With all of the ways that have been devised to harvest energy -- from the human heartbeat to the energy of a kicked soccer ball -- it seems that finding a way to use human movement to generate power would be the next logical step.
Now a sensor-enhanced fabric called “stretch sensors” designed by Danish company Danfoss PolyPower A/S can harvest the energy generated when someone engages in exercise or a sporting activity. The energy powers sensors in the fabric to provide people with information about their movement to a wireless device.
In this way, the fabric can be worn to help the person improve their performance in an activity, giving them information about their gait while running or helping them determine the correct angle of their elbow to improve their golf swing, as shown in this video:
The stretch sensors also can be used in other applications beyond human movement, such as to test the structural health of concrete beams or to test the strain on an underground storage facility for wind energy, the company said. Danfoss even claims this technology can one day be used to generate energy from ocean waves and is working on an installation of the material to do so.
There is a growing trend in the medical device industry in particular to use low-power sensors embedded in fabric to provide people with medical and health monitoring information either within the sensor or wirelessly to a device to promote wellness. Boston-based startup Rest Devices, for instance, has created a shirt with sensors to monitor people while they sleep to test for sleep apnea and other disturbances.
Because these sensors consume such little power, using an energy-harvesting design for medical sensors makes sense because it means they won’t depend on a battery that might have to be replaced or recharged once it runs out. The idea, then, is that by using this type of design, the sensors can sustain their own power source indefinitely or as long as they are needed.
The material used by Danfoss in its stretch sensors works by using DEAP (Dielectric Electro Active Polymers), which can be used for actuation, sensing, and energy harvesting, according to the company. EAPs are polymers that change size or shape when stimulated by an electric field, and they come in two forms: dielectric or ionic.
Dialectric polymers can produce actuation by electrostatic forces caused by two electrodes squeezing the polymer. In this way, a DEAP becomes a capacitor that changes its capacitance when a voltage is applied by allowing the polymer to stretch, compressing in thickness and expanding in area due to the electric field, the company said.
Danfoss claims that because of this fabric design, the sensors can withstand a significant amount of strain, are resilient, and can sense the shape and structures over more than one dimension. However, a user may have to make some compensation for the effect of environmental wear and tear or moisture on the fabric, depending on how the stretch sensor is used.
It would be very interesting to see this technology being used to harvest energy for more serious usage. I'd like to see kinetic energy of machinery stored as potential energy and this potential energy somehow used to generate electricity.
I've always wondered when my local gym would start using the energy generated by athletes and kick it back into the grid. Of course, I was thinking of putting generators on stationary bikes, treadmills and cross-training machines. But now I find there's yet another way to use the energy from athletes that would otherwise be wasted.
That is a really good idea, Chuck. I agree that this should be marketed and produced! I also like the idea of gyms reusing energy from the people working out there. At the very least, they can use it to power the gym itself, which must have one heck of an electricity bill (think of all those lights and machines). Surely with this potential, there is a better way.
That's the thing that covering all these energy harvesting technologies has showed me, Chuck. There is a huge amount of untapped potential out there, and with all the creative ways people are coming up with to harvest energy, surely there are even far more options. Human energy, wave energy...seems the sky is the limit. Of course there would be some type of hardware or device involved, but some of the devices and fabrics being developed seemed fairly compact and a small price to pay.
@Charles Murray, Imagine treadmill belt made form the stretch sensor fabric. External power supply will be required only to start the treadmill and later energy generated by athelete running on treadmill will be used to run the treadmill.
"Danfoss even claims this technology can one day be used to generate energy from ocean waves and is working on an installation of the material to do so."
Wow!!! energy generated by ocean waves. Ocean covers approximately 71% of the Earth's surface. If energy generation by ocean waves comes to reality then there will be no power cut issues. Energy generation by neuclear power house can be replaced by ocean wave power house which will inturn save our planet by nuclear hazards.
I found that impressive, too, AnandY. I'm still not exactly sure how they can pull it off but if they can there would be huge potential. I'm a surfer and am in the ocean nearly every day. I can tell you first hand how much power waves can generate! So this would be an incredible way to create electricity.
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