Horizontal Waterwheel (from: centrifugal force thread)

[RonL]

Horizontal Waterwheel (from: "centrifugal force" thread)

This is all over my head, but I'm in the water and I want to learn,

Maybe you guys need a mechanical challenge to apply your classical physics to.

I know very little of what has been said, or how to make calculations, but I think I have an understanding of mechanical things and how they work, size relations have a tendency to mess things up

In relation to what's been discussed, a project I would like to propose, is a horizontal waterwheel.

We start with a body of water around 10 feet deep, with a bedrock bottom. A perfectly flat mount point of suitable size is machined onto the surface of the bedrock, and a standpipe is secured in a perfect vertical position, this pipe will serve at least three functions, maybe more.

1.Two or more sections can be sealed to serve as compressed air storage.

2.A portion will serve as a conduit for water inlet at the bottom center of the waterwheel.

3.The top area will serve as a place to mount a compressor unit (air, and possibly a refrigeration system).

The wheel will be a shell of some diameter (in my case 10') and a depth of around 4', in the center a bearing sleeve is secured and braced as needed, with one or more holes to allow water to flow in.
Two or more air motors driving water pumps, are mounted and designed to move water discharge at a tangent to the inner curve of the shell.

At rest the shell sets in the water at a depth just short of sinking. Compressed air in the standpipe is used to start the motor driven pumps and as velocity builds, the water(inside the shell) starts to spill over the top. The reduced volume of water allows the shell to rise, reducing external friction against the lake body. As the shell rises up the standpipe, ports in both the pipe and sleeve align and water enters at the near void bottom center, which creates a continual replacement for the water being forced over the top.

With the help of friction tabs attached to the inner shell a great amount of kinetic energy from the rotating body of water will transfer torque to the shell, which in turn drives the air compressor mounted to the stand pipe.

Not sure if I have provided enough detail, (there are several ways to add to this basic design). Hope to see if anyone will have thoughts as to the forces, or non forces at play here.

My thoughts are, what's in play here is,
1. Gravity
2. Hydraulics (fluid dynamics)
3. Friction ( positive and negative)
4. Air compression and expansion (thermal transfer)
5. Heat pump cycle, transformed into mechanical functions (mentioned, but no details)
6. Solar transfer, Sun to Lake surface.

My main point here is based on the OP, and the general discussion, what's going on with the spinning water, and shell ?? I think that power can be removed as a results of gravity, and mass storage of energy between the sun and lake.

Some really sharp people have contributed to this thread and I hope to hear some good responses. I have the land, and most materials, but the time, manpower, and resources(financial mostly) exceed my limits.

Thanks for any input.

Ron

 

[Doc Al]

Note: I moved this post from the https://www.physicsforums.com/showthread.php?t=242311" into its own thread.

 

[RonL]

Note: I moved this post from the https://www.physicsforums.com/showthread.php?t=242311" into its own thread.

Thanks Doc Al (I think) Sorry if that was what is referred to as hijacking a thread, just thought it was in line with what was being discussed, at the beginning.

 

[DaveC426913]

When all is said and done, where is this device extracting energy from? (Gravity is not a source of energy.) The sun's heat?

 

[RonL]

When all is said and done, where is this device extracting energy from? (Gravity is not a source of energy.) The sun's heat?

The shell bottom does not rise to the surface of the water body, there will be a depth of some amount. The difference of height between surface, and shell bottom will cause water to flow into the low pressure void that results from the water spinning away from center and towards the shell sides.

Is it not gravity that gives a liquid the ability to exert pressure based on its depth?

 

[DaveC426913]

You're getting caught in the classic perpetual motion trap: if one adds enough flywheels and weights and frictionless surfaces, one can convince oneself on paper that one is getting energy out of the device.

The question is - all tweaks to your device aside - where is it getting the energy from? You could put a rock on a weigh scale and attach a generator to the rotating needle. You'd get some energy out of it as the rock descended but then what? You'd have to lift the rock back up.

Your device has a fancy valve/compressed air/inlet mechanism for "lifting the rock back up" but ultimately, it's going to take as much (actually more) energy to do get through the second half of your device's cycle as it got out of the first half.

 

[DaveC426913]

Above, we look at the top-down approach and conclude on general conservation principles that it won't work. Here we can look at it from the bottom up and we will find components that use energy but are not being accounted for.

Compressed air in the standpipe is used to start the motor driven pumps and as velocity builds, the water(inside the shell) starts to spill over the top.

How does "compressed air operate the pumps"? Are they electric pumps or are they just bladders? If electric, where does the electricity come from? If air, how are they refilled with each cycle? Can a given volume of air push any useful amount of water?

And: if either method is driven by the waterwheel itself, then that's energy not available for output, right?

Is it not gravity that gives a liquid the ability to exert pressure based on its depth?

The pressure exerted at depth is exactly balanced by the weight of the water above it. Look at a simple example: Take a 10 foot hollow pipe and submerge it 9 feet into the lake. The pressure at nine foot depth at the bottom of the pipe forces water up the pipe how far? Well to exactly the surface of the lake, right? No useful energy can be extracted from this.

 

[RonL]

You're getting caught in the classic perpetual motion trap: if one adds enough flywheels and weights and frictionless surfaces, one can convince oneself on paper that one is getting energy out of the device.

The question is - all tweaks to your device aside - where is it getting the energy from? You could put a rock on a weigh scale and attach a generator to the rotating needle. You'd get some energy out of it as the rock descended but then what? You'd have to lift the rock back up.

Your device has a fancy valve/compressed air/inlet mechanism for "lifting the rock back up" but ultimately, it's going to take as much (actually more) energy to do get through the second half of your device's cycle as it got out of the first half.

There would be a second part that I did not mention before for fear of confusion in the minds trying to grasp too much in one read.
This is a second unit that rotates counter to the main shell, the water that is forced up and over the rim of the main shell falls into the collector ring and cascades down at some angle through tubes that terminate right at the surface of the lake water. This forms a constant flow of water, and puts some opposing force to the action of the two part air compressor.

Now I'll try to explain where the energy is produced and expended.
First, any mechanical system has to have an initial input from an outside source to put it into motion.
Once in motion, the power to complete compression of air is applied to the rotor, or(rotor and housing moving in opposite directions) the resistance will be at a relatively small radius, this compressed air is applied to air motors driving high velocity water pumps, which in turn spins tons of water inside the shell, friction between the water and shell wall causes the shell to spin, the contact area of the shell wall is massive, and at a radius far greater than the compressor. The combined mass of water and weight of the shell along with the frictional torque that turns the shell as it drives the compressor units will exceed the energy to compress the air.

Now to the thermal portion, if a closed system heat pump cycle is put into play, the lake water is at say 80+ degrees, and a volume of water is exposed to an exchanger with enough capacity to reduce the water exposed to the exchanger to just above freezing, the weight of the water will be basically the same, and the shell will perform almost exactly as before.
At this point the gas of the heat pump cycle will be at a very high pressure due to heat from the water that flowed through or across the exchanger, and will drive an air motor in the same manor as compressed air. To make a working power cycle the two are married with a cross flow exchanger, and if the air is expanded enough the temperature will drop to the point of bringing the refrigerant back to liquid, and the now warmer air can be exhausted to atmosphere or slightly below lake water surface.(might still be cold enough to form ice?)

All this reduces to the simple facts, how hot was everything when started, how cold when the cycle finished. The very logic of heat pump theory tells me that energy can be taken, and a design that goes beyond Carnot efficiency can be built, and still stay within the first law.

I think compressed air, or a gas refrigerant is about the only way to perform a mechanical function that takes advantage of leverage(10's of feet, not hundreds), and have almost no loss of efficiency between the point of compression and the point of expansion.(a thought to ponder)

Takes me forever to put my thoughts out, and after submit reply, it seems there is always something that did not come out like I meant it.

Anyway, see if it makes sense. I think it does.:yuck:

Ron

 

[cesiumfrog]

I'll try to explain where the energy is produced ... a design that goes beyond Carnot efficiency can be built

Goodbye thread!

 

[russ_watters]

The combined mass of water and weight of the shell along with the frictional torque that turns the shell as it drives the compressor units will exceed the energy to compress the air.

No, it won't.

Dave is right. What you have here is an idea that is complicated enough that you can't see your conceptual error. What you need to do is make a diagram, then apply some real calculations to all of the steps in the process. You will find in the end that what you have is a very complicated device that does nothing at all.

Ron, you've been here a while. You should know by now that this is not a place for 'debunk my crackpot perpetual motion machine' discussions.