I need a 12v 5A power supply for a heating element. I found out there are two main types of smps: first one is mounted in a metallic case and usually cooled by fan (in some websites it is called "industrial smps"), second type is similar to laptop charger without any fan. It seems for long-time usage e. g. weeks or months of supplying power, the actively cooled would be more efficient but I am not sure. On the other hand, since its case is perforated, using it in industrial sites will attract dust and particles in the circuit. And maybe there are other pros and cons which I am not aware. So which one should I use?
closed as too broad by Marcus Müller, DoxyLover, Edgar Brown, Finbarr, RoyC Feb 17 at 18:02
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the actively cooled would be more efficient
I disagree, since the actively cooled SMPS needs that extra cooling and the airflow from the fan it could be (and probably is) less efficient than the fully closed SMPS.
The fully closed SMPS does not have this extra cooling. Assuming both SMPSs are well designed the closed SMPS needs to be more efficient as it cannot dissipate as much heat as the SMPS with the fan.
The increased effciency can be achieved by using a better design and/or better components which will very likely make the closed SMPS a little more expensive. However, a fan also costs money so in the end their prices could be quite similar.
As commented, a fan can fail and dust is an issue. Such a cooled supply does need some maintenance every now and then. I make it a habit of blowing out the dust at least once a year for my server which has an actively cooled SMPS.
The closed SMPS will still get warm so you have to give it some "breathing space". In my experience the closed SMPSs from reputable brands are very reliable and do not run very hot. My choice would be the closed SMPS!