A piezoelectric generator in public transport stations captures energy from commuters through the piezoelectric effect. The piezoelectric effect is a phenomenon where certain materials, such as certain crystals and ceramics, generate an electric charge when mechanical stress or pressure is applied to them. This electric charge can be harvested and converted into usable electrical energy.
In the context of public transport stations, the piezoelectric generator is typically installed in high-traffic areas where there is frequent foot traffic, such as the floor of entrances, exits, or walkways. As commuters walk or step on these areas, they apply mechanical stress or pressure to the piezoelectric material, causing it to generate small amounts of electric charge.
Here's a simplified overview of how the process works:
Piezoelectric Material Installation: Sheets or tiles of piezoelectric material are embedded within the flooring or other surfaces of the station. These materials are carefully chosen for their piezoelectric properties.
Mechanical Stress: When commuters walk, run, or move across the piezoelectric-equipped surfaces, their weight and movement cause the material to deform slightly. This deformation creates mechanical stress on the material.
Electric Charge Generation: The mechanical stress applied to the piezoelectric material causes the material's crystal lattice structure to generate electric charges. Specifically, positive and negative charges are separated within the material.
Charge Collection: The electric charges generated by the piezoelectric material are collected using electrodes attached to the material. These electrodes are connected to a circuit that allows the harvested electric charges to flow as a current.
Energy Conversion: The electric current generated by the piezoelectric material is typically an alternating current (AC). This AC current needs to be converted into direct current (DC) for practical use. An electronic circuit called a rectifier is used to convert the AC into DC.
Energy Storage or Use: The harvested DC electrical energy can be stored in batteries or capacitors for later use, or it can be directly utilized to power low-energy devices within the station, such as lighting, signage, information displays, or charging stations for mobile devices.
It's important to note that while the piezoelectric effect is a fascinating way to capture energy from human movement, the amount of energy generated per step or movement is relatively small. Therefore, the energy captured from a single individual's movements might not be significant. However, in high-traffic areas with many commuters, the cumulative energy generated can become meaningful and contribute to the overall energy needs of the station.