It is estimated by technologists that by the end of 2014, there will be more mobile devices than people. With so many mobile technologies being introduced so rapidly, new devices that recharge smartphones and tablets are being introduced to public spaces: the most recent of which provides energy for batteries taken from walking.
According to a 2009 study by the International Energy Agency (IEA), the electricity used by mobile devices accounts for 15 percent of all energy consumption in the world. The IEA also estimates that the amount of energy consumed in this area will double by 2022, and triple in 2033.
The IEA suggested that with these numbers, the need for smarter, and more convenient recharging methods will increase. A team of researchers at the Georgia Institute of Technology have answered this dilemma with a totally clean device that charges smartphones and other mobile devices with human motion.
The team is led by material scientist Zhong Win Lang, and they have created a backpack that captures the mechanical energy from the vibration of an individual’s walking and converts it into usable electrical energy. The technology is completely environmentally safe and, if adopted commercially, could greatly reduce the burden of non-renewable resources to charge smartphones and tablets.
Wearable generators that convert the body’s mechanical energy into usable electricity have been experimented with previously, but they have relied on fragile and bulky materials. Wang wanted to make that technology smarter, lighter, and more efficient. The material used to construct the new device that recharges smartphones with energy from walking is made of thin, lightweight plastic sheets arranged in a rhombic grid. The design can be compared to a collapsible cardboard box that holds six drinks.
As the user walks, the rhythmic movement of the body’s weight shifting from right to left causes the inside surfaces of the plastic sheets to come together, then separate repeatedly. This action causes electrons to be driven back and forth, which produces an electric current. The process is known as the triboelectrification effect, and it utilizes the capabilities of static electricity.
The key in Wang’s technology, what makes it produce enough electricity to power smartphones and tablets, is the addition of highly charged nanomaterials that optimize the contact of the inside surfaces of the plastic sheets. Wang has named his powering device the triboelectric nanogenerator (TENG).
Wang tested his new device to see how well it could charge smartphones with the energy from human walking, and said he has very satisfied with the results. Wang’s team exhibited that an average human with a walking load of two kilograms (the approximate weight of two liter bottle of soda), generated enough power to light 40 LED lights.
With this data, Wang hypothesizes that the average wearer will be able to generate two to five watts of energy, which is enough to power smartphones and/or other mobile devices. The researchers believe that their newly developed technology will be welcome news to military personnel, outdoor enthusiasts, field engineers, and emergency responders.
By Andres Loubriel