hydro power plant idea

[Sauron]

came up with this idea recently after viewing a show about how air balloons can safely lift large, heavy objects from the bottom of the sea. I would like to know, from a physics/engineering perspective, is this idea plausible or a complete joke?

 

Basically:

 

The lifting method employs air-bags. A balloon is attached to the load, and air is pumped into it, generating lift equivalent to the water displaced.

 

Crude drawing here:

 

http://vidlord.com/UnderwaterTurbineIdea1.jpg

 

 

See the following regarding air bag lifting large object from the sea:

 

http://www.patentstorm.us/patents/5516235/description.html

 

The tanks do not have to be hardened, expensive tanks but could be massive, ridged, cheap balloons themselves. There are relatively cheap air compressors that would fill the balloon quickly and efficiently although ideally the filled airbag would be reused and not have to be refilled. The entire process would have to be fully automated/computer controlled. Thanks for any feedback.

[insane_alien]

the problem comes in that you have to put a crapload of energy into the system by way of pumping air into the balloon. this air is by necessity at extremely high pressures compared to the source(atmosphere) and due to losses you'll end up using more energy than it produces.

 

with any system like this you have to look at where the energy input is(not the turbine as that is a converter and output). in this case it is pumping the air that is the input of energy.

 

basically what is happening is you are pumping the water out of a chamber with compressed air and then letting the water rush back in again. at best the system will give as much out as you put in.

[Sauron]

thanks insane_alien - that's exactly what i thought although the idea of filling a balloon with air didn't seem that energy intensive to me. I'll see if I can come up with a way to reuse the balloon that does the lifting. If that is possible do you see it as feasible or can you imagine a way to reuse the lifting balloon? Thanks!

[jbirdboy]

hmmm... where to begin, first off the "bladder" idea is just foolish and wasteful....so many things wrong i'm not even going to get into it....

 

the energy from the lift of the bladder can only be collected once, and ends as soon as it reaches the top???

 

if the energy of buoyancy can be captured again and again, the only thing restricting the possibility of capturing the energy is the depth/length* of when it starts and the mass of the buoyant gas.

 

this being said, the efficency is all relative to the lengths* you are willing to go....excuse the pun, and the minimum mass of gas that in return gives you a measurable and obtainable amount of energy.

 

Now here's the best part..... the obtainable amount of energy does not need to be very much at all.....why you might ask!?......well that just means it's going to take that much more energy to get there.......but it's not very much?.....well remember i said it's realitive to the length, because this length gives you more opportunities to harness this energy.....

 

next.... the gas transfer/relay/cycle is to be powered by not electricity(maybe very little for computing, but nothing big) it shall be driven by whatelse....gravity

 

this is a whole nother story, and spurs a whole new conversation....just think weight of under water, and weight above surface, use the weight of water above surface to off set the buoyancy of the gas.....

 

i have most of the math worked out, there is no question i have it figured it, now it's just fine tuning the thing for the best return......which realy only matters how big i want to make it

 

i would like to maybe get a little help.....maybe......certainly need some money to invest, i've made cheap protos but they are not nearly large enough(i'm talking small) and materials and construction was a little crude, again due to not having enough money to invest in it

 

i hope this opens your eyes and maybe you can start to think out side the box

[JPGreco]

You'd be better off building what would essentially be a water mill only upside down. This way, as air is released under water and begins to ascend, it will be gathered in one of the arms of the air wheel. As enough air enters the arm, it will start to spin the wheel. The cycle will repeat like a water wheel does.

 

I don't know if this would net or lose energy, I would assume it would lose energy unless you found an underwater natural source of either heat or gas that would spin the wheel.