Air circulates naturally, this idea won't work at all for other reasons but your calculations are: 1) for the whole city when these things are usually intended

Air circulates naturally, this idea won't work at all for other reasons but your calculations are: 1) for the whole city when these things are usually intended for households (and cities have many miles of pipes anyway.) 2) without mention of the rate of water extraction or energy use per liter which is usually what makes these obviously useless.