Since the device emits energy within a narrow range, perhaps it be possible to build a top-most layer that acts like an antenna for that range? Then you'd have

Since the device emits energy within a narrow range, perhaps it be possible to build a top-most layer that acts like an antenna for that range? Then you'd have a pump that absorbs heat from the environment, squeezes in into a narrow band, and emits it into a wire. Or, I suppose you could park a Stirling engine on it and generate power from the thermal gradient it must be producing.