Eli5: How hot would water have to be for it to be vapor coming out of the tap?
In: Physics
For water to be hot enough inside the pipe under pressure and become steam when it exits into an environment with normal pressure, it would need to have a temperature of 641°C.
If it already was steam inside the pipe, lower temperatures would be enough. The exact temperature depends on the pressure difference between inside and outside the pipe. If there was no pressure difference, 100°C would be enough.
Explanation:
Water needs to absorb 2260 Joule per gram to transition from “Water at 100°C” to “Steam at 100°C”. Water also needs 4.18 J per gram to increase by 1°C in temperature. If you prevent water from turning into steam with pressure, those 2260 Joule would be enough to heat it up by 541°C.
However, there is one little caveat. 641°C is right in the range where water cannot be a liquid anymore. You’re getting some weird super-critical fluid that is neither and both steam and water. You also need a really sturdy pipe to get there, we’re talking about pressures way above 220 bar/3200psi.
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