from Hacker News

The Water Abundance XPrize winner makes water from air

by sandyshankar on 10/25/18, 2:36 PM with 128 comments

  • by mchannon on 10/25/18, 5:08 PM

    Pretty disappointed with their choice of winner. Using refrigeration to maintain a dewpoint means that this appliance is pretty impractical below 50% relative humidity.

    Or in other words, this thing only makes water when you probably don't need water.

    Blow some nice 90 deg F 20% humid air past those coils, and you'll be blowing out a lot of 80 deg F 25% humid air out on the other side, getting bupkis for actual produced water, but sucking down plenty of juice. Slow down your intake fan to almost zero, and now your water produced goes up from zero, but the slowest of trickles.

    Gotta love all that ozone generator carbon filter garbage on the business end. It's all just bells and whistles to put lipstick on a three-legged pig.

  • by petermcneeley on 10/25/18, 4:39 PM

    I actually had a discussion on this subject with Phil Mason aka Thunderfoot who has a Phd in chemistry and is the creator of the video that is critical of this announcement ( https://www.youtube.com/watch?v=e3s-xI895zc )

    The discussion was about how much work is actually required to condense the water vapor. The fact is that it is thermodynamically possible to MOVE more heat energy (Q) than work (W) applied. The efficiency of heat movement is dependent on temperature gradient but is more than 100% efficient. So as bizarre as this sounds it actually requires effectively zero work to condense water from the air at 100% humidity.

  • by joshe on 10/25/18, 4:40 PM

    I don't know why this is attracting so much bitterness.

    If anyone is informed about water, it would be great to get a little more context, for example what other solutions like desalinization and other dehumidifiers cost in energy and dollars. (Yes, obviously nothing is going to be as cheap as putting a pipe in a river.)

    For example their FAQ says they use less than half the power of their competitors. That seems like a huge advance. And is $.02/liter amazing or just slightly better?

  • by ortusdux on 10/25/18, 3:46 PM

    Here is the website for one of the winners: http://www.skysource.org/

    From what I can glean online, the 150 gal/day unit costs $18k usd + $150-$300 in electricity a month if run 24/7 at $0.10Kwh. Ignoring electrical costs, it would take 1581 days to reach $0.02/liter. In that time you would use up $7.5-15k in electricity.

    The best estimate I could find is that the average US household uses 240 gal a day.

    A friend of mine had to drill a 980 ft well through bedrock. A well this deep requires a much stronger pump and more electricity. They are on their 2nd pump. I should ask them what that all cost.

  • by extrapickles on 10/25/18, 8:21 PM

    It looks like the winner is a standard dehumidifier bolted to a standard biomass generator that has a condenser from a high efficiency furnace bolted on to it.

    So the only "magic" they are doing is also capturing the water vapor from the generators combustion. While somewhat novel in combining it all, its all off the shelf tech.

    What I don't like is the lack of good hard numbers in its performance in a range of conditions as snake oil is extremely common in the water from air industry.

  • by nyrulez on 10/25/18, 3:26 PM

    I'm a bit irked that a technology of this significance has no videos or demos or actual use cases, just a PR blurb. Is it confidentiality, or is it too early stage? Otherwise X Prize becomes another congratulatory event. This feeling seems to run through the entire site as I click around.

  • by CompelTechnic on 10/25/18, 3:22 PM

    Does anyone have any details about their actual technical implementation? I'm sure it is interesting.

    I imagine it doesn't look too similar to a Tatooine moisture farm.

  • by travisoneill1 on 10/25/18, 3:50 PM

    2 cents a liter is not close to feasible for any sort of agricultural or industrial use and is an order of magnitude more expensive than residential tap water. Seems like cool tech, but I can't see how this is a solution to any type of water shortage.

  • by joshe on 10/25/18, 8:39 PM

    If it all works this would be useful. (Contary to all the negative comments about how pointless this is.)

    Not a water expert, but here's where this reported price ranks from some googling:

      Tap water in California:     $.0005 / liter [1]
  XPrize winner:               $.02 / liter
  Water truck delivery in CA:  $.01 - $.05 / liter [2]
  Desalination:                $.05 - $.30 / liter [3]
  Wholesale bottled water:     $.30 / liter [4]
  Walmart bottled water:       $.68 / liter  [5]
    If $.02/liter is right, this is close to the water truck in pricing. Also it seems like you could ship this with solar to disaster areas instead of flats and flats of bottled water and be up to 15 times cheaper. It could be an alternative to desalinization near the ocean where there is lots of humidity at 2 to 15 times expense. This seems useful.

    Tap water is awesome, btw. It's 100 times cheaper than all these options.

    [1] $.002 per gallon from https://www.wsj.com/articles/my-california-water-is-an-undil...

    [2] $200 for 5000 gallons to $500 for 2500 gallons for water truck delivery in California https://www.cnbc.com/2015/04/08/californias-four-year-drough...

    [3] https://www.quora.com/How-much-does-a-water-desalination-pla...

    [4] $1.22 per gallon from https://slate.com/business/2013/07/cost-of-bottled-water-vs-...

    [5] $.02 per fl oz from https://www.walmart.com/tp/bottled-water

  • by comesee on 10/25/18, 5:36 PM

    I don't get it, why don't poor communities build piping from their nearby water sources? People were able to do this 2000 years ago. Why do they need to invent a reverse-entropy machine?

  • by yourapostasy on 10/25/18, 7:11 PM

    When I looked into conventional dehumidifiers and air conditioners, what stopped me from systemically re-using air conditioner condensate even as gray water was finding out that it can contain trace amounts of heavy metals and industrial oils from the condensate going through less-than-ideal materials used for the coils and evaporator parts. Also, if you live in an area with air pollution, the condensate contains concentrates of the pollution, as well as allergens and biological contaminants. I'm hoping someone reading this might have looked into it more than I have, and can point me to some reading material that can help me either further work through or dismiss those concerns.

    When I read through the article, I didn't see any links to potability test results. So there might be a purification step after this gasifier powered water generator to turn the output of this into truly potable water, so the cost won't really be below two cents per liter in the field. Purification itself is an energy-intensive endeavor, whether to create purification materials or straight use of energy in more active systems, and is why potable water is a rough order-of-magnitude proxy for energy.

  • by 08-15 on 10/25/18, 4:38 PM

    "Skywater is an ideal solution for [...] Cooling Tower water recovery"

    Hilarious. If it was possible to recondense the evaporated water and somehow reject the heat to the air, there wouldn't be a cooling tower!

    Thunderfoot is right, it's a scam: https://www.youtube.com/watch?v=e3s-xI895zc

  • by beauzero on 10/25/18, 3:47 PM

    Good video on how we see an Adiabatic Cooling process drop moisture in nature. https://www.youtube.com/watch?v=XH_M4jItiKw edit: I personally didn't know what "adiabatic" meant.

  • by apo on 10/25/18, 6:05 PM

    Here's some background on alternative approaches:

    https://cen.acs.org/environment/water/stripping-air-moisture...

  • by foofoo55 on 10/25/18, 6:52 PM

    Articles all state "from air" but half the system uses pyrolysis (high heat to gasify without flame) to extract water from biomass.

    See also comments on slashdot from someone claiming to be from All Power Labs, the gasifier supplier:

    https://science.slashdot.org/story/18/10/22/079250/a-device-...

  • by VBprogrammer on 10/25/18, 4:03 PM

    I might be way off base here but is that Jim Mason - Founder of All Power Labs? In that case it hints that gasification could be part of the solution.

  • by carapace on 10/25/18, 9:04 PM

  • by foxhop on 10/25/18, 8:30 PM

    Another way: plant trees in the desert and form oasis. "Watch greening the desert" on Youtube. Basically trees cause rain.

  • by Avery3R on 10/25/18, 8:08 PM

    This website is like the perfect example of that "the web in 2018" post that was made a few days ago.

  • by peter_d_sherman on 10/25/18, 9:36 PM

    Will this work in a desert?

  • by luckydata on 10/25/18, 7:46 PM

    Now we just need the sandworms.

    Edit: not a big Frank Herbert crowd I see.

  • by post_break on 10/25/18, 3:23 PM

    Is this another one of those dehumidifier machines that promises it can deliver gallons when using a tarp, rope, and a bucket to catch rain water collects more water per year?

  • by corodra on 10/25/18, 4:03 PM

    It’s an overpriced dehumidifier. Pulling humidity out of the air. It’s not magic. It’s not new. There is water vapor in the air, every middle schooler knows this.

    They are in Hawaii. An outdoor dehumidifier will work great in a water abundant area. How well do you think a dehumidifier will work in a low humidity area? The places that need water the most. It’s not making water, it’s pulling out the humidity.

    This is such a scam.

    I feel like I’m taking crazy pills. All these “smart” folks gave up 1.5mil and there are tech folks here nodding their heads because it’s xprize. Y’all turned off your thinking just because it’s xprize.

    Say you want to help 3rd world poor and it gives you magic armor from logic apparently.

  • by rdiddly on 10/25/18, 3:45 PM

    Remove moisture from the air on any significant scale, and you're depriving someone else of rain, downwind. It's another finite resource. Unforeseen consequences abound.

    You know, there are places where water falls out of the air on its own, and if you don't spoil the hell out of the landscape you can even drink it. Give it a rest, humans.