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So if you want a liter, you have to supply 20 watts. For how long? Forever? Does the water instantly become turbid when power is removed?
Tsk, tsk, MIT. I would have thought an MIT journo would know what a watt is.
Edit: I wrote out the comment below criticizing the efficiency of this device, when compared to reverse osmosis RO desalination (100x less efficient). However, they’re not trying to be more efficient than RO devices, they’re trying to be more compact, portable, and avoid the need for filters. They’re solving for a different problem than I was measuring them against. In my race to criticize, I overlooked those key det…
The article says they can get 1 liter for every 20 watts. So that'd give them 17,597 ounces per kWh.
> requires only 20 watts of power per liter. So if you want a liter, you have to supply 20 watts. For how long? Forever? Does the water instantly become turbid when power is removed? Tsk, tsk, MIT. I would have thought an MIT journo would know what a watt is.
Not great phrasing I agree but the information is there.
> requires only 20 watts of power per liter. So if you want a liter, you have to supply 20 watts. For how long? Forever? Does the water instantly become turbid when power is removed? Tsk, tsk, MIT. I would have thought an MIT journo would know what a watt is.
> Their prototype generates drinking water at a rate of 0.3 liters per hour, and requires only 20 watts of power per liter. Not great phrasing I agree but the information is there.
Watts is a measure of power, not energy. The amount of power (given they use a pump and electrodialysis) shouldn't depend on the volume. Energy OTOH does.
So either their device requires 20W of power - which sounds reasonable as the image shows a Or the author left out crucial context (e.g. is the power draw correlated with the speed, i.e. 20W @ 0.3l/h).
The amount of energy would be 67Wh/l regardless given those numbers. It's just a confused mix of performance (processed volume per hour) and power requirements (which is independent of volume and should only depend on the performance).
Southern California is beginning to see more water restrictions - each and every desalination tech advancement is a very hopeful development for the region, and many others in the world that can't get enough freshwater. I hope they can generally work this up to factory scale and put it behind a solar farm and see if that can supply a lot of homes.
The problem is that southern California is trying to grow a shit-ton of crops that aren't suitable for the environment there. The almond industry is particularly guilty in this regard. Desalination will never scale to a level suitable to supply that industry. If anything they'll take that water and just grow even more crops, while still sucking the aquifer dry. Thing is, aquifers compact when you draw water from them…
Are you sure about that? It's simply a question of economics. As long fresh water from other sources is significantly cheaper, no one's going to invest in large scale desalination.
Once this changes it becomes a question of which is more expensive - shutting down the agribusiness or running large scale desalination (which has options, from nuclear to solar to the use of metamaterials).
Anyone else notice in the beach video that the researcher filled the cup using tubing that was previously on the ground, then drank it? Looks cool though :)
I guess if I dropped a drinking straw on the ground in an e.g. parking lot, I'd throw it away, but if I dropped it on sand in the beach, I would think "just wipe the sand off and it's clean!"
From the article: The limitations appear to be expensive materials and scale. 20w per liter .3 liters per hour
The article claims 3x more efficiency in a confusing sentence: ”Their prototype generates drinking water at a rate of 0.3 liters per hour, and requires only 20 watts of power per liter.” So the unit only produces 0.3 liters an hour but if you wait 3 hours and provide 20 watts of power (7watts/hour), you’ll have a full liter.
That doesn't make any sense. 20W of power draw over 3⅓ hours is ≈67Wh (Watthours, not Watts per hour), so 67Wh per litre (energy use; independent of time) and it takes 3⅓ hours to get this litre of potable water with 20W of power.
In other words to get 1 litre in an hour, the device might require ≈67W of power (assuming that kind of perfect scaling is even possible with their design).
Amazing! Is this a game changer?
Might be useful for certain niche applications, but outside of that it's more of a proof of concept at this point.
So how is this distinguished from existing commercially available continuous electrodeionization?