Gravity Mill - any comments to this idea?

[hartiberlin]

Here is the picture from TBird attached.
Many thanks.

[hartiberlin]

ln means "Logarithmus naturalis" and is the inverted function of
e^x

So if you want to to know x then you would
do ln (e^x) = x

Look on the windows calculator program, it is there under
scientific setup.

[hartiberlin]

Hi Pranja,
if you will work on the javascript,
maybe you can include also the weights in pounds and
the height in inches and the pressure in psi,
so our US friends, who don?t use the metric system
can also easier see their unit results.
Many thanks for this great work !

Regards, Stefan.

[tbird]

hi stefan,

thanks for posting my picture.  any idea why it wouldn't work for me?  and thanks for the explantion (still don't know what all that means).  if i ever need to use it, i'll call you.

i was trying to find out how much 1 cubic foot of lead weighs.  couldn't find anything i really understood, but did find the atomic weight of lead and water.  lead= 207.2  water=18  does that mean for the same volume lead would be 11.5 times heavier

you are pretty good with this stuff.  am i right?  if so, then that bottom space would need to be about 15% of the volume.  if that's the case, the compression would need to be a little over 2 bar at 10m so it would expand more than twice the size.   hmmmm....

tbird

[hartiberlin]

@prajna
okay, I will reply later,
but I just found a way it works in all cases !

TBird was totally right, when he said the shuttle must be precompressed !
That is the magic word !

Okay, let us start with 1/10 of the volume of my former example.
We just take a shuttle that is now 10 cm high and 1 meter diameter,
so it has 78,5 Liter volume and start at the top at seawaterlevel.
The shuttle is precompressed to 4 Bar !
Now to sink this shuttle we attach a weight of 80 Kg to it.
Now the shuttle together with the weight sinks down.

2. Now at 10 Meter deepth we let the shuttle expand itsself.
From the 4 Bar it had now at 10 Meter deepth there are also
2 bar pressure there due to the water pressure.
So the shuttle expands its volume now to double its size, so
to 157 Liter and being at 2 bar inside, as inside pressure = outside pressure= 2 bar.

Now 157 Liter means 157 Kg buoyant pressure minus the 80 Kg weight is
now 77 Kg or F= m x g = 77 Kg x 9,81 = 755,31 Newton upwards force.

This force now pushes the volume of  7854 Liter above it through a nozzle,
in the top of the pipe that is just at sealevel , so the 7854 Liter of water will be 1 Meter
above seawaterlevel, which will give us the mentioned  21,4 Watthours of potential
water energy.

3. Now at the top we must recompress the shuttle from now internally at 2 bar and
157 Liter volume ( 20 cm high at 1 Meter diameter)
back to 10 cm and 1 Meter diameter and 78,5 Liter volume at 4 bar.

This can be done again by using a pumping action, this time from the outside.
Now the formula for this is:
W= (P1-1 bar) x V1 x ln (V2 / V1)
So the energy W needed for this pumping is:
(200000 Pa - 100000Pa) x 0,157 m^3 x ln 0,5=-10882 Wattseconds / 3600= 3 Watthours !

So we only need 3 Watthours of energy to recompress the shuttle to 4 bar pressure and 78,5 Liter
volume and earn 21,4 Watthours by lifting the water up !

This is the real solution !
Many thanks to TBird to getting the idea with the precompression !
That is doing the real trick and we only need to do the compression at the top,
where it is much easier also.
In the deepth at 10 meters the shuttle can run against a rod, which will
switch its internal expansion control mechanism and the shuttle then expands itsself from
4 bar at 78,5 Liter    to    2 bar at 157 Liter just by itsself !

So we now have the final solution and can seek now to optimize the nozzle and
still try to use other and better and more usefull dimensions !

Regards, Stefan.

Hi All,
I recalculated this now for to see, if also a mechanical lever action can recompress
this shuttle from 2 bar back to 4 bar ( 400 000 Pascal) pressure and thus shrink the
volume again from 20 cm to 10 cm, so difference 10 cm= 0,1 Meter.

We can use then an external pressure of 4 bar to do this.
As we can also do it via a lever we must see, what force
4 bar means.
This can be calculated this way:

P= F / A ( means: Pressure= Force / Area )
thus
F= P x A ( means: Force= Pressure x Area)

Energy = F x s = P x A x s ( means Energy= Pressure x Area x distance)

So:
400 000 Pa x 0,785398 m^2 x 0,1 meter =8,7 Watthours

This 8.7 Watthours is bigger than the upper only 3 Watthours,
but this is logical, cause we apply already at the start 4 bar
where the shuttle only has 2 bar.
So at the start we could only apply 2,1 bar and so on rising,
until the 4 bar are reached, which would save us some energy
and if you do it with a syringe compression via air pressure,
you would only need the above 3 Watthours, so
doing it with a lever-torquearm  will waste some energy.

But anyway, it is still overunity !
COP = 21,4 / 8,7 =2,46

Enjoy !
Regards. Stefan.