In my experience, doing 3-6 reps is the sweet spot for this type of training. As this is done in a circuit fashion with incomplete rest, you'll be unable to perform the same loads as during traditional lifting sessions.
The water on your body changes to a gas called water vapor. Water turns into a gas through a process called evaporation. Heat makes water evaporate faster. All air has some water vapor. Tropical rain forests and deserts are both hot.
Evaporation happens when the liquid gets to its boiling point, for example the boiling point of water is 100 C. When the water gets to 100 C it cannot get any higher so the water evaporates. Which means that the liquid water has enough heat energy to leave its other particles.