Water and pressure reduction

[Low-Q]

It is clear the wall moves. What for me isn't clear is,i repeat,if when i remove the compression when the level of water is rised,how much energy the water returns... 100% of elastic energy due to liquid compression or less? Thx

If you compress water, It will "deform". Decompressing will make the water back to what it was.
The water responds to the pressure, and nothing more. The pressure is responsible for its compression, so removing compression, you also remove the same amount of energy you put into it when compressing.
Some loss will be found due to heat when compressing anything compressable.


Less useful energy out than energy in. Less than 100% efficiency.


Vidar

[MarkE]

It is clear the wall moves. What for me isn't clear is,i repeat,if when i remove the compression when the level of water is rised,how much energy the water returns... 100% of elastic energy due to liquid compression or less? Thx

It is always less than 100%.

[Gabriele]

And by reducing temperature of the water?from 4 to 0 °C the volume increase... we extract cinetic energy of molecules and we make work...

Than we return LESS heat to the water (cause frictions the water warm up) and we generate more energy... can this be a method to break 1st thermodynamc law...?