Refrigeration technology was introduced nearly a century ago, but it has changed little since. Now General Electric, the company that produced the first electric refrigerator, is looking to magnets as the next step in efficient refrigeration. It’s called magnetocaloric technology, and GE hopes it will be the way we keep cool for the next century.Refrigeration technology, whether you’re talking about an air conditioner or the refrigerator in your kitchen, is all about heat exchange. Thermodynamics doesn’t allow us to to simply destroy energy, so we move it from one place to another through vapor-compression. When a refrigerant is compressed, it gets warmer (absorbs heat from inside the refrigerator). That heat is then expelled outside of the system when the vapor is allowed to expand (heats the air in your kitchen). Magnetocaloric technology is operating a very similar heat pump, but it’s driven by magnetism rather than compression.The effects of magnetocaloric have been known about for decades, but it has simply never been practical before. Basically, some metals heat up when they are exposed a magnetic field. Take the magnet away, and they cool. General Electric realized this effect could be exploited as a heat exchanger in place of vapor compression. However, it used to only be possible with superconducting magnets cooled to very low temperatures. More advanced alloys and stronger magnets mean it can finally compete with traditional refrigeration.
To be workable in home refrigeration, the magnetic fridge needs about 100W of cooling. GE is currently at 60W with the prototype, but feels it can hit the mark within five years. When it’s ready for the market, GE expects the price to be on-par with regular refrigeration technology, but it currently costs four times more to make a magnetocaloric refrigerator than a regular one.
Even if the cost is a little higher than expected, GE says this tech will be 20% more efficient than today’s refrigerators. Cooling is one of the largest energy draws in the world, so this has the potential to save billions of dollars and reduce greenhouse gas emissions dramatically. It will also be more reliable because no special cooling fluids are needed — it’s just water.
There are still some tough engineering problems to be worked out. Placing such strong magnets in consumer appliances hasn’t been done before, so manufacturing is likely to remain difficult. Shrinking the footprint of the magnets while increasing efficiency is also a necessity. The device can currently be as small as a shoe box, but the team still needs to improve cooling efficiency to make it practical. If the company can work out the kinks, you could be getting your first magnetocaloric refrigerator in 2020.