It’s not the heat, it’s the humidity, they say. And according to one company with a distinct take on air-conditioning challenges, buildings can cut cooling costs substantially by dealing with the humidity separately. A central air-conditioning system made by Advantix Systems, formerly an Israeli company but now based in Miami, removes moisture from air and cools it with a mixture that is 60 percent water and 40 percent salt. Humid air is pumped past the salty mixture and water from the air tends to flow into the salt. If the salt is chilled, the air will be cooled, too. Finding...