Underwater Power Generation

http://en.wikipedia.org/wiki/Hydroelectric_power

http://en.wikipedia.org/wiki/Hydroelectric_power

Thanks but Hydro utilises the mass of water available at 1 atm,I am talking about the pressure available underwater at depths above 1atm.

There has to be a pressure difference to create the flow in a hydro scheme. Power generated in a hydro station is volumetric flowrate multiplied by pressure difference multiplied by efficiency.

The pressure available to most hydro stations is certainly greater than 1 atm absolute, otherwise the rotating parts would not turn.

So, in the conceptual scheme in the original post,

• Where is the pressure difference going to come from at these depths?
• How is the flowrate going to be established between those two pressures?
• How is the moving fluid going to be conveyed through a generator's turbine to produce power?

Thanks PWSlack,

The pressure I referred to as 1 atm is the surrounding air pressure,hence the differential on Hydro.

In response to your questions:

1.Assume available pressure of 1 atm at a depth of 1300ft ,Static pressure of water at depth 563 psi,theres the differential.The pressure of 1 atm would be created.....thats the tricky bit!

2.Forget the turbine for the moment,lets turn a piston engine.You have your differential available through valve gear as you would conventionally.

Discussion continues at #8 below.

Leon,

I really don't see where you're going with this or how you would get this to work.

I am sure you are aware that 'pressure' is different than 'energy'.

Please elaborate a bit more.

RScincy,

Yes,im aware thanks.

I will try to elaborate,imagine a single cylinder piston engine.Use water to drive the piston down at pressure.The water then has to be removed in order for the piston to rise,this is done by exposing said water to a much lower pressure,the piston rises under engine momentum because of the differential reduction,and stroke 1 is complete.Engine momentum would obviously benefit from a few more pistons!

Do you think this would work?

Forgot to mention that as in the case of a conventional engine,the crankcase would be sealed and held at 1 atm,thereby allowing the differential pressure to move the piston down.

And how would the water be exhausted from the system at 1 atm having turned the engine when the surrounding pressure is oh, say, 150m of water, or about 15 atmospheres, so as to sustain the flow? Isn't this the same problem as the designers of a hydroelectric scheme face?

PWSlack wrote:

And how would the water be exhausted from the system at 1 atm having turned the engine when the surrounding pressure is oh, say, 150m of water, or about 15 atmospheres, so as to sustain the flow? Isn't this the same problem as the designers of a hydroelectric scheme face?

This is,as I said earlier,the tricky bit.But lets say 1 atm is available at those depths,the water exhausted would be evacuated from the cylinder by engine momentum,therefore maximising the efficiency of the "engine"

The producing of 1 atm is possible even at these depths.The trick is,to be able to produce enough to cater for the volume exhausted by the engine,and the energy required to produce this to be small in percentage terms in relation to the total energy generated.

Are we happy thus far?

No, because the basic questions haven't been answered and a full understanding of the technique isn't yet available.

• Where is the pressure difference going to come from?
• How is the water going to be removed from the system so as to sustain flow from the high pressure source to the low pressure sink?

<....lets say 1 atm is available at those depths,the water exhausted would be evacuated from the cylinder by engine momentum,therefore maximising the efficiency of the "engine"....>

HOW?

Stupid question time: how do you supply the pressure, both positive and negative, and what powers the pressure supply?

DVader1000 wrote:

Stupid question time: how do you supply the pressure, both positive and negative, and what powers the pressure supply?

The pressure is there trust me.

Negative pressure is not required,just a much lower pressure in order to create a workable differential

Yeah, I know the pressure is there deep underwater. My question is, how do you create the pressure differential necessary to make it work? You can't simply use a U-tube with arms of unequal length, you need some means to propel the water to drive the turbine. How do you achieve this?

So do you agree it would work providing we have the pressure differential?

Creating the differential is the key,I know,its took some time to get my head around it but,up to now,will it work?

Thanks Gwen,much appreciated.

It will definitely work if there is a pressure differential, because a flow will be created until the pressure is equalized. The real key here is creating and maintaining that pressure differential without consuming energy to do it.

How do you intend to achieve this? THAT, my friend, is the key issue to resolve here.

It is the key,but it cannot be done without using energy.How much energy though?

Lets assume an engine of say 4 litre capacity,at a steady 3000 rpm,12000 cubic metres/min to move of water at the depth pressure.

Question,what opposite force would be required to a mass of 12000 cubic metres at say the depth pressure of 565 psi,in order to reduce its pressure to 1 atm.

To where? Where is this damn water going?

4 liters/revolution times 3000 rpm = 12,000 liters/minute = 12 cubic meters/minute. This moves the decimal point only three places, I admit, but quite likely it will affect this and other calculations.

Good question. Keep it going!

I wouldn't say research, but here is some conceptual ideas. I would recommend reading all posts, as there are ideas for lakes, oceans, tidal basins, etc.

I haven't yet seen any concept by which 1 atm of pressure can be maintained at depth without supplying external energy >= to that supposedly generated by the original process. Deep dark secret for now? Maybe someday, when I read the patent? Oooh, I can hardly wait to see this perpetual motion machine in operation.

You are right,energy would be needed to create the lower pressure,but lets say this was a small percentage of generated power,or lets say it was 70% of the generated power,which would be more acceptable,30% for no fuel used to generate or something higher?

Please state how rather than asking the question.

Im afraid I have many questions regarding this.

Its an idea,and only by discussing it can it be proved workable/crazy or otherwise.I would like to think that in the current scheme of things any discussion regarding easing the burden on mother earth would be welcomed by all.

Sure, if the energy needed to maintain the low-pressure condition were less than the energy produced by the piston process (by a suitable ratio compared to the cost of whatever equipment), this could work. But that is a trivially dopey point to make. You have consistently evaded any description of how this is to be done. Either provide a valid explanation, or produce a working model, or give up. Although I wouldn't invest so much as a nickel in this scheme, I hope I'm wrong, because success would be a good thing. But when you give empty verbalisms, rather than descriptions and calculations (like where did your 70% come from?), why should you expect anyone to take this seriously? This is not the way valid engineering works. But if you can separate some greenie fools from their money, more power to you; you will probably spend it better than they.

I have to argue the complete idea: it is not the pressure which makes an ICE working but the volumetric change over the burning of the mixture. (a gas turbine is the perfect example as there is no pressure difference before and after the burners, only a huge volumatric difference and a Gas turbine is

Pressure does not contain energy: you can build up enormous pressures without energy. Just look to the bottom of the chair: the metal tubes are quite thin, so calculate the pressure you create by sitting on it.

Did you have to apply energy? No, It will even require energy to remove it (getting out of the chair)

Energy harvesting needs a way to tap energy while it is going from the high potential to the low potential.

Surely the pressure applied to a piston with sufficient differential across the piston should cause it to move?

I think the key issue here is bringing the air from the surface down to the depth of the process. You will have to compress the air to the equivalent psi. This is the main energy consumption, not the "inflation" you mention. It is difficult to understand the verbiage of your description. For instance, what is an "inverted cylinder/piston" versus an uninverted set? A drawing would help.

I couldn't figure out why your comment was classified as "off-topic." It is definitely on-topic, but I think it misunderstands the main issue.

Descriptions of main working parts

1. Two stroke engine already discussed crankcase pressure at 1 atm, inlet/outlet valve arrangement as conventional ICE.

2. Two spheres each containing an inflatable "balloon", an inlet port for sea water via valve, and an inflation/evacuation port for the "balloon".

3. Inverted piston with inlet port connected via valve to the exhaust port of the ICE.

The two spheres are connected to two independent inverted pistons. Sphere 1 has its balloon inflated to a pressure say 2 x depth pressure, the upward force this creates evacuates the base of the cylinder, to a pressure of 1 atm, exhaust from the ICE is ejected into this space which increases accommodating the exhaust until full. Sphere 1 opens the valve to the water surrounding it, the transfer pump/valve arrangement opens and allows this balloon pressure into Sphere 2, the transfer pump completes the transfer of air from balloon 1 to balloon 2.Sphere 2 then carries out the same procedure as Sphere 1.

Sphere 1 sinks due to gravity; a simple valve allows the pressure below the piston to equalise to depth pressure, the piston falls by gravity to be filled again via the transfer pump when ready.

More than 1 inverted cylinder could be used, and each sphere could lift one cylinder and then another, the only restriction being the amount of rope, the mass to be lifted, and the density of the water as it rises.

The transfer pump is making the differential. Why would the efficiency be any higher at depth, than at sea level?

Bouyancy is making the differential acting on the inverted piston.

The transfer pump merely moves air around.

ok so you're moving the pistons up & down, which sounds a lot like a pump. The pistons are going to have rings which are going to have friction [losses]. Any crankshaft arrangement is going to be far less than 100% efficient.

What leads you to believe that the piston pump(s) are going to do more work [produce more energy] than the transfer pump is going to consume?

I suppose you could dispense with pistons & crankshafts all together. A nice linear generator, such as has been used connected to buoyed channel markers to take advantage of wave action. http://peswiki.com/index.php/Directory:Wave_buoys.

Ah back to where is the input energy coming from?

Transfer pump it looks like...

you could hook a cable to the whole rig wrap it around a shaft, drop it to the bottom, spinning a generator...

Why not simply use the transfer pump to create a water jet to drive the turbine? And what drives the transfer pump? Electricity? If so, why not just use the electrical power directly instead of putting it through a system that will create losses?

Ok,no problem,can you attach a file to a post?

Create a .bmp or a .jpg file, and use the camera button to attach it.

GA! This is clearly a form of PMM. No matter how you slice it, more energy is consumed than generated.

Just for completeness, link.

Leon,

I do admire the creative thinking, but from what I have been reading and what other people say, it sounds a bit like a perpetual motion device. If you are trying to capture electricity for some sort of alternative energy, I would say this will most likely not work. Remember, energy can (basically) only come from energy, nothing else. It is fairly easy to convert from one type of energy to another, but taking energy from pressure? I don't really see this working (hate to be pessimistic).

If you were to have an 100 watt device to create this lower pressure, what would the output (harnessed) energy be? It couldn't be over 100 watts, right? I mean, where would the energy come from? Maybe you get it at 100% efficiency (props to you), but to me, it does not seem as if one could harvest energy out of this device.

Regards

Hi RScincy,

Hydraulic pressure IS accumulated energy. Maybe the best way to understand this is to read about hydraulic systems for regenerative braking.

Leon: you may have something here. The only thing is to be sure what creates pressure and what source of energy re-creates it after one or more cycles of your machine is killing the original pressure differential.

Regards

Liquids have very little compressibility. The energy released is the product of volume change and the pressure. When a gas pressure vessel bursts it causes a lot of damage while a vessel having only liquid under pressure cracks, it just leaks.

There is something here Hottech,the pressure is constant,the differential is all that is needed to use it.Its been good to hear all views.

Im going to stick with this one till dead or otherwise.

Not pressure differential, rather temperature differential.

Ocean thermal energy conversion

http://en.wikipedia.org/wiki/Ocean_thermal_energy_conversion

This isn't what the OP was proposing. Looks a bit like a bad geothermo brojects.

A quote from the wiki article:

Earlier OTEC systems had an overall efficiency of only 1 to 3% (the theoretical maximum efficiency lies between 6 and 7%^[

Good afternoon Leon. I'm glad to see i'm not the only one looking outside the box in this relam. I was thinking more on the lines of an element/mineral that when put under pressure would release energy that could be used to produce power. Maybe we're not to far away from something like this as related to cold fusion. Thanks, I wish I had seen your post before I thought I was on to something! Darrell D. greencrow