A piezoelectric generator in pedestrian zones captures energy from foot traffic through the piezoelectric effect. The piezoelectric effect is a phenomenon in which certain materials, called piezoelectric materials (such as certain crystals and ceramics), generate an electric charge when subjected to mechanical stress or pressure. This can be achieved by applying a force or pressure on the material, causing its crystal lattice to deform and create a separation of charges, resulting in the generation of electric voltage.
In the context of a pedestrian zone, a piezoelectric generator system typically consists of the following components:
Piezoelectric Material: The walking surface is equipped with piezoelectric material elements. These elements are usually embedded within pads or tiles that are placed on the ground. When people walk on these pads, they apply a mechanical force or pressure, causing the piezoelectric material to deform and generate an electric charge.
Mechanical Stress: As pedestrians walk over the piezoelectric pads, their weight and movement cause mechanical stress and deformation in the piezoelectric material.
Electric Charge Generation: Due to the piezoelectric effect, the mechanical stress leads to the separation of charges within the piezoelectric material, generating a small electric voltage across the material.
Energy Harvesting System: The electric voltage generated by the piezoelectric material is then collected and processed by an energy harvesting system. This system typically includes electronic components such as rectifiers, capacitors, and sometimes voltage amplifiers. The rectifiers convert the alternating current (AC) generated by the piezoelectric effect into direct current (DC), which can be stored in a capacitor or a battery for later use.
Energy Storage or Usage: The harvested electrical energy can be stored in batteries or supercapacitors, or it can be used to power low-power devices or lighting systems in the pedestrian zone.
It's important to note that while piezoelectric generators can capture energy from foot traffic, the amount of energy generated is relatively small and depends on factors like the number of pedestrians, their walking patterns, and the efficiency of the piezoelectric materials and energy harvesting system. Therefore, piezoelectric generators are typically used for supplemental energy generation in environments with a high pedestrian flow, where the cumulative effect of many people walking can lead to a significant amount of harvested energy over time.