Discover a more efficient way to convert heat into electrical energy
An international team of scientists has discovered how to capture heat and convert it into electricity. This discovery, reported by Science Daily and published in the journal Science Advances, could lead to more efficient energy generation from heat emitted by sources such as car exhaust, interplanetary space probes, and industrial processes.
paramagnetic particles
"Thanks to this discovery, it will be possible to generate more electrical energy from heat than is currently being produced," says Joseph Hermans, co-author of the study, professor of mechanical and aerospace engineering, and Ohio State University's Distinguished Nanotechnology Researcher. "It's something no one thought possible until now."
This discovery relies on tiny particles called paramagnets, which are not magnets in the literal sense, but possess some magnetic flux. This is crucial because magnets, when heated, lose their magnetic strength and become paramagnetic. This magnetic flux, or what scientists call "spin," produces a type of energy called magnetohydroenergy, a phenomenon that, until this discovery, could not be harnessed to generate energy at room temperature.
Thermoelectric semiconductors
Hermans says: "The prevailing belief was that when a paramagnetic material is heated, nothing happens. But we found that this is not true. What we discovered is a new way to design thermoelectric semiconductors, which are materials that convert heat into electricity. The conventional thermoelectric materials that we have used for the past 20 years or so are inefficient and produce little power, so they are not commonly used. [The new] discovery changes this understanding."
Paramagnets for heat harvesting
Magnets are a key element in collecting energy from heat, because when one side of a magnet is heated, the other side - the cold side - becomes more magnetic, producing spin that drives electrons in the magnet and generates electricity.
The paradox lies in the fact that magnets, when heated, lose most of their magnetic properties, transforming into paramagnetic materials—or "semi-magnetic, but not fully magnetic," as Hermans calls them. This means that until this discovery, no one had considered using paramagnets to harvest heat, because scientists believed they were incapable of collecting energy.
one billionth of a millionth of a second
But what the research team discovered is that paramagnets only propel electrons for a fraction of a billionth of a millionth of a second—just long enough to make them effective energy harvesters. The researchers, an international team of scientists from Ohio State University, North Carolina State University, and the Chinese Academy of Sciences, set out to test the paramagnets to see if, under the right conditions, they could produce the necessary spin. Hermans concluded that they discovered the paramagnets do indeed produce the kind of spin that propels electrons, thus enabling energy harvesting.
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