3 ms·
This was brought up by someone else in another forum, but do the MIT desalination numbers make sense to anyone else? They claim that a box with a surface area
by SamBam 3y ago
This was brought up by someone else in another forum, but do the MIT desalination numbers make sense to anyone else?
They claim that a box with a surface area of about one square meter could desalinate 5 L of water per hour, using nothing but solar energy.
To evaporate one liter of energy of water takes 2.30 MJ, and that's assuming that it's already boiling point (the most efficient temp to evaporate). Solar energy maxes out at about 4.97 MJ per hour per square meter. That’s just a bit over 2 liters – and that’s assuming best case scenario and the sea water is at the boiling point.
So how is this box with 1 m^2 surface area gather enough sunlight to evaporate 5 L water per hour?
- mitthrowaway2 3y agoDisclaimer: I haven't looked into this at all. But on a first-principles basis, it should be possible as long as the desalination process recovers most of the evaporation energy during the condensation process.
- SamBam 3y agoThat could make sense. On that note, there are also desalination proposals out there that rely on heat pumps, where great is transferred from the condensing side to the evaporating side. (Obviously additional outside energy is required.)
- tomcam 3y agoGreat transferring is. Efficiency you must have.
- mycall 3y agoWhat if that box is put under pressure? Would that reduce the MJ necessary for the boiling point?
- SamBam 3y agoHow is the box coming under pressure without additional energy being introduced? If that energy is from the sun, then it's part of the same calculation. (And anyway, evaporation is faster under less pressure, but the same objections apply.)
- deleted 3y ago[deleted]