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Leo Ticheli · 12-10-2016, 06:13

I hope this post will stand muster; a previous attempt included a link to Indiegogo, which I now know is forbidden. I apologize.

I've got a Spectra on my boat, but I wonder if something like this could work at sea.

https://www.youtube.com/watch?v=9YWazc7ANAo

Fair winds,

Leo

senormechanico · 12-10-2016, 07:03

Maybe, but the air temp must be above the lower collection container's temp for it to work.
I can see lots of other disadvantages on a boat.

I'm going to stick with my solar panels and Spectra.

J Clark H356 · 12-10-2016, 07:49

This is just simple physics. All air has some moisture within it and when the air temperature reaches the dew point, moisture condenses. When you see clouds in the sky, the air has reached the dew point temperature (relative humidity of 100%) at that altitude. The temperature of the air goes down about 2 degrees centigrade for every 1000 feet of altitude. This is common knowledge among pilots.

What this device is doing is using soil temperature to lower the temperature of the surface of the container to at or below dew point and allow the moist air to condense (relative humidity of 100%) on the sides producing liquid water. Same principle as a glass of ice water in a room. Has an added disadvantage that mold grows when the relative humidity is over 70% and it is dark. This water would have to be filtered and somehow the container would have to have an anti-mold and algicide chemical agent to keep mold and other undesirables under control.

This is somewhat analogous to your bilge. Would you like to drink raw bilge water?

Sent from my iPad using Cruisers Sailing Forum

**a64pilot** · 12-10-2016, 08:36

Yeah unless its the size of a water tower I'd have to see it condense 37 liters a day to believe it.
An airconditioner which moves an incredible amount of air over the evaporator will condense what, maybe a couple of liters?

nitpik · 12-10-2016, 09:13

And, they claim it will work even without the wind? How is that?
Maybe if you add solar and a small battery to power the internal fan. Otherwise, there will be no fresh, moisture-laden air being pumped down into the underground reservoir.

expatri8 · 12-10-2016, 09:15

Quote:

Originally Posted by a64pilot

Yeah unless its the size of a water tower I'd have to see it condense 37 liters a day to believe it.
An airconditioner which moves an incredible amount of air over the evaporator will condense what, maybe a couple of liters?

Me too.
I spent a lot of time learning aerodynamics and fabricating propellers
for an airboat, and just the dead-simple math makes you realize this idea leaks.

If you just notionally propose that one cubic meter of air
has a few drops of water in it (~3ml, 3% by mass at 30 °C ),
and you could even fantasize about pulling a third of those drops out of that 1 m3
then you could see that to get a liter of h2o you will need to move a lot of air:
1000m3 of air moving past a (bulky) condenser 1m2 in size will,
at 1m/s (~2knots) speed, take 1000seconds to get you that liter.
Understand that 1m/s is not free energy:
you are pushing wind through it one way or another.
The air needs to be compressed then expanded again
The energy transfer by cooling alone is huge just to get that 1 liter,
not counting the energy needed to move all the air in the first place (maybe wind).

The idea will work - that much is true - but the dimensions are not realistic.
This would work for about a day or so in the desert you see in the video,
before the ground temperatures equalized.

manawatuman · 12-10-2016, 09:22

Bear Grylls taught me urine with a little johnny walker is very morish.

valhalla360 · 12-10-2016, 09:33

Quote:

Originally Posted by a64pilot

Yeah unless its the size of a water tower I'd have to see it condense 37 liters a day to believe it.
An airconditioner which moves an incredible amount of air over the evaporator will condense what, maybe a couple of liters?

This device is silly and won't provide any use.

An air/con will create quite a bit. I had the condensation drain block and after a couple days there was around 10 gal of water in the bilge (which is otherwise dry). Not that it makes any sense to use an air/con to create water.

lordgeoff · 12-10-2016, 13:18

Quote:

Originally Posted by J Clark H356

This is just simple physics. All air has some moisture within it and when the air temperature reaches the dew point, moisture condenses. When you see clouds in the sky, the air has reached the dew point temperature (relative humidity of 100%) at that altitude. The temperature of the air goes down about 2 degrees centigrade for every 1000 feet of altitude. This is common knowledge among pilots.

What this device is doing is using soil temperature to lower the temperature of the surface of the container to at or below dew point and allow the moist air to condense (relative humidity of 100%) on the sides producing liquid water. Same principle as a glass of ice water in a room. Has an added disadvantage that mold grows when the relative humidity is over 70% and it is dark. This water would have to be filtered and somehow the container would have to have an anti-mold and algicide chemical agent to keep mold and other undesirables under control.

This is somewhat analogous to your bilge. Would you like to drink raw bilge water?

Sent from my iPad using Cruisers Sailing Forum

Not sure how "zero energy" fits into this story. ......

SV THIRD DAY · 12-10-2016, 15:45

These have been around longer than I've been alive....

Rorzech · 12-10-2016, 16:51

It all depends on the relative humidity whether its 2 litres or 200 litres per day along with the BTU's

Rorzech · 12-10-2016, 17:01

If it came down to drink the bilge or die ,I'd probably use a straw and avoid the mould and oil and floating things as much as possible and only drink enough to just stay alive if it didn't kill me first. Ha Ha I guess you could take the water out of the bilge and filter it out the best you can and let the sun's UV kill the bacteria somewhat for you. Desperate times require desperate measures.Let's hope it never comes down to considering the bilge as a water source.