Author Topic: EEVblog #881 - Fontus Self Filling Water Bottle BUSTED!  (Read 33712 times)

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Online EEVblog

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EEVblog #881 - Fontus Self Filling Water Bottle BUSTED!
« on: May 17, 2016, 11:39:02 PM »
Dave does basic back-of-the-envelope thermodynamic calculations to prove the Fontus Airo & Ryde self filling water bottle campaign on Indiegogo is full of hot air instead of water.
It's 100% baloney!

 

Offline StuUK

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Re: EEVblog #881 - Fontus Self Filling Water Bottle BUSTED!
« Reply #1 on: May 17, 2016, 11:52:37 PM »
1,140% of $30,000 goal, oh jeez, yet more mugs out there.....
 

Offline elgonzo

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Re: EEVblog #881 - Fontus Self Filling Water Bottle BUSTED!
« Reply #2 on: May 18, 2016, 12:28:53 AM »
1,140% of $30,000 goal, oh jeez, yet more mugs out there.....
There is a sucker born every minute. And some of those suckers are probably from the campaigners social circle, to (*cough*) kickstart the campaign so to speak.

Also, tl;dr for those without time to watch the video: Indiegogo, duh...
« Last Edit: May 18, 2016, 12:33:09 AM by elgonzo »
 

Offline FrankBuss

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Re: EEVblog #881 - Fontus Self Filling Water Bottle BUSTED!
« Reply #3 on: May 18, 2016, 12:29:19 AM »

Online EEVblog

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Re: EEVblog #881 - Fontus Self Filling Water Bottle BUSTED!
« Reply #4 on: May 18, 2016, 12:50:16 AM »
Also, tl;dr for those without time to watch the video: Indiegogo, duh...

It's almost like that now.
Indiegogo = instant impractical ideas
Kickstarter = probably practical, will more likely fail on financials or production.
 

Offline elgonzo

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Re: EEVblog #881 - Fontus Self Filling Water Bottle BUSTED!
« Reply #5 on: May 18, 2016, 01:08:20 AM »
Also, tl;dr for those without time to watch the video: Indiegogo, duh...

It's almost like that now.
Indiegogo = instant impractical ideas
Kickstarter = probably practical, will more likely fail on financials or production.
I sometimes wonder whether there will still be anyone with a sincere and diligent project proposal in the future choosing Indiegogo as crowdfunding platform. "You are known by the company you keep" --  it's hard to argue against that...
 

Offline r4ptor

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Re: EEVblog #881 - Fontus Self Filling Water Bottle BUSTED!
« Reply #6 on: May 18, 2016, 01:20:25 AM »
Shit, this crap is even from my home country it appears.

Oh boy. I can say you one thing, we students here at the technical universities are laughing our ass of about this.  :popcorn:
 

Offline Razor512

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Re: EEVblog #881 - Fontus Self Filling Water Bottle BUSTED!
« Reply #7 on: May 18, 2016, 01:27:05 AM »
The device truly works, you can even observe the results, the reason why you are skeptical, is because you do not take the proper initial steps prior to viewing the product.

The first step requires you to fill the entire bottle with LSD, and then chug it.

The LSD then helps you to see the machine working as intended.

Without the LSD, logic takes over and thinks look disappointing.
« Last Edit: May 18, 2016, 01:40:23 AM by Razor512 »
 

Offline Arjan Emm

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Re: EEVblog #881 - Fontus Self Filling Water Bottle BUSTED!
« Reply #8 on: May 18, 2016, 01:45:24 AM »
I'm afraid the back of the envolope calculations are wrong. Atleast the 1L/h statement. Whatever time it takes, you always need a minimum of 2264 KJ of energy to produce 1 liter of water. So that's 2264000/60/150= 250 watts for 150 minuts or 2.5 hours. To produce 1l/h you need 630 watt. So 2.5 times worse as you  stated. 2264000/3600.
You devide by 2.5 twice for some reason. Very nice video anyway. Always good to see these scams busted. Keep it up !
« Last Edit: May 18, 2016, 01:58:37 AM by Arjan Emm »
 

Offline daqq

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Re: EEVblog #881 - Fontus Self Filling Water Bottle BUSTED!
« Reply #9 on: May 18, 2016, 02:08:08 AM »
Thanks Dave for the video. I particularly like your enraged super E letter used in system :)
Believe it or not, pointy haired people do exist!
+++Divide By Cucumber Error. Please Reinstall Universe And Reboot +++
 

Offline abaxas

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Re: EEVblog #881 - Fontus Self Filling Water Bottle BUSTED!
« Reply #10 on: May 18, 2016, 03:36:11 AM »
Who knows, maybe the solar cell is 100% efficient  O0
 

Offline bitwelder

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Re: EEVblog #881 - Fontus Self Filling Water Bottle BUSTED!
« Reply #11 on: May 18, 2016, 03:48:16 AM »
Who knows, maybe the solar cell is 100% 800% efficient  O0
That's more like it.
 

Offline Fady

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Re: EEVblog #881 - Fontus Self Filling Water Bottle BUSTED!
« Reply #12 on: May 18, 2016, 03:55:39 AM »
Where can I find the link Dave mentioned at 14:52?
 

Online Dr. Frank

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Re: EEVblog #881 - Fontus Self Filling Water Bottle BUSTED!
« Reply #13 on: May 18, 2016, 03:57:23 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).
So in 150 min = 2.5h, you would 'only' need a 100W panel.


This energy argument also is not directly convincing, if you think of physical 'heat pumps'.. (e.g. inversely running Sterling motor)
These machines have an efficiency, which is by definition >> 1, so you may pump these 905kJ out of the vapor by a fraction of equivalent in electrical energy, theoretically.

A practical machine of that sort (~ 40..60°C, 100% humidity) is the tumble dryer, which needs about 1.6kWh to condense several liters water out of the laundry.. if you have a modern device (EU energy rating A+++) with heat exchanger.

So the most obvious practical argument would be, that this device does not consist of the necessary miniaturized parts, like heat pump, condenser, heat exchanger, and so on.

Frank
« Last Edit: May 18, 2016, 04:52:41 AM by Dr. Frank »
 
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Online station240

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Re: EEVblog #881 - Fontus Self Filling Water Bottle BUSTED!
« Reply #14 on: May 18, 2016, 04:44:42 AM »
I lost it when it became clear Dave had put a stamp + name and address on the back of envelope calculations so he could mail it.
 

Offline SaabFAN

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Re: EEVblog #881 - Fontus Self Filling Water Bottle BUSTED!
« Reply #15 on: May 18, 2016, 05:16:10 AM »
Don't be too harsh on those people. They just forgot to mention the capsule with LIQUID NITROGEN to cool the hot side of the peltier-element.
Happens even to the best :D

Offline Arjan Emm

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Re: EEVblog #881 - Fontus Self Filling Water Bottle BUSTED!
« Reply #16 on: May 18, 2016, 05:23:27 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).
So in 150 min = 2.5h, you would 'only' need a 100W panel.
frank
If you keep on deviding by 2.5 at some point this becomes a viable device.
« Last Edit: May 18, 2016, 05:27:55 AM by Arjan Emm »
 

Offline Stebanoid

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Re: EEVblog #881 - Fontus Self Filling Water Bottle BUSTED!
« Reply #17 on: May 18, 2016, 05:37:11 AM »
Dave, in order to produce water from steam you have to take energy out of steam, not to bring it. You have to take 250 W from the freezer in the bottle - it's a different case.
Lat's do the math.

dew point for 40C 90% is Tc = 37 C = 310.15 K
ambient temperature Ta = 40C = 313.15 K
Diameter of a hot radiator d= 6cm= 0.06m
Speed of a cyclist = 15 km/h = 4.16 m/s
Isobaric volumetric heat capacity of air C=0.0013 J*cm^-3*K^-1 = 1300 J*m^-1*K^-1

So for Carnot cycle (ideal case) we have
W = Wh*(1-Tc/Th)
where W = power of the heat engine, Wh - Power of the heat source, Tc - temeperature of the cooler, Th - temperature of the heater.
Engine produces power W taking power Wh from the heat source and bringing part of it Wc to cooler.
As long as Carnot engine is reversable we can bring power to it taking power Wc from the cooler and moving Wh=Wc+W to the heater. We know that we have to move Wc=250W from the freezer. Let's find how much power W we need for that.
We know that Tc=310.15 K because it's a dew point we need to get water.
Let's find Th.
All Wt has to be blown out by air, moving through the radiator of the system.
Every second through the cylinder d=0.06 moving with a speed 4.16 m/s passes V=0.01 m^3/s of air.
If heat exchange is perfect air comes out with temperature Th and moves away
(Th-Ta)*C*V of power
Wh = (Th-Ta)*C*V
on the other hand Wh = W/(1-Tc/Th) = (Wh-Wc)/(1-Tc/Th)
Wh=Wc*Th/Tc

(Th-Ta)*C*V = Wc*Th/Tc
Th = V*C*Ta/(V*C - Wc/Tc)
= 333.8 K

W=Wc*(Th/Tc-1) = 19 W (to move 250 W from the bottle)

What's the size of a 19 W panel?
« Last Edit: May 18, 2016, 06:37:51 AM by Stebanoid »
 
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Offline Stebanoid

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Re: EEVblog #881 - Fontus Self Filling Water Bottle BUSTED!
« Reply #18 on: May 18, 2016, 05:46:43 AM »
Of course, if they want to use Peltier cooler with a 10% of efficiency of the Carnot cycle, they have to find 190 W of power. And because of that additional power we have to dissipate, our hot radiator will be much hotter and it leads to even less efficient cooling which leads to even more power consumption and so on.  :scared:
 

Offline TheAmmoniacal

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Re: EEVblog #881 - Fontus Self Filling Water Bottle BUSTED!
« Reply #19 on: May 18, 2016, 06:15:39 AM »
And what about the water in the bottle continuously evaporating and recondensing on the peltier? Lots of wasted energy.
I collect [corporate] mugs.
MTBF ~ 700.000 h
 

Offline Stebanoid

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Re: EEVblog #881 - Fontus Self Filling Water Bottle BUSTED!
« Reply #20 on: May 18, 2016, 06:33:59 AM »
In ideal case in thermally isolated bottle we have a water with temperature of the dew point and 100% humidity. But in real life it will take some energy of course.
 

Offline jmacqueen

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Re: EEVblog #881 - Fontus Self Filling Water Bottle BUSTED!
« Reply #21 on: May 18, 2016, 07:39:08 AM »
And then there's this paper from the "International Journal of Water Resources and Arid Environments" that draws a litre of water an hour using the same basic technology at 120w of solar power. Given they are likely at high temp and humidity..

But they use multiple peltier devices and they run the air first through the hot side heatsink so it can gain more moisture, and then run it through cold side heatsink.

But still published results of a liter per hour at just 120w solar.

http://www.psipw.org/attachments/article/273/IJWRAE_1%282%29142-145.pdf?

Could it be made even more efficient with better heat transfer technology in larger surface area heatsinks?
« Last Edit: May 18, 2016, 07:51:37 AM by jmacqueen »
 

Offline Stebanoid

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Re: EEVblog #881 - Fontus Self Filling Water Bottle BUSTED!
« Reply #22 on: May 18, 2016, 08:01:58 AM »
Yep. If we use cooled and dehumidified air for cooling of the hot radiator we will get Th=330
And W= 16.5 W
 

Offline Stebanoid

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Re: EEVblog #881 - Fontus Self Filling Water Bottle BUSTED!
« Reply #23 on: May 18, 2016, 08:10:01 AM »
Could it be made even more efficient with better heat transfer technology in larger surface area heatsinks?
From equation I got follows that yes.
But Israel uses reverse osmosis for water harvesting. I think that they did the math too and it's more efficient.
Basically water is not a problem in wet environment. It's usually a problem in dry climate. And you cannot harvest water from dry air. Dew point for 40C 20% is 13C. For 40C 10% is 3C !!!
 

Offline jmacqueen

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Re: EEVblog #881 - Fontus Self Filling Water Bottle BUSTED!
« Reply #24 on: May 18, 2016, 09:27:25 AM »
Yeah there is a lot of reverse osmosis water harvesting in that whole region. Seems to be the dominant technology, I assume that is for several reasons. Sailboats use R.O. pretty exclusively as well they call it a "watermaker", and you can even buy a hand pump R.O. system for your emergency lift raft or whatever.

In a survival situation I could likely use a couple of plastic garbage bags to harvest enough water to survive on using condensation, probably more than the indiegogo device can make.

I am curious though if that liter per hour at 120w they got in the paper could be refined and reduced to maybe 70w?, their heat sinks appeared to be off the shelf hack together stuff. How much room for improvement is there in improving thermal flow and surface area?? 10%?, 20%? 50%?
« Last Edit: May 18, 2016, 09:35:27 AM by jmacqueen »
 


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