Power Hump

[alpete]

Hi friends...!!!! I'm a fresher and I'm directed by the company which I work in, to do a project which they call as NEW PRODUCT DEVELOPMENT (NPD)..!!! So I've planned to fabricate a POWER HUMP for which I have relevant info from net..!! But my team lead told me to do a Voice Of Customer (VOC) first and try to find the need for my project...!!! Sadly I could find customers who were genuinely interested in my project...!! So I request you people to comment on the project I'm gonna undertake and help me with relevant info and answers...!!! Please find the attachment below and comment whether the project is feasible or no...!!! Please help me IF THERE ARE ANY NEW IDEAS for the NPD....!!!!

 

[alpete]

There was a mistake in my previous question.....!!! Apologies...... Sadly I couldn't find customers who were genuinely interested in my project...!!

 

[DRWeig]

It's a novel idea, but I see two problems with the energy analysis:

1.

A vehicle weighing 1,000 kg going up a height of 10 cm on such a rumble strip produces approximately 0.98 kilowatt power. So one such speed-breaker on a busy highway, where about 100vehicles pass every minute, about one kilo watt of electricity can be produced every single minute.

Kilowatts (kW) are instantaneous power, not energy. Energy is expressed in kilowatt-hours (kWh). Assuming that your power-per-crossing of 1 kW for a single axle is correct (it is not well-documented), the energy (kWh) per minute cannot be 1000 kWh. A vehicle traveling 10 MPH across a speed hump will have wheels on top of it for only a short time. If the speed hump is 2 feet wide and you can capture energy for the entire width, which you won't if it is built like the drawings, each pair of wheels will be on top pushing down for only about 0.2 seconds. So a single 2-axle car will only be contributing its weight for maybe 0.5 seconds at most. Thus, each car crossing will produce (1 kW x 0.5 seconds) / 3600 seconds per hour, or 0.00014 kWh. With a liberal estimate of bumper-to-bumper cars at 10 MPH, maybe 100 cars can cross in one minute. So one minute's production of energy would be 0.014 kWh. A day's time (1440 minutes) with cars crossing at 100 per minute during the entire 24 hours would yield 20 kWh. That's about $1.20 in my area. $440.00 per year. I'm going to guess, without trying calculate it, that the combined efficiency of the mechanism, power conversion, energy storage, and energy transport circuits will be less than 20 percent. So in the end, you'll have about $0.25 per day to sell. Not much, even with all the best-case assumptions above. That's not much, less than $100.00 per year. Toss into my calculations above some real-life load factors such as average number of cars per minute for an entire day, and you'll be in the vicinity of $5.00 or less per year area per speed hump. To achieve a 20-year payback, materials and installation would have to cost $100.00 total. No way.

2. The only reference you have to cost of manufacturing, installation, and tie-in to a nearby distribution circuit, is a bullet point that says the device is "economical." Goodness gracious! Make a thorough cost estimate for manufacturing, shipping, installation, and tie-in electrical work. Don't forget to put profit in there at each step. I don't think you will be comfortable using the term "economical" any more in describing this system.

In sum, it is a very interesting concept. It was also fun to analyze for a bit. My opinion, however, is that economic viability is nil and there is no way to sell it.

Welcome to eng-tips, by the way. Fun topic.

Good on ya,

Goober Dave

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[TheTick]

You may want to come up witha different name.

 

[vpl]

Maybe I'm just suspicious, but this sounds like a student assignment ... wrong terms, overuse of exclamation marks, plus the "I'm a fresher". Who describes themselves that way once there actually on a job? I work with a lot of new employees and not one would use that term.

Patricia Lougheed

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[IRstuff]

It's obviously school work, i.e., "Dept. of Mechanical Engineering, KSIT, Bangalore." Nonetheless, it's academically interesting.

However, a few comments:
> I can't tell how you got your ~1 kW per bump, and whether that accounts for generation efficiency. Non-continuous generators tend to be absurdly inefficient; if I assign a 5% efficiency, each car produces at most 27 mW*hr

> A major factor in the inefficiency is that you do not actually get to lift the ENTIRE vehicle's mass, since it's front wheels, lag, then rear wheels. The effective mass raised is much less than the total mass of the vehicle, and part of that is lost in the suspension system.

> The biggest problem is your duty cycle. A 10cm bump is GIGANTIC for probably 90% of drivers; if it takes 10 seconds for a car to traverse the bump, the frequency is reduced to 6 cars/ min.

> Assuming that frequency remains unchanged, I calculate about 235 W*hr of energy generated per day, which is barely enough to power about 6 houses in the US.

TTFN
faq731-376

 

[zdas04]

I have never had occasion to use and exclamation point in an Engineering document. Never. Not once. The OP used several dozen in one post and a dozen or so in his follow-up. I vote "student". Any future posting in this thread is very subject to disappearing if management is notified we have a student thread (I didn't red flag it, but someone will). Don't put much work into responses because they'll probably disappear.

David Simpson, PE
MuleShoe Engineering

"Belief" is the acceptance of an hypotheses in the absence of data.
"Prejudice" is having an opinion not supported by the preponderance of the data.
"Knowledge" is only found through the accumulation and analysis of data.

 

[IRstuff]

I think that it's not the run-of-the-mill HW posting, since he obviously did the work already, 70 pages worth, although there are grammatical and spelling errors. Additionally, the mechanization of the idea seems to be somewhat dubious, particularly the discussion about gears.

One major hurdle, from a practicality perspective is that mechanically movable devices in traffic lanes is a nightmare for maintenance. Openings, seams, gears, etc. all suffer from maintenance issues in traffic lanes.

TTFN
faq731-376

 

[Oldhydroman]

Is it just me, but does anybody else consider the idea of generating electricity by this means as little more than theft?

Why not ask each driver to hand over a thimble full of petrol as they pass a sign?

DOL

 

[vpl]

I live in the US Midwest where we deal with snow, ice and sleet on a regular basis, and I'm not even as far north as many people on this board. I can imagine how long something like would last -- less than one Chicago winter.

Patricia Lougheed

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[IRstuff]

Probably doesn't snow much in Bangalore, but monsoon is probably plausible.

TTFN
faq731-376

 

[alpete]

Thank you all so much for the response. As I am a newbie and its the first time I'm posting something in a forum, I didn't know the guidelines. Please excuse me and suggest me the rules to follow before I could post or comment anything.

 

[IRstuff]

OK, obviously I'm bored silly. Interestingly, the maximum energy extracted from the vehicle amounts to almost 1 drop of gasoline per car.

As for the OP's future postings, the basic rule is no asking for homework help.

TTFN
faq731-376

 

[CorBlimeyLimey]

http://www.wired.com/autopia/2011/11/drivers-generate-electricity-by-going-over-speed-bumps/

A few prototype examples shown at

http://www.youtube.com/watch?feature=endscreen&v=6tIMhWpLDfw&NR=1

 

[TheTick]

Lots of obsessing over power. Ultimately, there is only so much energy to be extracted from a single "bump": E = mgΔh.

 

[MintJulep]

does anybody else consider the idea of generating electricity by this means as little more than theft?

I was going to make the same comment, but you beat me too it.

I agree, it's taking energy (albeit a really small amount, as noted by others) without the consent of those who originally paid for it.

 

[FreddyNurk]

I can't imagine any driver being happy to drive over such a surface as described, at any time let alone peak hour. Considering that 10cm is about the height of a gutter, this to me seems the equivalent of turning nice smooth highways into cobblestones to rival the Paris-Roubaix cycle race.

100 vehicles certainly aren't going to fly by in a minute with such obstructions on the road surface. I've not looked at the document as yet though, I could be surprised.

 

[IRstuff]

oooh, I had a really bad answer earlier; I had used the OP's rate of cars and got a semi-tolerable answer, hence the 6 houses comment. My estimate appears to be low, relative to the cited article, but the device in the article appears to be more complex, since the cars have to drive a considerable distance on the device.

TTFN
faq731-376

 

[GregLocock]

As others have noted, it is a very inefficient way of burning gasoline to generate electricity. Firstly, cars are less efficient than oil powered power stations. Secondly, as the car mounts up onto the platform significant energy is expended as heat in the shock absorbers and tires.



Cheers

Greg Locock


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[berkshire]

Can I put about 10 of these things at 50 foot intervals down my street to get the speeding motorists to slow down?
As a courtesy I can then use the output to illuminate a sign, warning the motorists there are speedbumps ahead.
B.E.

The good engineer does not need to memorize every formula; he just needs to know where he can find them when he needs them. Old professor