I've used a computer fan controller, mounted in a 5 1/4" external drive box, to run a couple 12VDC fans. the controller has thermocouples that attach to the outputs or heatsink and ramp up the fans as the temp rises. The drive box has it's own 120VAC/12VDC power supply. The controller has a display to read temp etc. Find them on EBAY. Otherwise use 12 Volt fans and a 12VDC wall wart. for very quiet operation you can run the fans in series. If children with curious fingers won't be present remove the covers off of the outputs.