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MIT invents $4 solar desalination device
- baxtr 4y ago> The device worked for a week straight with no signs of salt accumulation, but we still don’t know exactly how long it could operate. Let’s maybe run it for a couple more weeks before we talk about it again?
- deleted 4y ago[deleted]
- autoexec 4y agodepending on how much clean water you get out of it in a single week it might still be worth it at $4 a pop even if it doesn't last much longer.
- political12345 4y agonot really: if average life is 2 weeks that means you need $100 per year for devices. Somalia gdp per capita is $500 (not taking PPP aince these will likely be imported). So 20% of anual income is quite high
- nonrandomstring 4y agoIt could save the lives of many people in a sudden water shortage until tankers arrive.
- autoexec 4y agoTech like this could even help some people in the US if their water becomes undrinkable for long periods of time due to some natural disaster or flint-like shenanigans.
- zwirbl 4y agoWhich ignores that it is 4$ per prototype and it works for longer than 1 week already
- tekknik 4y agofrom the article: “If it does prove durable, it could be a relatively cheap way to get freshwater to people in need of it.” The engineers are unsure of how long it will last and if it’s actually cost effective, yet there’s many HN comments here that seem to suggest they know better. Where are you getting your information that the rest of us are not privy to?
- cyberlurker 4y ago$4 for 4 people too.
- autoexec 4y agoThe economics might not work well for everybody. Although international aid might ease some of the burden it may turn out to not be a good fit for Somalia, but it might be helpful for others. As drought and desertification worsens, even parts of the western US and Mexico might find some benefit in something like this.
- tlamponi 4y agoIt's for a family of four though, so 5% of annual income on average, meaning for 50% of people it's still worse. I'd also think that the GDP doesn't factor in international aid, so 25$ per year for the poorest could be still better than the current alternative (no idea on what that is, though).
- DoingIsLearning 4y agoI don't get what is the expected failure here? Can't salt accomulation be flushed away? I think for example reverse osmosis machine also have to constantly flush filtration debris away from the main membrane to maintain efficiency.
- AstralStorm 4y agoThat is one of the reasons big scale RO is impractical for desalination compared to upcoming redox tech. Not only is it slow, energy intensive, but also you'd always be running at reduced capacity. In indistrial usage, a lot of the salt is removed before hitting RO filter. That said, it exists right now and is well tested.
- pbhjpbhj 4y agoHarvest the salt too, bonus!
- thematrixturtle 4y ago$204/year is approximately equal to the average GDP per capita for Burundi.
- avierax 4y agoIt may cost $4 in the economy where the study was conducted, it may end up costing more in less developed regions.
- eurasiantiger 4y agoClean water and sanitation access in Burundi is rapidly improving thanks to many international aid programmes, so perhaps this invention is not needed there—the country is bordered by freshwater lakes, after all. Your point still stands, but the $4 wouldn’t be paid by end users: it would likely be covered by these organisations, which would then be able to provide aid for a much larger population.
- Tepix 4y agoIdeally it would be cheap enough that they can afford it themselves without having to rely on aid programmes.
- wildmanx 4y agoAnd how sustainable is that solution?
- eurasiantiger 4y agoMore sustainable than having a growing population depend on surface water and open air defecation.
- wildmanx 4y agoThat's not an answer to my question. I meant, how sustainable is it to keep depending on foreign aid? Obviously dirty surface water that does not suffice for the whole population is not sustainable. But in the long run, creating new dependencies on aid can't be the solution. Any long-term plan that involves foreign aid is a bad plan.
- HWR_14 4y agoIt says it supplies 4x the amount of water a person needs (it supports a family of four). So, $1/person/week if it fails after a week and is not cleanable or fails because of a part that could be replaced
- oxfordmale 4y ago..and can it be mass produced at a reasonable cost. Scaling up a lab build product to an industrial scaled production line is a skilled profession. Not all products can make this transition.
- salty_biscuits 4y agoFresh water cost $1 per cubic metre. The availability of fresh drinking water in some countries is a political problem not a technological one.
- PakG1 4y agoDecentralizing technology has a history of enabling the disenfranchised to get what they couldn't get before. This could enable that. Admittedly, technology also has a history of enabling tyranny. But that doesn't make it untrue that technology has an ability to enable the disenfranchised to make better lives for themselves either.
- hackerlight 4y agoThat's the point. Devices like this are a way for people to be able to make their own fresh drinking water without needing a functioning state around them.
- salty_biscuits 4y agoThis is a good point but a sad situation. Without a functional state there are many other problems as well.
- doctor_eval 4y agoNone of which will be solved while the people on the ground are dying of dehydration.
- Adiqq 4y agoEven with functional state, lack of access to clean water might be new risk due to climate changes and general world instability. What if, prices of clean water will rise due to some events? Today we have energy crisis in Europe and who would expect 5 or 10 years ago that situation will go that bad, that rationing of energy will be considered? There are already some predictions that water scarcity problem will get worse, so it's very good that there are already prototypes that might provide cheap conversion of salt water to clean water. Future seems to be about minimizing costs and decentralization, so we can better sustain all people and save environment.
- teraflop 4y agoPrevious discussions: https://news.ycombinator.com/item?id=30342778 https://news.ycombinator.com/item?id=30342778 (10 comments) https://news.ycombinator.com/item?id=30503013 https://news.ycombinator.com/item?id=30503013 (24 comments)
- hntossaway 4y agoMaybe I'm crazy but does MIT get a disproportionate number of features on HN? For one of thousands of institutions in the US let alone the world, they're not the only ones inventing things. I feel like there's at least one MIT adjacent post in the top 5 each time I log on and it doesn't feel like a coincidence.
- Glawen 4y agoNow think about what is happening in the non English speaking world which get no news at all and what do you think happens with them.
- michaelscott 4y agoThis is such a good point, my mind has recently been opened to how much happens in the Spanish, French and Russian speaking parts of the world that I had no idea about because it just isn't in English. Does anyone know of resources that are HN-like or could be used to fill in the gaps on interesting developments in non-English countries/regions?
- nextstepguy 4y agoFour posts with NIT in the title as we speak. I never noticed.
- assusdan 4y agoThere is russian-speaking community https://habr.com/ https://habr.com/ which I found to be similar to HN (but less business-oriented). However, I do not know any easy way to exclude all translated from english-speaking sites articles and news to read only local ones.
- throwaway290 4y agoKeep in mind that posting translations of English articles, especially uncredited, is easy karma for Russian (and adjacent) native speakers who also know English.
- danw1979 4y agoMIT could pony up the $4 it would allegedly cost to build the family-sized device and demo it, proving it’s longevity, if it’s that simple ? All I’m seeing here is a petri dish sized experiment wrapped in a press release.
- akira2501 4y agoThose who can, do. Those who can't, advertise.
- O__________O 4y agoPublic Relations (PR) is not advertising.
- t-3 4y agoWhat is it then? I would class intentional communication with the public for the purposes of inculcating a positive association with your organization as advertising, and so would most people I know.
- O__________O 4y agoSimple Google would tell you more than I could and confirm this is common industry knowledge: https://www.google.com/search?q=advertising+vs+public+relations https://www.google.com/search?q=advertising+vs+public+relati...
- t-3 4y agoThose definitions are all just semantics, there's no real difference highlighted other than business specialties of advertising and PR firms.
- O__________O 4y agoThen you should be able to hire one to do the others job, which I assure you won’t work out well. If you have something notable and specific to add, please feel free to do so, otherwise you’re opinions are not backed by actually reasoning, and as a result, impossible to respond to with reasoning.
- t-3 4y ago
- bismuthcrystal 4y agoI'm almost not even bothering to read MIT links anymore... To anyone interested in a cheap method that actually works, search for OTEC.
- acatton 4y agoThis reads like a twitter thread :(
- vultour 4y ago> Researchers from MIT and China’s Shanghai Jiao Tong University have now created... Funny editorialising you did there.
- thematrixturtle 4y agoDon't blame the OP, the blog title is exactly as posted in the original source.
- yyy888sss 4y agoModern desalination plants produce at less than $1 per cubic meter, thats $0.001 per litre...
- once_inc 4y agoTrue, but those aren't readily available in Africa, and come with a significant amount of red tape. A DIY 4$ desalination solution is a boon to anyone close to the sea.
- O__________O 4y ago— Related official MIT press release: https://news.mit.edu/2022/solar-desalination-system-inexpensive-0214 https://news.mit.edu/2022/solar-desalination-system-inexpens... — Related research paper: http://doi.org/10.1038/s41467-022-28457-8 http://doi.org/10.1038/s41467-022-28457-8 — PDF of research paper: https://www.nature.com/articles/s41467-022-28457-8.pdf https://www.nature.com/articles/s41467-022-28457-8.pdf
- AnthonBerg 4y agoThank you! I would very much appreciate it if Hacker News could conveniently replace these newsbite-extracted-from-university-press-release-about-a-paper links with the paper itself as the main focus and then the university press release as supplementary material. As it is, this is a game of Chinese whispers, and it’s a subtle infohazard. To begin with the university press release tends to subtly misunderstand the paper and misrepresent it and its context. For instance there is a tendency for the PR team to claim that the results are unprecedented and hitherto unknown, simply because the PR team isn’t a field expert and doesn’t know that they don’t know what is known. (Let alone the impact of PR incentives.) Then the aggregator-newsbite-feed site misunderstands and misrepresents further.
- O__________O 4y agoWhile I agree having the best source is better, which is in my experience is better is random; sources including: press releases, press, paper, demo, Twitter, YouTube, etc. In my opinion, defaulting to only one would be bad idea; better to just review them and if needed on case by case basis email the mods to make a change it needed. I do think having a fields for “official source” or “notable coverage” might be a good idea, since it’s common to have a better non-official source or review an independent notable coverage — and dumping that into the comments in my opinion takes away from the core value of the comments.
- Zenst 4y agoI'd claim prior art upon this but just glad sanity prevailing.
- einpoklum 4y agoI didn't understand how the process works. When the denser, saltier water moves down, why doesn't salt accrue in the intermediate layer? Also, what happens to the "regular" salt water on the bottom? Does it get evicted? Or does the middle layer gradually float up?
- jt2190 4y agoSee these comments for links to better descriptions: https://news.ycombinator.com/item?id=32329545 https://news.ycombinator.com/item?id=32329545 The description in the Freethink article is incomplete.
- torstenvl 4y agoPut a bowl inside a larger bowl (elevated by a rock or something). Pour salt water into the larger bowl. Put cling wrap over the whole thing. Put a pebble in the middle of the cling wrap. Set in the sun.
- belter 4y agoYou forgot the last step, make a press release about a new MIT invention.
- scoopertrooper 4y agoThat's where the $4 come from.
- belter 4y agoIf they used a cloud service and rendered some PDF's this might be net negative...
- sp332 4y agoThat doesn't sound like it would meet the drinking water needs of a family of four, but the one in the article does.
- lopis 4y agoI don't know man, the article doesn't seem to be a device, more like a method, and their only example was a tiny tiny vial. I can't tell how big the device for a family of 4 would be. The man in this video [0] claims to be able to collect 10 liters of water in a day. His simple facility is less than 2 square meters but easily scalable. [0] https://www.youtube.com/watch?v=dIPSqszu8qg https://www.youtube.com/watch?v=dIPSqszu8qg
- edm0nd 4y agoThey just need a bowl 4x the size then :D
- 4y ago
- ketzu 4y agoWhenever this comes up, I mostly get annnoyed of 2 very different mentions of 4$: > it can be made from just $4 worth of materials. > it would cost just $4 to build These are not the same thing. Also I lack context of the cost of other desalination techniques and life spans of each.
- jvanderbot 4y agoThe article they "summarize" is much better: https://news.mit.edu/2022/solar-desalination-system-inexpensive-0214 https://news.mit.edu/2022/solar-desalination-system-inexpens...
- photochemsyn 4y agoHere's the open-access report and the summary figure: https://www.nature.com/articles/s41467-022-28457-8#Fig1 https://www.nature.com/articles/s41467-022-28457-8#Fig1 It does look like an optimal growth chamber for salt-tolerant and heat-tolerant microalgae, (i.e. biofouling is likely) but maybe wrapping the whole thing in aluminum foil will block enough light to keep growth levels relatively low.
- soliton4 4y agonot only drinkingwater may be the outcome of this theoretical $4 device. one obsticle to produce cheap hydrogen is that one can not just apply electrolysis to salt water. and many areas with lots of sunlight have limited freshwater to split into its atomic compounds. i am thinking large scale solar in the sahara, used for electrolysis of mediteranian and atlantic sea water
- randito 4y agoHere's a great comment for how it innovates on solar still principles: https://hackaday.com/2022/06/06/this-4-desalination-device-provides-drinking-water-for-the-whole-family/#comment-6481379 https://hackaday.com/2022/06/06/this-4-desalination-device-p...
- datacruncher01 4y agoLooking at the design, I believe they should also be able to generate electricity from the setup. They have salty water with an insulated spacer to retain heat on the evaporation layer to make it more effective in removing water. This in turn is creating a saltier layer of water that diffuses into the lower layer via holes in the spacer. That means there is a salinity gradient between the top most layer and the bottom layer which should have an electric potential. Neat.
- pradn 4y agoI don't mind that MIT has a great reputation and a great PR team. It's okay to put out new ideas and inventions that may not pan out. But the breathless coverage of their work by news organizations, little more than rephrasing press releases, that's what irks me. They also suck the oxygen out of the space for other science coverage, as if there's not good work being done at dozens of other institutions around the world.
- itsoktocry 4y ago>But the breathless coverage of their work by news organizations, little more than rephrasing press releases, that's what irks me How else would stories like this reach the hoi-polloi, if not for media covering their press releases? >They also suck the oxygen out of the space for other science coverage Media is not scarce. I've never even heard of Free Think.
- pradn 4y agoI criticize not science/engineering journalism itself, but uncritical regurgitation of press releases and overly focusing on some institutions. Website space is infinite but space on the front page is not, and space on newsfeeds is not.
- cvccvroomvroom 4y agoUh, what's the point? You can make a massively more efficient survival desalination device using less materials by making a solar distiller. Maybe $2 for a piece of plastic and 2 buckets. Edit: I don't know if this would be the most useful way to provide water at scale. Dumping small water contraptions on a poor country may not be as sustainable or as efficient as investing in long term water systems.
- speby 4y agoThis is interesting, at least. The 1-week 'test' so far is certainly a bit premature to declare success. Let's also not forget about the need to sterilize the water further, thru boiling, or reverse osmosis, or whatever else, in order to eliminate bacteria, viruses, etc.
- gardenfelder 4y agoLess colorful version: https://news.mit.edu/2022/solar-desalination-system-inexpensive-0214 https://news.mit.edu/2022/solar-desalination-system-inexpens...