Duke Leto wrote: Tell me more Mr. Kitty. It’s much better than balancing my checkbook!

Reduce the issue to lowest common denominators… the current multi-stage flash distillation process with its graduated stages of vacuum chambers, countercurrent heat exchangers and the myriad of pipes, pumps, valves and controls to make it all work… and contrast with the waste heat from an FF unit evaporating seawater straight up, without vacuum tricks, and condensing the steam on a nearby air-cooled surface.

No matter how sophisticated you make a real-life FF desalination unit the cost will be only a fraction of the cost of using current tech.