Hydraulic Piston to Electric Power Generation?

I couldn't agree more, but I don't know of any off the shelf equipment available and scalable in the same way as hydraulic actuators..

It's been a year or so since I looked into piezoelectric.

I'm thinking with piezoelectrics you will need some kind of a force multipler mechanism driven by the pedestrian's weight, sort of like the spring and hammer used to start butane lighters. Still, it's difficult power to utilize, high voltage and minuscule current.

I can't imagine people would be happy with the sidewalk sinking more than a few inches.

Energy is force x displacement. If your spring exerts a force (F) and the person's weight is W, and the piston moves down a distance d, then the amount of energy per person is (W-F) x d + F x d = W x d (foot pounds). Multiply by the number N persons passing in unit time to calculate power. A hydraulic motor driving a generator could be used to charge a battery.

Your math is well received, but I'm a little rusty. Thanks for the jumping off point.

I just recall my son’s college project in which he pursued similar concept.

The project in brief is that the first step of a staircase has the two times width of rest. Say the steps are of 8” width, the first is of 16” width. Of this 16” first 8” is phony, in sense, not rigid as rest. But second half is also rigid as others.

The first step is supported by four spring at corners. One or two pumps (cylinder, plunger with respective suction/discharge ball valves) were arranged around the center.

The idea is, when people going up would press the phony step and intern the hydraulic system beneath it. This would give successive pumping. An accumulator could make a steady flow.

Although as college project it passed through, it had some issues, like:

· Phony step was not uniformly working, was always inclined one way or other on pressings.

· Plunger being, often pressed inclined caused leaks and messed around.

· The first-time users were baffled and even tripped.

Ultimately the boy’s examiner/evaluator did not merit the concept but the result. So, my son did not pursue his concept.

I personally feel his concept is worth perusing, even for commercial exploring.

For a misbegotten project like that, I would flunk both the student and the professor.

I disagree. Documenting and analyzing why a design approach failed to produce the desired function is precisely what should happen in academia and any R&D environment. Now if the project required pursuing a flawed approach, I would reserve the A grade to only the brave student(s) that refused the flawed approach if they accurately predicted how others would fail.

I'm all about rigid and uniform stairs.

Ever get that hitch in your step when you're defending stairs and you think there's one more step at the bottom?

..maybe if you enjoy life as a live action Gumby.

..still a very good project.

Misbegotten (bad, foolish, ill-conceived, inappropriate), is dismaying comment

On the war of the currents, Edison, in the beginning of the fight, criticized the Tesla’s AC system as ill-conceived.

In our case, the project was not ill-conceived. The concept was well conceived, but with limited time and budget had ended up as unpresentable. As an experienced engineer, I look at the functional failures of components can be tuned up and perfected. Had there been a compelling need, I am sure to make this perfectly workable. The main culprit was O-ring that caused water leak at the pump plunger and messed around the exhibit area. O-rings fails, it failed even on hi-end projects like Challenger space shuttle.

One does not mess with stairs in such a manner. Period.

You could make it a linear generator with a permanent magnet passing copper coils generating current flow.

I would model it after a V8 engine with the hydraulic motor driving a crankshaft that had linear generators for each cylinder.

I've sent a few emails to a company touting a ' rotary linear actuator ' to no avail. I like the idea, but I'm concerned about availability.. again. Hydraulic wins.

Durable, scalable, tested, universal.. What's not to love?

Similar systems are the cornerstone of wave to electric technology..

Why a V8 when a single piston is simple and scalable?

I did not take your 'for instance' as an example, but instead was thinking of a power source for a machine converting hydraulic power to mechanical electrical generation...If you had a heavily traveled sidewalk, such as in a big city, and the walking was converted to hydraulic pumping action then you could have a centrally located generator...

When did a spring become a dampener?

Misuse of term. There won't be a spring..

Or sidewalk.. or person..

That kisses most of the OP goodbye.

In my earlier draft I must have made that distinction?

It doesn't change the description of the forces involved.

Teeter-totter actions of tiny electromagnets mounted levers underneath the slabs as people passes by and steps on them.

If you made an exercise machine that powered a TV, computer or a bunch of machines powered a refrigerator, you could sell hundreds in California now.

All joking aside, I wish the best for all in California during these blackouts. Hopefully, progress can be made to harden the grid better so power line initiated wildfires and blackouts are a thing of the past.

That may be the straw that breaks the crazy camels back... California has been lost to well meaning but misguided laws...A plan for strategic logging could solve this wildfire threat, and be profitable to boot....but that won't happen, the do-gooder's are too busy opposing Trump...seriously? rent control?

https://news.google.com/search?q=california%20%20new%20law&hl=en-US&gl=US&ceid=US%3Aen

You would not create sufficient energy to be worthwhile. Let is assume that the floor tiles are 4" square and that the plaza is a 300' x 300' train station concourse that has between 500 and 3000 people crossing it at any one time (average 1000 allowing for out of rush hour periods). That's very crowded. With a stride length of nominally 36" and allowing that people cross the plaza in different directions, rarely taking the shortest path from one side to the other, assume that each person uses 140 steps to cross in one minute. Given the size of human feet each step will depress 2-4 tiles, say 3 on average. So the 100lb is spread over 48 square inches giving a hydraulic pressure of 2lb/in². To avoid trip hazards and being sued several hundred times per day, each tile can only realistically be depressed by ¹/₁₆" when stepped on. This gives a hydraulic displacement of 1"³. So the power input is 1000 x 140 / 12 / 12 / 12 ft³/min. Or 81 ft³/min at a pressure of 2psi. Put this flow through a hydraulic intensifier to increase to working pressure of 100psi to drive a generator via hydraulic motor and you have 1.62ft³/min to drive your motor (assuming a 100% efficient system????).

Your capital cost is 810,000 hydraulic tile actuators at say $1 each to make (additive manufacturing in two parts using ceramic material joined with a full area diaphram, return spring, 2 integral non-return valves and pressure and return pipes manifolded to plug into the adjacent tile with integral push fit connectors and O rings) plus $2 each to lay. Roughly $2.5 million. Put two bicycles rigged up to dynamos in one corner of the plaza and invite people to exercise on them while waiting for their train and you are likely to generate the same amount of energy for $1100 tops!!!!!!!!!!

I am being purposely vague.

There are no people and plazas.

..just the 'mystery' force I've been eluding to since my first post at cr4.

Being not real people in a not real plaza, any chance that instead of hopping off, the not real people might be content falling through the floor of the not real plaza?

That would certainly have advantages for electric power generation. For one you could forgo reciprocation and use rotation directly.

These not real people insist that reciprocation is taken care of before any rotory actions will be considered.

Surely it's a compromise, but they are strong in numbers and willing to work long hours for free.

It would be much more efficient to use the energy more directly, conductor movement & magnetic field, accumulate into a storage system (battery) until you have enough to generate usable electric, like tide machines. Wind the coils outside the sidewalk panel gap, magnets on the moving part.

Or use a magnetic piston bouncing up & down in a non-conducting cylinder (ceramic or fiberglass) with embedded coil, convert movement directly to electricity.

Heat, seal leakage, friction all indicate poor application potential for hydraulics, intense force in a small package with locational flexibility is why we generally use hydraulics...?

Right ot 3.56 he sums it up, but find anybody selling a ready made linear generator?

There are only about a million papers on the subject and another 10,000 companies pretending to work on them..

Where are they?

I'll make my own if I need to.

fiddle faddle

My earlier mention of tidal generation was wrong, it is wave generators that generate similarly to the sidewalk scenario. I got them crossed up. There are a couple in commercial operation, interesting read...

https://en.m.wikipedia.org/wiki/Wave_power

Quite a few years ago I had a guy call into the company I worked for with a similar idea but on a grander scale.

Banks of hydraulic cylinders under the road at toll booths and under railway lines in shunting yards.

Never heard of it coming to anything.

The thing to remember is "you get 'owt for nowt. Or on plain English you get nothing for nothing.

Someone has to pay and it is the driver of the car who has to rev his engine a bit more to get out of the dip in the road.

John

Maybe you could just set up a row of turnstiles that would turn generators....use the power to charge a battery bank...run all the lights...no people no lights haha...might help to make it downhill....

No people, place or thing required to be the right location on earth to extract.