I am just double checking an idea that I've always figured was true, but never really asked someone who knows about. In basically any machine that is not 100% efficient, the only "place" the lost energy (due to the inefficiency) can go is into its surroundings as heat energy, or radiation, correct? If this is so, how easily/effectively can radiation be contained and transferred back into heat energy? How is this done? (I assume just very reflective surfaces surrounding the thing that is emitting radiation) Thanks.