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drun3 t1_j1zgz3p wrote

Reply to comment by tucci007 in Ventilating Entertainment Center by GrnMtnTrees

I’ve always been taught to install enclosure fans blowing into the cabinet with the idea that you’re slightly pressurizing it and therefore dust isn’t being drawn into it through the seams. Genuinely curious what the reason you’ve heard for the opposite?

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shoziku t1_j1zs5mx wrote

Just using normal physics. You can't add cold, you can only remove heat. Exhaust fans work with this principle and not against it.

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furlongperfortnight t1_j20lpo3 wrote

Adding cold air however is a breeze.

Both positive and negative pressure systems work, and both have their own advantages.

In OP's case i'd go for a balanced system: two low speed 200mm fans, one intake one exhaust, both with filters (to keep pressure balanced).

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drun3 t1_j22kfo8 wrote

Either way you’re just getting airflow from the outside, so the cooling capacity is basically the same. The airflow patterns will be different inside the box of course, but either way you’re just exchanging air

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tucci007 t1_j201qdh wrote

where were you taught this? to remove the heat you want to suck it out of there, not keep it in; and you want to draw in cool air at the same time, so you get a circular flow of cool in from the bottom, and warm out at the top, also heat rises so it's a natural flow assisted by the exhaust fans; dust will be blown in by the fans in your scheme, much more than any drawn in 'at the seams', which won't happen since air will be drawn in the holes drilled at the bottom.

if dust is a concern put some thin cloth over the intake holes and remember to vacuum them occasionally

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drun3 t1_j22jf2o wrote

We do this at NREL for plc enclosures installed outdoors specifically. We always have a fan on one side and a louver on the opposite (both with filters), so the airflow is basically the same whether your fan is pointed in or out.

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