When an Enclosure Air Conditioner is the Right Equipment Cooling Choice
Modern electrical enclosures are often not cooled by natural convection because of the extent of the heat produced by the equipment inside. While forced convection methods by cabinet fans and air-to-air heat exchangers are simple and economical, an enclosure air conditioner is the right equipment cooling choice for many scenarios. Here are some common cases when an enclosure air conditioner is the best choice.
High Heat Load
Moore’s prediction about the ever-increasing density of transistors on chips has increased the heat dissipation of Variable Frequency Drives. A 25 HP drive with an efficiency of 95% produces almost 1 kW of heat in the enclosure. Cabinet fans and air-to-air heat exchangers are ideally suited for low to moderate heat applications. Efficient cooling and temperature control in higher heat applications are provided only by enclosure air conditioners. Digital controllers in air conditioners are easily programmable and can be set at desired temperatures. Air conditioners with thermal expansion valves easily maintain the enclosure temperature at preset values regardless of the heat load variation in the enclosure.
Fluctuating Ambient Temperatures
Manufacturers design their electrical equipment for use over a certain temperature range. VFDs can operate at a maximum of 40 °C (104 °F) while most other electrical equipment such as switches and electrical batteries need to be operated at temperatures below 35 °C (95 °F). Above the maximum allowable temperature, the performance, reliability and lifespan of equipment gets halved for every 10 °C (18 °F) above 70 °F. In environments where the ambient temperature drifts to values above the maximum allowable temperature of the equipment, open loop cooling systems are not viable options. Enclosure air conditioners have closed loop cooling systems that cool the enclosure below ambient temperatures.
Outdoor Enclosures Subject to Solar Heat Gain
Outdoor enclosures may be exposed to direct incident radiation from the sun and high ambient temperature. The contribution to the overall heat load in the enclosure by solar heat gain and ambient temperature can be pretty dramatic. On an average day, the incident solar radiation can be as high as 10 to 18 W/ft2. Cabinet fans provide a constant convective heat transfer that is not responsive to solar time or external temperature. On the other hand, enclosure air conditioners with thermal expansion valves are capable of reacting immediately to heat load changes within the enclosure.
High Levels of Dust, Dirt and Pollutants in the Environment
In locations such as flour mills, cement processing plants, wood and paper mills where air pollution is a problem, it is prudent to isolate your valuable electrical equipment from the ambient air. Dust and dirt tend to settle on equipment surfaces and can cause their rapid deterioration and failure. For instance, electrical relays and switches have mechanical moving parts that are affected by dust and particulate matter. Not only do they inhibit their optimal performance but also they can cause short-circuits and fires. The ideal solution for cooling equipment in dusty locations is the use of a sealed enclosure with an enclosure air conditioner designed for use in dusty environments. Some manufacturers offer additional options such as extended filters and coated coils for use in highly polluted areas.
Enclosures in Humid Areas
Humidity and dispersed oils in the air can affect electrical equipment in a multitude of ways – pitting corrosion, moisture absorption by equipment, short-circuiting and premature aging. It is highly recommended that you use a sealed enclosure in humid areas to protect your equipment from moisture. Enclosure air conditioners are excellent solutions for enclosures located in humid environments. Equipped with efficient condensate management systems, they can not only dehumidify the air going inside the enclosure but also direct the condensate out of the enclosure by boiling it off.
Use in Hazardous Locations
Petrochemical plants and coal mines are notorious for their potentially hazardous environments. The presence of flammable substances in the ambient air increases the risk of fire and explosions. These applications require the use of a NEMA 4X sealed enclosure with enclosure air conditioners specially designed for hazardous duty.
Enclosure air conditioners find applications in many industries due to their efficient design, versatility, easy programmability, and remote monitoring. They can fulfill application requirements that cabinet fans and heat exchangers cannot.
If you are interested in knowing more about the use of enclosure air conditioners for your application, our expert sales team at Thermal Edge can assist you with sizing the AC and adding requirement-specific features.
