A hydropower based power-generating fitness system and some questions

Question

I'm currently researching and experimenting a system concept about hydropower-based fintness. I recorded my initial experiment footage and you can watch the video on Youtube.

Befor talking about this idea, I must tell you that I AM NOT going to make human force a major source of energy.

All I want is to build a system which allows higher variety of exercises and can efficiently utilize the energy generated by users. If the users see the result of their workout can both benefit their own health and the environment, they might be more willing to do exercise regularly.

The Idea:

The system collect and sore the work done by users in the form of water potential energy. Common methods of generating electricity by exercises are restricted because they have to keep the motor spinning. In my case, the users can do more kinds of exercises with different training style.

Here's some example:

1.Lifting up bottles filled with water The simplest one, which I chose in my experiment. If the user like dumb bell or kettle bell, this will be their choise.

2.Pump integrated cable machine / rowing machine The weights connected to cables are replaced with pistons. When the user pull the cable, the pistons will pump the water up.

3.Spinning bike If the user really like this classic exercise, they can use a pedal water powered pump like this on Youtube to store energy

The water lifted/ pumped will be converged to the upper water tank. There will be only one hydro-power generator which convert the potential energy into electricity. We can control the output of electricity by adjusting the rate of water flow. Therefore, we can generate power according to the need of the facility.

This system don't require every exercise equipment to be installed with generators and we don't have to setup complex electricity wires.
The batteries are also not need in this system. Without those expensive components, this system will be much cheaper to build and maintain.

My initial experiment and result:

Height of hydralic head: 170cm

Water tube diameter: 1/2 inch

Flow rate: 47.5 ml/Sec

Voltage:4.8V Current:46 mA

Please check the Youtube video I mentioned earlier for detailed footage.

The generator I used:

This is much like a "cross flow" generator, but have only one water input.

You can easily find on Amazon by typing "BQLZR Portable Micro-hydro Generator Water Charger High Efficiency 3.5W "

Working pressure: 0 to 1.75 Mpa

Test pressure: 1, 2 MPa

Temperature range:0 to 120 degrees Celsius

Maximum Flow: 30l/min

Flow range: 1.5-20L/min (press 0.05-0.2MPa)

Shell material: nylon

Size: approx. 8 x 4cm/3.15 x 1.57"(L X D)

The system successfully generated electricity and I could easily keep the water flowing. However, this is obvious that the electricity generated was too weak to be utilized.

My next setp: I'm planning to build a system which have 10~5W output per second. I had bought a 795 DC-motor.

The energy generated will be converted by a DC-converter module which have 5V output.

This system will be able to charge common electronics like tablets and smartphones. If I make any further result, I'll post them here.

And finally here are my questions:

1.Do you think there's any drawback/bugs in this system besides the problem of water storage and leaking?

2.Is there any existing system which have similar concept?

3.Do you know suitable parts for my next experiment?

Answer 1

The water system is a near closed system that just needs to be filled-up occasionally and then mostly the same water is used over and over.

The water pumps are simple mechanical devices on each exercise machine.

The water pumped to the roof just has one generator to turn when it flows down.

Basically, I would use the exercise system to charge DC batteries and have a DC lighting system. Then a single solar panel could also charge the batteries. And small wind turbines are available if there is good wind.

So the drawback to the system as described is that it would be better if combined with other systems.

However, the system as described does not use batteries but uses a flow of stored water to generate electricity that directly charges a lap-top-computer. So the logic of the system does hold-up to scrutiny.

Answer 2

I think your entire premise is flawed. You are doing two things at the same time:

1. Using human power to produce electricity (an exercising person can produce 100-200 watts), and then directly...
2. ...storing the electricity

I'd say you should do this:

1. Using human power to produce electricity (an exercising person can produce 100-200 watts), dumping the electricity to grid
2. Taking electricity from the grid, and storing the electricity into potential energy of water

...so the two components (human power generator and electricity storage unit) don't need to be in the same room.

In fact, perhaps you should decide which area you are planning to be professional it. Are you planning to be a professional engineer that's specialized in turning human power to electricity (hint: you can only get 100-200 W from a single human)? Or are you planning to be a professional engineer that's specialized in grid energy storage (hint: it's difficult to do it in a way that's economically feasible)?

So, I think you are needlessly tying the two parts of the process, human power and grid energy storage, together. Let the human power be generated by human power experts. Let the grid energy be stored by grid energy storage experts.

For (2), there's plenty of prior art in the form of pumped hydropower, so perhaps you should specialize only in (1)?