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>> 1.5 gallons of fresh drinking water per hour for every square meter of solar collecting area. So a football field could collect around 8,000 gallons of wate

>> 1.5 gallons of fresh drinking water per hour for every square meter of solar collecting area. So a football field could collect around 8,000 gallons of water per hour. Let's say you can get 5 hours of good sunlight per day = 40,000 gallons of water. >> The team’s demonstration device can achieve an overall efficiency of 385 percent in converting the energy of sunlight into the energy of water evaporation. >> Theoretically, with more desalination stages and further optimization, such systems could reach overall efficiency levels as high as 700 or 800 percent So now we're looking at 80,000 gallons of water per day. >> Unlike some desalination systems, there is no accumulation of salt or concentrated brines to be disposed of. In a free-floating configuration, any salt that accumulates during the day would simply be carried back out at night through the wicking material and back into the seawater. >> In production, they think a system built to serve the needs of a family might be built for around $100.

numbsafari 7y ago
If I am reading [1] correctly, NYC needs approx. 1 billion gallons of water per day. So, they would need an array of 12,500 football fields to meet their needs. [1] https://data.cityofnewyork.us/Environment/Water-Consumption-In-The-New-York-City/ia2d-e54m https://data.cityofnewyork.us/Environment/Water-Consumption-...
- deleted 7y ago
  [deleted]
- zamalek 7y ago
  > 1 billion gallons of water per day * How much of that water need be drinkable? * How much of that water can be salinated (e.g. for flushing)? * How much of that water can be partially desalinated (e.g. for showering)?
  - ebg13 7y ago
    Indeed. If you do only the drinking water, 2L per person per day for 20 million people is only 10566000 gallons or 132 football fields.
    - MayeulC 7y ago
      And for those who wonder like I did, I counted around fifty of those on that page: https://www.nycgovparks.org/facilities/football https://www.nycgovparks.org/facilities/football
      - ebg13 7y ago
        Ok, but if you use those then you don't have anywhere to play. I think more importantly, 132 football fields is about the same as the total floor area of the Pentagon.
        taneq 7y ago
        Install the solar panels over the football fields as roofing.
        MayeulC 7y ago
        If you can afford it, and/or land/actually mounting the panels is the most expensive part, I'd recommend to install photovoltaic panels instead, though, as they are more versatile. And it would simplify plumbing a lot to put everything in the same place, vs pumping brine up many roofs, and water down again.
  - bluGill 7y ago
    This doesn't matter as NYC is built on a river that provides plenty of fresh water every year. It needs to be treated and filtered, but at much less cost than desalination.
    - sbierwagen 7y ago
      Describing the Hudson as drinkable is somewhat ahistorical: https://en.wikipedia.org/wiki/Pollution_of_the_Hudson_River https://en.wikipedia.org/wiki/Pollution_of_the_Hudson_River In any event, NYC gets its water from upstate, not locally: https://en.wikipedia.org/wiki/New_York_City_water_supply_system https://en.wikipedia.org/wiki/New_York_City_water_supply_sys...
      - e12e 7y ago
        Still, compared to space needed for desalination, it's not obvious that the current scheme uses less area (I do assume you can still do some things, like hiking, in most of this area though) : "One of its largest watershed protection programs is the Land Acquisition Program, under which the New York City Department of Environmental Protection (DEP) has purchased or protected, through conservation easement, over 130,000 acres (53,000 ha) since 1997"
  - numbsafari 7y ago
    I like your line of thinking, except now you would need to introduce two independent clean water sources, label things appropriately, retrofit all existing plumbing, etc. also, the salt in the water would be corrosive and require totally different infrastructure. In the end, I’m not sure if it wouldn’t just be easier to make sure that all the water is potable.
- numbsafari 7y ago
  Per the original comment about 5 sq mi: Based on this random article I found from 2015 [1], the average cost per build able sq ft in Manhattan was getting to $1200. So, if you magically found 5 sq miles in NYC, it’d cost around $167.3B just for the land [2]. I’m guessing you’d want to build it outside the city and pump it in via aqueduct. Following the article, an array of off-shore desalinated that pumped water back to the city would probably be the most economically viable solution and could probably be built with other kinds of offshore utility systems to try and share costs. [1] https://therealdeal.com/issues_articles/486631/ https://therealdeal.com/issues_articles/486631/ [2] https://www.wolframalpha.com/input/?i=%241200+per+square+ft+*+5+square+miles https://www.wolframalpha.com/input/?i=%241200+per+square+ft+...
  - gpm 7y ago
    New york city is 468.484 sq mi in size... so we're talking about covering 1 to 2% of it in these panels... I'm pretty sure that much roof space is available. Of course it probably makes more sense economically to do it offshore or just have a giant field somewhere outside of NYC and pump the water in, but you could find the space inside the city if you really wanted to.
    - shkkmo 7y ago
      I think you'd lose a bit of efficiency have to pump circulated seawater to the roof tops to not only provide water to desalinate, but also to flush out the accumulated brine overnight.
      - thombat 7y ago
        Those skyscrapers teem with occupants, each with a bladder, each one a source of saline. The spare water and power we use for growing cucumbers in the hydroponic gardens. The waste brine we use for picking those gherkins, which makes the ideal beer-time snack for those occupants as they re-fill their bladders...
- mateo411 7y ago
  Yes, but they get the majority of their water from the Catskills. Water is delivered using the force of gravity.
markdown 7y ago
> So a football field could collect... 40,000 gallons of water. How many swimming pools of water is that?
- miscPerson 7y ago
  40,000 gallons is approximately 150,000 L, while an Olympic pool is in the area of 1,000,000 L. So around 0.15 Olympic pools — roughly, a football field would fill an Olympic pool in a week.
valw 7y ago
And assuming a person needs 0.5 gallons (2 liters) of drinkable water per day, we get that 1 square meter provides drinkable water for 15 to 30 people. Not bad! Of course, once we factor in cleaning uses of unsalted water, the picture is less pretty. Still, not bad.

numbsafari 7y ago

If I am reading [1] correctly, NYC needs approx. 1 billion gallons of water per day. So, they would need an array of 12,500 football fields to meet their needs. [1] https://data.cityofnewyork.us/Environment/Water-Consumption-In-The-New-York-City/ia2d-e54m https://data.cityofnewyork.us/Environment/Water-Consumption-...

deleted 7y ago
[deleted]
zamalek 7y ago
> 1 billion gallons of water per day * How much of that water need be drinkable? * How much of that water can be salinated (e.g. for flushing)? * How much of that water can be partially desalinated (e.g. for showering)?
- ebg13 7y ago
  Indeed. If you do only the drinking water, 2L per person per day for 20 million people is only 10566000 gallons or 132 football fields.
  - MayeulC 7y ago
    And for those who wonder like I did, I counted around fifty of those on that page: https://www.nycgovparks.org/facilities/football https://www.nycgovparks.org/facilities/football
    - ebg13 7y ago
      Ok, but if you use those then you don't have anywhere to play. I think more importantly, 132 football fields is about the same as the total floor area of the Pentagon.
      - taneq 7y ago
        Install the solar panels over the football fields as roofing.
        MayeulC 7y ago
        If you can afford it, and/or land/actually mounting the panels is the most expensive part, I'd recommend to install photovoltaic panels instead, though, as they are more versatile. And it would simplify plumbing a lot to put everything in the same place, vs pumping brine up many roofs, and water down again.
- bluGill 7y ago
  This doesn't matter as NYC is built on a river that provides plenty of fresh water every year. It needs to be treated and filtered, but at much less cost than desalination.
  - sbierwagen 7y ago
    Describing the Hudson as drinkable is somewhat ahistorical: https://en.wikipedia.org/wiki/Pollution_of_the_Hudson_River https://en.wikipedia.org/wiki/Pollution_of_the_Hudson_River In any event, NYC gets its water from upstate, not locally: https://en.wikipedia.org/wiki/New_York_City_water_supply_system https://en.wikipedia.org/wiki/New_York_City_water_supply_sys...
    - e12e 7y ago
      Still, compared to space needed for desalination, it's not obvious that the current scheme uses less area (I do assume you can still do some things, like hiking, in most of this area though) : "One of its largest watershed protection programs is the Land Acquisition Program, under which the New York City Department of Environmental Protection (DEP) has purchased or protected, through conservation easement, over 130,000 acres (53,000 ha) since 1997"
- numbsafari 7y ago
  I like your line of thinking, except now you would need to introduce two independent clean water sources, label things appropriately, retrofit all existing plumbing, etc. also, the salt in the water would be corrosive and require totally different infrastructure. In the end, I’m not sure if it wouldn’t just be easier to make sure that all the water is potable.
numbsafari 7y ago
Per the original comment about 5 sq mi: Based on this random article I found from 2015 [1], the average cost per build able sq ft in Manhattan was getting to $1200. So, if you magically found 5 sq miles in NYC, it’d cost around $167.3B just for the land [2]. I’m guessing you’d want to build it outside the city and pump it in via aqueduct. Following the article, an array of off-shore desalinated that pumped water back to the city would probably be the most economically viable solution and could probably be built with other kinds of offshore utility systems to try and share costs. [1] https://therealdeal.com/issues_articles/486631/ https://therealdeal.com/issues_articles/486631/ [2] https://www.wolframalpha.com/input/?i=%241200+per+square+ft+*+5+square+miles https://www.wolframalpha.com/input/?i=%241200+per+square+ft+...
- gpm 7y ago
  New york city is 468.484 sq mi in size... so we're talking about covering 1 to 2% of it in these panels... I'm pretty sure that much roof space is available. Of course it probably makes more sense economically to do it offshore or just have a giant field somewhere outside of NYC and pump the water in, but you could find the space inside the city if you really wanted to.
  - shkkmo 7y ago
    I think you'd lose a bit of efficiency have to pump circulated seawater to the roof tops to not only provide water to desalinate, but also to flush out the accumulated brine overnight.
    - thombat 7y ago
      Those skyscrapers teem with occupants, each with a bladder, each one a source of saline. The spare water and power we use for growing cucumbers in the hydroponic gardens. The waste brine we use for picking those gherkins, which makes the ideal beer-time snack for those occupants as they re-fill their bladders...
mateo411 7y ago
Yes, but they get the majority of their water from the Catskills. Water is delivered using the force of gravity.

markdown 7y ago

> So a football field could collect... 40,000 gallons of water. How many swimming pools of water is that?

miscPerson 7y ago
40,000 gallons is approximately 150,000 L, while an Olympic pool is in the area of 1,000,000 L. So around 0.15 Olympic pools — roughly, a football field would fill an Olympic pool in a week.

valw 7y ago

And assuming a person needs 0.5 gallons (2 liters) of drinkable water per day, we get that 1 square meter provides drinkable water for 15 to 30 people. Not bad! Of course, once we factor in cleaning uses of unsalted water, the picture is less pretty. Still, not bad.