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#33972 - 04/16/10 11:31 PM Re: Harnessing the power of the sun [Re: paul]
kallog Offline
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Registered: 03/17/10
Posts: 1100
Not sure about the industrial process, I think it involves membranes and some chemical.

Some problems like flow resistance of gasses can be reduced as low as you like. Just use wider pipes, slower speeds, etc. Charging the gas or particles suspended in it would create a current flow as the charges move, so that consumes energy just like any electric circuit.

But all these negatives aren't really bad. If you can gain arbitrarily more energy by floating the container up a higher distance, then eventually it'll overcome every inefficiency. Practical details like building a tower into space aren't a problem. It would still be a rewrite of accepted thermodynamics even if we can't actually do it today on Earth.

I think the critical issue is that nothing at all can be gained from bouyancy. Efficiency improvements always asymptotically approach the theoretical limits, which are below what's required for perpetual motion.

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#33973 - 04/17/10 01:23 AM Re: Harnessing the power of the sun [Re: kallog]
paul Offline
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Registered: 03/21/06
Posts: 4136
Kallog

Quote:
It would still be a rewrite of accepted thermodynamics even if we can't actually do it today on Earth.


I've always considered that systems that do not use heat as its prime mover
should not be bound by thermodynamics.

the system we are discussing here is the system that uses buoyancy as the prime
mover and the electrolysis system that uses heat/energy to remove water from the
containers at the bottom of the tank is a seperate system.

Quote:
I think the critical issue is that nothing at all can be gained from bouyancy.


sure it can , by enclosing the tank at the top we can pressurize it.

since buoyancy is due to pressure.

http://www.youtube.com/watch?v=G3_yiwyezPY

I dont think this will work if you have a oppossing container but if you are using only buoyants going up or down , it will work.

if the tank is completely filled with water except for a small area inside a cylinder at the top that has a plunger piston inside it , a small force applied with your hand can greatly pressurize the entire tank to a higher pressure or throw a vacume on it as pressure is distributed equally in a fluid.


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_________________________
3/4 inch of dust build up on the moon in 4.527 billion years,LOL and QM is fantasy science.

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#33979 - 04/17/10 01:59 PM Re: Harnessing the power of the sun [Re: paul]
kallog Offline
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Registered: 03/17/10
Posts: 1100
Originally Posted By: paul

I've always considered that systems that do not use heat as its prime mover
should not be bound by thermodynamics.

Some of the laws specify thermal processes. But the 1st law of thermodynamics is the law of conservation of energy, and applies to all energy forms. People have been searching hard for violations to this ever since it was discovered, but it's never failed yet.

But yea heat engines are pretty useless at converting energy. They're bound by the 2nd law which restricts their theoretical maximum efficiency to much less than 100% in most cases.

As a side note, compressing air is a thermal process. It generates heat, so it's less efficient than an elastic spring.


To make it sink you have to use energy to compress the air. If you recover that while it floats back up then you can't recover it from the expansion of the bottle/piston. So you come out even at best.

If you make it sink so deep that the pressure of the water compresses the air in the floater automatically and pushes it down further, then to bring it back up you have to expand that air. Doing that means lifting the column of water above it. So the deeper it goes the more energy you need to do a complete cycle.

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#33982 - 04/18/10 12:36 AM Re: Harnessing the power of the sun [Re: kallog]
paul Offline
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Registered: 03/21/06
Posts: 4136
Quote:
The first law of thermodynamics, an expression of the principle of conservation of energy, states that energy can be transformed (changed from one form to another), but cannot be created or destroyed.



Quote:
The first law of pigs feet, an expression of the principle of conservation of pigs feet, states that pigs feet can be transformed (changed from one form to another), but pigs feet cannot be created or destroyed.



you cannot create or destroy anything.
you can only change something from one form to another.


the first law of paul , an expression of the principle of conservation of common sense , states that only energy is energy.

Quote:
As a side note, compressing air is a thermal process. It generates heat, so it's less efficient than an elastic spring.


compressing a spring also generates heat.
so there both thermal processes.

Quote:
To make it sink you have to use energy to compress the air. If you recover that while it floats back up then you can't recover it from the expansion of the bottle/piston. So you come out even at best.


that makes no sence , the expansion must happen before it floats back up.

ie.. the bottle will expand by itself.
the float at the bottom then rises due to buoyancy.

Quote:
If you make it sink so deep that the pressure of the water compresses the air in the floater automatically and pushes it down further, then to bring it back up you have to expand that air. Doing that means lifting the column of water above it. So the deeper it goes the more energy you need to do a complete cycle.


first the video of the cartesian diver didnt have air inside it , it is just a piece of wood that has a metal paper clip attached at the bottom.

but since you mentioned compressing air lets suppose it was a inverted drinking glass , that had some air at the top.

you pressurize the bottle and the glass sinks , you compress it even more and the air at the top of the glass will compress even further , but as soon as you release the bottle or decompress the bottle the air at the top of the glass will expand on its own due to the decrease in water pressure as it rises to the surface.

so you only put energy in once , it is a small amount of energy compared to the amount of energy you can get back..

Quote:
Doing that means lifting the column of water above it. So the deeper it goes the more energy you need to do a complete cycle.


if you were standing on the bottom of the ocean , and you held out your hand , all the water from your hand to the surface of the ocean and all the air from the surface of the ocean to outer space would be sitting on top of your hand.

but you wouldnt feel it.

and you could easily lift your hand , because the pressure underneath your hand would be the same as that on top.

these guys can explain it in this video much better that I can

http://www.youtube.com/watch?v=j7EA1KRK7eI&feature=related



.
_________________________
3/4 inch of dust build up on the moon in 4.527 billion years,LOL and QM is fantasy science.

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#33984 - 04/18/10 03:20 AM Re: Harnessing the power of the sun [Re: paul]
kallog Offline
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Registered: 03/17/10
Posts: 1100
Originally Posted By: paul
The first law of pigs feet, an expression of the principle of conservation of pigs feet, states that pigs feet can be transformed (changed from one form to another), but pigs feet cannot be created or destroyed.


I don't understand your point there. Clearly pigs feet aren't conserved. So are you saying the 1st law is just made up? Well yes it probably is just made up. There are lots of conservation laws that are just made up, and they're made up when we notice something seems to always be conserved. Of course it might be disproven oneday, but so far that hasn't happened, despite a monumental amount of effort trying. You're not going to disprove it in the same conventional ways that've been attempted over and over again before.


Quote:
first the video of the cartesian diver didnt have air inside it , it is just a piece of wood that has a metal paper clip attached at the bottom.


Yes it does look that way. But in that case, how does it work? A conventional cartesian diver has air inside the floater. The video you just posted has air in the dropper.


Quote:
if you were standing on the bottom of the ocean , and you held out your hand , all the water from your hand to the surface of the ocean and all the air from the surface of the ocean to outer space would be sitting on top of your hand.

but you wouldnt feel it.


Yes, but so what? If your hand had a little bit of bouyancy it'd float up. But if it's bouyant how did you get it down there in the first place? You had to consume a huge amount of energy pushing it all the way down.

If the bouyancy was due to some incompressible foam or pressure vessel, then you can't change the bouyancy by pressurizing the ocean. If the bouyancy was due to gas in a flexible container, then that gas can be held in compression by the huge water pressure. To expand it you have to use a huge amount of energy opening up a bubble under the ocean, working against the column of water above you. The deeper you are the more energy this requires.



Edited by kallog (04/18/10 03:21 AM)

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#33994 - 04/19/10 02:13 AM Re: Harnessing the power of the sun [Re: kallog]
paul Offline
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Registered: 03/21/06
Posts: 4136
Quote:

I don't understand your point there. Clearly pigs feet aren't conserved.


if you burn a pigs foot it is transformed into other stuff.
if you burn gas it is transformed into other stuff.

neither is destroyed.

so both are conserved.

and you cannot create pigs feet or gas.

Quote:
So are you saying the 1st law is just made up?



energy is not a fuel of any type.
it is the result of a force.
if that force is gas or pigs feet or anything that burns burning under a boiler producing steam , or sunlight producing steam and then that steam produces a force then it is that force that is energy.

you cannot destroy a force. you can only transfer a force from one object to another object.

you cannot create anything , so you cannot create a force on a object that would transfer that force to another object.

the first law is 100% correct , its just used improperly as it is only used in thermodynamics and it applies to everything.

Quote:
But in that case, how does it work?


when the bottle is squeezed the air at the top of the bottle is compressed and the pressure of the air and the water in the bottle both increase to the degree of pressure placed on the bottle by the force he is applying with his hands.

in a closed container pressure is equally distributed in all directions , this means that the water pressure surrounding the object is equal everywhere on its outside.

and buoyancy is due to a pressure difference at the top and the bottom of a submerged object , since there is no pressure difference there is no buoyancy.

and it sinks.

the object floats in the bottle because it is placed in the bottle at 1 atm.

he then places a cap on it , but the pressure remains at 1 atm.


it only sinks when the pressure in the bottle no longer differenciates.


Quote:
Yes, but so what? If your hand had a little bit of bouyancy it'd float up.


does you hand float up when you go outside?

Quote:
But if it's bouyant how did you get it down there in the first place? You had to consume a huge amount of energy pushing it all the way down.


a submarine floats on top of the water.

but if you release air out of the submarine , the submarine sinks.

all the way down to the bottom.


the reason they dont sink all the way down below their rated depth is because they dont allow all the air out of the submarine.

they intentionaly keep some compressed air inside to ballast the submarine at a desired depth.

or to obtain neutral buoyancy under water.

do you have a physics book?

_________________________
3/4 inch of dust build up on the moon in 4.527 billion years,LOL and QM is fantasy science.

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#33995 - 04/19/10 03:28 AM Re: Harnessing the power of the sun [Re: paul]
kallog Offline
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Registered: 03/17/10
Posts: 1100
Originally Posted By: paul
if you burn a pigs foot it is transformed into other stuff.
if you burn gas it is transformed into other stuff.

neither is destroyed.

I think you're talking about conservation of energy there. As you just said, if you burn a pig's foot it's not longer a pig's foot, it's other stuff.

So the convervation of energy isn't obvious and meaningless. Most things aren't conserved. Energy seems to be. Electric current isn't conserved, temperature isn't conserved, pressure isn't conserved, force isn't conserved. These quantities can be converted to other forms, but that counts as "destroying" them. Energy doesn't suffer this problem because every form that it can be converted to is also classified as energy.

Quote:

the first law is 100% correct , its just used improperly as it is only used in thermodynamics and it applies to everything.

If it's correct then no perpetual motion machine can produce energy. Or are you saying _everything_ is conserved, not just energy? That really is just a twisting of the English language and has nothing to do with science.


Quote:

in a closed container pressure is equally distributed in all directions , this means that the water pressure surrounding the object is equal everywhere on its outside.


No. Even with the applied pressure, there's still the same pressure gradient caused by gravity. They didn't even make your claim in the video. Maybe there's a hole drilled up the middle of the wooden(?) floater?

If the pressure gradient dissapeared, then any floating thing would sink, including the air at the top of the bottle!


Quote:

does you hand float up when you go outside?

Huh? How is that relevent? Please say what you mean directly.


Quote:

they intentionaly keep some compressed air inside to ballast the submarine at a desired depth.

No. A submerged submarine isn't in stable equilibrium. It's either sinking or floating. They have to continually adjust the bouyancy to maintain a fixed depth hydrostatically.


Quote:

do you have a physics book?

I have quite a few. Why do you ask? I don't refer to them much anymore because the internet is easier.

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#34003 - 04/19/10 03:19 PM Re: Harnessing the power of the sun [Re: kallog]
paul Offline
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Registered: 03/21/06
Posts: 4136
Quote:
Or are you saying _everything_ is conserved, not just energy?


YES !! twist twist twist ... but maybe Im just untwisting something that was previously twisted up in a knot.

Quote:
No. Even with the applied pressure, there's still the same pressure gradient caused by gravity. They didn't even make your claim in the video. Maybe there's a hole drilled up the middle of the wooden(?) floater?

If the pressure gradient dissapeared, then any floating thing would sink, including the air at the top of the bottle!

Galileo's Thermometer


A beautiful instrument, known as a Galilean thermometer, relies on buoyancy to measure temperature. The device consists of a sealed vertical glass cylinder mostly filled with a clear liquid. In the liquid are colorful glass bulbs, each having a precise density and a tag indicating a particular temperature. As the temperature changes, the glass bulbs rise and sink. The temperature is read by looking at the tag attached to the lowest floating bulb.

if the temperature increases , the pressure also increases.
that is why the above thermometer works.

there is no air being compressed inside the bulbs as a result of the fluid pressure inside the cylinder.

the pressure inside the bulbs increase due to the temperature inside the bulbs.

the only changes are the temperatures and pressures inside
the thermometer.

and of course the bulbs moving up and down with the changes.


Like a Cartesian diver, or any other object in a fluid, the only factor that determines whether an object will float or sink is the object's density in relation to the density of the fluid displaced by the object when submerged. If the object's density is greater than the density of liquid displaced, the object will sink. If the object's density is less than the density of liquid displaced, the object will float. If the object and liquid have the same density, a condition called neutral buoyancy, the object will remain suspended at a certain depth without rising or sinking. Neutral buoyancy is achieved by fish, sunken logs, scuba divers and submarines.


here is a image that describes the effect of decreasing and increasing density of a fluid and a given object.



Quote:
No. A submerged submarine isn't in stable equilibrium. It's either sinking or floating. They have to continually adjust the bouyancy to maintain a fixed depth hydrostatically.



why ?

does the pressure outside constantly change?
does the weight of the submarine constantly change?
does the gravity constantly change?

why would they need to adjust anything when nothing outside the sub changes?

_________________________
3/4 inch of dust build up on the moon in 4.527 billion years,LOL and QM is fantasy science.

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#34012 - 04/20/10 04:19 AM Re: Harnessing the power of the sun [Re: paul]
kallog Offline
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Registered: 03/17/10
Posts: 1100
Originally Posted By: paul

Galileo's Thermometer

if the temperature increases , the pressure also increases.
that is why the above thermometer works.

It's not because of pressure. The temperature of the water is what's important - higher temperature expands it, reducing the density, allowing more bubbles to sink. Pressure inside the bubbles is immaterial. Pressure in the water/air would also have no effect because it doesn't change the pressure gradient.


Quote:

only factor that determines whether an object will float or sink is the object's density in relation to the density of the fluid displaced by the object when submerged. If the

Exactly. Doesn't matter what the pressures are. Except where pressure also affects density, such as with the air trapped in the floater of a cartesian diver.

And this is where perpetual motion doesn't work. Changing the density consumes energy. Growing a bubble of gas at the bottom of the ocean uses a huge amount of energy because it has to lift the heavy column of water above it. When the object floats up, the column of water drops back to where it was, releasing the energy - and wasting some of it.

Quote:

float. If the object and liquid have the same density, a condition called neutral buoyancy, the object will remain suspended at a certain depth without rising or sinking.

...

Why ?

does the pressure outside constantly change?
does the weight of the submarine constantly change?
does the gravity constantly change?

why would they need to adjust anything when nothing outside the sub changes?


Because a neutrally bouyant object at some in-between depth is a state of unstable equilibrium. You can't adjust the bouyancy to be exactly neutral so it'll always be trying to go up to the top or down to the bottom. You can keep it at a fixed depth by increasing the density when it starts floating up, and reducing it when it starts sinking.

You can see in your picture of the Galilean thermometer that all bubbles are at the top or bottom, they don't hover in the middle. It's even more clear in the green boxes picture. The tiny density change caused it to sink all the way down, or float all the way up, not stop in between.

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#34021 - 04/20/10 07:15 PM Re: Harnessing the power of the sun [Re: kallog]
paul Offline
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Registered: 03/21/06
Posts: 4136
Kallog

Quote:
You can't adjust the bouyancy to be exactly neutral so it'll always be trying to go up to the top or down to the bottom. You can keep it at a fixed depth by increasing the density when it starts floating up, and reducing it when it starts sinking.



it'll always be trying to go up to the top or down to the bottom.

so if a submarine is at near neutral buoyancy , and it could be adjusted to remain at near neutral buoyancy but is not adjusted then it begins to drop to the bottom.

how far will it drop before it will stop , or will it just keep going?

or if it begins to go up to the top , how far will it go up?

you seem to think that the waters density will change at a certain depth , but I dont think so.

if the subs density does not change and the waters density does not change , then why would it rise or fall?

in the thermometer the density is changed by temperature
however the thermometer would not work if there were no air above the water that would allow for the compression of the water thus allowing the change of density.

when I said that it is the temperature and pressure inside
the thermometer that is the reason it works I was right.

without the air at the top it wouldnt work.
you couldnt change the density of the water without the air.

the only reason the density changes is because of the temperature , and the pressure is the result of the temperature.

the density is the result of the reason why it works.

what you are saying is sort of like saying my car wrecked itself.

I was not at fault because I was only driving the car.



















_________________________
3/4 inch of dust build up on the moon in 4.527 billion years,LOL and QM is fantasy science.

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#34024 - 04/21/10 03:36 AM Re: Harnessing the power of the sun [Re: paul]
kallog Offline
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Registered: 03/17/10
Posts: 1100
Yes, a submarine would keep floating all the way to the surface if it was slightly bouyant. Or it'd sink all the way to the sea floor if it was slightly denser than water.

It's the pressure gradient around it which causes bouyancy, not the pressure.

The pressure gradient is constant with depth, even though the pressure itself changes.

The pressure gradient is a function of the density of water. Changing the density changes the pressure gradient, and changes the bouyancy of things submersed in it.

Regarding the thermometer. You're mistaken. Water is incompressible, so when you apply pressure it doesn't increase in density - at least not significantly. However thermal expansion does cause a significant density change, and this is the effect that's used.

We can see who's right quite easily:

You say that increasing temperature will increase the density and cause more bubbles to float up.

I say that increasing the temperature will decrease the density and cause more bubbles to sink.

Which way do they go in real life?

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