I came across this video promotion for a self filling water bottle device, being marketed by a company called Fontus. It supposedly can refill itself by condensing water straight out of the air, being powered by a small solar panel, thus providing water in remote areas. They’ve managed to acquire about $350,000 worth of crowd funding. However there’s a slight problem, it can’t possibly work! Its quite literally “vapourware”. Vlogger Thunderf00t, aka Phil Mason does a more complete debunking here, but in short such a device (even if it worked) would deliver such a ridiculously low level of water, that you’d be better off seeking other alternatives.
Figure 1: The Fontus self filling water bottles, camping and bike versions [Source: Fontus, 2016]
And this is merely one of a number of similar devices doing the rounds. There’s also the Waterseer device. This has also attracted quite a bit of publicity and funding, claiming to be able to deliver as much as 14 gallons of water a day. But again it can’t possibly work and it has been debunked by Thunderf00t and quite a number of others online. Quite clearly those behind these devices are either scammers, or yet another proof of the Dunning-Kruger effect.
Figure 2: The Waterseer scam device [Source: Treehugger/Waterseer 2016]
What initially tickled my spidey senses was the solar panel on the bike version of the self filling bottle. Its stuck between the legs of the rider. Solar panels need good sunlight to be effective, if they are shaded they’ll provide negligible power output. Even the larger panel is simply too small (and curved, so it will shade itself if its not stretched out properly and thus not deliver any significant power). Furthermore the thermal properties of water involve some rather large numbers. Its specific heat capacity is about 4200 J/kg/K. That means that in order to heat 1L of water (roughly 1 kg) from 20ºC to 100°C you need to apply 336,000 Joules of heat. And that doesn’t boil the water, you’d need to overcome the latent heat for that, meaning you need to add a further 2260 kJ per kilo (i.e more energy than it takes to get it to boiling point!).
And condensing water out of the atmosphere requires a lot more energy than simply heating it up, especially if you are using a Peltier type device. Using Fontus own data, Dave Jones from EEVblog points out that under ideal conditions you could only generate 1L of water per 250 Wh’s of energy (about 900 kJ, enough to make nearly three litres of tea and keep Mrs Doyle happy). There is simply no way a small badly shaded solar panel is ever going to output anything like that sort of power. Indeed he goes on to work out the size of solar panel you’d need (again under ideal conditions) and as you can see, it ain’t small. And the actual performance of Peltier effect dehumidifers in more normal conditions will be a lot worse than this.
Figure 3: The estimated size of a solar panel you’d need to actually operate a self filling water bottle under ideal conditions [Source: EEVblog, 2016]
And similarly the Waterseer can’t possibly work, indeed on the porky scale of 1 to 10, if Fartus Fontus are a 9, Waterscamer Waterseer are a 12. It relies on the temperature gradient between the air and the soil (which is generally around about 10-15°C in the UK) to cool and condense water. However, this ignores just how much energy it takes to actually condense water from vapour to a liquid (again 2260 kJ per kg). And ground temperature conditions vary worldwide, with soil temperatures generally higher in hot countries.
Furthermore, you start dumping kJ’s worth of heat into the ground, its going to start heating up (especially if there’s 30°C of air above and thus nowhere for the heat to go). This is a problem with ground source heat pumps, if you pump too much heat out, you can end up freezing the ground. So essentially a Waterseer faces the opposite problem, eventually the ground temperature will equal the air temperature. Indeed given the better insulating properties of soil compared to air, at night the temperature gradient will reverse! Keep in mind that for the 11-14 gallons they talk about it supplying, that works out at a need for the ground to absorb heat at a rate of between 1 – 1.4 kW’s. To give you some idea of how hard that is consider the image below of the ground coil for a GSHP with a level of heat abstraction in the kW range. And this is a forced convection device, in which we are circulating water via a pump.
Figure 4: Ground source heat pump coils in the kW scale
And this presents another problem for Waterseer, its wind turbine driven pump won’t work all of the time. A small vertical axis wind turbines, particularly one that close to the ground is going to have a very low capacity factor, 10-20% by my estimate. And furthermore, the amount of water in the atmosphere is tiny, a few ml’s of water per cubic metre of air, so you’d need to pump a significant quantity of air through the system. Even if we assume the higher figure for wind turbine capacity factors and we assume it works 50% of the year (i.e. during the day) that implies a year round capacity factor of 10%. And remember, the lower the capacity factor, the higher that rate of heat loss needs to be (the estimates I gave earlier assumed a 100% capacity factor). So the reality is that such a device will only work relatively infrequently and with a level of output a fraction of what’s advertised.
And this is an important point to be made when dealing with water. Whether you are pumping water or heating it up, you need something with a descent power output for it to be effective. Generally you want something in the range of a few hundred watts. So a couple of square metres of PV or solar thermal collectors would do the trick. Anything smaller than this (a tiny wind turbine or a 10-20 Watt PV panel) will struggle to produce any meaningful output. They are designed to charge phones or run a few low voltage devices. Pumping, heating or condensing water is generally going to be outside of their pay grade. I don’t mean to be rude, but you could literally generate more water and energy peeing on either of these devices!
And why reinvent the wheel? It may have escaped people’s attention, but we live on a planet covered by water. Unless you’re in the middle of the Sahara, there’s always going to be water available somewhere nearby. The problem isn’t so much a lack of water, its a lack of clean drinking water. Its always going to be a lot easier to just purify water than to trying to conjure it out of thin air (or indeed easier to simply sink a well or collect rain water). Already a whole bunch of water purification kits aimed at hikers are available. These can involve use of water purification tablets, or filters (which often come with a hand operated pump) or simply carrying a big gas cylinder and boil everything. Which of these is the best option largely depends on the circumstances. Indeed, I’m forced to conclude that the developers of our self filling bottle have never actually been on an expedition to a water scarce area, so they hadn’t even done the most basic market research.
Figure 5: A variety of water purifier kits are now on the market, with some being supplied to developing world countries which lack good water supplies [Source: Go Outdoors ND]
For the purposes of desalination, or more static applications, there’s a solar still, which in good sunlight can deliver 4-5 litre’s of water per day per m2 of area. Although that’s obviously not going to be portable and takes time to set up, but an option to consider for static applications (again I’m forced to the conclusion our Waterseer lot have never even visited a village in the developing world!). If you want more significant levels of water delivery on a more reliable basis and a still, well or rainwater harvesting aren’t really viable options (e.g. you are on a boat), then you can use reverse osmosis or the MSF method (Multi Stage Flash, basically boiling it). The energy consumption rates aren’t small, about 3-4 kWh/m3 and 10-25 kWh/m3 respectively (so again, you need a decently sized source of energy). But that’s still a level of performance that’s 10 to 80 times better than either of our water woo devices can offer (and that’s comparing practical real world values to our water woo devices running under ideal conditions!).
Of course, I’d have to point out that the Fontus designers appear to be arts students and product designers. If there’s anything more dangerous than a Trump presidency, its art and design students who think they know something about physics and engineering.
Figure 6: How great products are developed [Source: Scott Adams ND]
The normal route for product development is you start off with the marketing department asking the engineers to come up with some device (our customers would like to be teleported to important world events, or the theatre). The engineers respond by suggesting the marketing department stop smoking crack, then propose that as an alternative they can build this box through which you can view faraway events. The engineers develop their gizmo, which they call a TV (engineer’s like acronyms, you’re lucky we didn’t invent the fork or it would be called an MPF), which turns out to be a massive steel box that weights 2 tons, requires a 3 phase supply, two PhD’s to set up and can communicate with alien races if required. It is at this point that the product designers get involved and the product goes through various design iterations until you end up with something a customer might actually want to buy.
In effect the development of both of these products worked in reverse. The product design/arts students started off with an idea, did a slick advertising campaign and sold the device before considering any of the technical questions, or even conducting the most basic market research. Its only now, after they’d done all the pretty sketches and collected lots of awards that they’ve paused to consider the engineering. I mean its not as if engineering is complicated, its not like it involves maths or science or anything like that! Unfortunately, this is a trend I do see occurring more often, we engineers tend to get consulted much later in a product design process, usually after the arty types have painted themselves into a corner.
Figure 7: Bad product design can lead to things like this $400 dollar juicing machine that can be replaced by simply hand squeezing the bags it comes with….or a $50 blender! [Source: BBC, 2017]
Now if this was simply a tale of how a couple of fraudsters/morons managed to con a lot of naive people on the internet out of their money via scam starter kick starter, I’d leave it at that. However, both of these water woo devices have been heavily promoted by a wide variety of popular science articles, very few of whom really gave either device any sort of critical review. By way of example, here’s an article from Time and another from Popular science (after being exposed by EEVblog Popular science deleted their original Waterseer article, the one I’ve linked too is the replacement).
Fontus won a design award from Dyson and Waterseer has the backing of Berkeley university and the US peace corps. I mean science is under attack enough from anti-vaxxers & climate deniers, without us adding BS like this to the mix. Sooner or later the Daily Fail or some other right wing rag is going to pick up on this and have a field day. And for once they’ll be right.
That said, I do know people who work for Dyson…..and lets just say they do a good show of pretending to be boffins (he backed brexit….yet believes in Britain so much that he’s fired lots of brits so he could move a factory to Asia).
As for Berkeley, well you need to understand that universities, particularly those in the US and England, have gotten pretty mercenary over the last few years. Frankly, if I wanted to execute someone in the most painful way possible, I’d attach dollar bills to them and then throw them into a pit full of university vice-chancellors. The units of universities responsible for prostituting themselves bringing in private capital are easy to identify, they usually have words like “innovation” or “entrepreneur” in them, or they are named after some rich guy (rather annoyingly one uni I was working for won an award for being “entrepreneurial university of the year”, which is a bit like being called the best brothel in town). These institutes are the hide out for academic staff who are too dumb to teach, or too incompetent for any funding body to give them access to public money. Well I think you can guess which part of Berkeley is backing Waterseer.
Certainly what this saga shows is the need for people to undertake due diligence. Any website allowing a company to crowd fund should require that they undergo some level of professional scrutiny. You get a lawyer and an accountant in to go over the books and the contracts and make sure they aren’t a bunch of scam artists or bull$hitters (such as the guys behind the recent Fyre Festival in the Bahamas). Bringing in a few engineers and technical experts to review the proposal is another important step.
And if you are going to be a science journalist, you have a responsibility to do some sort of fact checking too, don’t just report verbatim what anyone says. I mean if any of the science journalists who promoted these devices wants a good technology story I know a bloke down the pub who reckons he can run his car off of water. Are you going to shortlist him for a Dyson award?
And the first question you need to ask, when it comes to assessing the technical merits of any proposal is, has somebody tried this before? Because I can all but guarantee you someone will have. And if someone hasn’t, then there’s probably a good reason why. Which leads us to the second question, why did the product or idea fail the last time? This should give you a clue as to whether or not its worth pursuing.
For example, electric cars were quite popular back in early days of the motor car. However, they were quickly superseded by petrol powered cars due to the range issue. Obviously since then concerns about climate change and advances in batter technology means that electric cars are back on the agenda. While I’m personally doubtful we’ll ever see a like for like replacement of petrol powered cars, certainly there’s a wide range of roles they can perform and thus a wide avenue for research and development here.
Figure 8: Rocket man…..for about ten seconds, then you’re out of fuel!
By contrast a jet pack was a bad idea when it was first proposed, and given that the laws of physics haven’t changed, its still a bad idea today. Anyone working on one of these is wasting their time. Advances in battery technology makes a flying car a bit more plausible. But only if we can ignore the fact that they would be very expensive, have a very high rate of energy consumption and are much more challenging to fly. There is no way they could ever replace existing aviation or land vehicles (save one or two niche roles). Indeed most “flying cars” under development aren’t really flying cars, just high Cooper-Harper scale aircraft with an extended taxi capability.
By I digress, the irony is that public bodies get a lot of stick for wasting public money (in particular the EU), but if you applied for research funding for either of these water woo devices you’d get shot down in one of the many layers of peer review. And this is what worries me, because such silliness threatens funding for real researchers who are trying to make a difference and solve the world’s water crisis.
For example, lets suppose I applied for a grant too drill a few wells in Africa, or maybe develop a more efficient reverse osmosis device, or perhaps I want to design some sort of low cost solar still. Would I get funding? Well you could just see some populist, Trump/Brexiter appointee pointing to the Time article above and say, oh that’s a waste of money, why these boffins will soon develop a device that conjures water out of thin air. And similarly, will any of the suckers investors who’ve backed either of these devices ever donate or invest in system that could theoretically make a difference after getting burned in the spectacular fashion they are about to be? This stops being a joke when the world’s growing water crisis is made harder to solve.
Figure 9: Some things never change! The gullible will always be exploited
What these examples show is just how easy it is for style to triumph over substance. It shows just how technically illiterate people have become these days, even so-called science journalists. Far too many people these days view technology like its some sort of mobile phone app, have a problem? install technology. Well it ain’t so, if the world’s problems could be solved so easily, don’t you think someone would have already done it?
We are truly in the “post truth” age when you see devices like this being openly promoted by university departments and in the national press, and it then falls to vloggers and bloggers on the internet to call them out. As the line in the play Juno and the Paycock goes “when ignorance is bliss tis folly to be wise”.