Actually this won't work. The condensers in a refrigerator are not meant to be operated constantly, they kick on and off. As soon as you put a heat source, i.e. a cpu, into your fridge, the condenser will go into constant draw. This will burn it out in approximately 1-3 days. You COULD however swap the condenser from something that is meant to have a constant draw like a window A/C unit. But even then, you'd have trouble keeping it cool effectively.