ok THIS one i actually know, its my trade. those big evaporative cooling towers work by boiling off water on purpose — thats the whole trick, the phase change is what pulls the heat. so "closed loop" still evaporates, you gotta keep topping it up. a facility that size can boil off a few hundred thousand gallons on a hot day EASY. the only way to use less water is to use way more electricity for chillers instead. water or watts. theres no free version. i wire these fields for a living