Pavegen To Tap Pedestrians For Power In the UK 197
Posted
by
samzenpus
from the electric-slide dept.
from the electric-slide dept.
An anonymous reader writes "Several years ago Laurence Kembell-Cook unveiled Pavegen floor tiles, which capture kinetic energy from footsteps and convert it to electricity. Now after two years of product testing and picking up a slew of awards across the U.K., Pavegen has received its first commercial order — to light up the new Westfield Stratford City Shopping Centre."
Laws of Thermodynamics... (Score:5, Interesting)
Walking on these floor tiles requires more energy than regular floors.
So are they going to start paying brits for all the extra food that they need to eat in order to power these things?
Re:Laws of Thermodynamics... (Score:5, Interesting)
Perhaps walking on these tiles costs the same amount of energy as regular tiles, but some of the energy that is normally wasted as heat and sound is captured and turned into something useful...
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Have you ever walked in sand?
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A 5 millimeter flex is not even remotely comparable to walking in sand.
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Of course not, but both require a relative amount of extra work. Sand if just a great deal more. An example that someone would surely agree takes more energy to walk on is needed. Then by extrapolation the tiles take more emery too. Albeit less.
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It is. Just look at how much 5mm is. It sounds small, but for walking its pretty annoying.
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On the other hand, if you're walking on regular tiles, and step on this flexing tile, without properly anticipating the different feeling, it may throw a person off-balance.
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Your mother was a woman who worried alot, wasn't she?
Re:Laws of Thermodynamics... (Score:4, Interesting)
Man this kind of argument pisses me off.
"5 isn't even remotely comparable to 1000".
Sure it is. It is 1/200'ths as much. Plenty comparable.
5 mm flex is not even remotely comparable to world peace, chuck norris, or boreal toads. a flexible floor IS comparable to walking in sand.
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It's like comparing apples and oranges.
Apples are green.
Oranges are orange.
Apples are not oranges.
There; comparison succesfully completed.
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And that orange spray paint they use.
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If this was a troll rather than just extreme pedantry, my apologies to the rest of the
Re:Laws of Thermodynamics... (Score:5, Informative)
Actually, a softer (energy-absorbing) surface is more comfortable to walk on, provided it doesn't absorb excessive amounts.
The plastic tracks in stadiums are softer than asphalt, which again is softer than concrete. Guess which one people like to run on best?
Some athletes from poor countries practice on alphalt and find they run slower in a stadium. Concrete would be even faster, but it tends to wreck your knees unless you have good shoes, which, again, absorb energy.
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Rubberized tracks are springy, i.e. they store a little energy and return it to you. Good shoes do the same. This surface would not - I would think it would feel mushy.
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The Pavegen floor tiles flex a slight 5 millimeters when stepped on
That's an extra half cm against gravity for each step - so I don't think it is energy that is normally wasted as heat and sound - that is energy that you are being forced to supply.
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You have to push through that resistance. That uses more energy. As to other posts about heat/vibration/sound energy, some of that will be gathered I'm sure but that's a minuscule amount of energy.
The extra energy may not be noticeable and may result in a more comfortable floor though, like you said. Walking on a thick carpet would probably make you use more energy than these plates and people pay extra for them.
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You have to push through that resistance
Have you ever even tried walking? You don't push through resistance on the ground. You place your feed above it and then your weight pushes through the resistance. The energy you put in is in lifting your foot and transferring your weight to it. You push downwards into the foot that you are stepping off, but that one will already be on the solid ground with the switch depressed.
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Does climbing stairs require more energy that walking on a flat surface?
This is like climbing 5mm high stair steps.
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I don't think so. When you climb stairs you are increasing your gravitational potential energy. When walking over these tiles you are not. I think it is more like walking on a thick carpet or sand.
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It is like climbing 5 mm high stairs: you step off the tile you are currently standing on (which is 5 mm lower due to your weight) on to the next tile which is up at ground level, 5 mm higher.
When you're climbing actual stairs, you gain gravitational potential energy because you're going up, but on this contraption you sink back down 5 mm with each step, and what would have become your potential energy is now harvested to power the lights, or whatever they plug into it.
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Even if that were true (instead of the tiles just using the energy already dissipated as waste heat and sound), people in developed countries consume far more energy than they expend. The remainder is stored in fat reserves or excreted as waste. That's where this would come from; it'd be an exercise opportunity.
(Come to think of it, it would be worth a thought to install generators in gyms for the same effect.)
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or not step on the green tiles.. from all the pictures i've see it looks like they use them as designs rather than blanketing them. If it is that much of an issue for them they can just not step on them
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In the shopping malls I've seen, the injured and disabled are normally not a regular part of the crowd.
You're in the US so I'm not sure what the situation is over there, but here in the UK we have laws to enable access to facilities for the disabled and it's quite common to see disabled shoppers. Of course, I don't know if they would cover having to expend extra physical effort in order to shop there. I mean, a ramp causes a wheelchair user to expend extra energy but it still satisfies the letter of the law (as opposed to making the store owner put in elevators or lower the whole building a few cm), so this
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If you're disabled and in a wheelchair, as long as the ramp is sane (it needs to be) there's no reason why you're any different to anyone else. Got a few friends who are wheelchair bound, and some of them are a damn sight fitter than I am!
They're not invalids. They just have a disability, and these wouldn't bother them at all.
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Two thoughts come to mind:
* This may be a good way to reduce obesity levels in society.
* Shopping centers with supermarkets and/or food courts will make a killing.
Rule #1 of supermarket shopping: never shop while you're hungry.
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Think of it as a public service - most tubby city workers could probably do with some more energy expenditure in their day.
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Think of it as a public service - most tubby city workers could probably do with some more energy expenditure in their day.
People in London are, on average, thinner than the rest of the UK. Although children in London, on average, are more obese.
Walking to and from a station, somewhere at lunchtime, and maybe somewhere after work on the way home is hardly a lot of walking, but it's more than people who drive to work and park right outside. (Conversely, city children perhaps spend less time outside, but I can't find figures for this.)
(I'm surprised the official website [westfield.com] for the new shopping centre has "Getting Here by Car" above
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That it requires more energy is an added upside to the tiles, it's a selling point.
With the current health issues people have with not enough exercise and hyper-caloric diets, having these is actually a (very mild) health benefit for the people. People who are already getting enough exercise won't mind the tiny bit extra, so the only people left who will complain about this are lazy fucks.
And I hope you're not telling everyone on slashdot that you're a lazy fuck, are you?
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Only if people aren't compensating the extra energy by eating more.
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So are they going to start paying brits for all the extra food that they need to eat in order to power these things
I don't think there's any problem of people eating too little food over here, in fact it might even help with the current obesity problem...
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So are they going to start paying brits for all the extra food that they need to eat in order to power these things?
No, quite the opposite! It is a shopping center, after all.
Not only will people be providing electricity to help power the area, they'll be forking over more money into the center's restaurants and food stands from working up an appetite.
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That assumes that there is no waste involved in walking. There is a lot of waste in walking. Notably you land with more force than necessary and usually your body absorbs that energy as shock. If the floor tiles absorb that instead, it actually makes it easier on you to walk on it while harnessing the waste energy. There is no free energy, but there are ways to recover waste energy and sometimes that is a mutually beneficial thing.
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Hey, I'm all for fatties working harder, but spare a thought for the elderly with limited mobility. It would be a shame if they couldn't go out shopping.
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Make a separate entrance for fat people. Problem solved.
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Uh, no, in order to tap energy from pedestrians, the tile needs to give or flex a bit when you step on it. This takes more energy than walking on a perfectly rigid tile. When walking on rigid tiles, the body stores some of the landing energy in muscles and tendons by stretching them out. When the leg is lifted, the stored energy is released.
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It's a bit of both. Of course, we're talking about very small amounts of energy robbed from the body, but we're also talking about an even smaller amount of energy that the tile produces.
The energy to produce the tile, plus the energy to produce, package, and distribute the extra food needed to power them will not be gained back by this "green" tile in its entire useful life.
Basically it's just a feel-good project with no tangible benefits.
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Got anything to back this up ?
Or, maybe once a year, when you were already somewhat hungry, the small extra effort in the mall makes you decide to get a slice of pizza that you wouldn't eat otherwise.
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Fair point- although I question if the difference in "flex" between walking on these tiles and walking on concrete is going to be much more than the difference between me walking in trainers and me walking in hard-soled shoes.
So onto the second point- when the UK (as with most of the Western world) is staring down the barrel of an obesity crisis- is it a bad thing if walking on these surfaces gives your calf muscles a bit of a work out? Would people really eat more, or would they eat the same but be a (very
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It would be hard to demonstrate either way, since the differences in energy are so small, they'd be considered noise.
Despite that, we can agree that ultimately, this energy is provided by food calories, which are highly inefficient.
For each food calorie, we use about 10 fossil fuel calories for growing, processing, packaging and transporting the food. On top of that, muscles are only 25% efficient, and the electric tile probably doesn't exceed 50% efficiency in recovering the ene
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Since the "body" is nonlinear, taking it through a slightly different path when in contact with the "floor" may in fact transfer some of the energy that would be otherwise wasted -- our body only got so many degrees of freedom, and a moving tile could supply virtual degrees of freedom that potentially make our gait more efficient, and then simply bring the efficiency back down by retrieving the energy that's now not wasted in our musculoskeletal system. This requires a completely active system, though, with
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Go for a walk on a trampoline sometime.
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Woo! Diet tiles:O) I should buy mum some for Christmas!
A proper present for piezo pedestrians.
It might even provide power to cameras.
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Only if these tiles somehow improve the energy efficiency of walking itself.
Otherwise the energy will be extracted from an equally unefficient process.
Errors in article (Score:5, Funny)
I was curious how much energy these things produce:
It produces 2.1 watts for how long? 1 second? 100ms? I guess it could make some LEDs flash.
Also:
Wow. Will his prize be in the form of a giant cartoon-style weight with "10,000 lbs" written on it? Perhaps they'll drop it on his house.
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Also:
Wow. Will his prize be in the form of a giant cartoon-style weight with "10,000 lbs" written on it? Perhaps they'll drop it on his house.
You do have to wonder if that journalist has ever been outside of the US.... or maybe he was assuming that the original definition of "pound sterling" [wikimedia.org] was still in use?
Re:Errors in article (Score:5, Insightful)
It produces 2.1 watts for how long? 1 second? 100ms?
For as long as you keep walking, I guess. As long as you produce a Joule each second, you're producing 1 Watt.
The potential energy in a gravitational field is m * g * h, so if you sink 5 mm with every step, you're producing 9.81 * 0.005 = 0.04905 Joule for every kg of body weight at each step. If you take p(ace) steps per second while walking, you're producing p * m * 0.04905 Joules per second, i.e. Watts, as long as you keep walking. So an 80 kg (~160 lbs) person who walks at 2 steps per second could theoretically (i.e. at 100% efficiency) produce 2 * 80 * 0.04905 = 7.8 Watts. So 2.1 Watts means a 30% efficiency. Doesn't seem unbelievable to me.
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It produces 2.1 watts for how long? 1 second? 100ms? I guess it could make some LEDs flash.
Just as well. It needs some way of powering the light in the middle of the floor tile.
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It produces 2.1 watts for how long? 1 second? 100ms? I guess it could make some LEDs flash.
RTFA - it's even better than you think.
The Pavegen floor tiles flex a slight 5 millimeters when stepped on, capturing kinetic energy which is either stored in lithium polymer batteries beneath its surface or converted into 2.1 watt-hours of electricity and distributed throughout surrounding lights. (emphasis mine)
TFA says it produces 2.1 Watt hours for every step someone takes on the tike. Since 1 Wh is 3600 J, we can conclude it produces about 7.5 kJ at every step (according to the website)... and it takes this kinetic energy from the human shoppers.
7.5 kJ of kinetic energy, in a human... hmmm... what are the shoppers doing? Freefalling from 500 m altitude onto those tiles? Jumping off speeding trains into the tiles?
The problem is that 7.5 kJ of kinetic energy, for a human of
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Perhaps the number is in aggregate for the whole installation? What would I know, I'm not reading the article.
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2.1 watts! We could power... a few LEDs! Or... a calculator!
Seriously, what idiot bought this?
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In other words, enough to power the little led in the paver for a little while. Not anywhere near enough to ever power the main lights in a mall, as the article suggests. It's a novelty, but not really green in any meaningful sense - amount of energy expended to create these things will never be recouped in useful light generated. Now, it's not a bad thing to have cool light up pavers, but these inhabitat articles never get beyond the breathless press release stage and actually look at what they're consumin
The power source is made out of people (Score:2)
entrepreneurialism in the UK dead since '80s (Score:2, Insightful)
There have been very few interesting inventions in the UK since the '80s, and when they are the authorities / marketroids / everyone are so keen to say "LOOK BRITAIN ISN'T DEAD YET!" that every so often there's a hilarious amount of hubbub surrounding nothing.
Thatcher taught the current 30-somethings that there is no personal gain in actually producing anything (and it's still communist to do anything other than for personal gain): if you want to get rich, become a middleman. So that's where most of the int
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The first prototypes appeared around 1986. My ARM2 desktop dates from '88 or '89. The decade itself was full of interesting academic developments because the education system hadn't yet been broken thanks to the tying of higher education with private investment (Acorn was the result of money following brilliance - today brilliance must follow money), the repurposing of polytechnics, the introduction of the one-idiot-size-fits-all national curriculum and the sell-off of exam boards to private publishing hous
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Well ARM is gaining a lot of importance *now*, regardless of their history. Besides ARM is improving their product continuously - as you have to when you want to compete in such a fast-changing market. Anyway, Britain is still one of the leading industrial countries in the world. Whether it's living up to its potential is another matter.
Being German I also have my doubts about our supposedly "dominant economy". We don't train anywhere near enough engineers, we have a lot of unemployment etc ... the grass
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How's that? The unions, while they may have been overzealous about it, were all about the working man getting paid a fair wage for his work, emphasising that productive work has intrinsic value. And perhaps most of that overcompensation was just a response to the knowledge that the management was going to try and bargain them down as much as possible anyway.
Thatcher went out of her way to break the back of the unions. That should be a great sign that what they stood for runs counter to the rabid capitalism
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I blame political correctness to a certain degree as well. Apparently it's no longer acceptable to celebrate ability differences in school, and all children are praised relentlessly regardless of whether they sit there reproducing the works of Einstein or just barely managing to navigate the boogers to their mouth.
"The Incredibles" pins it right to the mat....
When everyone's super ... no-one will be!
Why would you bother to succeed if you're getting the rewards (praise is like crack to a 7 year old) without any effort?
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To the best people, praise and money are distractions at worst, tools at best. Achievement is its own reward.
Praise and money are only useful - and perhaps wasted - on the mediocre.
10,000 lbs prize (Score:2)
WOW, that's more than four tons! But of what?
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Which is 0.02 lb which means 10000 lbs of £1 is equal to £500,000 which is a very impressive prize fund.
£1 coin contains 70% copper, 5.5% nickel, 24,5% zinc
Copper = $3.1640/lb = ~$0.04/coin
Nickel = $8.3801/lb = ~$0.01/coin
Zinc = $0.8484/lb = ~$0.005/coin
Total ~$0.05 of material in a coin
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Greenwashing... (Score:2)
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Did you read the article? It talks about the energy cost of making the tiles, and the recycled truck tyres that go into them among other things, as well as keeping the production facilities closer together to minimise transportation costs during construction.
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Yeah, people always forget to factor in the energy required for manufacturing. It's important to quantify it in all "green" tech, but for energy harvesting applications it can completely outweigh the benefits.
Wouldn't roads be better? (Score:2)
Trucks are heavier than Oprah and friends.
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Tapping people like this can be spun as a health-benefit, exercise is widely believed to be beneficial for most people. The fact that it is inefficient is of little concern as the source is so cheap.
Tapping cars on the other hand leads to the consumption of more fuel, increasing carbon emissions, and is basically one of the least efficient ways of generating electricity that anyone takes seriously.
10000lbs (Score:2)
...you've just got to love the US-centric journalist or sub-editor who doesn't know what the UK's currency is.
Maybe it's time to employ some people who have a little more worldly experience than the dolts they have there right now?
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The UK is only semi-metric. Our packaging labels are metric courtesy of an EU directive, but most people over about 30 still think in imperial measures for many quantities, and many of our goods and services are still customarily measured in imperial.
Our customary beer order (and milk bottle) is the pint (a proper imperial pint of 20oz, not your pansy-arsed 16oz American pint). We discuss people's height in feet and inches, and their weight in stones and pounds. We're probably more likely to ask the greengr
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In England the spirit measure was 1/6 gill which was smaller than the new 25ml but in Scotland it was 1/5 gill which was larger.
Tim.
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I'm from the UK, and I think you are 10 years off on your 30-ish limit for imperial measures - I'm well over 30, and everyone my age is pretty much metric only.
The pint of beer is still a pint of beer because of an exception in the law for traditional reasons, the pint of milk isn't actually allowed to have the "1 pint" label larger than the metric label - and again the milkmans pint of milk is an exception to the law.
Height and weight depends on where you are and who is taking the measurement, same goes fo
Waste of energy in manufacture (Score:5, Insightful)
Some quick back of the envelope calculations: FTFA, each tile generates "2.1 W" per step. If we assume a typical step time of 500ms based a pace of 120 steps per minute this could be interpreted as about 1.05J captured per step.
The casing is made from stainless steel which required about 53 MJ/kg [bssa.org.uk] for production in 2004. If we assume a tile casing mass of 2kg that is 106 MJ required for the steel production alone.
The shopping centre may be open around 10 hours a day with perhaps 20 seconds between each step averaged over a typical day. This is 1800 steps per day at 1.05J per step giving a total of 1890 J captured per day. Assuming 100% efficiency and a never-closing shopping centre, this gives an energy breakeven for the steel alone of around 56000 days or 153 years.
I know that other factors are in play such as the potential to raise awareness of environmental issues but this is ridiculous. I noticed that the award that the guy is in the running for is sponsored by Shell and part of me suspects that they know that these things are crap but want to be seen to promote something like this which appeals to the public and appears "green".
Re:Waste of energy in manufacture (Score:4, Informative)
You also have to take into account the amount of energy taken to make the ceramic floor tile that this replaces. It probably won't zero out the stainless steel energy, but grinding clay and baking it in a kiln uses some energy.
Your math is very flawed (Score:2)
You have a huge flaw in your math here:
"This is 1800 steps per day at 1.05J per step giving a total of 1890 J captured per day."
Wrong. Depending on what your point of measure is (you don't say really), it is either 1800 steps per day PER FILE, or 1800 steps per day PER PATRON.
Either of these would multiple the daily output by at least thousands of times.
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If it's per-tile, it'd also multiply the energy involved in manufacturing the things.
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You can work out the energy like this:
The height is 5 mm. Weight is, (we'll be generous) 100 kg. So the energy is at most 5 joules per step. Generating 2.1 W therefore needs 1 step every couple of seconds, which sounds like a reasonable maximum. So even the pathetic 2.1W figure is hopelessly optimistic.
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How much energy does it take to make the tile that would otherwise be installed?
Make sure you subtract that.
I mean, we solved the green energy problem in the 50s - nuclear reactors. Lots of them. for some foolish reason, people have decided against them.
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That is soooo true. It's not free energy. Walking on those tiles will be like walking on soft ground, their feet will get tired. They better install more benches for people to sit on in the mall, they're going to need them.
Cool! (Score:2)
Not a bad idea (Score:2)
Yes, the average slashdotter can do the calculations in his head and deduce that this will not produce useful quantities of energy, but that does not make it a bad idea.
This guy will get millions in venture capital while you guys are still slaving away at the bottom of the R&D department of some big corporation.
And should the "green" venture capital ever run out, I'm sure he can re-brand this as a military application (power for smart landmines perhaps?) and get another billion from the ministry of defe
As the Beatles said in "Taxman" (Score:2)
"If you take a walk I'll tax your feet".
Prophetic words indeed
Wow... (Score:2)
And that's not to the idea of the tiles, which seems to me to be great and laudable, it's a "wow" to the nit-picky posts that seem to have proliferated about "oh, they're stealing my energy from walking, who will pay for the extra effort" and such like..
Seriously people! The body is designed to absorb shock from walking (all that cartilage in the joints and such like). Hey, to improve on that, shoes were designed to help absorb impact, and let the joints last even longer. Anyone ever thought of asking Ni
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It would tax a cars fuel on flat ground or ramps uphill. Going downhill your using brakes not fuel.
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Glad to see you appreciate people for more than just their contribution or lack thereof to social welfare programmes.
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