Cooling Towers and Closed-Circuit Coolers are essential components of modern Commercial Air Conditioning Systems and Industrial Manufacturing/Process Cooling Systems. In Virginia, North Carolina, and other states with hot and humid summers, Cooling Towers, when paired with a Water–Cooled Chiller, Water Source Heat Pump, or a Process Condenser Loop, play a vital role in keeping a building comfortable for employees and customers and/or maintaining precise operational temperatures for your Manufacturing and/or Process equipment.
In this article, we will discuss the fundamentals of Cooling Towers and Closed Circuit Coolers, how they work, and best practices for proper maintenance.
Table of Contents
HOW DO COOLING TOWERS WORK?
Cooling Towers are typically the final step to rejecting heat from your HVAC system and/ or Process Equipment to the exterior of your building using fluid as a Heat Transfer Medium. Heat absorbed from the HVAC System or Industrial Process is injected into a Condenser Water Loop and transported through the Cooling Tower, where the heat is rejected to the air outside your facility through evaporation.
Cooling Towers use water, air, and a fill material medium to remove excess heat from indoor spaces. The Cooling Tower process starts with water circulation through the HVAC system. The heat exchange medium must have a large surface area. Metal or fiber-reinforced plastics are common choices.
Water is pumped into the Cooling Tower and sprayed through nozzles over the surface of the fill material. Dry air is moved rapidly across the same fill media by the Cooling Tower Fan(s). Forced evaporation occurs once the water contacts the heat transfer medium.
The evaporation of water causes heat to transfer from the water to the atmosphere. The cooled water is returned to the HVAC and/or Process System to absorb heat and start the cooling process again.
HOW DO CLOSED-CIRCUIT COOLERS WORK?
Closed-Circuit Coolers work much the same way that a Cooling Tower does. However, a Closed-Circuit Cooler does not open the water Loop to the atmosphere. This is advantageous in some systems susceptible to contaminants or particulates, requiring a specific pH or utilizing an anti-freezing agent like Propylene Glycol.
Closed Circuit Coolers, like Cooling towers, use water and air to remove excess heat from indoor spaces. The Closed-Circuit Cooler uses a Hydronic Coil as the “Heat Transfer Media”. This is typically a Galvanized Tube & Fin coil installed perpendicular to the forced stream of air in the Closed-Circuit Cooler.
The cooling process starts with water circulation through the Closed-Circuit Cooler’s Coil. Water is pumped from the Sump Basin in the Closed-Circuit Cooler and sprayed through nozzles over the coil’s surface. The Cooling Tower Fan(s) moves dry air rapidly across the same coil. Forced evaporation occurs once the water contacts the heat exchanger coil.
The evaporation of water causes heat to transfer from the water in the coil to the atmosphere. The cooled water is returned to the HVAC and/or Process System to absorb heat and start the cooling process again.
WHAT DOES PROPER MAINTENANCE LOOK LIKE?
Proper maintenance of your commercial HVAC Cooling Tower or Closed-Circuit Cooler is essential to ensure optimal performance, energy efficiency, and longevity of your machine. A preventative or routine maintenance plan for your Cooling Tower can prevent breakdowns, reduce repair costs, improve indoor air quality, and mitigate unforeseen production downtime.
REGULAR CLEANING
The amount of water that runs through a Cooling Tower or a Closed-Circuit Cooler makes them susceptible to damage from dirt and debris. Additionally, scale build-up from minerals, particularly calcium, potassium, and magnesium, creates an inefficient system. Therefore, regular cleaning of the heat transfer medium, basin, and nozzles are necessary to ensure efficient operation.
WATER TREATMENT AND TESTING
The water in Cooling Towers and Closed-Circuit Coolers can contain contaminants from bacteria, algae, and other impurities. Algae growth is exacerbated in humid conditions, as we experience in Virginia and North Carolina, causing rapid growth. Treating the water with biocides, algaecides, and corrosion inhibitors can prevent the development of harmful organisms and the build-up of scale in your system. Limiting these contaminants will improve the overall quality of the water that’s cycled through and help maintain the efficiency and integrity of your hydronic system.
INSPECTION AND REPAIR
Regular inspections are necessary to identify potential problems like leaks, damaged parts, and worn-out components. Fast repair of these issues can prevent additional problems while extending the Cooling Tower or Closed-Circuit Cooler’s life. It is beneficial to have a systematic maintenance plan, like our Care® Maintenance Plan.
UPGRADES AND RETROFITS
Over time, Cooling Towers or Closed-Circuit Coolers may need to be updated for improved efficiency. Upgrading or retrofitting your Cooling Tower or Closed-Circuit Cooler with new components or parts can improve performance and energy efficiency while reducing operating costs. Ask us how we can help lower your operating costs!
MONITORING AND RECORD-KEEPING
Monitoring the performance of your Cooling Tower or Closed-Circuit Cooler through sensors and data analytics can help identify trends, diagnose problems, and optimize operations. Record-keeping of maintenance activities, repairs, and upgrades can also provide valuable insights into the history of the Cooling Tower. These records will inform future maintenance and replacement decisions.
Cox-Powell has partnered with DST to house all elements of monitoring and record-keeping while being able to see real-time insights. See more:
Monitoring the performance of your Cooling Tower or Closed-Circuit Cooler through sensors and data analytics can help identify trends, diagnose problems, and optimize operations. Record-keeping of maintenance activities, repairs, and upgrades can also provide valuable insights into the history of the Cooling Tower. These records will inform future maintenance and replacement decisions.
In conclusion, Cooling Towers and Closed-Circuit Coolers are critical in controlling indoor HVAC temperatures in large commercial buildings or Industrial facilities. They use a combination of water, air, and a heat transfer medium to reject heat from the water loop to the atmosphere. With regular cleaning, water treatment, proper maintenance, and repairing or replacing components when necessary, your Cooling Towers or Closed-Circuit Coolers will help provide your facility with comfortable temperatures well past its life expectancy.
Cox-Powell has over 70 years of experience helping commercial and industrial clients with their Cooling Towers. Are you interested in hearing more about our Care Service Plans® for Cooling Towers or Closed-Circuit Coolers?
