The volume of people who visit shopping centers daily is ideal for piezoelectricity
Piezoelectricity is a property possessed by some crystals , which can become electrically polarized if they are subjected to a certain pressure . This phenomenon can also develop in the opposite direction: these crystals, subjected to an electric field, deform due to the action of internal forces.
A process for crystals
When a piezoelectric crystal is subjected to mechanical stress , it achieves electrical polarization in its mass and, on its surface, electric charges and a potential difference are produced. Generally, this effect is reversible since, if the crystals are no longer subjected to the electric field or external voltage, they return to their original shape.
It is important to mention that synthetic or natural crystals that have piezoelectricity do not have a center of symmetry . In this way, compression causes its center of gravity to dissociate from negative and positive electrical charges. Faced with this situation, elementary dipoles arise in its mass and charges of opposite sign appear on the facing surfaces.
Tourmaline and quartz are piezoelectric materials. In fact, the brothers Jacques and Paul Curie discovered piezoelectricity by analyzing the compression of quartz. These physicists warned that, when this mineral is compressed, a separation of charges occurs, favoring polarization.
In short, it can be stated that a piezoelectric crystal, when deformed or hit, produces voltage ( electrical tension ). Therefore it is capable of generating electrical energy .
Applications of piezoelectricity
An example of the use of a piezoelectric crystal can be found in electric lighters or spark lighters . These devices have a button: when said button is pressed, a spring hammer is activated that impacts against a piezoelectric crystal, creating an electric current that causes a spark .
This property is also used to create special plates that are placed on the floor of certain public spaces, so that self-sustaining energy is produced by receiving people's footsteps. To estimate the impact that this can generate in the transition towards greater care for the environment, just take a look at the influx that airports and shopping centers have, which is estimated in thousands per day, and keep in mind that for Each step can get about 7 watts .
A subway station in Japan, for example, uses this technology to produce the electrical energy it needs to function completely autonomously. If piezoelectricity were used on a highway, on the other hand, by placing the plates on the pavement, the passage of cars could be sufficient to meet the electrical needs of the streetlights and illuminated signs along the entire road . If we added to this the production of clean energy in the cars themselves, the result would be optimal.
With piezoelectric plates under the road it would be possible to illuminate cities in a sustainable way
More focused projects
Until the end of 2020, piezoelectricity application tests focused on very large spaces, but future plans always included smaller areas, such as the home and office . In fact, the Dutch establishment Natuur Café La Porte has a system in its revolving door that generates electrical energy every time a customer uses it, to supply all the lighting in the premises.
Like any revolutionary proposal that requires a considerable economic investment to take the first step, it takes a long time to convince all citizens to bet on its advantages . Something similar happens with solar panels, which have existed for a long time and there are still few homes that use them. However, the most important thing is to continue promoting all projects that result in greater respect for the planet, based on the understanding that it does not belong to us but that we must return the resources it provides us.