At my first job, the central computer system was inside a giant glass room that was refrigerated. That was a long time ago. The circuitry in computers gets hot and a small fan is enough to cool most personal computers. There are some high tech cooling systems you can buy and make, most of them have a heat exchanger recirculating fluid lines filled with glycol from inside the computer to a tank inside a small freezer. I've built one before. I don't know much about computers, but I know you don't want your circuits to overheat! I think the idea is you don't want to subject the circuits to any extreme temperature changes, so it's best to just keep it at steady cool temp.