I needed a way to hide my Home Server and my UPS (Uninterruptible Power Supply) away in a cabinet, for aesthetic and organisational reasons. I do live in Florida, however, and was concerned about the summer heat affecting my components - sealed up in a wooden box.
So, I added some ventilation and some extra bits and bobs. Here goes...
1 x Dark wooden cabinet (purchased from Target - relatively cheaply)
4 x Swivel castors
2 x 90mm USB powered fans
1 x 120mm USB powered fans
1 x USB Hub with switches on each port
1 x Top Mounted USB port/cable run
Thanks to the flimsy nature of the backing to the cabinet, I was able to easily cut out 2 x 90mm holes and 1 x 120 mm hole - screwing the fans into place using the supplied mounting screws. I added a drop or two of superglue on the 120mm fan to hold it in place. My rationale for the fan placement is thus; cool air likes to hover about the floor, so my big 120mm fan is the intake. Hot air loves to be on top, so my 2 x 90mm fans are my exhaust. Make sense?
Unfortunately, there's a shelf in between the bottom fans and the top - so I cut an air duct through it to act as a conduit for the hot air. Added bonus of being able to thread cables between the top half and the bottom half.
I stuck my USB Hub on to the side of the box and plugged my fans directly into this. The Hub, in turn, connects to my server. This means that if my server isn't running, the fans won't run - wasting energy. I also use it to power an LED light strip so I can find things inside the cabinet.
It's been running flawlessly for over a year - there's a very noticeable increase in temperature inside the cabinet if I turn the fans off for any length of time, especially in summer. Success!