Renewable energies seem to be the energy future of the planet, but they still have the limitation of depending on the cycles of the sun and the intensity of the wind. Therefore, scientists strive to find solutions to these problems.
We have already talked to you before about various solutions that seek to solve the problem of the irregularity of renewable energy production. Examples of this are solar panels capable of creating energy at night or the Energy Vault invention, which takes advantage of gravity to generate energy.
But they are not the only ones and the project presented by MIT researchers (Massachusetts Institute of Technology) is one more alternative in the quest to turn solar and wind energy into viable options on a continuous and permanent basis.
A thermal battery that stores renewable energy
The basic principle of this new discovery from MIT is a battery capable of store the renewable energy produced in the form of heat. This is based on the physics of semiconductors.
In the semiconductor alloysthere is an energetic gap formed by the distance between the valence shell of the electrons and the conduction band.
“It will have to be kept inside a warehouse filled with inert gas, such as argon gas”
When electrons jump from the first to the second, there is a release of energy directly proportional to the distance between them. In the case of this thermal battery, a succession of layers stacked one on top of the other. Thanks to that, it is possible to capture all the photons that drive the electrons, regardless of the energy they contain.
The key, however, is where these photons come from. “We were sending electricity to a resistive heater that was a few meters away”Asegun Henry, a mechanical engineer at MIT and author of the new study, explains to Gizmodo that has just been published in Nature.
“This resistive heater was like a complex filament in a light bulb: a conductor that glows and overheats when energy passes through it. The hot metal released photons that were captured by the alloy layers, generating electricity in the heat engine.”. In these tests, the researchers have verified that an element heated between 1,900 and 2,400 ºC provided them with the best efficiency.
In its real-world application, a renewable energy source would be responsible for powering the resistive heaters that heat the liquid metal. The liquid metal would then be pumped over blocks of graphite, something Henry describes as having “the Sun in a box”. This sun would operate at half the temperature of the real one and then power the resistive heaters that send photons to the heat engines, stored one on top of the other in a large array.
oxygen free environment
One of the main obstacles to overcome is that this “encapsulated sun” must operate in an oxygen-free environment, so the ideal would be to find a way to operate remotely.
“It will have to be kept inside a warehouse filled with inert gas, such as argon gas”Henry explains. “That environment is airless, so you can’t just walk in there.”
“We’d like to be able to go take a look during annual maintenance, so you just cool down the system, or cool down a part of it, and then send someone out,” says Henry. “If there is an emergency, you could cool down the system and essentially send someone out with scuba gear and an oxygen tank.”.
The proven thermophotovoltaic cell or heat engine measures 1 square centimeter and operates with 40% efficiency. It is a promising result, but the real challenge is to scale this technology for its application in a power plant, thus being able to connect to the existing network.
Source: Gizmodo