There do exist "evaporative coolers", sometimes called "swamp coolers". The trick is that they require water and raise the humidity of their surroundings. But they tick all the boxes you listed - plenty of delta-t, extremely low power, no external tubes or parts.
It's not magic because it relies on the "fuel" of cool water to evaporate.
It's not magic because it relies on the "fuel" of cool water to evaporate.