Hydro Power

Which paddle design is most effective in producing electricity from a home-made hydroelectric generator system?
Skylar Taron
Grade 7

Hypothesis

If there are three different types of paddles:  Cups, Spoons, and Half-Pipes, then the cups will work the best because they can hold more water and will therefore have more mass and momentum when spinning on the wheel.

Research

What is Hydroelectricity?

Hydroelectricity is a form of renewable energy where a turbine harnesses the power of water to create electricity.  Hydroelectricity can occur in many different ways, but one thing that they all have in common is that they use some sort of turbine.

How does a turbine work?

A turbine consists of a series of blades.  The blades move in a circular fashion from something like wind, water, steam, combustion gasses and even something as simple as a crank.  When the blades move and are connected to a drive shaft of a generator, the generator is able to convert mechanical (kinetic) energy into electric energy.  That electric energy then powers what is called "the load."

How does a generator work?

An electric generator converts kinetic energy into electric energy by passing copper wire through a magnetic field created by a permanent magnet, producing a flow of electrons.

Why do I think the cups will work the best?

Out of all three options, I think the cups will work best, the spoons will be the next best, and the half-pipes will be last.  The reason why I think the cups will perform the best is because they have the best ability to hold water, and therefore, the cup will get heavier and have more mass, which will be good for achieving more torque.  One disadvantage about the cups though is that they will have a lot of weight.  So when they are moving to their lowest point on the wheel, they go really fast, but as soon as they have to go up to their highest point on the wheel, they would want to slow down.  One advantage I could predict about the spoons is that they have a large surface area compared to their mass and maybe they'll be able to spin faster.  I think the half-pipes will perform last because they are the heaviest of all three paddles and the water will have a harder time pushing them.  Also, because of their shape, they will want to flick the water away.

Variables

Manipulated Variables

Paddle Design:  (1) Spoons, (2) 70ml cups (ie. metal shot glasses), (3) PVC half cut pipe pieces.

Ways of Measurement:  (1) Volts (unit of electric potential difference), (2) LUX (unit of illuminance), (3) RPM (revolutions per minute)

Responding Variable

The amount of volts, rpm, and LUX being produced

Constant Variables

Wood, Motor, Wheel, Gear, Chain, Volt Meter, Screws, Bolts, PVC Light Pole, Water Pressure, Angle Iron, Amount of Water

Procedure

1. Build the Wheel

  1. Remove the rear wheel from a 16" diameter kids bike.  Remove the tire and innertube.  Clean as required.
  2. Attach the new 25H 68 tooth gear to the face of the existing bike gear.  Make sure the new gear is centered on the exisitng bike gear.  Secure the gear with a chemical weld.
  3. Drill 14   3/32" holes around the circumference of the wheel, centered between the spokes, approximately 3.25" apart.

2. Build the Wood Stand

  • Main Platform
  1. Assemble one 14" long 2x8 wood platform and four 9" long 1x3 wood legs.
  2. Attach the four 9" 1x3 legs vertically to the edge of the 2x8 platform at each corner.
  3. Secure with 2 screws at each connection to create a "table-like" structure.
  • Base Structure
  1. Attach two 22.5" long 2x2 wood runners horizontally to the bottom exterior face of the 1x3 legs using two screws at each connection.
  2. Align the ends of the runner to the outside face of the back table legs.
  3. Secure with two wood screws at each connection.
  • Light Pole Support
  1. Use a hole saw to drill a 2.25" diameter hole in the 2x8 platform for the ABS light pole to pass through.
  • Horizontal Cross Brace
  1. Attach one 11.5" long 1x3 wood board horizontally between the runners and directly beneath the hole for the light pole.
  • Light Pole Base Assembly
  1. Build a square "box" using the two 4" long 1x3's and the two 2.5" 1x3's.  Attach with 1" brad nails and secure the assembly to the center of the 1x3 cross brace.

3. Build the Light Pole

  1. Wrap a 55" long white 2" diameter PVC pipe with a 39' long micro LED string light in a spiral fashion.  Use clear tape (or glue) to secure the light strip to the pipe.

4. Connect Everything

  1. First, get two 29" long perforated steel angles and put the wheel's axle into the 7th hole on each angle to keep the wheel in place using washers and bolts.
  2. Then, connect the two steel angles to the wood "table" using bolts and screws.
  3. Wrap the chain around the bike gear and the gear on the motor.  Pull the motor away from the bike gear to make the chain as tight as possible.  Once the chain is taut, use a drill and four screws to connect the motor to the wood structure.
  4. Now, using a hole saw, make a 2.5" diameter hole in the table top that is lined up with the square "box" underneath.  Slide the 55" light pole through the hole and into the square box to stabilize the light pole.

5. Build the Hose Stand

  1. Get two 12-3/8" threaded rods and put them through the first hole on the steel angle.  Connect them using four bolts.
  2. Take the 7" steel angle and put it through the two rods to fasten.  Use four bolts.
  3. Use the metal clamp and connect it to the 7" steel angle using 1" of metal rod and a bolt.

6.  Attach the Hose

  1. Remove shower head.
  2. Screw on a garden hose adapter to the shower pipe.  Then, screw on the 6 ft. hose to the adapter.  Connect the other end of the 6 ft. hose to an additional adapter.  That end will connect to a garden nozzle.  Slide the garden nozzle into the metal clamp until tight and secure.

7.  Make the Paddles

  • Prepare the Cups
  1. Drill a hole in a metal shot glass cup about 2cm from the top of the cup.  Repeat for all 14 cups.
  2. Place a screw through the drilled hole and fasten with a bolt.  Repeat for all 14 cups.
  • Prepare the Spoons
  1. Using a grinder, carefully cut off the handle of a spoon so that the spoon is a total of 3.5" long.  Then, drill a hole in the handle of the spoon about 1/2" away from the end.  Repeat for all 14 spoons.
  • Prepare the Half-Pipes
  1. Take a 3" long 2" diameter ABS pipe and cut it in half lengthwise.
  2. Cut each half of the pipe in 2-5/8" segments for a total of 14 half-pipe pieces.
  3. Drill a hole about 1/2" from the straight edge of each half-pipe piece.
  4. Place a bolt through the hole with a washer on each side fo the ABS pipe and secure with a nut.  Repeat for all 14 half-pipes.

8. Test the Cups

  1. Take all 14 cups and connect each one of them to the wheel by threading the screw on the cup through the hole in the wheel and fasten with a wing nut.
  2. Connect the wires from the generator to the voltage meter.  Turn water on. Using a phone with a camera, record a video of the voltage meter for 1 minute.
  3. When reviewing the video, every 5 seconds, record the voltage by writing it down on a piece of paper.  Once the minute is over, take all of the data and calculate the average.
  4. Next, wrap a piece of colorful tape around a couple spokes on the wheel as a marker/identifier.  Turn the water on and record a slow motion video of the wheen as it spins.  The video should be 1 minute long.  Watch the 1 minute video and count the numer of revolutions the wheel made by using the colorful marker/identifier.
  5. Finally, take the wires of the generator and connect them to the light strip on the PVC light pole.  Point a LUX meter at the light pole 1m away from the light source, and take a 1 minute long video.  Review the video and record the LUX number every 5 seconds.  Take all of the data and calculate the average.

9. Test the Spoons

  1. Remove all of the cups from the previous step.  Attach all of the spoons by threading the bolts through the holes in the wheel and fasten with wing nuts.
  2. Repeat the last three similar steps that were used for "Testing the Cups."

10. Test the Half-Pipes

  1. Remove all of the spoons from the previous step.  Attach all of the half-pipes by threading the bolts through the holes in the wheel and fasten with wing nuts.
  2. Repeat the last three similar steps that were used for "Testing the Cups."

 

Observations

Testing the Cups

  1. Water shot out of the cups vertically to the ceiling.
  2. The chain would never hit the wood when using the cups.
  3. The cups were very loud when they were spinning.

Testing the Spoons

  1. Lots of water was sprayed horizontally rather than being shot straight up.
  2. The spoons were the loudest of all three paddle designs.
  3. Visually, the spoons looked like they were spinning the fastest compared to the other paddles.
  4. The light produced was a bright cool white color vs. a warm white/yellowish color.
  5. The chain hit the wood sometimes, but not very often.

Testing the Half-Pipes

  1. The chain kept hitting the wood.
  2. This was the quietest of all the other paddle designs.
  3. Just using the naked eye, these paddles looked to be going the fastest.
  4. The water sprayed forward.
  5. One of the paddles rotated 180 degrees early in the test.
  6. The water is getting past the curtains with ease and my floor is very wet.
  7. I started to smell burning and I'm guessing the hydroelecric wheel has burned out some of the lights.
  8. I had to keep modifying the shower curtain to contain the spraying water.
  9. On the 2nd attempt, the lights burned out.

Analysis

When measuring circumference, the gear on the wheel is 439.93mm and the gear on the generator is 73.5mm, therefore, the gear on the bike is 5.6 times larger than the gear on the generator.

The average RPM (revolutions per minute) for the cups was 352.33rpm.  The average RPM for the spoons was 398.67rpm.  And the average RPM for the half-pipes was 438rpm.

The average voltage for the cups was 17.33 volts.  The average voltage for the spoons was 19 volts.  And the average voltage for the half-pipes was 21.67 volts.

The average LUX for the cups was 15.2 lux.  The average LUX for the spoons was 16.766 lux.  And the average LUX for the half-pipes was 19.3 lux.

Some errors that were present throughout the full experiment could have been from the multimeter because it didn't seem extremely precise.  Also, the nozzle spraying the water was spraying a small bit of water out of the connection between the adapter and the nozzle, which could have impacted the results.

Conclusion

In conclusion, my hypothesis was incorrect because out of the three paddle designs, the one that I thought would be the best actually performed the worst. The best paddle design for a homemade hydroelectric water wheel is the half pipes. On a separate note, this generator maxes out at 24 volts and takes 2,750 RPM to achieve 24 volts. I was expecting about 60 RPM on the wheel which would correlate to about 336 RPMs at the generator, but instead, I was averaging 396 RPM at the wheel and at the generator that would be 2,217.6 RPM at the generator.

One thing I would do differently next time would be to have a higher volt generator. This would increase the possibility for more volts, and more power. 

Another thing I would change for next time would be the size of the wheel. The wheel I was working with for this experiment was from a kids bike. So having a bigger wheel would increase the amount of angular momentum resulting in more RPMs which would generate more power, and therefore, increase the results.

Having a bigger gear next time would also help the results. This would make the difference between the size of the big gear on the wheel and the little gear on the generator greater. The reason why this would be better is because the amount of times the big gear makes a full rotation will determine the amount of times the little gear will make a full rotation. In my experiment, for every time the big gear made one rotation, the little gear would have made 5.6 rotations. So if I had a gear that was 10 times larger than the small gear, I would be able to achieve more RPMs at the generator. This would result in more electrical power output. 

It would also be handy next time if I had a better multimeter, because the one that I had during this experiment was not very precise, and I had to round to the nearest volt. If I had a digital multimeter, the amount of volts on the reading would be more specific and exact. This would result in more precise results and measurements.

The final big thing I would change would have to be the lights. The lights that I used during this experiment were meant to be powered with very little volts. But, the electrical power that I was achieving was way too much for the lights to handle and it resulted in them burning out. Having better lights would not only avoid the chances of them burning out, but they would also provide more LUX. This would help increase the results.

The high pressure nozzle that I was using was good and, honestly, better than I thought it would be. This increased the power and pressure of the water making the wheel spin faster, thereby increasing the RPMs and the power being generated.

Application

Sustainability is the ability to exist and develop without depleting natural resources for the future.  If a person wanted to achieve a more sustainable residence, and if they had a stream or other natural water source on their property, they could build a contraption similar to what I made in order to harness a form of renewable energy.  This experiment would inform them of the best paddle shape they could use if they ever wanted to build their own hydroelectric generator system.  In an emergency power outage, this contraption could serve as an alternate light source - or - serve other potential power needs.

Hydroelectricity is a form of renewable energy. Renewable energy is a much safer, more environmentally friendly, and overall healthier form of energy. While renewable energy may have a high initial cost, it is well worth it, because sources of non-renewable energy make great negative impacts on the world and affect climate change. For example, coal, natural gas, oil, and nuclear energy are all forms of non-renewable energy and all create a negative impact to the world in some way. All of them contribute to air pollution. Air pollution can cause harm to agriculture and wildlife as well as damage the ozone layer. Renewable energy, on the other hand, is much safer for the environment and is more sustainable.

If you scale up the idea of my contraption and use something like this on your property, you could easily power your home. This would be a great environmentally-friendly and cheaper way of producing electricity. By using renewable energy, you are helping to slow the negative impacts of climate change. If more of the world started to use renewable energy, it would help the environment and create better living conditions for future generations. If you lived in a super rainy area of the world, you could set up a kind of rain collection/gutter system that harnesses the drainage volume and place the hydroelectric generator system under it. This is just one of the many ways you can incorporate environmentally friendly electricity into your lifestyle.

Unfortunately, most of the world uses non-renewable energy sources. In fact, around 85% of the world’s energy comes from non-renewable resources. The reason for this is mainly because it’s cheap and easy. If the world doesn't start to use more renewable energy strategies, we could seriously harm the ozone layer, creating more radiation from the sun to the earth, which can be bad for people and other living things on our planet.

Only around 10% of Alberta uses renewable energy. The other 90% comes from coal and natural gas. There are many ways Albertans could start using more renewable energy sources. For example, Alberta appreciates a lot of sun exposure every year, so perhaps solar panels would be a better way of producing electricity. Another one could be Indonesia. In 2020, 82% of Indonesia’s power came from non-renewable sources. But, they are known for having lots of volcanoes, so geothermal energy would be a great way to produce healthier electricity. Renewable energy helps climate change because it emits little to no greenhouse gases. So although it is not necessarily being super positive to climate change, at least it’s not impacting it in a terribly negative way like the path we're currently on. 

Sources Of Error

  1. - The Lights burned out. This occurred from the unexpected high amount of power being generated. There was too much power being produced and the light strip could not handle the load. A simple way to fix this would be to get higher power lights.

    - The Multimeter was not precise enough to differentiate between the small readings the machine was achieving. The multimeter I used was analog and readings were taken from a dial with a line indicator. This made it difficult to determine the exact amount of volts being produced. While it would be more expensive, a digital multimeter would have been much better.

    - The chain started to get loose over time. Though I don’t know exactly why this happened, I do have a good reason why it may have. I think this was happening because early in the testing stage, there were bolts that secured the axle to the steel angle. But, when I tested it with the bolts on, I noticed that after a little while of the wheel spinning, the wheel started to go slower, and I believe that that was because the bolts were getting tighter, resulting in more torque. I decided to take the bolts off so that any time in the experiment, they wouldn’t randomly get tighter. But, there was a consequence when taking the bolts off. This allowed the wheel to move side to side more freely. So, at some points in time the wheel would be far from the generator making the chain tighter but at other points this made the wheel go closer to the generator making the chain looser. The way I would fix this is to try and make a combination of both. I would find a way to secure the axle without creating extra torque. 

    - When I was putting each paddle on, the tightness of the wing nut for each paddle could have been different making some loose and preventing the wheel from spinning as much as it could have. The way I could have fixed this issue is by just screwing on the wing nut as tight as I possibly could.

    - When turning the water back on for each trial, it was possible that sometimes I wasn’t pulling the faucet handle enough, limiting the amount of water, and the resulting water pressure. The way I would fix this in the future is by simply pulling the tap handle as far out as it possibly goes. This would make the pressure for every trial the same.

     

Citations

National Geographic Society. (2023, October 19). Hydro Electricity. National Geographic Educationhttps://education.nationalgeographic.org/resource/hydroelectric-energy/ 

Energy Imformation Administration. (2023, October 31). Electricity Explained: How Electricity is Generated. Energy Imformation Administration. https://www.eia.gov/energyexplained/electricity/how-electricity-is-generated.php#:~:text=A%20basic%20electromagnetic%20generator%20has,becomes%20a%20separate%20electric%20conductor

Technological Solutions, Inc. (2024). The Environment: Hydropower Energy. Ducksters. https://www.ducksters.com/science/environment/hydropower.php 

Kiddle Encyclopedia. (2024, January 23). Hydroelectricity Facts for Kids. Kiddle Encyclopedia. kiddlehttps://kids.kiddle.co/Hydroelectricity 

Book: DK(2018, July 3)How to be good at science, Technology and Engineering 

Shinn, Lora.(2022, June 1). Renewable Energy: The Clean Facts. National Resources Defense Council. https://www.nrdc.org/stories/renewable-energy-clean-facts#sec-whatis

 

Acknowledgement

I would like to thank my mom, Amy Adams and her partner, Ryan Mislan.  My mom helped me edit my writing and she helped me with the layout of my trifold presentation.  She also helped me "water-proof" the bath-tub/shower area to contain all of the splashing water from the experiment.  My mom's partner, Ryan, helped me figure out how to design and build the contraption for my experiment and he helped me figure out how to do my testing procedure and calculate results from the data. I would also like to thank the teachers that have helped me throughout this science fair. Specifically Ms. Berkell, Mr. Blakney, and Ms. Strother.