In this blog post, we will look at the principles and possibilities of harvesting technology that collects minute amounts of energy that is wasted in everyday life.
Smartphones, watches, laptops, light bulbs, heating. What do these have in common? They are all powered by energy. Almost all the devices we use require energy, which is converted into various forms for use. Some devices convert electrical energy into light energy, while others convert electrical energy into kinetic energy. For example, the light bulbs we commonly use convert electrical energy into light energy, and cars obtain kinetic energy by burning fuel. However, most of the energy is released in the form of heat energy and is lost in the process. This is a common occurrence in everyday life, but it is also an aspect that we easily overlook.
Energy efficiency is the ratio of effective energy output to input energy. For example, the energy efficiency of a fuel cell is about 60%, which is a fairly high figure. However, the remaining 40% of energy is still wasted as heat, which can be very inefficient. We often think of electricity as being used efficiently, but in reality, a lot of energy is wasted. In particular, the energy loss that occurs in large-scale industries and transportation is greater than we imagine. As such, efforts are needed to reduce the loss that occurs in the process of converting energy, and this can maximize the utilization of energy resources.
In this situation, the technology that has recently attracted attention is energy harvesting. Energy harvesting is a technology that collects energy that can be wasted in everyday life and converts it into electricity, using various forms of energy that we often overlook. It collects the thermal energy emitted when the aforementioned devices operate, or converts the minute pressure or friction energy generated when we touch a smartphone or press a laptop keyboard into electricity. On a larger scale, vibrations and heat generated when a car or plane is in operation can also be collected and utilized.
For energy harvesting, a device is needed that can effectively collect energy emitted from the surroundings. There are several principles that can be applied to this device. The first is the piezoelectric effect. The piezoelectric effect is the conversion of mechanical energy such as vibration, pressure, and shock into electrical energy through a piezoelectric element. This principle can be easily found in everyday life, for example, the piezoelectric effect is used in a recorder that stores sound waves in the form of radio waves. By applying this principle to energy harvesting, it is possible to develop a remote control that produces electrical energy from the pressure generated when a person bends the knee or elbow joint, or converts kinetic energy from pressing a button into electricity. This is one of the ways to efficiently use energy that naturally occurs in everyday life.
Another principle applied to energy harvesting devices is the thermoelectric effect. The thermoelectric effect is a phenomenon that shows the relationship between thermal energy and electrical energy. In particular, when two substances with different temperatures are joined by the Peltier effect, a voltage difference is generated due to the temperature difference, and an electric current flows. If this device is attached to a device, the heat generated by our body or machine can be converted into electrical energy and used. For example, if this technology is applied to portable electronic devices, the thermal energy generated when the user walks can be converted into electricity to charge the device.
In addition, principles such as the photoelectric effect and electromagnetic resonance can be used for energy harvesting. The photoelectric effect is a phenomenon in which electrons move and current flows when light of a certain frequency or higher is shone on a metal, and it can be used to convert the light energy of sunlight or light bulbs into electrical energy. This technology can be used to efficiently use light energy to generate electricity without directly using sunlight. Next, electromagnetic resonance is the generation of electrical energy when an external alternating magnetic field is applied, causing the electron or nuclear spin system of atoms with magnetic moments to absorb the energy of the resonance frequency. This can be used to develop a system that converts the energy of the magnetic field generated when a card is swiped or tapped into electricity.
Energy harvesting technology is still in its infancy and has not yet been commercialized, but its potential is endless. The examples presented here are technologies that are currently in development or in the experimental stage. However, if all of these energy harvesting methods are perfected and integrated in the future, we will no longer need to charge our machines or carry batteries. Innovative devices such as wearable computers will emerge, and these devices will be able to absorb various types of energy emitted from the surroundings and use it as their own energy. In the near future, we may see the advent of a time when we can effectively absorb and use various types of energy generated in our daily lives by simply wearing a device on our wrist.
And perhaps energy harvesting technology can slow the depletion of our planet’s resources by maximizing energy efficiency. This could play an important role in solving the energy problems we face and contribute greatly to environmental protection. If this technology is commercialized, I expect it to have a positive impact not only on the environment but on humanity as a whole. I hope this groundbreaking technology will be realized in the near future, and I am curious to see how the changes it will bring will change our lives.
