Comment by dredmorbius

The principle cooling mechanism is vapourisation.

The heat of vapourisation for water, converting liquid to steam, is 40.66 kJ/mol, or 2257 J/g. It takes a lot of energy to boil off water.[1]

That compares with the latent heat of liquid water, the energy required to heat one unit of water by one degree, which is 4.2 J/g*K (where K is the delta temperature in Kelvin).

Raising the temperature of input by, say, 10 degrees, would only reduce the cooling factor by less than 2%.

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Notes:

1. Which is why live steam is so dangerous. Steam condensing will release a huge amount of thermal energy, making steam burns especially harmful.