Author Topic: half baked ocean depth pressure scheme (Read 4487 times)

timewarp · « **on:** January 21, 2009, 10:46:26 PM »

Someone with a better grasp of physics than my own may be just what I need. Simply knowing if friction losses in what I have in mind are higher than the amount of power that could be produced would tell me all I really need to know whether or not there is any potential in my idea.

The concept is to use the pressure of deep water to compress air, which would be returned to the surface where electricity could be generated from the compressed air. What I have in mind is to use something like a conveyor belt to squeeze a flexible hose (something like fire hose), trapping a "pocket" of air that the conveyor can take down to the depth needed to get the best working pressure for the system. The flexibility of the hose would allow the air to be compressed within the hose, and the "conveyor" would be needed to trap the air against flowing backwards up the hose. The compressed air would be collected in rigid pipe at the bottom, and piped back to the surface for air driven motors to use on generators.

Sorry, I really should have a sketch to send along to maybe make the idea a bit clearer. If the potential energy of the compressed air is higher than the friction losses from the conveyor system, maybe there is some potential there. It's an idea that's been in my head for years, but until the internet made it easier to find other people that may be able to help me with the engineering/physics, the idea hasn't gone anywhere.

hansvonlieven · « **Reply #1 on:** January 21, 2009, 11:03:34 PM »

G'day timewarp,

There is more than friction losses involved here. In order to transport an air filled container of some sort to the ocean floor you must also overcome buoyancy. At sea level the air would take up a considerable volume, which decreases as the container sinks. The displacement of water caused by the air container at the start up would create buoyancy. Try pulling a balloon down to any depth and you get an idea how much power is required to do so. I haven't done the maths on this but my estimate is that there is no gain.

An interesting idea nevertheless that I have not heard expressed anywhere.

Keep trying

Hans von Lieven

sm0ky2 · « **Reply #2 on:** January 21, 2009, 11:06:31 PM »

it requires more energy to overcome the bouyancy than can be retrieved by decompressing the air.

it is FAR more efficient to compress the air using a standard compressor.

no gain to be had by this sort of thing....

hansvonlieven · « **Reply #3 on:** January 21, 2009, 11:09:28 PM »

LOL smoky, I love those simulcasts

Hans

CARN0T · « **Reply #4 on:** February 08, 2009, 04:47:41 AM »

Hi, Timewarp,

Wait a minute, what if you don't have to pay to put the "air" at the bottom of the ocean? Then you get all sorts of power out, right? If you could generate a lot of small bubbles in the water, they would pump water upward as they rose-- that's a great water pump in itself. Or, you can harness the high pressure of the "air" as you intended. What are the possibilities for this "air"?

Let's see-- the deep ocean is at about 4 degrees C. Is the water saturated with any gas? If so, warming the water reduces gas solubility, causing bubbles to form. If you make a closed loop of pipe that draws down warm surface water, with a heat exchanger at the bottom, then the loop might be self-powering. Maybe. But the water probably doesn't have a suitable gas unless--

Methane. People are worried that at any moment, the ocean depths might warm up enough to release methane that is stored there. The oil companies are like wolves smelling blood over this one. They want to mine the methane and test operations are going on as we talk. The methane is stored on the ocean floor as "methane hydrate," a compound with water that is very unstable. Just a little warming and it converts to a gas and wants to bubble up.

Recent scientific reports indicate that the shallow sea shelves along the coasts of the Arctic Ocean are already beginning to "off-gas" methane from the sea floor. But deep methane occurs almost everywhere in the oceans.

That was fun, but let's try one more time. The deep ocean floor is a carbonate ooze. That's how limestone forms. What if a little acid got into that ooze? CO2 would be released. Again, if you primed a loop carrying acidic water from the surface, it might be self-powering.

I know these are half-baked answers, but that's just perfect here, right?

Ernie Rogers

Cairun · « **Reply #5 on:** March 03, 2009, 05:00:36 AM »

i have thougth of similar concepts. the problem is the deeper the water the higher the water pressure and the more difficult to bring air down.
nice idea though.
keep trying

Philip Hardcastle · « **Reply #6 on:** March 03, 2009, 10:23:17 AM »

@timewarp,

You are a genius, but not with air, with water.

In the above ground world there are solar chimney power generation plants but the efficiencies are low unless they have very high chimneys.

With your idea modified we could put solar power down an evacuated mirrored wall tube.

Then we have a bit of ocean 5,000 meters deep and put in a big bore tube with a water turbine in the tube. The sun heats the water with a starting temp of say 4C (maximum density) which expands and rises through the tube and does work through the turbine.

Now I have not done the maths here but it seems offhand that the conversion efficiency of the solar energy could be quite high, perhaps 20% which is way better than solar chimneys on the ground (just 4% for 1,000m high). When the water get to the top excess heat could be extracted for other puposes such as greenhouses given that you would also have the ability to partially evaporate sea water and condense it as fresh water in a green house. So you could have fresh water and electricity from a simple relaible device.

Mind you the number of 5000m deep areas of water near to shore is probably limited but it could lead to a floating island with water, power and food. Ocean front land would sell for at least a million a block!

What is interesting is that ideas lead to ideas.

Regards

Phil

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Author Topic: half baked ocean depth pressure scheme (Read 4487 times)

timewarp

half baked ocean depth pressure scheme

hansvonlieven

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sm0ky2

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hansvonlieven

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CARN0T

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Cairun

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Philip Hardcastle

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