6 ms·
> 1.5 gallons of fresh drinking water per hour for every square meter 7 litres per m^2 per hour.
by eterevsky 5y ago
> 1.5 gallons of fresh drinking water per hour for every square meter
7 litres per m^2 per hour.
- vagrantJin 5y agoThank you.
- im__so__meta 5y ago5.78 liters per square meter actually, per the article.
- sdoering 5y agoSo in ideal conditions one could expect to provide about 12 to 15 people with drinking water per square meter. For me this is an impressive number. If I calculate one unit with 300 dollars this would mean 5.5 cents per person per day for one year for fresh drinking water. And after that only a little bit for maintenance probably.
- _0ffh 5y agoHmmm, yes it is. It's nearly too impressive! From the article "The team estimates that a system with a roughly 1-square-meter solar collecting area could meet the daily drinking water needs of one person.", which sounds very different. On this Q&A page [1] Zhang is quoted "Our current strategy, for example, is to use an assembly of 100 of these devices to achieve an area of 1 m2, which will increase the total production by 100 times to create 10-20 liters of clean water per day." I don't want to sound too negative, but something doesn't add up here. Still, enough water for one person per square meter of desalination plant is an impressive result I think. The oceans are big. [1] https://www.techbriefs.com/component/content/article/tb/features/qa/36379 https://www.techbriefs.com/component/content/article/tb/feat...
- hexane360 5y ago96.3 um/s! That's enough to drain a 6 foot deep swimming pool in 5.27 hours.
- sMarsIntruder 5y agoReally thanks for the conversion.
- I_complete_me 5y agoAssuming 1.5 US gallons, this converts to 5.678 litres.
- Jenk 5y agoNearly 2ml per second? (My faith in my own maths is weak ..)
- femto 5y agoA comparison with reverse osmosis: 2.46kWh/m^3 (energy consumed per unit of water produced) is claimed for reverse osmisis [1]. This equates to 8.86MJ/m^3. Output for this still is 7L/(m^2.h) Assume a solar flux of 1kW/m^2. Energy consumed per unit of water is 1kW/m^2 / [7L/(m^2.h)] = 3.6MJ/0.007m^3 = 514MJ/m^3. Assuming the above is correct (check anyone?), the still uses 58 times more energy than reverse osmosis. The solar energy may be "free" but with a 20% PV cell efficiency a reverse osmosis system would produce about 11 times more water per unit area of solar collector? [1] http://www.ijesd.org/papers/243-B20001.pdf http://www.ijesd.org/papers/243-B20001.pdf
- jeroenhd 5y ago> In production, they think a system built to serve the needs of a family might be built for around $100. I think this is much more important to a great many people than the theoretical efficiency of reverse osmosis. Percentages greater than 100% always do well in media reports about these topics, but they're not necessarily the point of the exercise. If the goal was to produce a system that's as efficient as possible, the researchers wouldn't have used household-style supplies but more expensive, advanced materials. Reverse osmosis is great for a central area such as a large city in a place with reliable distribution, but in many places around the world, an independent, affordable system that can turn seawater into drinking water for a family or two has much more value.
- londons_explore 5y agoNothing about reverse osmosis can't be scaled down in size or cost. The actual membranes are $9 for enough for 100 gallons per day (retail prices, [1]). High pressure pumps and hoses scale linearly. Solar panels scale linearly. Filters scale linearly. In fact, using this solar fountain [2] as the basis for the design, and switching the pump impeller for a high pressure version, and the nozzle for an RO membrane and hose, you immediately have a drinking water machine for a few people for $20. The fountain already has a pre-filter built in. [1]: https://www.aliexpress.com/item/32669709750.html https://www.aliexpress.com/item/32669709750.html [2]: https://www.aliexpress.com/item/1005002883892948.html https://www.aliexpress.com/item/1005002883892948.html
- midasuni 5y agoAmerican gallons are smaller than U.K. gallons.
- midasuni 5y agoAmerican gallons are smaller than U.K. gallons, which is where I suspect you got the 7l (6.8) from
- ghshephard 5y agoBack of the envelope - say that you could get 7-8 hours of sunlight a day that could destill water. That would mean ~50 liters/day. ~20 Days to get 1m^3. Reverse Osmosis costs approx $0.50/m^3 water, so your payback on a $100 system would be ~200 * 20 Days or 4,000 Days to equal what you could get for spending $100 on buying water from a reverse osmosis system. The objective here isn't large scale economics, but self sufficiency.
- MauranKilom 5y agoLooking at a 10+ year time frame, I feel that maintenance cost would become the dominating factor. For both.
- jillesvangurp 5y agoI think the difference here is that the materials used are cheap and easy to procure. That sounds like maintenance should be straightforward. The difference between producing water locally and shipping/trucking it in is probably huge in places without water pipes. A couple of gallons a day goes a long way. Scale it up a little and now you are irrigating your vegetable garden as well.
- ghshephard 5y agoThe Reverse osmosis cost estimate was based on a 10 year committed Hyflux Desalination commercial contract with the PUB in Singapore (from about 5 years ago, so might be less expensive now, actaully) - so includes maintenance costs. Regardless - this isn't a scale able solution, but doesn't need to be - should work fantastic for a small family with negligible environmental impact.
- mianos 5y agoThere are a lot of quite liveable islands that are deserted only due to lack of fresh water. This could change that.
- tonyhb 5y agoOr maybe we don't have to spread humans everywhere like a malignant cancer, leaving at least these Islands to nature.