Engineered Plastic vs. Fiberglass Cooling Towers

Cooling towers are a vital part of HVAC systems in so many buildings: hospitals, schools, manufacturing plants, processing plants, and more. More than ever since the COVID-19 pandemic, it’s imperative to ensure that you have clean air circulating throughout the building and air conditioning that does its job when the weather outside is warm.

However, the construction materials used in your cooling towers matter quite a bit to help make maintenance easier and protect against constant repair and replacement. You also want to protect against harmful bacteria. Engineered plastic (HDPE) and fiberglass are two prevalent materials used today in cooling tower construction.

Read on to learn more about the options in cooling tower materials for your next project.

What Is a Cooling Tower?

A cooling tower works to help cool down a building, but it’s not quite an air conditioner but works instead on a different heat transfer type. A cooling tower removes heat from water through an evaporation process while water is recirculating through the unit. Warm water and cool air combine, and heat is released through vaporization. This cools the water, which is returned into the air conditioning equipment that cools the air.

The other application for cooling towers is cooling of manufacturing processing equipment. The process continues continually, keeping the air cool inside the building or the manufacturing process.

What Are the Different Types of Cooling Towers?

There are several different types of cooling towers, which may be adequate for different types of needs. For instance, a hotel or hospital may not require the same size tower as a large industrial plant. They are usually classified by the type of draft (airflow) or by the airflow direction.

  • Crossflow cooling towers have a horizontal airflow, and hot water flows downward. However, these are not the most efficient systems.
  • Counterflow cooling towers have air that moves up toward the counter-current while hot water flows downward. These are more efficient than their crossflow counterparts.
  • Natural draft cooling towers are the type used for large power plants and have a hyperbolic shape.
  • Mechanical draft cooling towers used forced air and have centrifugal or propeller fans. These are very reliable towers but require a lot of power to run and are costly.
  • Induced draft cooling towers have a fan on top of the cooling tower. They use 75% less energy than forced-air towers, so they are more efficient.
  • Forced draft cooling towers are similar to induced draft but are not as often used as challenges for water distribution and energy efficiency.

Cooling Towers: Plastic vs. Fiberglass

When it comes to cooling towers, the materials of construction used to matter very much. First, as a company, you don’t want a cooling tower that has a life expectancy of 15 years or less. Secondly, cooling towers are notoriously prone to Legionella bacteria, which is the cause of Legionnaires' disease, atypical pneumonia that is very serious and requires emergency care. However, with the right materials and upkeep, you have a far lesser chance of your towers growing Legionella.

Metal is a common building material when it comes to cooling towers, but it is not recommended. It can rust and corrode, it is prone to bacteria, and often, your tower may only have a life expectancy of 10-15 years. So, metal is to be avoided if it is at all possible.

Pultruded Fiberglass Reinforced Polyester (FRP) is another common material used for cooling towers today. Fiberglass cooling towers have some benefits over metal towers in corrosion resistance.

Fiberglass cooling towers are typically made with many panels that are gasketed together. The fiberglass can become brittle from UV exposure, making crack repair an issue.

However, it can be nearly as costly as stainless-steel towers. If buying FRP from overseas, you will very often receive degraded quality, which will decrease your tower's lifespan.

HDPE (high-density polyethylene) cooling towers are one of the better choices for materials of construction. This is an engineered plastic cooling tower that is highly resistant to corrosion and has a life expectancy of 20+ years. It is also a more efficient and economic choice, as HDPE reduces costs, maintenance, downtime, and water treatment chemicals.

Another advantage is the molding process allows for seamless construction so there are no joints that need welding ot gasketing to prevent leaks.

HDPE cooling towers are also easier to install, and being of a lighter weight, are much easier to install on rooftops for smaller applications, such as hospitals and schools.

Overall, when it comes to materials, HDPE is the better, more economical choice for cooling tower construction, and towers made with HDPE are highly efficient and environmentally friendly cooling towers.

To learn more about cooling towers or to request a quote, contact Delta Cooling today at 1(800)BUY-DELTA or send us an email at info@deltacooling.com.

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