GE develops high-tech fridge magnets that could save the world billions of dollars in energy costs
One of the world’s biggest draws of electricity is refrigeration and air conditioning. (Yes, it’s somewhat ironic that, by trying to stay cool, we pump millions of tons of greenhouse gases into the atmosphere). General Electric, GE, believes it has discovered a new method of magnet-based refrigeration that is 20-30% more efficient than existing refrigeration technology, which almost universally uses a liquid refrigerant and compressor. GE launched the first commercial electric refrigerator in 1927 — and fridges have fundamentally remained unchanged for almost 100 years. GE hopes that its magnet-based tech can become the refrigeration method of choice for the next 100 years.
At the heart of GE’s new refrigeration technology is the magnetocaloric effect. The magnetocaloric effect, like vapor-compression refrigeration (the method used in all modern cars, fridges, etc.) was discovered a very long time ago, but there have always been large barriers preventing its commercial adoption. Basically, some metals get warmer when exposed to a magnetic field, and then cool down again when the magnet is removed. By doing this repeatedly, you can create a heat pump that moves thermal energy from one place and deposits it elsewhere. (This is exactly what your AC unit does, incidentally.)
For a variety of reasons, though, it has never been possible to build a commercial magnetocaloric refrigeration unit. For a long time, researchers could only make it work with superconducting magnets that had to be cooled to very low temperatures — which made it useful as part of a larger, cryogenic cooling system, but useless for room-temperature situations. In recent years, the development of better magnetocaloric materials and strong room-temperature magnets has allowed the technology to inch slowly forward. To put this in perspective, the GE researchers say they’ve been working on magnetocaloric refrigeration for 10 years, and it took them five years to create a “huge machine” capable of reducing the temperature by around 1 degree Celsius (2 degrees Fahrenheit). Now, they’ve created a desk-sized device that’s capable of cooling by around 44C (80F) — more than enough to power freezers, fridges, and air conditioning units.
“We’ve spent the last 100 years to make the current refrigeration technology more efficient,” says Venkat Venkatakrishnan, one of the researchers who is working on GE’s magnetocaloric refrigerator tech. “Now we are working on technology for the next 100 years.” Apparently GE has demonstrated the tech to the Department of Energy, White House, and EPA. “We believe we are the first people who shrunk it enough so that it can be transported and shown. We were also the first to go below freezing with the stages,” Venkatakrishnan says. (Read: Wristify: A personal Peltier wrist cooler that could save the US millions in energy costs.)
Now, then, it’s just a matter of size. In the video above, you can see GE researcher Michael Benedict holding up what appears to be a prototype for magnetocaloric cooler that would fit inside a modern fridge or air conditioner. The team is now working on a unit that can drop temperatures by around 57C (100F), while consuming even less power. There’s no word on the current efficiency of the system, only that their eventual goal is to be 20-30% more efficient than vapor-compression refrigeration. If such efficiency gains can actually be realized, billions of dollars in energy costs could be saved — billions of dollars that, rather neatly, would end up in GE’s pockets.
Author: Sebastian Anthony
Published: Feb 11, 2014
Original Source: ExtremeTech