A load-reducing backpack that powers electronics by harvesting energy from the long-distance walks might sound like a project that you'd dream of as a child; however, not all dreams have to stay as dreams. Researchers have designed a load-suspended backpack that not only makes loads feel about 20 percent lighter but also harvests the wasted energy from human motion to power small electrics.
The study has been published in ACS Nano.
Converting mechanical energy into electricity
Hiking or anything that requires long-distance walking can become even more daunting than it should be when you add a heavy bag into the mix. Hikers, soldiers, and school children all know the burden of a heavy backpack which causing cumulative fatigue. Labor-saving and biomechanical energy harvesting seems to be the way to go when dealing with such problems, and this team of researchers has done just that.
While triboelectric nanogenerators, which are small devices that convert mechanical energy into electricity, were used to make such backpacks, they were problematic since they had relatively low power outputs. They didn't have load-lightening or shock absorption either which prompted Zhong Lin Wang, Jia Cheng, and colleagues into designing a better prototype.
The conversion of electricity was achieved with 14 percent efficiency thanks to the movement between the frame of the backpack and its load. The researchers showed that this process could power LEDs, an electric watch, and fluorescent tubes.
To save labor and absorb shock, their load-suspended backpack has two elastomers that are incorporated into it, decoupling the simultaneous movement of the load and the human body. With this unique design, the backpack allows a reduction of 29 percent in the vertical swaying of the load and 21 percent in the vertical force on the wearer, according to the researchers.
Once conversion efficiency is improved, the researchers state that this backpack could be particularly beneficial for athletes, explorers, and disaster rescuers who work in remote areas without any access to electricity.