Simple

A Magnetic Fridge with No Freon and No Compressor ⚡ экспресс

Original: "Magnetocaloric effect of Fe47.5Ni37.5Mn15 bulk and nanoparticles: A cost-efficient alloy for room temperature magnetic refrigeration"
arXiv:2410.15776 · 2024-10-21 · CC BY · ⏱ 1 min · Materials
Scientists have proposed a cheap alloy for magnetic cooling that works at room temperature.
Abstract

Picture a fridge that chills without freon, just by flipping a magnetic field. It uses a metal that heats up when magnetized and cools down when the field disappears. Scientists have cooked up a cheap alloy of iron, nickel, and manganese that runs at room temperature. But shrinking it to nanoparticles spoiled its mojo, thanks to carbon gunk. So, can we make magnetic cooling a budget buy for everyone?

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An ordinary fridge compresses gas that harms the planet. The alternative is magnetic cooling. Inside some materials, atoms act like a swarm of tiny compasses. Turn on a magnet—all compasses instantly align in one direction, releasing heat. Turn it off—the needles return to chaos, absorbing heat from their surroundings. This cycle can cool without noise or harmful refrigerant.

Scientists took readily available iron, nickel, and manganese and cast a chunk of alloy. In it, the compasses work together at room temperature, absorbing nearly 300 joules of energy per kilogram—enough for a household appliance. Then they tried to turn the alloy into nanopowder to boost the effect through ultra-small sizes. But the laser processing inadvertently saturated the particles with carbon. The foreign atoms disrupted the compass alignment, shifting the cooling far from room temperature.

The magnetic fridge’s worst enemy isn’t heat—it’s carbon. Even a tiny impurity wrecks the synchronized dance of the magnetic arrows.

Bottom line: Cheap alloys work great as long as they stay solid. To move to nanotechnology, we need carbon-free methods. Quiet and safe fridges are closer than they seem, but the quirks of materials aren’t quick to open the door.

🎯 Effect discovered in 1881 waited over a century for its moment: only cheap alloys could bring magnetic cooling out of the lab.

🎬 In Dune, Arrakis has no compressors—perhaps magnetic systems will one day become just as silent and unseen.

Scientists
Christian DopplerD. B. McLaughlinDidier QuelozMichel MayorR. A. RossiterJacob Bekenstein
Tags
entropy carbon spectroscopy
Laws
second law of thermodynamicsDoppler effectBekenstein-Hawking entropyMaxwell's equationsPlanck's lawPlanck–Einstein relation
Original: arXiv:2410.15776 · CC BY · bridge42worlds