Secrets of Reliable Ventilation

Want a powerful and energy efficient thermal management solution for a control cabinet? The answer, as Bob Dylan and others have noted, is blowing in the wind. And you can get the wind to blow the right way by using forced ventilation. The result will be cost savings and longer life for the enclosure and the components within it.

But, heed a word of warning: there are a lot of fans out there. Somebody will always offer a cheaper one. I’m all for saving money, but you need to be careful.

Here are guidelines to keep in mind to help make sure that an initially less costly fan doesn’t end up being more expensive in the long run. Let’s start with two basics.

First, know the flow. How much air do you need to move to get the enclosure to the target temperature? The answer depends on the heat generated by the enclosure equipment, how much of that is dissipated to the outside, and other factors.

Second, go with the flow. Make sure the right amount of air is flowing, given the fan, its placement, any filters, and other parameters. You need a safety margin when it comes to flow rate. Our ProClima software can help ensure you achieve both of these first two requirements.

A fan is more than a motor with blades. It has to be properly sized for the job, of course, and it should also be made of the right material and with the proper quality to last as long as needed. It should also have other features, like thermal protection to guard against overheating of internal circuits. For examples of the right way to do this, take a look at our ClimaSys family of ventilation fans.

Ok, we’ve got the right fan. Now we have to install it. That brings up other four other tips.

Bottom is better than top. In general, a fan installed at the bottom of an enclosure will last longer than one placed at the top. That’s because the air rising out of an enclosure will be up to 20^o C hotter than the air entering it. That temperature difference can cut the lifetime of the fan in half.

Filtration is a must. The size and density of dust in the air will determine the required minimum filter performance. Filters will have to be replaced, with a frequency that depends on the dust and pollutant load they face. Maintenance people will thank you if you keep this in mind when placing and sizing the filter.

Properly orient the fan. In other words, know which components need cooling. For instance, a fan should be within 10-15 centimeters of a variable speed drive because such drives can produce a lot of heat. The question of whether a fan should blow in or out of an enclosure is complicated and may depend on the enclosure and the components within it. Suppose you have an IP54, IP55 or equivalent environmental requirement. Then you don’t want to over- or under-pressurize an enclosure. Otherwise, you end up with problematic dust where you don’t want it.

Don’t make the fan work harder than necessary. You can extend the life of a fan – and reduce the frequency of filter changes – if you only run the fan when required. To do that, you need to measure the temperature and install a control element. The payoff can be a fan that lasts 50 percent longer.

Keep these secrets in mind and a fan will work. All you need is for the difference between the outside air and the target temperature is at least 5^o C. So, if the outside temperature is 30^o C and the target is 35^o C, then forced ventilation can be a good solution.

With the right fan, an energy efficient and powerful thermal management solution for a control enclosure can be a breeze. For more information about our ClimaSys CV solution, please click here.

Tags: ClimaSys, Enclosures, ProClima, thermal management, ventilation