gruntguru - reading my entire response might help you understand why pumped water would work best. If not, then please suggest a workable solution for the original problem. Solutions will be graded on cost, system efficiency, and total power output, with no extra credit for snark.
No snark intended. However:
- Pumps and turbines are high efficiency machines in large sizes. Power output of a gym doesn't suggest large pumps/turbines.
- High efficiency is obtained in a defined operating range. Gym output probably varies constantly between zero and 100%
- High efficiency pumps and turbines are normally high head machines. Gym in multi-story building might qualify.
- If high head is not available, the mass of the stored water will be significant.
The best storage system for such a small energy source is the grid.
Next best would be battery storage. Buy a Tesla Power Wall.
I assume a "gym" to be a place where less than 100 humans are simultaneously feeding energy into exercise machines. Provided that assumption holds, I will stick to my assertions.
I wonder if E-bikes have regenerative braking? If so, after getting home on your 25mph E-bike, instead of plugging it in to recharge and then going to the gym for the workout you missed while riding your E-bike, just put it on rollers and ride with the regenerative braking engaged for a few hours...
"Schiefgehen wird, was schiefgehen kann" - das Murphygesetz
At this point, I'll shift to using the equipment to mechanically drive a belt that brings coal to the surface for burning in a steam generation plant. But then cut out the middle men/women and use the electricity to operate sealed electric motors to drive the belt.
You are merely transferring energy from one form to another, all at the cost of the energy required to accomplish this transformation. If you starved all those gym people, they wouldn't have any energy that needed to be transformed thus saving this transformation energy. A penny saved.............
Good idea, extracting energy (in computing power) from humans without paying for it. And we could connect it to the cloud. And we could call it Windows 10.
Why wouldn't it be cost-effective? The total output wouldn't be much, but you could probably do it for less $/w than solar cells, as long as the storage is provided by the gym members in their cars.
When electric cars become common place their use as temporary storage devices for excess power from solar and wind will also become common place. Because they spend a large part of the day in a parking space, and the cost of connecting parking to the grid is negligible, compared with other options such as pumped storage the marginal cost is negligible. It's just a matter of time.
gruntguru was right. I was referring to a gym, sorry I wasn't very specific at first.
Storage of water would also be an good idea, though would it be cost efficient to connect a machine a piece to a pump??
Plus, what I want is to combine several bikes, mechanically; will a power split device, a back drive differential work, of is it possible to use something like an automatic derailleur set, what I mean by that is, a chain sprocket mechanism, one end connected to the bike and the other to a common shaft that connects at least 2 bikes in series, which automatically shifts gears in order to maintain uniform speed. I'm not sure u'll get the latter part though... ! Just imagine something like a tandem bike or a sociable
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