Is this possible ? 2

[nbucska]

Humid air contains more energy than the same amount of
dry air and water at the same temperature.

Would it be possible to take humid air ( e.g. at sea )
compress it, with heat exchenger cool it, precipitate
the water and recover the energy from heat and pressure
to drive the compressor.

Would this be useful for producing clean water?
Perhaps even end up with some energy left over ?


Plesae read FAQ240-1032
My WEB: <

http://geocities.com/nbucska/>

 

[MortenA]

The "solar tower" (see link:

http://www.economist.com/science/displayStory.cfm?story_id=4455446

) seems more feasible.

Here the solar heat and condensing humidity is used to generate power by creating an artificial tornado is a stack.

Best regards

Morten

 

[zdas04]

This is an odd thread. Yes, you can get water vapor to condense by changing its pressure and temperature. The problem is that the process has a very low effeciency (on the order of 10% of the energy input is used for water production). You would be way ahead to accelerate the evaporation by recovering some of the waste heat from the engine.

Nothing about this process is "perputual motion", it would require a huge energy input.

David

David Simpson, PE
MuleShoe Engineering

http://www.muleshoe-eng.com

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

The harder I work, the luckier I seem

 

[handleman]

Oil and water do separate themselves spontaneously. However, the separation is mechanical. During the mixing of an oil-water suspension there is energy stored as surface tension potential (surface area vs. volume ratio is high) and gravitational potential (water is heavier than oil). Comparison does not apply.

 

[nbucska]

Thank, Morten, this seems to prove that the idea is possible and Mr. Michaud has found a way to realize it.

Would a star an acceptable expression of thanks?


Plesae read FAQ240-1032
My WEB: <

http://geocities.com/nbucska/>

 

[rb1957]

an interesting article, but i can't help but wonder if the tornado will from if there's a turbine taking energy out of the system ? and if the tornado is solar powered, how will it keep running ?

just another skeptic ...

 

[JStephen]

"this seems to prove that the idea is possible"- with the exceptions that the compression and cooling in the original scenario have been removed, and the process now requires heat input from solar.

" and Mr. Michaud has found a way to realize it"- but in fact it seems Mr. Michaud is a long ways from realizing even his idea.

The original cycle is very close to running an evaporative cooler in reverse, for what that's worth.

 

[unclesyd]

Back in 70's there was an attempt to develop a non Freon auto air conditioner "Rovac" using air.
The automobile use didn't workout so an attempt was made to use it in a mode similar to original post, cool the house and get potable water. My last information was that work was continuing but results had been as expected.

As for trapping water it is being done on a very large scale in Chile and Peru using fine mesh nylon nets as collectors tied to a central cistern. It is giving thousands of people clean fresh water for the first time.

As for the water collecting on a sail as you will definately get wet standing under a sail if the boat isn't moving too fast.

 

[blfarrar]

Compressing air whatever the humidity means the air is heated up, cooling this in a heat exchanger presumably at the same pressure will put air through dew point & dry or de humidify the air this water can be drained off with a slight loss of pressure.

The condensate will be water with all the impurities from the air & process (non-potable) & will have contamination from the compression process (possibly oil).

The amoung of energy used in compression, cooling the heat exchanger (pumps), a source of cooling for the heat exchanger either sea water or some form of fridge take energy away from the mass of compressed air.

The amount & form of energy left in compressed air has to be less that that invested in the system & has to be in a usable form - essentially any compressed air "motor" is inefficient as it kaes air at one pressure & releases it to atmosphere in one pass.

Energy is used & not multiplied or for that matter easily stored.

Bruce L Farrar.
Works Engineering Manager
Marshalls Mono PLC.Brookfoot Works.
Halifax W.Yorks UK

 

[schmilton]

There is a commercial unit for condensing water from humid air.

http://www.wataireindustries.com/

They even have residential units. They have quite a bit of information on their site.

 

[unclesyd]

Here is the patent to the above machine. I am digging for my literature on the Rovac as this looks like the problems with moisture in the Rovac have been put to use making water instead of causing ice formation.

http://patft.uspto.gov/netacgi/nph-...50&s1=6957543.PN.&OS=PN/6957543&RS=PN/6957543

 

[blfarrar]

I have accessed the site for the commercial water generators, fair play guys I have learnt something I wasnt aware of.

Refering back to the original question this product is not quite the same in terms of recovering energy to drive the device (which simply cannot be done due to inefficiencies)

One question that puzzles me still is that the atmosphere contains all sorts of contamination (one in particular legionella is present in most of the air we breath - its only when it becomes waterborn, is incubated, then atomised into droplets breahted by susceptible people a problem arises)

How does the system overcome this contamination ?

Commercial fresh water generators (evaporating or distilling) sea water into fresh potable water have to take the water past 180 deg f & have certain restrictions if the sea water contains effluent (as most coastal water does) - simply passing the water condensed by refrigeration through filters etc etc - I will get some data from the makers & update my head with the latest technology !!

I am interested as to how much power these units use in electrical terms & whether these are used in marine environments - as the system gets around the destruction caused by sea water - the marine engineers curse !

Bruce L Farrar.
Works Engineering Manager
Marshalls Mono PLC.Brookfoot Works.
Halifax W.Yorks UK

 

[Jabberwocky]

I think it was mentioned briefly above:

http://en.wikipedia.org/wiki/Ocean_thermal_energy_conversion

There are plans to use the temperature differential between shallow and deep water to generate power. Honestly I've never heard of it actually being used, but we'll see what happens as oil $ continues to rise.

 

[rb1957]

in Toronto, they're using cold water (from the bottom of the lake) as an airconditioning refridgerant for some the city buildings ... it'll save electricity.

 

[unclesyd]

There was a big experiment off Hawaii several years ago that eat up a lot of money. I remember that we had a Hx on order and it was put aside while the fabricator work on a super large Ti exchanger for the Hawaii Thermal Project.


I think this project was like the Oil Shale project out west, it got over fertilized with money and died.

Anecdote:
I was instrumental in purchasing an all SS centrifugal compressor leftover from the Oil Shale Project. It was brand new in the box and only 10 years old. There was a very good discount on it.