7 Reasons Electrical Enclosure Cooling Is Necessary
The use of electrical enclosure cooling systems has grown exponentially in the last few decades. Reasons for this growth include higher cabinet heat loads and the use of more sophisticated electrical drives and equipment. Concurrently, there has been a desire to reduce costs and this has led to the placement of electrical enclosures closer to the plant and equipment, thus exposing these enclosures to harsher environments.
History of Enclosure Cooling
Traditionally, electrical enclosures were naturally ventilated and it was relatively rare to even see fan-assisted cooling. Inevitably, many enclosures operated at elevated temperatures, but prevailing attitudes were that this was acceptable. These views slowly changed as PLCs, variable speed drives, and similar equipment became more common and maintenance staff began to experience output variability, nuisance tripping, and the unexpected failure of electrical equipment.
The reasons were eventually linked to high enclosure temperatures, and this gradually led to the widespread application of enclosure cooling systems. Initially, interest focused on the use of cooling fans but, as it became apparent that fans were of limited benefit in higher ambient temperatures or dusty environments, enclosure designers began to specify enclosure air conditioning.
Here are seven important reasons why enclosure cooling has become so necessary.
Reasons for Enclosure Cooling
Although there are many factors why enclosure cooling is specified, some are related to unique, site-specific needs. However, the most consistent and common reasons are:
- Control maximum enclosure temperature: Unlike traditional electro-mechanical components, power electronic devices such as variable speed drives have relatively low maximum operating temperatures. Few devices can be used above 120 °F, and there are many drives that are limited to 105 °F. Yet summer temperatures in U.S. can exceed 105 °F, and many areas get pretty close to 120 °F.
- Keep out dirt and debris: Enclosures need to be sealed against the entry of dirt, dust, and fibers that coat surfaces and cause contamination and temperature rise. This precludes the use of natural ventilation or fans and enclosure cooling with an air conditioner, air to water heat exchanger or air to air heat exchanger is required.
- Prevent entry of corrosive vapors: Similarly, corrosive vapors and gases need to be excluded as they damage and corrode copper components. This is especially an issue in coastal areas.
- Prevent water entry: In food manufacturing, equipment needs to be frequently washed down and enclosures must be sealed to resist high pressure water sprays.
- Extend component life: It’s a well-known fact that the life of electrical equipment is halved for every 20 °F increase in temperature. VFDs, PLCs, and similar equipment usually have relatively low maximum operating temperatures and operating such equipment close to or above its design temperature reduces equipment life.
- Prevent malfunction due to overheating: PLCs, industrial controllers, and drives are designed to operate within tight parameters. If allowed to operate above their recommended temperature, output variability that affects device stability leading to equipment malfunction can be expected.
- Remove excessive heat: The heat load of modern electrical enclosures is much higher than in the past. In part, this is due to the proliferation of electronic drives that generate a substantial amount of heat. For example, a 50 horsepower drive generates nearly 1,500 watts of heat that has to be removed from the enclosure.
Enclosure Cooling Improves Reliability
Although specifying enclosure cooling adds to the initial cost of an electrical enclosure, long term operational costs are likely to be significantly lower because the equipment inside the enclosure will be operating at a temperature that’s within the manufacturer’s specifications. This will enhance reliability and reduce the incidence of premature failure.
If you want to better understand why enclosure cooling is necessary, contact Thermal Edge’s technical experts who will demonstrate how enclosure cooling can reduce your costs.