Is Critiquing Green Ideas Considered Taboo in the Scientific Community?

[The Wizard]

@ jack action,

the energy produced by the cars powertrain propels the vehicle over the road surface. Depending on a large number of factors, size of tyre, tread pattern, road surface material, gradient, engine output, gearing, use of accessories define how much energy is required to achieve a given speed and maintain it.

As the vehicle is driven the tyres create friction between the road surface and the tyre which produces heat. The vehicle also creates another power source and that is weight which presses down on the road surface causing Deflection. This deflection has nothing to do with heat of any kind, it is a simple mechanical reaction to the force being applied from above. If the force being applied already exceeds the force required to move a sub-component a minimal amount of 0.1mm it is a zero rated byproduct.

The idea of using the Piezo is the Zero emissions, by using a fuel based generator you have Co² emissions and noise.

 

[russ_watters]

If that works, maybe we should just make stiffer roadbeds then, and reduce the energy wasted by all vehicles, all the the time they travel. We'd save even more because we wouldn't need to convert anything, it would all be a direct savings of fuel."

your comment is very true, harder roads would indeed save a large amount of fuel but the initial road building costs would be higher and the division of costs would be hard to share. Example the state or city is responsible for the road maintenance costs but the fuel savings would be in the pocket of the vehicle owner and the general savings in the economy because of lower fuel imports etc.

Since the costs are borne by the drivers either way, it doesn't make much sense to try to generate more in taxes by purposely making cars less efficient. Instead, tax rates should be adjusted to account for increases in fuel efficiency -- which they are.

To answer your remarks about the use of Piezo units on the suspension, the Piezo acts as a switch to control electronic suspension components, the power generated is simply used to trigger a Canbus signal.

Are you saying that's how they are actually used today? That's fine, but a quick google tells me people are indeed researching energy harvesting in the shocks.

Regarding your comment of energy input...

The force required to trigger the piezo is so negible compared to force already being excerted by the vehicle on the road surface that it is virtually unmeasurable.

It isn't clear to me why you think this matters. The difficulty in measuring a small variation of a large number (on the input) vs a small number by itself (on the output) doesn't impact the physics of the situation.

You are aware that conservation of energy applies and that therefore negligible input energy results in negligible output energy, right? A separate post tells me that you may not accept the role of energy conservation here:

The vehicle also creates another power source and that is weight which presses down on the road surface causing Deflection. This deflection has nothing to do with heat of any kind, it is a simple mechanical reaction to the force being applied from above. If the force being applied already exceeds the force required to move a sub-component a minimal amount of 0.1mm it is a zero rated byproduct.

It sounds to me that you are saying you can extract output energy from this process with no additional input energy. Is that what you are saying? If that is what you are saying, it is a direct violation of conservation of energy.

Consider a spring (because that's what we have here). If you push this spring down 1m with a force of 2N, you store 1J of energy. When you release the spring, it gives 1J back. There is no energy left over to extract from the system.

If, instead, you add an energy harvesting device (an electric generator of any type), what happens is the force required to compress the spring goes up and the difference in force time distance is the energy that can be harvested. The input rises to provide the output. That's what is happening here (though for the piezo it is more deformation, not more force, that provides the output).

@ russ_watters,

as piezo parts are made of metal and hardenened ceramics they are just as hard if not harder than concrete or asphalt or mud or stone road surfaces so your statement is not true.

The most common piezo material is plastic, and "metal piezo" sounds like a contradiction in terms. Could you provide a link to such a device? I'm aware of ceramics. I probably should have set this asside because I don't want it to get in the way of the more direct problem I was discussing:

Deformationor Deflection as it is known, of a road surface varies according to a lot of factors and the deflection rate decreases with the depth and materials used in the substructure. There is no change in the rolling resistance between the tyre and road surface if you mount a sub-surface device,the co-efficients involved do not change, especially where a deflection of only 0.1mm is involved.

In the scenario you are describing you replace a piece of a road with a piezo material with the same stiffness. The catch is, the stiffness drops when you plug it into collect the electricity. So when you first build the road it feels identical, but then when you turn on the energy harvesting, the rolling resistance goes up.

 

[russ_watters]

Now that is interesting and a horse of a different color, I'd like to hear more. It seems to me a car suspension can be (or are?) designed to absorb energy (I couched that, as I'm thinking that theoretically, the spring/absorber return all energy to the system?). So if converting some of that energy from mechanical to electrical can be part of the damping, it is workable. Whether it makes sense from a power/weight/cost/size standpoint is another matter, but it would be interesting to see the numbers behind it.

I own a pair of skis that are equipped with this. They have LEDs on them that light up when skiing over rough terrain (or if you whack them with your knuckles), dissipating the vibrational energy.

This is, of course, why they are also used in microphones.

For car shocks they offer better dampening and energy production simultaneously.

 

[russ_watters]

Er, I missed this before;

Any deformation of the road surface created by the weight of a vehicle will not be given back to the wheel as the wheel would have already left the point of deformation before the return to the original state would exist...

That's the loss! With an elastic road surface, most of the energy of deformation is returned by the road pushing the wheel back up, just like in the spring example in my previous post. With a piezo(like a memory foam mattress), you decouple the input and return, and the difference is the energy loss!

 

[JBA]

OK, I get point but even the piezo chip will have some elasticity and I certainly don't mean to imply that there is 100% free energy to be gained here. So let's just say that this is another potential means of delivering energy to a location where installing the wiring or expanding or installing a power grid is not feasible or desirable; or, even if it is simply for aesthetic purposes, such as a number of upper class neighborhoods that have demanded underground power distribution systems to eliminate power poles and overhead wring in spite of its higher installation and potential maintenance costs). There are currently piezoelectric walkways, and bike path sections already operating in parks in Europe where this technology places the energy generation burden directly upon the users (not the power grid) for the safer lighted pathways that benefit those users.

As to the economics of the process, in that respect, there are too many current technologies that were "too expensive" (the cell phone as an obvious latest example, that in their earliest stage was too expensive for general population access). Thankfully technology marches on and once a new concept is brought to light then the world of technology becomes aware of it and it attracts those who are interested, or see a potential, begin to seek answers to improve that technology. As soon as we start to impede the flow of "look at this" or "what about this" scenarios based on something as simplistic as "it is just not economical" or "I can't see any future in that" we are seriously impeding scientific investigation; and, that is exactly what has been happening across this country in many industries as the corporations operate with their total focus on satisfying the investment community.

Thankfully, we still have Steven Jobs, Bill Gates and Elton Musk type individuals that are willing to take the longer view. If the short term "we have to meet the investor's quarterly profit projections" goal now driving our corporations had been historically allowed to control our global technological development then we would still be lit only by the sun and moon and traveling by foot. To paraphrase an old short quote "it was a brave man who mounted that first horse"; but, apparently he thought it was worth the risk.

With regard to the piezoelectric shoes, while making the sensors large enough and flexing them far enough to get usable power for such ideas as powering electronic accessories may not be worth the energy required from the user; using that technology to power small LED type shoes that can make children and/or runners more visible at night might be worth the energy penalty. It all has to do with individual possible applications.

As someone who spent more than half of my 40 years in new product development engineering, I have seen too many examples of "hell, that could never work" ideas turn into "well, damn, will you look at that" results.

 

[jack action]

The vehicle also creates another power source and that is weight which presses down on the road surface causing Deflection. This deflection has nothing to do with heat of any kind, it is a simple mechanical reaction to the force being applied from above. If the force being applied already exceeds the force required to move a sub-component a minimal amount of 0.1mm it is a zero rated byproduct.

The energy source with a weight $mg$ is called potential energy and it is equal to $mgh$, where $h$ is the 0.1 mm you are talking about. Two possible scenarios:

1. The car must go «uphill» 0.1 mm and then will sunk under its own weight to go back to the road level;
2. The car will sunk 0.1 mm when passing over the piezo and must «climb out» of the hole to go back to the road level.

Either way, the car must climb a small hill when it goes over a piezo and that will necessarily require wheel power.

You cannot repeatedly create energy with a weight without someone lifting it between cycles.

Even if you tell me the car will not rise, but only part of the tire will deform, still this will necessarily increase the rolling resistance of your tire, no matter how insignificant you think it is. By comparison, the power produced by the piezo will also be insignificant compared to the car power.

 

[mfb]

@JBA and @The Wizard: You keep shifting the goalpost around. In some posts you make the system inefficient to highlight that it wouldn't have an effect on the car, in other posts you make the system efficient to get some energy out. You cannot have both.

As someone who spent more than half of my 40 years in new product development engineering, I have seen too many examples of "hell, that could never work" ideas turn into "well, damn, will you look at that" results.

I'll bet that none of these examples violated conservation of energy.

Shifting things from the "that doesn't work" category to "we did it" is part of the job for every scientist, but if it violates fundamental laws of physics you should have extraordinary evidence for such a violation, and you cannot prove this violation using the laws you try to violate.

 

[russ_watters]

There are currently piezoelectric walkways, and bike path sections already operating in parks in Europe where this technology places the energy generation burden directly upon the users (not the power grid) for the safer lighted pathways that benefit those users.

Fine. Like I said, it's the just incorrect marketing that would lead me to deny her the prize. I can envision scenarios where it is worth the trade-off and know of other energy harvesting devices (indoor "solar" power, flow powered devices) that are successful and therefore proven worth the trade-off. Get rid of the "green" label and market it honestly as a "leech" and I'm onboard.

 

[russ_watters]

I'm going to expand on @jack action's lead and go into some detail on the nuts and bolts of rolling resistance and how exactly a piezo cell could be made to impact it.

Rolling resistance has 3 somewhat inter-connected components:
1. Inelastic deformation of the tire.
2. Kinetic friction due to slippage due to deformation.
3. Inelastic deformation of the ground.

Obviously, #3 is the one we are concerned with. In general/for a quality road, it is a couple of orders of magnitude smaller than the other two. But it works identically to #1. Here's how it works:

As described, an elastic object is like a bunch of little, connected springs. Apply a force and the springs compress. Release the force and the springs expand back to their original length. For the most part, energy is conserved in this process and the spring gives back almost all of the energy it absorbed. Applied to a car, the tire and road are literally shoving each other out of the way, but then they both rebound and push each other back, recovering the energy it took to shove each other out of the way. In other words, we said the car is basically climbing a hill all the time. Well, that's what the front of the tire is doing. The back of the tire is traveling down that hill (er - the previous hill).

But springs, roads and tires are not perfectly elastic. There is a component of inelasticity, which means that when they spring back, they do so imperfectly: with less force than it took to compress them. That means the hill they are rolling down isn't as steep as the hill they are driving up. The rolling resistance is the difference between the compression force and restoration force (adjusted for the angle of the contact to get it in the direction of motion of the car).

A simple piezoelectric device you can buy and play with for a couple of bucks is just a strip of plastic, to be used as a vibration sensor. Flick it and it vibrates - and it has a certain inelasticity that dissipates the energy and causes it to eventually stop vibrating. But otherwise, like the road rebounding, this is a pretty elastic situation.

Now, when you hook the device up to a circuit, you change its mechanical properties. How exactly depends on the circuit, but I'll give a simple example that dovetails well with what we are discussing. Let's say that for the deflection part of the cycle you leave the circuit open. At max deflection, you have a certain voltage and charge available and at that moment you shunt it to something that can harness it. What you just did is to siphon-off some of the elasticity of the device, making it rebound with less force and lower amplitude.

Applied to a road, the connection should be obvious: When you implant the device in the road, you can say the elasticity is the same as the concrete you replaced, if you choose it that way. But when you turn it on to extract the energy, the impact is to not rebound as well, opening a new gap between the compression and the expansion, creating new rolling resistance.

 

[NTL2009]

OK, I get point but even the piezo chip will have some elasticity and I certainly don't mean to imply that there is 100% free energy to be gained here. So let's just say that this is another potential means of delivering energy to a location where installing the wiring or expanding or installing a power grid is not feasible or desirable; ...

I think the critics here have said all along that efficiency isn't the primary constraint for remote power. But the presenter put this in the context of the world's energy supply. That is the issue.

... As to the economics of the process, in that respect, there are too many current technologies that were "too expensive" (the cell phone as an obvious latest example, that in their earliest stage was too expensive for general population access).

Oh please. Now you've touched on a hot button.

I worked on the pre-cellular tele-comm equipment (IMTS). I worked with the R&D engineers to deliver the equipment for the initial Washington-Baltimore cellular trials. I worked on the teams that brought you the first portable cell phone, and the first pocket-sized cell phone. I have sat and talked with the key players in the cell phone industry.

Not every new idea follows the path of cell phones, computers, semi-conductors, etc. Gordon Moore himself has addressed this fallacy. Just because our tablets and smartphones today have more power than a room sized computer back in the day, is no reason to think everything will progress at that rate. That tech had an extreme amount of potential growth before hitting the limits of physics, unlike most other technologies.

Bell Labs was working on the concept of the cell phone years (decades?) before the technology existed to make it feasible. Why? Because they could see the progress in technology, and could see that there was a pathway towards achieving this. They knew it was complex, so they started working through the concepts, realizing that it was likely that one day, the technology would catch up, and they wanted to be ready.

If you can show us there is a pathway for piezo elements in a roadway, to someday be viable as anything beyond niche applications, please share.

Thankfully technology marches on and once a new concept is brought to light then the world of technology becomes aware of it and it attracts those who are interested, or see a potential, begin to seek answers to improve that technology.

Piezo technology has been around a while and is well understood, both its advantages, and its limitations.

Thankfully, we still have Steven Jobs, Bill Gates and Elton Musk type individuals that are willing to take the longer view. If the short term "we have to meet the investor's quarterly profit projections" goal now driving our corporations had been historically allowed to control our global technological development then we would still be lit only by the sun and moon and traveling by foot. To paraphrase an old short quote "it was a brave man who mounted that first horse"; but, apparently he thought it was worth the risk.

And if we also did not look at every new idea critically, and evaluate the risk/reward/feasibility, we would still have hordes of people trying to turn mud into gold, or develop perpetual motion machines.

... As someone who spent more than half of my 40 years in new product development engineering, I have seen too many examples of "hell, that could never work" ideas turn into "well, damn, will you look at that" results.

I've heard that applied to some new technology as well (CDMA to be specific), but as was mentioned earlier, it didn't break the laws of physics.

 

[NTL2009]

OK, I think this thread is in need of a bit of levity.

Other than learning of the piezoelectric effect somewhere along the way in my studies, my first real awareness of them being used in a product was in the Ovation guitar ( I may have seen piezo tweeters, or piezo microphones or strain gauges, but this was at least more interesting to me, and made more of an impression). Instead of a contact microphone that was sometimes used to capture the direct vibrations of an acoustic guitar, or the electromagnetic pick-ups in an electric guitar, the Ovation guitar used piezoelectric pickups. They were mounted under the 'bridge' (where the vibrating string lengths are terminated at the body), and I think a separate one was used for each string, so the volume/tone could be balanced independently.

https://en.wikipedia.org/wiki/Pickup_(music_technology)#Piezoelectric_pickups

I also recall that unlike most electric guitars with coil pickups, the Ovation required a 9 Volt battery. The output impedance of the piezo was so high, that it couldn't drive the standard guitar amplifier properly, so the 9 V battery was used to power an FET buffer.

Hmmm, high output impedance - hard to get much useful power out of such a device. Fortunately, guitars don't need to produce a lot of power, the amplifier takes care of that. The 'power' is in your choice of chords (for you distorted guitar fans - 'never play the third!')

 

[JBA]

I am only pursuing a discussion and not a heated discourse on my part. No animosity felt or intended.

I have not said nor implied that every brain child would turnout to be the next great idea; and, every new concept will at some point have to face scrutiny, due to the scientific principal we all support (unless it is a political idea and then all bets are off).

There are dozens wild ideas generated all the time, but some of those so judged in history turned out not to be so crazy is the point I am trying to make.

I simply believe that it is really bad idea to allow the current primarily corporate view of "yes but what will it do for me today" to invade the world of scientific investigation and pursuit of new ideas.

 

[russ_watters]

...every new concept will at some point have to face scrutiny, due to the scientific principal we all support...

There are dozens wild ideas generated all the time, but some of those so judged in history turned out not to be so crazy is the point I am trying to make.

I don't agree, and others have provided examples (or pointed out that examples you provided were invalid). Indeed, you can't even get a patent on an idea that violates conservation of energy, so before anyone even knows about it, it has to have already passed scientific muster. I think you would be hard pressed to actually come up with an example of an invention that was believed to be scientifically impossible for a while before being proven valid. The closest would be a new scientific principle (like superconductivity) that was invented by scientists that brought applications with it. That cart *never* leads the horse though, though the internet is awash with crackpot perpetual motion machines that try.

I simply believe that it is really bad idea to allow the current primarily corporate view of "yes but what will it do for me today" to invade the world of scientific investigation and pursuit of new ideas.

I would agree if such an animal existed, but it doesn't in general and doesn't factor in here. @mfb brought up the amount of energy generated, but it was a side issue, after the first 10 posts pointed out the violation of conservation of energy. And his point wasn't wrong; it was another flaw in the way the project was presented. As a smilar example, a "solar" powered automatic faucet is generally a leech, but even if it is under a window, no one is going to claim you can provide grid power with it.

 

[NTL2009]

...
I have not said nor implied that every brain child would turnout to be the next great idea; and, every new concept will at some point have to face scrutiny, due to the scientific principle we all support (unless it is a political idea and then all bets are off). ...

OK, but you do seem to be treating this one as a'great idea' w/o applying what many of us consider a reasonable amount of scrutiny. I was just pointing out that seems to be a recurring theme among many, especially when it comes to anything with the 'green/renewable' label attached to it.

... There are dozens wild ideas generated all the time, but some of those so judged in history turned out not to be so crazy is the point I am trying to make. ...

I don't give much credence to the usual "people laughed at so and so" that we hear from the green 'critics of the critics' so often. First, many of those who said "it could never be done" were people w/o the knowledge to make a sound judgement. And today is different from history. Today, we have a sound understanding of the underlying principles, and at a more detailed level, computer modelling. We rarely need to build a prototype and do so much trial and error just to determine if something has a chance at success. Yes, we prototype to work out details, characterize and so forth. But, for example, that solar powered plane group didn't need to actually build a plane to realize the whole concept was very, very marginal, and a long, long ways from being able to carry a near-normal payload at near-normal airspeed. And no amount of prototyping would get them there until batteries and/or solar panels make a leap in power/weight performance.

I simply believe that it is really bad idea to allow the current primarily corporate view of "yes but what will it do for me today" to invade the world of scientific investigation and pursuit of new ideas.

As @russ_watters pointed out - is this common? And I'll make the counter-point that I believe it is a really, really bad idea to treat anything and everything with a 'green/renewable' label as something that can't be critiqued and analyzed without the critic being labeled a 'naysayer' or 'Luddite' or 'shill for the oil companies', or 'someone who doesn't care about the planet' - and I see this all the time on the comments section of green sites. I hate to even say it, but "solar roadways" anyone? Gimme a freakin' break! That is stupid on top of stupid with a side order of stupid, drenched in stupid sauce. It's a mosh-pit of stupid ideas combined, and not one of them has any merit whatsoever in a general sense, either stand-alone or combined (maybe, maybe some will work OK in some very limited niche applications). Yet, it has a cult like following. Makes me sad, depressed even.