Comment by card_zero

Not if it produces less heat than it converts, the rest being lost as ... ah, wait a minute. Well anyway it would only produce as much heat as it converts, so this perpetual cycle couldn't do any useful work. Perpetual useless motion is allowed, isn't it?

Oh, I see it now, you're suggesting that it could just passively create a gradient that could produce power in a more conventional way, like via an engine, until I guess the device kicks in again and re-establishes the gradient (producing more power of its own in the process). Yes. That does sound like impossible free energy.