Evaporation+Condensation+Gravity = Overunity

[broli]

We all know if we leave a dish of water in open air that the water will evaporate over time. The reason this happens is because Temperature is a measure of the AVERAGE kinetic energy (speed) the molecules of water have. Some of these molecules have thus a higher kinetic energy than others and these molecules are able to escape from the liquid-air interface. As these high speed molecules escape the overal temperature of the leftover liquid naturally lowers. The reason why you don't end up with a dish of ice is because the environment keeps pumping its energy back into the water and thus this cycle continues until no water is left.


But when this happens in a closed container over time you will end up in an equilibrium state, what's known as the vapor pressure of a liquid. That is the point when there is an equal amount of high speed molecules leaving the liquid-vapor interface as there are entering it.


However if you add two extra variables to this closed system:
1) the environment temperature
2) gravity


You can essentially extract limitless energy from the ambient temperature using gravity and bypass the second law of thermodynamics as the law only applies to closed systems.


You DO NOT need a temperature gradient between the liquid and the top of the container for condensation to happen. This happens due to the same reason you have molecules leaving the liquid-vapor interface. Some of those high speed molecules will hit the roof and collect there to form drops/film and essentially "heat" the container up as they transfer their energy, which is its own regards attached to the ambient temperature. Thus the container will act as a heat sink and give this acquired heat off to the environment. This in turn will cool back the container. It's the very fact the environment is a huge buffer to temperature change that this works.


You can even do this experiment in your kitchen. Take a plate and put some water in it, cover the plate with aluminiumfoil or plastic wrap. Leave it in a place with stable temperature for a while. When you come back you will notice some condensation on the foil. This means some molecules traveled from the liquid to the roof of the container against gravity. If these drops where to fall back they would be able to perform work against a generator of some kind.


The problem here is that the amount of work you can extract from this is very tiny but this is more of an engineering and material issue than concept problem. For instance if the roof is superhydrophobic and spiky, drop formation is encouraged instead of sticky film formation. One example of this is to use a graphene coating.


Such device would allow you to extract energy from the ambient temperature day and night.

[Pirate88179]

This is the reason that Niagara Falls works as a power generating station.  If you really look at it though, you will see it is actually solar powered as the water would not be upstream from the falls without the sun.  Your experiment with the plate and the foil is interesting but remember that "ambient" temperature gets its energy from somewhere....either the sun or the home heating device inside the house.  Without the sun, earth would be a minimum of -250F.


I always thought a scaled up version of an evaporation tower could be used to generate some electricity but, probably not a lot due to the time involved.  I also thought about using capillary attraction and a series of small I.D. tubes to raise water up for power generation but that too would take a long time and it would only go so high and would need many levels to get high enough to do any good.


Anyway, in my opinion, calling evaporation overunity would be the same as calling solar cells overunity as they are both powered by the sun.


Bill

[broli]

Yep you are correct on all counts, essentially the sun is the power source here. Overunity refers to the closed system + gravity and sun as it heats up the ambient environment. However the point of this device is that it does not need a temperature gradient to operate so it can operate continuously.


The real question is can appropriate materials enhance the power output.


Attached are some pictures of the simple experiment. The container with alcohol was left in a dark, draft free cupboard for a few hours. Droplet formation can be seen on the clinging foil and the foil is bulging due to the vapor pressure.

[vineet_kiran]

I feel that it is due to the presence of air inside the container.    What happens if density of air is increased by applying pressure using a tube water column fixed to the side of the container?

[vineet_kiran]

https://www.youtube.com/watch?v=3h49i1iDNP4

Nice video showing desalination by evaporation.

Europe is getting heated up and facing drought whereas few Asian countries like South Korea,India etc., are receiving heavy rains.  It means hot and dry air moving from Europe, collect water vapors while moving above oceans and dump it as rain on Asian nations and it is said that it is because of climate change effect caused by global warming process.

Is it possible to use same effect to get fresh water from sea water?  In the experiment shown in video,  if we fill the container with green house gases like CO2 and apply some pressure to increase gas density will not the evaporation process get accelerated?

If it is done on a large scale by inserting a huge baseless container to some depth in ocean and fill top portion with green house gases under pressure, will not we get large quantity of fresh water which can solve drought problem?