The Future of Desalination

If one has enough power, then one can do anything.

Reverse Osmosis can produce a precursor to potable water from seawater at around 3.8kWh/tonne; it doesn't matter where that power comes from.

Well we need to keep searching for the cheapest and most sustainable ways of producing fresh water, it's not a problem that is likely to go away...This should I think be handled on a case by case basis, what works the best in one area might not be the best choice in another...so a portfolio of methods is needed, and each should be improved over time....I think solar distillation still has a lot of potential that needs to be explored, after all that is what drives the Earth's fresh water cycle...Nuclear as a source of heat should be cheap if properly addressed and managed....

I have had experience with wire-guided vehicles that used wires and magnets embedded in the concrete floor to mark key points in the navigation.The driving wheel generated pulses to determine position,and the magnets were used to compensate for any accumulated errors,such as debris coating the wheels,slippage,etc.The magnets also were used to mark intersections by having a pattern of north-south seeking reed switches or hall effect sensors.The reed switches were more reliable in the long term.

The system was very robust by design.The magnets and reed switches were very durable.The only problem was vibration affecting the terminals of the on-board electronic connection terminals.This was corrected by putting a drop of Glyptol on each screw head.This also provided security to prevent tampering.

Instructions were sent wirelessly to each vehicle,and a handshake signal was used to maintain connection integrity.

These problems occurred during the acceptance stage,and were solved before being put to task,very few problems afterwards.

The price of power will determine the <...cheapest...>. RO benefits from significant power savings when a pressure exchanger is in the equipment in service, however it is difficult to get much below 3.8kWh/tonne on seawater->potable.

Evaporation, using low-grade heat from the engines of ocean-going vessels that would otherwise be wasted, has been used as a method of producing a precursor to potable water for many decades.

The principal issue with processing any water source, to potable, is the re-hardening of the water afterwards. Getting Ca⁺⁺ above 60ppm is the challenge, otherwise the water remains unpalatable and of reduced benefit to health.

Re-hardening units, typically containing crushed calcium carbonate, need to be recharged at intervals according to consumption, and the calcium has to come from somewhere. Like, a quarry, for example.

All this is established technology.

Yip. And then the small matter of getting rid of the leftover brine, specifically if the water source is a contained one without continuous replenishment or circulation to diffuse the brine.

Would it improve the performance of the desalination dome if the glass segments were focused lenses to concentrate the sunlight striking the surface of the dome;perhaps Fresnel lenses with the focal point on the surface of the liquid?

The top of the dome could also be concave,or funnel shaped to aid in collection of the condensate.

Perhaps floating the dome on the surface of the water would make pumping the water unnecessary.

I would think algal growth in the dome would be a problem, or maybe it's too hot, but certainly some type of growth, bacterial or fungal....maybe a hydrophobic coating on the interior surface would help, the exterior too for that matter...certainly the design of the dome has so many possibilities to increase efficiency...maybe robotic sucker fish to clean the algae off, possibly a byproduct...

Desalination by country - Wikipedia