Comment Re:Oh good lord. (Score 1) 225
Heat is a waste product, efficient energy use doesn't necessitate heat.
Not sure if I'm feeding a troll now, but, yes it does. "Using" energy specifically means transforming it such that the entropy increases. The energy doesn't disappear, you can only change its form. And the form where it has the highest entropy (i.e. where you have extracted all useful work), is heat.
All a Dyson sphere does is exploiting the energy difference between its interior and its exterior. All the energy passes through it; the sphere just maximises the entropy as it passes through, in order to perform as much useful work as possible. If it emits anything other than pure black-body radiation, that means it has inefficiencies.