chain and bucket hydro system

[loadstone]

Thought i would start this topic to discuss the building and efficiency of a chain and bucket hydro system. Attached to keep every thing is one place is the excel sheet I did for calculating watts off of a stream using the chain and bucket idea. Need to come up with another name but this will work for now.

Jon

I included in the sheet a calculator that tells how much your system will earn in a Month/year.....I still need help in calculating losses due to resistance. I am not sure what efficient percentage it will run but I am sure it will run better than turbines or paddle wheels.

[loadstone]

Any thoughts on this system so far, especially on how to calculate the resistances into the chart. I am wondering if this will take an actual build to do the final calculations.

Jon

[keithturtle]

How much weight can you get hanging on the downward side of the chain bucket array?   Total weight falling should give an idea of power available, and flow adequate (CFS) to fill the buckets and distance of fall should be all the numbers you need.   Still, building it will tell.   It's all weight, no velocity head dynamic in this setup.

I think

Turtle

[RP]

Unless I'm missing something this is identical to an overshot water wheel where the total height difference of the chain is equal to the diameter of the waterwheel.

[loadstone]

Hey Rp,

Thanks for your comments. Yes and no. The difference is this. An over shot wheel is only 63 percent efficient because its weight is not applied at all times 90 deg to the axis. This means that there is a loss while one container is waiting to arrive at the 3 o'clock or the 9 o'clock position. The same is with an internal combustion engine. When the piston is top dead center and the combustion phase takes place it is timed so that the maximum torque is taking place as close to 90 deg on the cam, but the losses are exactly proportional to the slow burn of the gasoline (leaded unleaded....or octane) 90 deg is the sweetspot anything less or more has a degree of loss of efficiency. The only way around it that I can see is to apply a system where the force is always applied at 90 degrees to the axis. I am sure there are other arrangements other than what I have written about but to me it is the simplest. For instance if you have a wheel with 12 pockets able to hold 10 pounds each, such as an overshot wheel. and you add up all the weights, the weights at 12 and 6 do not apply force, the weights at 1 and 5 are only applying a very small force etc. etc... if you divide the cubic inches of one pocket by 231 and multiply by 8.33 and multiply by the number times the number of pockets to give you the actual weight on the wheel, then find the torque that the wheel is putting out, the difference is right at 63 percents. The chain and containers/bucket is closer to 100 percent - frictional losses that apply to any system. That difference in efficiency can mean $100s or $1000s of dollars of savings, by simple changing designs. I will make an excel sheet soon of the efficiency of an overshot wheel in comparison to this design.

Jon  

Attached is a screen shot of the difference between the two systems as show by an engineering program (which is free by the way). The paddle wheel number is higher (but still 20 % less than the other shown) because the place that I measured it from is not at the center of gravity of the weights attached to the paddle wheel. The actual difference is closer to 63% or 37% inefficient.

If your not concerned about money, there is nothing like sitting on a grassy slope watching a water wheel.

[RP]

Sorry but the torque will be exactly identical between the two systems.  If you redo the simulation with all the measurements correct you'll see this.  Here's the logic behind it from two angles:

1.  Yes the wheel loses some torque due to trigonometry and the angle of force of gravity but this is exactly made up by the fact that the longer path adds more buckets than could fit in a straight line.

2.  If what you say is correct then we could easily construct an "overbalanced system" kind of perpetual motion device using a path for the chain in the shape of a capital "D" with the round side on the right always weighing 63% less than the straight side on the left.  The device would rotate counterclockwise forever.  Of course this is not the case because of point 1 above.


***  NOTE:  I am aware that perpetual motion and over unity devices are strictly forbidden on the forum.  I am only using one as an example thought experiment to demonstrate a point.

[loadstone]

You could be right, I have made some real blunders in my life...this would be one of the smaller ones. I am working on the numbers. of a stream 10 feet head 100 gallons per minute.


Jon

[keithturtle]

Possibly some wisdom in these pages, from 1908

http://books.google.com/books/about/Water_power_engineering.html?id=bWYJAAAAIAAJ

It can get tedious at times

Turtle

[camillitech]

Along the same lines, this may be of interest http://www.rexresearch.com/gilmartin/gilmartin.htm though it does seem to have died a death 

Cheers, Paul

[loadstone]

Hey, geat find,

This is exactly what i was talking about.....even though someone else came up with the idea, posibly first. I am still working on the math for the paddle wheel in an excel sheet form for others on the board to make use of.

Jon

[loadstone]

I will use this calculator for the comparison

http://www.waterwheelplace.com/electricity.html

[kevbo]

RP is correct, here is another way to look at it:

All the potential energy is due to the head (height change) available. 

The rate at which the water moves downward, not around, determines how much power it is giving up.  So only the downward component of the motion uses any of the water's potential energy.

The water at the 12 O'clock position is not moving downward at all, so you are not losing power. AND you get to capture some kinetic energy from the inflow from the flume.  As the water moves around the wheel, the downward component of motion increases exactly at the rate that the tangential force increases.

A bucket chain might be useful if you had a low flow, high head location, and didn't want to build a huge wheel.  Seems like a whole lot of joints in the chain to give trouble though.