4 ms·
> Why can't it cool down more than ambient air? You put in X amount of power, and you get out 2X amount of power as light -- therefore additional energy is bein
by khafra 14y ago
> Why can't it cool down more than ambient air? You put in X amount of power, and you get out 2X amount of power as light -- therefore additional energy is being taken in as heat and converted to light.
Light is a more highly ordered form of energy than thermal noise; it can be used to do work. If you could convert thermal noise into light and beam it away, you could use that as the cool side for a heat engine and have a perpetual motion machine.
- Cushman 14y ago> If you could convert thermal noise into light and beam it away, you could use that as the cool side for a heat engine and have a perpetual motion machine. By "beam it away", I assume you mean into space or somewhere else you don't care about heat being. In this case, the cold side of the device isn't the real cold sink, it's just a proxy for the several million cubic lightyears of background-temperature near vacuum which will eventually wind up absorbing the light. Aliens on a distant planet may be able to extract power from the light; bully for them, but I already had to pay extra for shipping, so there's no funny business going on. What makes you think that violates thermodynamics? (For what it's worth, "perpetual motion machines" are not outlawed by classical thermodynamics, only those which do additional work. There's nothing in theory which prevents you hooking up a 100% efficient emitter and a 100% efficient receptor up with superconducting wire and letting it run forever, so long as you don't extract any energy from the cycle, for example by observing that it is taking place. There may be something in quantum physics which states that such a system would have to leak information about itself somehow, but I don't know enough to say.)