Desalination system could produce freshwater that is cheaper than tap water::A new solar desalination system takes in saltwater and heats it with natural sunlight. The system flushes out accumulated salt, so replacement parts aren’t needed often, meaning the system could potentially produce drinking water that is cheaper than tap water.
Evaporating water and condensing it has been done. We don’t use this method for desalination since it is more energy intensive (read expensive) than reverse osmosis, which itself is also quite energy intensive.
Their solution uses the sun, so…
To produce systems energy would be needed too, and all “green” solutions have terrible EROI sometimes even negative, so… this solution have economically better alternatives that already in use