Wastewater treatment facilities and chemical processing plants are known to be highly corrosive environments. The presence of chlorine or hydrogen sulfide gas in these locations creates a toxic atmosphere that can quickly deteriorate sensitive electronic components, forcing frequent repairs, expensive replacements, and unscheduled downtime. When cooling electrical equipment in corrosive locations, one should take extra care to select a solution that can stand up to the harsh airborne contaminants.
Here are 3 frequently asked questions to consider when cooling electrical enclosures in corrosive environments.
The reason cooling is of special concern in wastewater treatment plants and chemical facilities is due to the presence of corrosive gas in the atmosphere. Airborne corrosives generally cannot be removed by standard filtration methods, which precludes using forced convection cooling devices such as filter fans and blowers. While there are scrubbing techniques that can rid ambient air of corrosives, they can be complex, costly, and sometimes ineffective. For these enclosure cooling applications, sensitive electronic components require isolation from corrosive substances and airborne contaminants.
In most corrosive environments, the best thermal management solution is closed-loop cooling. By circulating cool, clean air within an electrical enclosure (and through heat-producing elements), closed-loop cooling systems help protect sensitive electronic components and prolong their lifespan.
Closed-loop cooling products, such as enclosure air conditioners or heat exchangers, consist of two separate circulation systems in a single cooling unit. One system recirculates clean cooling air throughout the sealed enclosure, while the other discharges the heat removed from the cabinet via either ambient air or water. If the corrosive atmosphere is within an acceptable temperature range, air-to-air heat exchangers can provide ample cooling for the enclosure. When high ambient temperatures and corrosives are present, an air conditioner or a water-to-air heat exchanger must be employed to cool the heat-sensitive components. Regardless of the cooling device chosen, it must be constructed of appropriate corrosion-resistant materials, or treated with corrosive-resistant coatings, to ensure long, trouble-free operation.
3. What NEMA ratings are advisable in corrosive atmospheres?
In wastewater treatment applications, corrosive chlorine and/or hydrogen sulfide gasses may be present and both are particularly troublesome for exposed copper tubing if left uncoated. NEMA 4X cooling units, such as GuardianX Series Air Conditioners, have stainless steel shells and the proper coil protection for corrosive environments. These cooling units also utilize a closed-loop system to prevent contaminants from entering the enclosure.
The main factor in determining whether to use a NEMA 4X air conditioner or heat exchanger is the temperature that must be maintained within the enclosure. A heat exchanger will keep the internal cabinet temperature at or above ambient, while an air conditioner can bring the temperature below ambient.
The actual performance varies with the cooling capacity of the unit selected; therefore, a sizing & selection guide may help determine which cooling system is best for a particular application. Additionally, it is important to review all of the conditions involved, as a thermal management system can usually be designed or customized to meet specific requirements.
To learn more about enclosure cooling solutions for corrosive environments or other locations, contact the experts at Kooltronic.
