That actually makes no sense. You can't use (destroy) energy, you can only run it through processor, which will change it into heat while transistors inside are switching on/off. It is like a water wheel doing work by water flowing through it, but ultimately amount of water before and behind water wheel is same.

Thus the question still stands, what happens to heat in such thing? Does it get recycled by some unknown device? Then it is closed system, you don't need input from outside. It won't get recycled? Then such device needs to get hot from dissipating that heat.