Electricity for the Gym

While talking about how to give energy to a small town in Guatemala, the suggestions of using exercise equipment came up during the brainstorming process. Although it did not fulfill the requirements for that town, it got me wondering why none of the equipment in our gyms is set up to store energy. After all, after an initial investment, it’s free energy.

On average, you could produce enough energy to power a 25watt light bulb for 8 hours by cycling for one hour (1). And bikes aren’t the only thing that could produce power. Basically anything that moves: elliptical, treadmills, and stair steppers for example could be made to provide power for other electrical devices such as the light, TV, and speaker system.

Without the data about how many people typically use the gym on a given day, how long each person typically spends on the equipment in question (so total time not including stretching and any weight work), and how much power the gym uses in a given day I can only hypothesize what percentage of the total electricity could be provided by the work out equipment. However, I believe it to be a sizable amount and so wish to find someone who I could ask to get these numbers (the real trouble is figuring out who).

All the same, assuming that such a system was possible and practical, I can start figuring out what exactly it would entail. Although including a battery makes the overall transfer of energy less efficient, it allows for energy to be stored and then used at a later time. Assuming the use of a battery, running all of the power generated into the battery would make for less circuitry as a separate control circuit would be needed to make the electricity straight from a bike into usable electricity if it didn’t go through the battery. By storing any energy in the battery before using it, there it only the need for one control circuit to make sure that the voltage and current leaving the battery meet the specifications of the circuit it is powering.

Some pieces of the system to consider:

1. Wires. While these seem rather simple, wires might actually pose a problem. There are signs in the gym that tell you to leave any possessions in the lockers because they don’t want any accidents. Wires running across the gym floor from the exercise equipment to the battery may be tripping hazards. And not laying the wires on the floor might require more money to route them through the floor.
2. Battery. This will most likely be the most expensive part of the system. Finding a battery that doesn’t require too much maintenance, is safe, and holds enough power can be challenging. All the same, it’s definitely possible (I already know a lot about battery research from the project for San Mateo – I will expand on this issue in more detail once I get the specifications for the particular system).
3. Exercise Equipment. The equipment itself uses some of the power it generates in order to power a display and some circuitry to calculate the time, calorie count, distance, and speed. The excess power must be removed from the equipment in a way that does not interfere with these functions.

While I do not know enough yet to do the calculations about how much power could be produced, the size of the battery needed, and the cost of such a system, I do know enough to start looking for someone to ask for the information needed. If it works out and I find someone who can help, you’ll find an update (I'm hopeful to find the information as you can tell by this post getting its own label in expectation of more to come).

1. http://www.gizmag.com/the-pedal-a-watt-stationary-bike-power-generator-create-energy-and-get-fit/13433/