[fatnoah]

> I don't think they are boiling it. It read to me like they're just evaporating the water in some efficient way, rather than boiling

There are definitely efficiencies to be had, though I don't know enough of the math to judge one vs. the other. During my brief patent career, I wrote the patents for a distillation system where the main elements involved heating water that was distributed across rotating blades (heat + surface area + air movement) to evaporate the water. When the water was collected, it passed through a heat exchanger that exchanged heat with the in-flowing water. The result was a very efficient system on a small scale, at least.

[genewitch]

the swamp cooler panel seems more durable than rotating blades, maybe*. If i were going to desal it'd be with solar; which seems inefficient but one could precipitate "CO2" out of the water as calcium carbonate during the same process. Emergency water supply for tropical weather aftermath, during the quiet season park upstream from a coral reef that's in danger.

*edit: although window and wall unit HVAC use the blades to fling water around so the condenser gets the coolest possible air