Research and development activities in energy harvesting focus on gathering energy from various sources such as vibrations, heat, light and human motion. Researchers nowadays are exploring opportunities for leveraging the benefits of energy harvesting technology across various application domains.
Along these lines, researchers from Keio University in Japan are involved in the development of human-powered escalators. The research team is investigating different types of energy harvesting transducers that function as a battery.
The researchers are developing a power-harvesting floor mat for humans and automobiles, through which they hope to harvest enough human power to ultimately operate an escalator. The research project titled 'electricity generating floor', aims to generate electricity from vibrations when a person steps on the floor. A piezoelectric element is used to generate electricity from the floor mat.
The research team is interested in leveraging the bidirectional property of sensors in developing the energy harvesting devices. The concepts of resonance energy – which is generated when people walk across the floor – and peizoelectricity are integrated to develop a practical energy harvesting device.
Development efforts started in October 2006 at Marunouchi North Gate of JR Tokyo station for testing the power generation capability and durability of the mats. The next step was to develop devices to power escalators and lights using the 'electricity generating floor', thereby creating environmentally friendly railways and stations.
The research project is now in its second stage. JR-east (the Japanese railway company) is experimenting with a power harvesting mat of 90 square metres in the Tokyo station. Yoshiyasu Takefuji, a professor in the faculty of environmental information at Keio University, says: “The generated power is sufficient to operate one unit of the Suica system.” Suica is the rechargeable contactless smartcard that is used as a fare card on train lines in Japan.
The research team believes that if the new device can continuously harvest power without any disturbance, there are possibilities for many new applications based on this technology. As the device does not require any other equipment for power generation, it could be used as an auxiliary power source for hospitals and households in the event of power failures due to natural disasters such as typhoons and earthquakes.
Several patents have been filed on piezo-based energy harvesting sensor technology by the research team. Patents also include efficient energy storage circuits, as it is important to store the harvested energy in capacitors without any leakage. Takefuji believes that it may take four or five years to commercialise the energy scavenging sensors.
For more information contact Patrick Cairns, Frost & Sullivan, +27 (0)21 680 3274, [email protected], www.frost.com
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