What Are the Best Methods for Cooling Electrical Enclosures?

Electrical enclosures contain components that naturally generate heat. That’s why electrical engineers must take care to select the most appropriate solutions for keeping the temperature in an acceptable range. The available processes take heat from an enclosure’s inside and transfer it to the outside, thereby ensuring the components stay within an acceptable temperature range.

Consider How Design Choices Combine for Best Results

When engineers work with metallic enclosures and back panels, thermal conduction can help transfer component heat into the backplane and the enclosure’s skin. This process makes heat generated inside an enclosure end up on the exterior. However, if the outside air is extremely hot, thermal conduction alone will not likely provide the desired temperature-reduction effects.

Another fundamental practice is to increase the enclosure’s size, thereby providing a larger surface area for heat exchange. Moreover, placing components most at risk of overheating near the enclosure’s bottom is a sensible design choice since warm air rises, pushing cooler air down.

Installing a fan system could promote evaporation or thermal conduction through air movement. Moreover, an engineer might use a venturi-style air cooling system that brings compressed air to the enclosure. This setup requires using a thermostat-controlled valve that moves compressed air through a venturi and relies on a one-way valve to send the internal air out the back of the enclosure.

Addressing excessive humidity in the enclosure’s environment is another effective solution. Humidity makes it easier for air to retain heat. Thus, lowering the humidity causes a cooling effect. The crucial thing to keep in mind is that it’s usually best to consider how various cooling methods work together to keep an enclosure at the desired temperature. Succeeding in your aims may mean starting with the enclosure itself, then doing things to affect the environment.

Understand What Impacts Enclosure Temperature

Selecting the most appropriate approach to cooling an enclosure also requires knowing about the potential factors that make heat levels rise. Statistics indicate that every temperature increase of 18 degrees Fahrenheit causes a 50% reduction in electronic component reliability. Maintaining an adequate temperature in an enclosure requires knowing what influences the associated warmth.

For example, an enclosure in direct sunlight will get hotter faster than one in a shady spot. Also, choosing a non-metallic container material or opting to paint the enclosure will cause better results than unfinished metal. Temperature problems could also arise if you do not use a dust-proof enclosure. Particles of dust insulate components so that they do not receive the full cooling effects of any methods used.

If the enclosure’s environment is less than about 130 degrees Fahrenheit, refrigeration systems could be effective cooling mechanisms. However, users must take care to filter the external air. When contaminants get into the enclosure, they could make the condenser section’s head pressures rise. If that occurs over a prolonged period, the conditions could cause a premature failure of that part. Additionally, all refrigeration systems need periodic maintenance.

Alternatively, if you want a passive cooling system that does need maintenance, heat pipes could provide the necessary thermal conductivity. Heat pipes can operate in an extremely broad -271 Celsius-2000 Celsius temperature range. That’s one reason why exceptionally demanding applications, like those associated with spacecraft, use them. Cooling systems used for electronics temperature control typically consist of a copper heat pipe inside a copper envelope.

Confirm a Client’s Needs Beyond Cooling

Cooling requirements are often only one entry on a client’s lengthy list of needs. For example, a person may need a cabinet made with a hygienic design in mind. If a food and beverage manufacturer needs an electrical enclosure, they may insist that it has an easy-to-clean design.

Most electrical enclosures not made with hygiene in mind have numerous areas that could trap dirt. The same could happen with recessed surfaces or those with non-rounded corners. Installing drain slopes for an enclosure helps water run off of it during cleaning.

Besides the design principles that support hygienic conditions, engineers must determine which cooling method works best in environments that receive frequent cleanings. An air/water heat exchanger is an often-chosen and clean choice. It’s also a cost-effective solution due to its low maintenance and reduced energy costs.

This example shows why engineers cannot look at cooling methods alone. They must also take the time to determine what other needs clients have. Doing that typically rules out particular cooling approaches. Then, engineers narrow their options while taking a holistic view of client needs.

Note the Electronic Components’ Specifications

When selecting the best cooling methods for enclosures, people must prioritize the sensitivity of the electronics inside. Fortunately, finding the right approach can go beyond making an educated assumption based on experience.

The National Electrical Manufacturers Association (NEMA) defines various grades for electrical enclosures associated with North America. Similarly, the International Electrotechnical Commission (IEC) has Ingress Protection (IP) ratings for enclosures, and Underwriters Laboratories (UL) publishes them, too.

Steve Sullivan, a training and development supervisor at Rittal North America, LLC, advised that electronic component specifications serve as starting points for selecting cooling methods.

He clarified, “Usually the specifications on these electronic devices will detail the cooling requirements and even the preferred enclosure type, in terms of protection ratings such as NEMA, UL, or IP.”

“In such cases, you need to gear the climate control to those specifications. And keep in mind that the enclosure and the cooling device will likely need to match in rating. For example, if you have a NEMA 4 enclosure and put a NEMA 12 filter fan on it, the panel would then de-rate to NEMA 12,” he continued.

Sullivan also brought up how fans are among the most common cooling methods for enclosures, but they only move the air. One option he cited for bringing the enclosure below ambient temperature was to put them indoors or in climatized containers. You could then rely on fans to move the nearby cool air into the enclosures.

No Single Best Method To Choose

This overview emphasizes that there is no universally superior option for cooling electrical enclosures. Selecting the most appropriate options requires assessing numerous factors, including the average environmental temperature, a component’s specifications and any necessities associated with a client’s industry. Taking the combination of influences into account helps prevent unexpected consequences and stop premature failure of temperature-sensitive parts.