91–100 of 133 posts
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.
If you don't have drinking water, five to ten cents per day is a pretty good deal! It really doesn't matter that tap water somewhere else in the world is one cent.
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.
Earlier quoted context omitted.
Generally a lot of electrical appliances are advertised with kW or W actually meaning kW-hour and W-hour (and yes, this is awful, but it's pretty standard). So your interpretation as 1.8kW is about right. It varies, as does output, because (as the numbers mention) this all varies wildly by atmospheric temperature and humidity. (By the way, running the numbers I'm seeing it as 62.77L/kW vs. 50L/kW, which is a 25% impr…
groan So when they write kW/hr, they mean kWh/h, which is kW, because they expect readers to be confused. But if that's the power of the machine, it shouldn't vary. Just like my car produces 70kW, not "7-70kW/hr depending on road conditions". This machine would run a max power all the time, wouldn't it? > 25% improvement Serves me right for trying to compute in my head. Qualitatively, it makes no difference, though:…
Chilling below the dew point doesn't add much, if any, performance.
(And yeah, that kW = kW-h convention hurts my brain.)
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?
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 effi…
At 100% humidity, sure. If it's raining, it takes no work to get wet. I have a unit in my garage that can actually produce water at less than 10% relative humidity, moves a lot more air so it has more chances to actually capture the water, and smokes these other units under price/performance, particularly when tested in a desert. It's not a dehumidifier-based system. It's also cheaper to build. Email me for details.
> Thanks for reaching out. Mine uses a deliquescent salt, which requires no energy to absorb water from the air. It's pretty messy, but does the job. Getting the water back out is where the energy is required, and this is non-trivial, but still far better than those dehumidifier approaches, which are unfortunately the perpetual motion machines of our era.
Edit: not a big Frank Herbert crowd I see.
Earlier quoted context omitted.
groan So when they write kW/hr, they mean kWh/h, which is kW, because they expect readers to be confused. But if that's the power of the machine, it shouldn't vary. Just like my car produces 70kW, not "7-70kW/hr depending on road conditions". This machine would run a max power all the time, wouldn't it? > 25% improvement Serves me right for trying to compute in my head. Qualitatively, it makes no difference, though:…
As someone else noted, this system functions by using a refrigerator to keep air in the condenser at the dew point; the power required to do this varies based on humidity (changes the dew point) and temperature (changes the temperature gradient your refrigerator has to maintain between the dew point and the outside temp). Chilling below the dew point doesn't add much, if any, performance. (And yeah, that kW = kW-h co…
Power consumption doesn't depend on humidity. Capacity does. So if they quoted "0.8-1.8kWh/l", that would make sense (but be ridiculously low). If they quoted 1.8kW and 40-100l/d, that would make sense, too. But 30gal/d and 0.8-1.8kW implies that the machine throttles the compressor in order not to exceed the advertised capacity, which it doesn't reach under real world conditions anyway.
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.
Nobody subscribes to any quaint notions anymore such as "Extracting water from air is known as rain, and it's free," or "There are already too many humans, living in too many inhospitable places, enabled by technology," or even something as simple as "Hey I can keep two contradictory ideas in my head at the same time like 'I work on technology' yet 'Technology always has a downside'?"
There's an old apocryphal saying along the lines of (please say this in the stereotyped voice of Tonto or any Native American portrayed by Hollywood): Red man build small fire, keep warm. White man build big fire, keep warm by chopping wood.
Just thought I'd throw that in, since it's roughly analogous.
The human population needs to be cut back to within a sensible ecological planetary carrying-capacity, not be further propped up by ever-more exotic tech. The cutback will happen regardless, when these technologies inevitably fail or lead to worse problems that feed back on each other. But it's still frustrating that everybody wants to just rush headlong into the brick wall instead of hitting the brakes, and that anybody who has any foresight is automatically some Luddite or old-timer. Like people fresh-out-the-womb are the smartest ones, and the unquestioning belief in tech is anything but gullibility! Give me your money then!
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?
Ancient Roman Empire was politically stable. When this is not the case one really needs very local water sources.