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Award-winning device harvests energy from railway track vibrations

By

November 28, 2012

Researchers from Stony Brook University have developed a device capable of harvesting ener...

Researchers from Stony Brook University have developed a device capable of harvesting energy from train-induced rail track vibrations to power signal lights, structural monitoring systems or even track switches (Image credit: Lei Zuo)

Much of the abundant mechanical energy around us is irregular and oscillatory and can be somewhat difficult to efficiently tap into. Typical energy harvesting systems tend to be built for low power applications in the milliwatts range but researchers from New York's Stony Brook University have developed a new patent-pending electromagnetic energy harvester capable of harnessing the vibrations of a locomotive thundering down a stretch of track to power signal lights, structural monitoring systems or even track switches.

As a train rolls down the track, the load it exerts on the track causes vertical deflection. This displacement could engage a regenerative device like an electromagnetic harvester and generate enough power to operate local railway applications, which is especially useful in remote areas where electrification is not cost effective. Harvesting such energy is much more efficient with regular, unidirectional motion, but track vibrations caused by a moving train are pulse-like, bidirectional and somewhat erratic.

Professor Lei Zuo and graduate students Gopinath Reddy Penamalli, Teng Lin and John Wang from the University's Department of Mechanical Engineering claim to have designed a new harvester capable of converting irregular, oscillatory rail track vibrations into regulated unidirectional rotational motion, similar to the way that an electric voltage rectifier converts AC voltage into DC.

"The U.S. has the longest rail tracks in the world, approximately 140,700 miles; that are often in remote areas," said Professor Zuo. "It is very important but also very costly to power the track-side electrical infrastructure, such as the signal lights, cross gates, track switches and monitoring sensors. Our invention (the Mechanical Motion Rectifier based Railroad Energy Harvester) can harness 200 watts of electric energy from train-induced track deflections to power the track-side electrical devices. By using two one-way clutches, the innovative mechanical motion rectifier converts the irregular up-and-down vibration motion into unidirectional rotation of the generator, thus breaking the fundamental challenge of vibration energy harvesting and offering significant advantages of high efficiency and high reliability."

Impact forces from repeated loading/unloading are also said to be reduced thanks to the incorporation of a flywheel to stabilize the generator. According to Professor Zuo, the technology enables a generator to rotate in one direction with relative steady speed in a more efficient speed region, and changes the negative influence of motion inertia into a positive, thereby reducing mechanical stress and increasing system reliability. Bench testing of system prototypes has resulted in mechanical efficiency of between 55 and 72 percent.

"Such a design not only avoids the challenges of friction and impact induced by oscillation motion, but also enables us to make full use of the pulse-like features of track vibration to harvest more energy," he said.

Professor Zuo estimates that the implementation of such a device could save more than US$10 million in trackside power supply costs for the New York State area alone, together with a reduction of 3,000 tons of carbon dioxide every year.

"If 10,000 units of 200 watt harvesters are deployed in New York State with 20 percent duty cycle, the energy benefits will be 400,000 watts, or 3.5 x 10^6 kWh per year," he explained. "At an average retail price $0.14 per kWh of electricity for the transportation sector, this annual electricity saving will be half a million US dollars in New York State alone."

The team was awarded the "Best Application of Energy Harvesting" at the 3rd Energy Harvesting and Wireless Sensor Networks USA awards held in Washington on November 7 – 8, and has already licensed the technology to Electric Truck/Harvest NRG for commercialization.

Source: Department of Mechanical Engineering, Stony Brook University

About the Author
Paul Ridden While Paul is loath to reveal his age, he will admit to cutting his IT teeth on a TRS-80 (although he won't say which version). An obsessive fascination with computer technology blossomed from hobby into career before the desire for sunnier climes saw him wave a fond farewell to his native Blighty in favor of Bordeaux, France. He's now a dedicated newshound pursuing the latest bleeding edge tech for Gizmag.   All articles by Paul Ridden
17 Comments

Hmm, interesting. But as I understand it the vast majority of trains in remoter parts of the States are infrequent freight trains. Would this device be able to generate enough power to send signals down the line to operate signals, switches, etc, some distance ahead of the train (no point on a signal or crossing alarm going on just as the train is passing).

Wouldn't solar/ micro wind turbine/ battery combos be better, as used in the UK for traffic signage?

bergamot69
29th November, 2012 @ 01:44 am PST

Worth a quite a bit, I'll bet. Where I live, the metal thieves regularly remove earthing strips from the electified lines. I imagine they would be more than tempted by this little item.

Perhaps a better solution is to do away with any form of light system whatsoever and devise one where the signaling information is superimposed on the overhead power line supply; in much the same way that computer networks use domestic mains within a house today.

Mel Tisdale
29th November, 2012 @ 03:07 am PST

As train traffic is less often,using this on roads will give more output.

Sinnadurai Sripadmanaban
29th November, 2012 @ 07:23 am PST

How about instead of vibration you use magnets? IE as the train moves by rotate the generator. Now this would only be useful in areas with fast moving trains but I would think that ROI could be greater.

Ervin Kosch
29th November, 2012 @ 08:13 am PST

This a mechanical device which spins up substantial vertical displacements into electrical energy. It presumably has a permanent magnet component and other temperature sensitive bearings, ice and water sensitive elements.

The latter are exactly the harsh conditions remote rail locations will present and this invention is not even begun to be ready for them.

Great that the inventors sold early and have a day job.

attoman
29th November, 2012 @ 09:24 am PST

Actually it does not have as Attoman assumes, a lot of temperature sensitive bearings and elements. One wonders why you people take a first iteration of a device and mock it so often-you must know all there is to know! It will be housed in a box eventually and bolted intensely to the ties. Solar is not always shining nor wind always blowing-but the trains are most always rolling. Electric Truck has license to this and also has a magnetic shock absorber that converts wasted kinetic energy of shocks into electricity-heavier vehicles work best-adding them on trains, tricks and busses would be sensible and save considerable amounts of fuel.

Regen brakes only work when braking shocks bounce continuously.

ZekeG
29th November, 2012 @ 10:07 am PST

Sounds like this device might be a good candidate to charge the battery if it could harvest them vertical motion from an automobiles suspension.

Patrick Hilke
29th November, 2012 @ 10:09 am PST

re; funglestrumpet

In the USofA most of the railroads diesel-electric propulsion and don't have overhead power lines.

re; attoman

That is a proof of concept prototype but I see nothing that would indicate that it is temperature sensitive, and wrapping it up in a sealed plastic box would keep dirt and moisture out.

Slowburn
29th November, 2012 @ 10:46 am PST

Why not just use solar panels? This device just seems pointless.

Rann Xeroxx
29th November, 2012 @ 01:00 pm PST

"Why not just use solar panels? This device just seems pointless."

try to stand by the track when a moving freight train passes by, the up & down motion is tremendous, since each rail car weights a few tons, the up & down motion on the rail is unreal, it can turn out some serious serious energy, either hooking up a motor or a spring loaded magnetic coil to move against some rare earth magnets planted solid to the ground totally stood still.

Jimbo Jim
29th November, 2012 @ 02:14 pm PST

Well,what about Solar Roadways concept applied to rail beds? Modular solar panels resting on the rail beds. They want to put modular solar panels on roadways and generate huge amounts of solar electricity. http://www.gizmag.com/solar-panel-roads/12780/

michael_dowling
29th November, 2012 @ 02:42 pm PST

All these other "what about solar" etc. have nothing to do with this-the sun does not shine every day. And the total output is not much until collected over days with a large array.

This technology is interesting in the gears are running the generator in both directions-as the track goes down and then up again and again.

ZekeG
29th November, 2012 @ 03:10 pm PST

@Ervin Kosch

Yes, you could generate electricity via the magnetic effects of the passing train. But that would merely be stealing energy from the passing train. [I.e., we would be slowing the passing train as we grab some of its kinetic energy and convert it into electrical energy.]

The value of the proposed idea is that we are harvesting the otherwise wasted kinetic energy (i.e. vibrations of the track) and converting that waste into useful electricity.

PaulW
29th November, 2012 @ 11:36 pm PST

$300 in materials to generate 8 cents of electricity over its projected lifetime. Its a shame that someones intellect and time was wasted on this project.

JBar
30th November, 2012 @ 07:25 am PST

The project I worked on :D

To answer a few questions I see:

Solar panels may not be as reliable, since they depend on climate conditions. We also think there is more energy harvesting potential from the track vibrations. And finally, nothing stops you from harvesting from both sources (solar and track oscillations), since installing solar panels won't interfere with the MMR harvester.

To get a good idea of how much energy is dissipated into track ballast material, here are a few youtube videos:





With these videos, and knowing the weight of the trains, you can imagine how much energy gets dissipated into the ballast when a train passes over.

There are a lot of methods mentioned in the comments. Overall, you can compare how much energy those methods harvest, and how much space those types of harvesters would need. A lot of other methods don't turn up as much power, or might be stealing energy directly from the horizontal motion of the train :0

John Jiao Wang
30th November, 2012 @ 08:49 am PST

re; JBar

Where and when you need electricity varies the price. The price of electricity in Alaska was so high when they built the oil pipeline that an oil company built a facility with a solar power collector.

Slowburn
1st December, 2012 @ 05:16 pm PST

Well a tip-of-the-hat to the engieers who designed this. I C lots of great applications outside the RR one though. Anywhere where there is oscilation to take advantage of..... I work on RR track as a hobby, I guess we'd have to stop tamping the ties and work the rail joints a lot more to really make this thing sing. I in this context I wonder what the defination of 20% duty cycle is. Not even a busy commuter line would reach that level of exposure. /DL

DL
26th June, 2013 @ 05:49 pm PDT
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