Reduce Water Usage, Eliminate Excess Waste

With this technology, manufacturers can expect water-friendly results that include:

• a closed-loop design that ensures the water is never exposed to outside elements for contamination or evaporation and never disposed of into groundwater;
• water returning from the process that is re-pumped into heat exchangers and cooled with ambient air flow, providing clean water at the right temperature year round; and
• advanced controls that ensure the most efficient use of water, even during extremely hot and cold weather conditions.

A closed-loop, dry-cooling system like the one shown here can provide up to a 98% reduction in process cooling water. For example, it uses only 20,000-40,000 gallons per year, compared to a 100-ton cooling tower’s annual use of up to 1.5 million gallons.

Besides its closed loop construction, this technology operates differently than other options because of what is called an adiabatic chamber. To maintain water below a set point in hot weather (85°F or above), outside air passes through the adiabatic chamber before reaching the heat exchanger. In this chamber, a fine mist of water is pulsed into the incoming air stream. The mist evaporates instantly, cooling the air before it impinges on the cooling coils that carry the process water; hence the term “dry-cooling.” This chamber drops the temperature to at, or below, the set point.

This fine mist, the only consumed water in the system, is only activated in temperatures over 85°F. Because of this, the system runs for much of the year without needing more water than it contains, using it over and over within the closed-loop process.

Intelligent Controls

An intelligent control system makes any necessary adjustments, seeking optimized equipment operation and conservation of resources. It takes into account real-time ambient temperature and continuously adjusts the system’s fan speed, adiabatic functions, free-cooling valve, and pumping stations, all without the need for an operator.

During colder months, in situations in which antifreeze is not acceptable, the system has a fully automatic, self-draining option that protects it from freezing. It also provides free cooling when used in conjunction with chiller water systems, which means the compressors turn off when the outside air temperature drops below a set point, and the system uses ambient temperatures to cool the process water.

Recent updates to this process have improved heat rejection through a redesigned and more efficient adiabatic chamber. The latest iteration features an enhanced, V-shaped adiabatic chamber that allows for greater, unrestricted airflow into the unit. This produces greater overall cooling capacity, better humidification of the air in the adiabatic chamber, and reduced air pressure within the cooling chamber.

As the food and beverage industry faces environmental challenges, rising sustainability objectives, and higher quality requirements, closed-loop dry-cooling systems may be the answer.

Fosco is industrial markets sales manager for Frigel North America, a global manufacturer of process cooling and temperature control equipment. Reach him at [email protected], or for more information, go to www.frigel.com/na.