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Show HN: Open-source atmospheric water generator – first lab reports

62 points by clayrichardson 11y ago

clayrichardson 11y ago
Hey everyone, I'm around for a bit to answer any questions you might have :)
- jat850 11y ago
  How does it taste? :) And what plans do you have for tackling the pH and turbidity level issues? edit Missed the note on turbidity. I'm guessing a follow-up test might show that resolved?
  - clayrichardson 11y ago
    It tastes surprisingly good, although not as good as some of the Ozarka bottled spring water I've had, but almost. We're going to try and find another remineralization filter, or we might add electrolyte mix instead. The second lab report was from the isolation of the remineralization filter, and we showed that the turbidity was indeed added by that filter.
    - jat850 11y ago
      That's great! I had missed the test0 procedure text, but it did seem clear after reading it.
- zzalpha 11y ago
  So... this is basically a dehumidifier. Dehumidifiers typically use some sort of air cooling to reduce water below the dew point to draw water out of the air. And that takes a lot of energy. So what is the purpose of this device? It can't be to provide potable water to areas without it, since those same areas are likely to lack a significant source of power. I don't mean to be overly cynical, but I feel like I'm missing something here.
  - exhilaration 11y ago
    https://en.wikipedia.org/wiki/Atmospheric_water_generator https://en.wikipedia.org/wiki/Atmospheric_water_generator I thought the same thing but reading their site led me to the above Wikipedia page which suggests there are other ways to do it than just dehumidification but I'm not sure what method they're using.
    - clayrichardson 11y ago
      For simplicity and adoption, we're utilizing mechanical refrigeration since parts and HVAC(R) skills have been widespread over the past several decades. EDIT: Spelling is hard. Clarification is hard.
  - homero 11y ago
    It has Wi-Fi
    - clayrichardson 11y ago
      Indeed. Ideally, we'd like to include a mini-datacenter module, allowing for data storage, streaming, and processing. We'd like to be able to gather metrics from these machines all over the world, and identify trends in things such as the weather, water production and consumption, efficiency, power generation and carbon sequestration, as well as identify opportunities to improve the operation of the machines through software updates.
  - clayrichardson 11y ago
    Indeed, it is energy intensive. That can be addressed with the implementation of the power supply module. Ideally, we'd like to use gasifiers and build upon the open source work by http://www.allpowerlabs.com/ http://www.allpowerlabs.com/ If it takes a lot of energy, and we implement carbon-negative power generation, then we increase the rate of carbon sequestration :)
  - clayrichardson 11y ago
    It's also going to be the centerpiece for a water-conscious art installation addressing the global water crisis at Burning Man, pulling water out of some of the driest air on the planet :)
- monkmartinez 11y ago
  Not likely to work well in place like Tucson, AZ... due to the consistently low relative humidity or am I reading this wrong? Right now, for example in Tucson, AZ: humidity at 14% with a temperature of 76F and dew point of 24F. High will be 90F :( with Humidity around 6% mid-afternoon.
  - clayrichardson 11y ago
    Interesting. With 32.2C ambient, 14% RH, 1.35C DWP, the absolute humidity is 4.78 g/m^3 With 24.4C ambient, 14% RH, -4.80C DWP, the absolute humidity is 3.12 g/m^3 Absolute humidity here is specified as grams of water per cubic meter of air. This is similar to the AH at BRC. Our current model assumes a DWP of -10C — 10C, so we can predict similar performance. We're not taking into account volumetric capacity and the thermal interface of the heat exchangers. If you know anyone able to help point us in the right direction with those calculations, it would be much appreciated! Our current understanding is the enthalpy of vaporization + fusion for water is (2257 + 333.55) = 2590.55 J/g we want to pull out of the air. This is assuming we can process enough air, since the dew point is below freezing a fair amount of the time. This is by using this equation specified in the NASA technical note [0]: =((0.21668*((TMPC+273)^-1))*((DWPC+273)^-4.9283)*(10^(23.5518+(-2937.4/(DWPC+273)))))*1000 [0]: http://www.nasa.gov/centers/dryden/pdf/87878main_H-937.pdf http://www.nasa.gov/centers/dryden/pdf/87878main_H-937.pdf EDIT: Formatting is hard. Added source. Clarification.
    - FiatLuxDave 11y ago
      Physicist here. I'm confused why you are using the enthalpy of fusion in your calculation, since your project does not appear to be freezing the water after condensation. Also, you seem to be using the enthalpy of vaporization from boiling at 100 C in your calculations, which is incorrect for use around 30 C. A better way to calculate your energy needs would be to look at a steam table, such as the one on Wikipedia's water data page, then take the deltaHvap. This is the accurate enthalpy of vaporization. https://en.wikipedia.org/wiki/Water_%28data_page%29 https://en.wikipedia.org/wiki/Water_%28data_page%29 In theory you need to add the amount of energy to cool the air/vapor mixture to the dew point. However, this amount will likely be small enough to be within your experimental error. For low humidity applications (like Burning Man), you can assume you are cooling mostly air, which is around 1.2 Joules/K per m^3. At 30 K temp differential, and humidity of 4 g/m^3, this is only 9 joules per gram water, or pretty much negligible. So, you are looking at a deltaHvap of around 2420 to 2450 J/g in this temperature range. This is reasonably close to your original estimate of 2590 J/g, and the good news is that the error is in your favor.
- gravypod 11y ago
  Have you thought about using an attached TEG [1] and a few 9volts to increase the amount of water produced as an optional strap-on. [1] - https://en.wikipedia.org/wiki/Thermoelectric_generator https://en.wikipedia.org/wiki/Thermoelectric_generator
  - clayrichardson 11y ago
    Interesting. I haven't thought about combining it with the mechanical refrigeration process! I'll run the numbers on that, thanks. The initial proof-of-concept I threw together with spare parts actually used a spare TEC (19911-5L31-15CQ) [0] I had laying around. [1] [0]: http://www.customthermoelectric.com/tecs/pdf/19911-5L31-15CQ_spec_sht.pdf http://www.customthermoelectric.com/tecs/pdf/19911-5L31-15CQ... [1]: https://openawg.github.io/2016/01/27/blueice-alpha.html https://openawg.github.io/2016/01/27/blueice-alpha.html
    - gravypod 11y ago
      That's basically the same thing as what I'm asking. I'll be happy to read the numbers when you get it going.
- Mithaldu 11y ago
  I have a question about your website. While trying to figure out what exactly you're doing i browsed around a bit and eventually ended up here: https://openawg.github.io/#about https://openawg.github.io/#about Which has a bunch of footnotes, many with one footnote per concept, where the footnotes are almost all wikipedia articles. Why don't you just link the words instead?
  - clayrichardson 11y ago
    Ah, that makes sense, thank you for the feedback. When I was drafting it in Google Docs, I was using footnote annotations, and I just copypasta'd it over.
phieromnimon 11y ago
Can you please explain how this differs from a dehumidifier?
- clayrichardson 11y ago
  The only difference is the addition of a filtration system to render potable water. Dehumidifiers are not designed to produce potable water. Adding a filtration system removes the contaminants from the non-food grade components and anything else which was once floating in the air.
sevensor 11y ago
> The lower the pH, the more basic the water. It's been a couple of decades since I took chemistry, but I think you've got that backwards.
- clayrichardson 11y ago
  Oops, thanks for the feedback. Fixed :)
toomuchtodo 11y ago
Would it be possible for me to use something like this on a boat I live on to generate fresh water?
- clayrichardson 11y ago
  It would, but it would most likely be less efficient than filtering the water you're floating in :) A good way to increase the efficiency of this machine would be to increase the relative humidity by adding moisture. This is the reasoning behind our next planned experiments of reclaiming water from urine! You might be able to get away with using the reverse osmosis system we have, [0] but send the water to a lab to test influent (intake) and effluent (output) before consuming :D [0]: http://123filter.com/catalog/ispring-7-stage-75-gpd-reverse-osmosis-uv-filter-system-rcc7ak-uv_cpath-70_1_67.html http://123filter.com/catalog/ispring-7-stage-75-gpd-reverse-...
  - toomuchtodo 11y ago
    Thanks for the reply! I'd of course use a watermaker first (very simple operation, relying on only a pump and a membrane) but its always smart to have redundancy in life critical systems ;) Absolutely love your project. I think its going to help a lot of people!
    - clayrichardson 11y ago
      Thank you! I hope it does too.
  - mathiasben 11y ago
    lol, that does desalination?
    - toomuchtodo 11y ago
      It probably does, but not as effectively as a marine-grade watermaker. http://www.westmarine.com/watermakers http://www.westmarine.com/watermakers
heavenlyhash 11y ago
> pH does not have a MCL (Maximum Contaminant Level) defined in the EPA's National Primary Drinking Water Regulations [...] but does have a [..limit defined in..] non-mandatory guidelines for aesthetics Wait, there's not a pH range limit on drinking water in the U.S.?!
- clayrichardson 11y ago
  Right? I was thinking that was quite odd as well. I wonder how the current primary and secondary drinking water regulations came to be.
- webkike 11y ago
  If I had to take a guess, the EPA probably issues MCLs for acids and bases and not the resulting pH of them combined.
- dnautics 11y ago
  Probably because distilled water with no buffering salts can have a huge range of pH and is effectively harmless.
rootedbox 11y ago
The problem places have with lack of good water; is a lack of money. Not a lack of water. There are way more energy / cost efficient ways to produce water than a dehumidifier. If you want to get into solving clean water; you really should be working on cheap energy.
- clayrichardson 11y ago
  Our current approach is to get the AWG module working, then add a module which boils urine and feeds the vapor into the AWG module for distillation and filtration. Ideally, we'd like to use a gasifier for carbon negative power generation, as local biomass can be utilized. Does this make sense, or do you have a more effective approach?
  - rootedbox 11y ago
    Like I said.. There isn't a 'lack' of water.. there is a lack of energy for purification in rural places.. In these places you should be figuring out purification via chemical and physical methods. https://s-media-cache-ak0.pinimg.com/736x/83/a6/d9/83a6d988650f72e279c10f6d5851736a.jpg https://s-media-cache-ak0.pinimg.com/736x/83/a6/d9/83a6d9886...
RIMR 11y ago
Ok, I really hate to shit all over somebody else's livelihood, but this whole project seems like a total waste of time. A dehumidifier isn't a complicated mechanism. This is not a novel invention. It also isn't going to produce a sustainable amount of drinking water at a price affordable to the people who need it most. The team running this seems to just be a group of friends who have none of the experience actually make a difference. We've got an Artist/Engineer, and artist, another artist, another Engineer and a product manager who have no meaningful job descriptions (apparently they "do things"), A "Web Engineer", and an advisor whose only task appears to be possession of knowledge of chemistry. It doesn't seem that this team was chosen due to what they could accomplish, but instead because they all pitched in to get an IndieGoGo project going... I'll give them credit for their cause. At least their hearts are, presumably, in the right places, but this little device isn't going to change the world even a little bit. It would win the science fair without a doubt, but it's not much more impressive than that.
- clayrichardson 11y ago
  Where should we spend our time instead? Definitely not novel at this stage, but once we modify the AWG to achieve water reclamation from urine, would that be considered novel? The next milestone is to create open source designs for larger-scale, commercially available machines that are prohibitively expensive, and improve upon them. The machines exist and there is a market for them. Is it not worth the time and effort to increase access to technologies like this? Not just knowledge of chemistry, but actively developing eyedrops to cure cataracts :) http://www.viewpointtherapeutics.com/team/ http://www.viewpointtherapeutics.com/team/ EDIT: Wording. Added question.
  - RIMR 11y ago
    >Where should we spend our time instead? That's for you to decide. There's nothing wrong with your project, I just don't see any real-world utility. >once we modify the AWG to achieve water reclamation from urine, would that be considered novel? Not at all. It wouldn't even be a "Atmospheric Water Generator" anymore. You would just be putting an evaporator in a closed space with your condenser... This isn't a new or novel technology, and it's already available for public use. >Not just knowledge of chemistry, but actively developing eyedrops to cure cataracts :) That's really cool, and I am not doubting her credentials, but it has nothing to do you with your AWG. We're talking about a device that condenses water vapor into liquid water. If you have access to Freon and and a pump (or even ice cubes and a glass) you can achieve the same thing. Again, I don't take any personal offense to what you're doing. I would never invest in it because I don't think any amount of funding would ever turn this project into a success. It doesn't even address the real issues behind water scarcity, which has nothing to do with a shortage of liquid water...

clayrichardson 11y ago

Hey everyone, I'm around for a bit to answer any questions you might have :)

jat850 11y ago
How does it taste? :) And what plans do you have for tackling the pH and turbidity level issues? edit Missed the note on turbidity. I'm guessing a follow-up test might show that resolved?
- clayrichardson 11y ago
  It tastes surprisingly good, although not as good as some of the Ozarka bottled spring water I've had, but almost. We're going to try and find another remineralization filter, or we might add electrolyte mix instead. The second lab report was from the isolation of the remineralization filter, and we showed that the turbidity was indeed added by that filter.
  - jat850 11y ago
    That's great! I had missed the test0 procedure text, but it did seem clear after reading it.
zzalpha 11y ago
So... this is basically a dehumidifier. Dehumidifiers typically use some sort of air cooling to reduce water below the dew point to draw water out of the air. And that takes a lot of energy. So what is the purpose of this device? It can't be to provide potable water to areas without it, since those same areas are likely to lack a significant source of power. I don't mean to be overly cynical, but I feel like I'm missing something here.
- exhilaration 11y ago
  https://en.wikipedia.org/wiki/Atmospheric_water_generator https://en.wikipedia.org/wiki/Atmospheric_water_generator I thought the same thing but reading their site led me to the above Wikipedia page which suggests there are other ways to do it than just dehumidification but I'm not sure what method they're using.
  - clayrichardson 11y ago
    For simplicity and adoption, we're utilizing mechanical refrigeration since parts and HVAC(R) skills have been widespread over the past several decades. EDIT: Spelling is hard. Clarification is hard.
- homero 11y ago
  It has Wi-Fi
  - clayrichardson 11y ago
    Indeed. Ideally, we'd like to include a mini-datacenter module, allowing for data storage, streaming, and processing. We'd like to be able to gather metrics from these machines all over the world, and identify trends in things such as the weather, water production and consumption, efficiency, power generation and carbon sequestration, as well as identify opportunities to improve the operation of the machines through software updates.
- clayrichardson 11y ago
  Indeed, it is energy intensive. That can be addressed with the implementation of the power supply module. Ideally, we'd like to use gasifiers and build upon the open source work by http://www.allpowerlabs.com/ http://www.allpowerlabs.com/ If it takes a lot of energy, and we implement carbon-negative power generation, then we increase the rate of carbon sequestration :)
- clayrichardson 11y ago
  It's also going to be the centerpiece for a water-conscious art installation addressing the global water crisis at Burning Man, pulling water out of some of the driest air on the planet :)
monkmartinez 11y ago
Not likely to work well in place like Tucson, AZ... due to the consistently low relative humidity or am I reading this wrong? Right now, for example in Tucson, AZ: humidity at 14% with a temperature of 76F and dew point of 24F. High will be 90F :( with Humidity around 6% mid-afternoon.
- clayrichardson 11y ago
  Interesting. With 32.2C ambient, 14% RH, 1.35C DWP, the absolute humidity is 4.78 g/m^3 With 24.4C ambient, 14% RH, -4.80C DWP, the absolute humidity is 3.12 g/m^3 Absolute humidity here is specified as grams of water per cubic meter of air. This is similar to the AH at BRC. Our current model assumes a DWP of -10C — 10C, so we can predict similar performance. We're not taking into account volumetric capacity and the thermal interface of the heat exchangers. If you know anyone able to help point us in the right direction with those calculations, it would be much appreciated! Our current understanding is the enthalpy of vaporization + fusion for water is (2257 + 333.55) = 2590.55 J/g we want to pull out of the air. This is assuming we can process enough air, since the dew point is below freezing a fair amount of the time. This is by using this equation specified in the NASA technical note [0]: =((0.21668*((TMPC+273)^-1))*((DWPC+273)^-4.9283)*(10^(23.5518+(-2937.4/(DWPC+273)))))*1000 [0]: http://www.nasa.gov/centers/dryden/pdf/87878main_H-937.pdf http://www.nasa.gov/centers/dryden/pdf/87878main_H-937.pdf EDIT: Formatting is hard. Added source. Clarification.
  - FiatLuxDave 11y ago
    Physicist here. I'm confused why you are using the enthalpy of fusion in your calculation, since your project does not appear to be freezing the water after condensation. Also, you seem to be using the enthalpy of vaporization from boiling at 100 C in your calculations, which is incorrect for use around 30 C. A better way to calculate your energy needs would be to look at a steam table, such as the one on Wikipedia's water data page, then take the deltaHvap. This is the accurate enthalpy of vaporization. https://en.wikipedia.org/wiki/Water_%28data_page%29 https://en.wikipedia.org/wiki/Water_%28data_page%29 In theory you need to add the amount of energy to cool the air/vapor mixture to the dew point. However, this amount will likely be small enough to be within your experimental error. For low humidity applications (like Burning Man), you can assume you are cooling mostly air, which is around 1.2 Joules/K per m^3. At 30 K temp differential, and humidity of 4 g/m^3, this is only 9 joules per gram water, or pretty much negligible. So, you are looking at a deltaHvap of around 2420 to 2450 J/g in this temperature range. This is reasonably close to your original estimate of 2590 J/g, and the good news is that the error is in your favor.
gravypod 11y ago
Have you thought about using an attached TEG [1] and a few 9volts to increase the amount of water produced as an optional strap-on. [1] - https://en.wikipedia.org/wiki/Thermoelectric_generator https://en.wikipedia.org/wiki/Thermoelectric_generator
- clayrichardson 11y ago
  Interesting. I haven't thought about combining it with the mechanical refrigeration process! I'll run the numbers on that, thanks. The initial proof-of-concept I threw together with spare parts actually used a spare TEC (19911-5L31-15CQ) [0] I had laying around. [1] [0]: http://www.customthermoelectric.com/tecs/pdf/19911-5L31-15CQ_spec_sht.pdf http://www.customthermoelectric.com/tecs/pdf/19911-5L31-15CQ... [1]: https://openawg.github.io/2016/01/27/blueice-alpha.html https://openawg.github.io/2016/01/27/blueice-alpha.html
  - gravypod 11y ago
    That's basically the same thing as what I'm asking. I'll be happy to read the numbers when you get it going.
Mithaldu 11y ago
I have a question about your website. While trying to figure out what exactly you're doing i browsed around a bit and eventually ended up here: https://openawg.github.io/#about https://openawg.github.io/#about Which has a bunch of footnotes, many with one footnote per concept, where the footnotes are almost all wikipedia articles. Why don't you just link the words instead?
- clayrichardson 11y ago
  Ah, that makes sense, thank you for the feedback. When I was drafting it in Google Docs, I was using footnote annotations, and I just copypasta'd it over.

phieromnimon 11y ago

Can you please explain how this differs from a dehumidifier?

clayrichardson 11y ago
The only difference is the addition of a filtration system to render potable water. Dehumidifiers are not designed to produce potable water. Adding a filtration system removes the contaminants from the non-food grade components and anything else which was once floating in the air.

sevensor 11y ago

> The lower the pH, the more basic the water. It's been a couple of decades since I took chemistry, but I think you've got that backwards.

clayrichardson 11y ago
Oops, thanks for the feedback. Fixed :)

toomuchtodo 11y ago

Would it be possible for me to use something like this on a boat I live on to generate fresh water?

clayrichardson 11y ago
It would, but it would most likely be less efficient than filtering the water you're floating in :) A good way to increase the efficiency of this machine would be to increase the relative humidity by adding moisture. This is the reasoning behind our next planned experiments of reclaiming water from urine! You might be able to get away with using the reverse osmosis system we have, [0] but send the water to a lab to test influent (intake) and effluent (output) before consuming :D [0]: http://123filter.com/catalog/ispring-7-stage-75-gpd-reverse-osmosis-uv-filter-system-rcc7ak-uv_cpath-70_1_67.html http://123filter.com/catalog/ispring-7-stage-75-gpd-reverse-...
- toomuchtodo 11y ago
  Thanks for the reply! I'd of course use a watermaker first (very simple operation, relying on only a pump and a membrane) but its always smart to have redundancy in life critical systems ;) Absolutely love your project. I think its going to help a lot of people!
  - clayrichardson 11y ago
    Thank you! I hope it does too.
- mathiasben 11y ago
  lol, that does desalination?
  - toomuchtodo 11y ago
    It probably does, but not as effectively as a marine-grade watermaker. http://www.westmarine.com/watermakers http://www.westmarine.com/watermakers

heavenlyhash 11y ago

> pH does not have a MCL (Maximum Contaminant Level) defined in the EPA's National Primary Drinking Water Regulations [...] but does have a [..limit defined in..] non-mandatory guidelines for aesthetics Wait, there's not a pH range limit on drinking water in the U.S.?!

clayrichardson 11y ago
Right? I was thinking that was quite odd as well. I wonder how the current primary and secondary drinking water regulations came to be.
webkike 11y ago
If I had to take a guess, the EPA probably issues MCLs for acids and bases and not the resulting pH of them combined.
dnautics 11y ago
Probably because distilled water with no buffering salts can have a huge range of pH and is effectively harmless.

rootedbox 11y ago

The problem places have with lack of good water; is a lack of money. Not a lack of water. There are way more energy / cost efficient ways to produce water than a dehumidifier. If you want to get into solving clean water; you really should be working on cheap energy.

clayrichardson 11y ago
Our current approach is to get the AWG module working, then add a module which boils urine and feeds the vapor into the AWG module for distillation and filtration. Ideally, we'd like to use a gasifier for carbon negative power generation, as local biomass can be utilized. Does this make sense, or do you have a more effective approach?
- rootedbox 11y ago
  Like I said.. There isn't a 'lack' of water.. there is a lack of energy for purification in rural places.. In these places you should be figuring out purification via chemical and physical methods. https://s-media-cache-ak0.pinimg.com/736x/83/a6/d9/83a6d988650f72e279c10f6d5851736a.jpg https://s-media-cache-ak0.pinimg.com/736x/83/a6/d9/83a6d9886...

RIMR 11y ago

Ok, I really hate to shit all over somebody else's livelihood, but this whole project seems like a total waste of time. A dehumidifier isn't a complicated mechanism. This is not a novel invention. It also isn't going to produce a sustainable amount of drinking water at a price affordable to the people who need it most. The team running this seems to just be a group of friends who have none of the experience actually make a difference. We've got an Artist/Engineer, and artist, another artist, another Engineer and a product manager who have no meaningful job descriptions (apparently they "do things"), A "Web Engineer", and an advisor whose only task appears to be possession of knowledge of chemistry. It doesn't seem that this team was chosen due to what they could accomplish, but instead because they all pitched in to get an IndieGoGo project going... I'll give them credit for their cause. At least their hearts are, presumably, in the right places, but this little device isn't going to change the world even a little bit. It would win the science fair without a doubt, but it's not much more impressive than that.

clayrichardson 11y ago
Where should we spend our time instead? Definitely not novel at this stage, but once we modify the AWG to achieve water reclamation from urine, would that be considered novel? The next milestone is to create open source designs for larger-scale, commercially available machines that are prohibitively expensive, and improve upon them. The machines exist and there is a market for them. Is it not worth the time and effort to increase access to technologies like this? Not just knowledge of chemistry, but actively developing eyedrops to cure cataracts :) http://www.viewpointtherapeutics.com/team/ http://www.viewpointtherapeutics.com/team/ EDIT: Wording. Added question.
- RIMR 11y ago
  >Where should we spend our time instead? That's for you to decide. There's nothing wrong with your project, I just don't see any real-world utility. >once we modify the AWG to achieve water reclamation from urine, would that be considered novel? Not at all. It wouldn't even be a "Atmospheric Water Generator" anymore. You would just be putting an evaporator in a closed space with your condenser... This isn't a new or novel technology, and it's already available for public use. >Not just knowledge of chemistry, but actively developing eyedrops to cure cataracts :) That's really cool, and I am not doubting her credentials, but it has nothing to do you with your AWG. We're talking about a device that condenses water vapor into liquid water. If you have access to Freon and and a pump (or even ice cubes and a glass) you can achieve the same thing. Again, I don't take any personal offense to what you're doing. I would never invest in it because I don't think any amount of funding would ever turn this project into a success. It doesn't even address the real issues behind water scarcity, which has nothing to do with a shortage of liquid water...