases the salt concentration in the water. The water is open to the atmosphere.
- Closed loop: The closed loop design does not expose the cooling water to the atmosphere. An external circuit uses cooling water as a spray to produce a cooling effect. An internal circuit transfers heat via heat exchangers. The advantages of a closed loop system include keeping the process fluids clean and separated and cooling fluids at a higher temperature.
Cooling Tower Service Procedures
When it comes to cooling tower water treatment, We handle them all and will tailor a maintenance program to meet your specific needs. We’ll work closely with your team to provide a cost-effective solution based on the type of cooling tower equipment you use at your facility. As an ISO-certified company, we can complete high-quality work that exceeds your expectations.
Due to its exposure to the outside environment, the cooling tower is the primary source of contamination within your system. Acting as a large air washer, the “open” tower water loop accumulates airborne particulate and promotes biological growth. Through evaporation, it also concentrates mineral content.
We utilize a full line of corrosion and scale inhibitors, white rust preventatives, and microbiological inhibitors to create a custom chemical plan that addresses these problems and others to keep your cooling towers running efficiently.
Because we don’t sell these cooling tower water treatment chemicals, we have a shared interest to keep your system’s operating costs as low as possible. We offer our services at an affordable, guaranteed annual price to fit your company’s budget. With our transparent pricing structure, you’ll never have to worry about hidden fees or add-on expenses driving up costs.
Chemicals
It’s at this phase of the process that chemicals are typically added to the water. These chemicals can include:
- Scale inhibitors– Inhibitors like phosphoric acid can prevent the formation of scale deposits
- Corrosion inhibitors– Inhibitors like bicarbonates are able to neutralize acidity within the water, which helps to protect any metal components
- Algaecides and biocide– Chemicals like bromine can lessen the growth of biofilms and microbes
If you perform extensive water treatment before reaching this phase of the water treatment process, it’s likely that you won’t need to use as many chemicals, which can save you a significant sum of money.