### Author Topic: EEVblog #881 - Fontus Self Filling Water Bottle BUSTED!  (Read 42099 times)

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#### EEVblog

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##### Re: EEVblog #881 - Fontus Self Filling Water Bottle BUSTED!
« Reply #25 on: May 18, 2016, 09:53:30 am »
Sorry Dave, at 4:50 you made an error of units  in your calculation, mixing Energy and Power, or missing the evaluated time:
905kJ/l = 251Wh/l (not Watt/l).

Yes, that's been fixed in annotation.

Quote
So in 150 min = 2.5h, you would 'only' need a 100W panel.

No.
You have to extract 2264kJ just for the phase transition to get 1L of water from the air in 1 hour. 2264kJ = 628Wh
So that's 628W if you do it in an hour, or 251W if you do it over 2.5 hours.

#### rs20

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##### Re: EEVblog #881 - Fontus Self Filling Water Bottle BUSTED!
« Reply #26 on: May 18, 2016, 10:19:52 am »
You have to extract 2264kJ just for the phase transition to get 1L of water from the air in 1 hour.

<pedantic>FTFY. You don't need any time measurements in this statement at all. 1L of water condensed is 2264kJ, no matter if it's a nanosecond or a year.

#### EEVblog

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##### Re: EEVblog #881 - Fontus Self Filling Water Bottle BUSTED!
« Reply #27 on: May 18, 2016, 10:53:31 am »
<pedantic>FTFY. You don't need any time measurements in this statement at all. 1L of water condensed is 2264kJ, no matter if it's a nanosecond or a year.

Yep, correct.
I have a bad habit of always anchoring everything to a time reference for this thing, because this product and it's claims are all about time.
So I'll rephrase:
You have to extract 2264kJ just for the phase transition to get 1L of water.
For 1 hour reference:
2264kJ = 628Wh
So that's 628W if you do it in an hour, or 251W if you do it over 2.5 hours.

#### AF6LJ

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##### Re: EEVblog #881 - Fontus Self Filling Water Bottle BUSTED!
« Reply #28 on: May 18, 2016, 10:58:06 am »
I knew there was a reason why I had to replace the shunt across my BullShit meter from a piece of twelve gauge wire to a piece of 00.
Sue AF6LJ
Test Equipment Addict, And Proud Of It.

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#### EEVblog

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##### Re: EEVblog #881 - Fontus Self Filling Water Bottle BUSTED!
« Reply #29 on: May 18, 2016, 11:45:08 am »

#### Muttley Snickers

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##### Re: EEVblog #881 - Fontus Self Filling Water Bottle BUSTED!
« Reply #30 on: May 18, 2016, 11:45:32 am »
The mathematics and physics involved here are outside the realm of my capabilities so I am happy to sit this one out and will simply wait for the rain to come over so I can fill my water bottle or turn the tap on, either way 100% guaranteed with little effort, risk or outlay.

https://www.metabunk.org/fontus-self-filling-water-bottle-indiegogo-scam-campaign.t7495/

Australia Post are really going to struggle with this one below.
One smart cookie, better make that two for good measure.

#### EEVblog

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##### Re: EEVblog #881 - Fontus Self Filling Water Bottle BUSTED!
« Reply #31 on: May 18, 2016, 01:19:13 pm »
Some people giving them the what-for:

#### nitro2k01

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##### Re: EEVblog #881 - Fontus Self Filling Water Bottle BUSTED!
« Reply #32 on: May 18, 2016, 02:17:27 pm »
Paul's comment is now gone, but Antonio's is still up.
Whoa! How the hell did Dave know that Bob is my uncle? Amazing!

#### SEKCobra

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##### Re: EEVblog #881 - Fontus Self Filling Water Bottle BUSTED!
« Reply #33 on: May 18, 2016, 02:29:36 pm »
Im from Austria and I tried looking up what kinda funding they got, but it doesn't seem like they got actual government support. Probably just saying that to seem more legit.

#### SEKCobra

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##### Re: EEVblog #881 - Fontus Self Filling Water Bottle BUSTED!
« Reply #34 on: May 18, 2016, 02:38:17 pm »
He used the word investor on indiegogo, he doesn't know what he's talking about either ^^

#### Halcyon

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##### Re: EEVblog #881 - Fontus Self Filling Water Bottle BUSTED!
« Reply #35 on: May 18, 2016, 05:48:09 pm »
The thing is, even if magic happened and it was able to provide any decent quantity of water, I'm not sure I'd want to be drinking all the crap and contaminants from the air, especially from the 'Ryde' version where it's going to be sucking in diesel particulate and car exhaust (assuming that most people ride on or near roads).

I can have fairly pure, clean water straight out of most taps (not to mention the added benefit of fluoride). The Fontus is just one damn expensive water bottle. I have a plastic water bottle that holds more water than this thing and even has a little carbon filter built-in.

I also find their claim of "No need to plan your tour around water resources" a bit rich. One would die of dehydration if they were to follow this advice together with "Forget about carrying heavy water loads!"

Anyway, maybe after all this, they'll take Roohparvar's approach and claim "big Coca-Cola" is preventing them from producing the product as it'll hit their bottled water sales or such nonsense, or there was a flood and their "engineering team" is working hard to get the product out to backers... "soon"...
« Last Edit: May 18, 2016, 05:56:47 pm by Halcyon »

#### VK3DRB

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##### Re: EEVblog #881 - Fontus Self Filling Water Bottle BUSTED!
« Reply #36 on: May 18, 2016, 10:03:09 pm »
From their website:

"Atmospheric water is clean and does not contain harmful micro-organisms." Haven't they heard of the common cold? Or the Spanish 'flu.

"... (iii) even non-production of the Perk. In the latter case there will be no Perk delivered to the Contributor. Contributions will not be refunded. By making a Contribution the Contributors explicitly acknowledge the risks associated with the occurrence of one of the aforementioned events." In other words, "A fool and his money are soon parted."

This story about being scammed beggars belief ...

#### rollatorwieltje

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##### Re: EEVblog #881 - Fontus Self Filling Water Bottle BUSTED!
« Reply #37 on: May 18, 2016, 10:15:53 pm »
One of the AC units we have drains into a bottle as the drain pump is horribly noisy. It "produces" about 1 or 2 liters over night (depends on conditions of course), and that is a "2kW" unit unit. It draws about 600W when running. And I'm not sure if I would actually want to drink that, considering how horrible it smells. I may be slightly behind schedule on cleaning my AC units though.

Somewhat ironically the optimal conditions for this device are actually "rainforest". You'd be better off actually waiting for rain if you want fresh water

#### Fungus

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##### Re: EEVblog #881 - Fontus Self Filling Water Bottle BUSTED!
« Reply #38 on: May 18, 2016, 10:34:24 pm »
Paul's comment is now gone, but Antonio's is still up.

#### Fungus

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##### Re: EEVblog #881 - Fontus Self Filling Water Bottle BUSTED!
« Reply #39 on: May 18, 2016, 10:36:27 pm »
One of the AC units we have drains into a bottle as the drain pump is horribly noisy. It "produces" about 1 or 2 liters over night (depends on conditions of course), and that is a "2kW" unit unit. It draws about 600W when running. And I'm not sure if I would actually want to drink that, considering how horrible it smells. I may be slightly behind schedule on cleaning my AC units though.
You obviously don't live in a very humid place. I can fill 2 or 3 buckets a day in summer, no problem.

#### SydB

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##### Re: EEVblog #881 - Fontus Self Filling Water Bottle BUSTED!
« Reply #40 on: May 18, 2016, 10:51:08 pm »
What a shame the \$300,000 was not directed into scientific research instead. The internet is the snake oil salesman's dream.

Be careful regarding latent heat. Gas to liquid phase change is a release of energy (hydrogen bonds formed = energy release). On the surface of it, then why would we need to input energy? Because we need to cool and dump the heat somewhere (including most of the energy we put in to doing that!). This is why anybody that has had anything to do with Peltier cooling knows that you need 'big' surface areas and 'big' energy (pumps for liquid cooling or fans for air cooling) to make 'much' difference. (It is why domestic refrigerators still do not, generally, use Peltier cooling; it is not practically very efficient. Sure, they are now used for 'beer coolers' but these can only manage a few degrees of temperature change and the costs and practical manufacturing aspects work out better for a Peltier cooler + heatsink + fan compared to a pump + pressurised (special) gas fridge system.)

It is quite an interesting topic. For example, consider if it is possible to actually use the energy generated from the phase change to dump the excess energy (e.g. drive fans)! It is some nice physics that brings in thermodynamics, heat engines and, importantly, practicalities for an engineer. The inefficiencies of energy conversion will/may (never say never) sting you every time.

In summary, dumping the heat energy generated from changing water vapour to liquid (through cooling) requires energy but how much is not immediately apparent simply from a latent heat calculation. See heat engines. But absolutely, this device concept appears to be rubbish; primarily because of the practical cooling required and the scarcity of water in air.
« Last Edit: May 19, 2016, 12:12:12 am by SydB »

#### EEVblog

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##### Re: EEVblog #881 - Fontus Self Filling Water Bottle BUSTED!
« Reply #41 on: May 18, 2016, 11:40:55 pm »
In summary, dumping the heat generated from changing water vapour to liquid requires energy but how much is not immediately apparent simply from a latent heat calculation.

Of course. But good enough for a back-of-the-envelope ballpark feasibility calculation (which some people seem to forget this was).
If the calc came out well within an order of magnitude, then you go "ok, lets look deeper into the practical implementations" etc and you wouldn't write it off.
But when the calc comes out well over that, possibly two orders out of the ballpark, you take your bat and go home.

Of course, no calculation was even needed, simply looking at the measured outputs of other commercial dehumidifiers is enough to tell you the Fontus stands no chance of working as claimed. You can bet your bottom dollar if the likes of Delonghi and GE et.al can't even get close, some dude on Indiegogo with admittedly zero data, and not even a fully working prototype, is probably not going to do it.

But that's just closed minded me. Insert analogy about the horse and cart and the automobile here

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##### Re: EEVblog #881 - Fontus Self Filling Water Bottle BUSTED!
« Reply #42 on: May 18, 2016, 11:55:43 pm »
In summary, dumping the heat generated from changing water vapour to liquid requires energy but how much is not immediately apparent simply from a latent heat calculation.

Of course. But good enough for a back-of-the-envelope ballpark feasibility calculation (which some people seem to forget this was).
If the calc came out well within an order of magnitude, then you go "ok, lets look deeper into the practical implementations" etc and you wouldn't write it off.
But when the calc comes out well over that, possibly two orders out of the ballpark, you take your bat and go home.

Of course, no calculation was even needed, simply looking at the measured outputs of other commercial dehumidifiers is enough to tell you the Fontus stands no chance of working as claimed. You can bet your bottom dollar if the likes of Delonghi and GE et.al can't even get close, some dude on Indiegogo with admittedly zero data, and not even a fully working prototype, is probably not going to do it.

But that's just closed minded me. Insert analogy about the horse and cart and the automobile here

you linear thinker,..

#### SydB

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##### Re: EEVblog #881 - Fontus Self Filling Water Bottle BUSTED!
« Reply #43 on: May 19, 2016, 12:19:15 am »
In summary, dumping the heat generated from changing water vapour to liquid requires energy but how much is not immediately apparent simply from a latent heat calculation.
Of course. But good enough for a back-of-the-envelope ballpark feasibility calculation (which some people seem to forget this was).

Dave, I am not trying to be awkward here but can you help me understand why a calculation of latent heat should, in any way, imply how much energy you need to dump that heat? Your video was about using fundamental physics to establish the device is rubbish so where is the fundamental physics that connects latent heat to dumping it? I don't get it.

For example, let us say we need to dump 1kJ of heat energy and we are at a temperature above ambient. That will require a lot less energy if it is sitting in a river of liquid nitrogen compared to sitting in a vacuum.
« Last Edit: May 19, 2016, 12:20:55 am by SydB »

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#### Groucho2005

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##### Re: EEVblog #881 - Fontus Self Filling Water Bottle BUSTED!
« Reply #44 on: May 19, 2016, 01:13:07 am »
The internet is the snake oil salesman's dream.
Love it, this goes in my box of cool quotes.

#### Razor512

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##### Re: EEVblog #881 - Fontus Self Filling Water Bottle BUSTED!
« Reply #45 on: May 19, 2016, 02:28:15 am »
It takes a long time the generate the water, and the container needs an opening in order for the water to drip into. How much water will evaporate, and either disappear, or re-condense on the cooler, as compared to new water entering the container?

#### Stebanoid

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##### Re: EEVblog #881 - Fontus Self Filling Water Bottle BUSTED!
« Reply #46 on: May 19, 2016, 02:49:41 am »
In summary, dumping the heat generated from changing water vapour to liquid requires energy but how much is not immediately apparent simply from a latent heat calculation.
Of course. But good enough for a back-of-the-envelope ballpark feasibility calculation (which some people seem to forget this was).

Dave, I am not trying to be awkward here but can you help me understand why a calculation of latent heat should, in any way, imply how much energy you need to dump that heat? Your video was about using fundamental physics to establish the device is rubbish so where is the fundamental physics that connects latent heat to dumping it? I don't get it.

For example, let us say we need to dump 1kJ of heat energy and we are at a temperature above ambient. That will require a lot less energy if it is sitting in a river of liquid nitrogen compared to sitting in a vacuum.

Look at my calculations here http://www.eevblog.com/forum/blog/eevblog-881-fontus-self-filling-water-bottle-busted!/msg942834/#msg942834 we need 16W to dump 250 W in the best case. With Peltier modules we need more then 10 times more  because of their poor efficiency.

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#### matkar

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##### Re: EEVblog #881 - Fontus Self Filling Water Bottle BUSTED!
« Reply #47 on: May 19, 2016, 05:32:36 am »
I haven't looked at the comments, maybe someone pointed this out already.
I stopped watching somewhere after Dave mentioned the 2264 kJ/kg for phase changing. There is your mistake. Right at the beginning. You're dealing with humid air, not clean water vapor. Entirely different equations apply there.
What you need to look is Mollier diagram for humid air. I couldn't find a decent diagram online but here is an example: http://www.engineeringtoolbox.com/psychrometric-chart-mollier-d_27.html
If we extrapolate the diagram you can see you need to take away roughly 10kJ from 1kg of humid air to extract 0,02 kg of water from the air with 90% humidity and 40°C by cooling it to roughly 18°C. So in total you'd need 500kJ of energy to produce a liter of water from 50kg of humid air.
The greater the humidity and higher the temperature the easier it is to extract the water from the air.

I won't do further analysis if the thing is viable from the electrical standpoint. I just wanted to point out the mistake.

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#### nwvlab

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##### Re: EEVblog #881 - Fontus Self Filling Water Bottle BUSTED!
« Reply #48 on: May 19, 2016, 06:58:02 am »
What makes me sad is that you can't even report this campaign to Indiegogo (I tried, but there's no option like "this cannot work").

Because the campaign does not contain prohibited content. It "just" contains things that simply do not work :/

#### jmacqueen

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##### Re: EEVblog #881 - Fontus Self Filling Water Bottle BUSTED!
« Reply #49 on: May 19, 2016, 07:19:45 am »
"If we extrapolate the diagram you can see you need to take away roughly 10kJ from 1kg of humid air to extract 0,02 kg of water from the air with 90% humidity and 40°C by cooling it to roughly 18°C. So in total you'd need 500kJ of energy to produce a liter of water from 50kg of humid air.
The greater the humidity and higher the temperature the easier it is to extract the water from the air."

That seems to line up pretty well with the paper that showed a solar powered peltier device prototype that when tested delivered 1 liter of water per hour on 120w of solar. That would roughly line up with 500kj I think. http://www.psipw.org/attachments/article/273/IJWRAE_1%282%29142-145.pdf

Dave has to be way off in his calculations, I have a little window AC unit that draws about 500 watts that condenses out more than a liter an hour, easily filling a bucket in one day running only intermittently. I actually kept a bucket under it to catch the "distilled" condensed water for other uses.

Smf