Efficient hydro Idea

[gsmsslsb]

I have an idea of a mor efficient hydro but I dont know if my working out is correct.
Take a look at the picture.
Imagine a water tower 10 metres high with an air lock at the bottom.
The whole thing is full of water for a start.
step 1) The upper doors close.
step 2) The lower doors open and 1 cubic meter of water flows out.
Step 3) One float moves into the air lock.
Step 4) The lower doors close under the float.
Step5) The upper doors open and the air lock fills with water
Step 6) The force of floatation lifts the float 10 meters to the surface providing power.
I am wondering if this would be more efficient than a pelton wheel or water turbine.
By my calculations
                       1000 kg-force = 9806 newtons
                       9806 newtons over 10 meters = 98060 joule
                       98060 joules = 27.23889 watt hours
If the floats move at pproximately 20 meters a minute then ther is 27.24watts poduced every 30 seconds by a float rising 10 meters.

Are these figures right
It seems like a miserable amount of power for 1 ton force
Anyone let me know
Thanks

[fritznien]

numbers look good. the problem is how you get the water up the tower, as it takes as much to get it up as you can get letting it back down.
pumped storage runs as high as 85% efficient for utilities but i don't think anyone dose it small scale.
fritznien

[gsmsslsb]

I already have a pipe with 100 meters head from a stream but I want to get more power out of the water than running it through a turbine

[fritznien]

a 100m head delivers 980 watts per kg per sec.
a 10m tower just 98 watts.
micro turbines are off the shelf, see homepower magazine.
they provide steady power, using batteries you can cover peak loads.
a good turbine is over 90% efficient.
they can run for years with little maintenance.
your tower will not produce anymore energy, no one has made a buoyancy engine work,lots of threads here.
everytime you put your float into the tower it costs energy,either to push the float in against pressure or in lost water,you don't get any extra back.
not to mention the increased complexity of the system.
good luck with your system.
fritznien