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Your next fridge could keep cold more efficiently using magnets

By

February 13, 2014

A bottle of beer is cooled using the new magnetic refrigeration system developed by GE

A bottle of beer is cooled using the new magnetic refrigeration system developed by GE

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The fridge is the most common of common household appliances. Despite improvements in efficiency over the years, they remain one of the biggest users of electricity in the home, relying on chemical refrigerant and a compressor to transfer heat from the inside to the outside of the fridge. GE researchers have now developed a new type of refrigeration technology using magnets that is more environmentally friendly and is predicted to be 20 to 30 percent more efficient that current technology ... and it could be in household fridges by the end of the decade.

Magnetic refrigeration is not a new idea. Ever since German physicist Emil Warburg observed in the 1880s that certain materials changed temperature when exposed to a changing magnetic field – known as the magnetocaloric effect – there have been efforts to create refrigerators based on the technique.

Such magnetic refrigeration systems were developed as far back as the 1930s, and researchers at the Los Alamos National Laboratory (LANL) in New Mexico successfully achieved a few degrees of refrigeration in the 1980s. However, the technology has failed to make it into household refrigerators as it relies on superconducting magnets that themselves need to be cooled to extremely low temperatures, making it not cost- or energy-efficient for household use.

GE teams in the US and Germany turned their collective efforts to the task a decade ago and built a cascade from special magnetic materials. Each step of the cascade lowered the temperature slightly but after five years of work they were only able to realize cooling of just 2° F with a prototype that Michael Benedict, design engineer at GE Appliances, describes as a "huge machine."

A breakthrough then came courtesy of the research team's materials scientists who developed a new type of nickel-manganese alloys for magnets that could function at room temperatures. By arranging these magnets in a series of 50 cooling stages, the team have managed to reduce the temperature of a water-based fluid flowing through them by 80° F with a device that is, according to Benedict, "about the size of a cart."

Michael Benedict (left) and Venkat Venkatakrishnan using GE’s magnetic refrigeration syste...

"Nobody in the world has done this type of multi-stage cooling,” said Venkat Venkatakrishnan, a leader of the research team. "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."

The team has demonstrated the system for experts from the Department of Energy (DoE), White House staffers and the EPA and is now working to further refine the technology. They hope to achieve a 100° F drop in temperature at low power, with the ultimate goal of replacing current refrigerator technology, possibly before the end of the decade.

"We’ve spent the last 100 years to make the current refrigeration technology more efficient,” said Venkatakrishnan. "Now we are working on technology for the next 100 years."

The magnetocaloric refrigeration technology is explained in the following video.

Source: GE

About the Author
Darren Quick Darren's love of technology started in primary school with a Nintendo Game & Watch Donkey Kong (still functioning) and a Commodore VIC 20 computer (not still functioning). In high school he upgraded to a 286 PC, and he's been following Moore's law ever since. This love of technology continued through a number of university courses and crappy jobs until 2008, when his interests found a home at Gizmag.   All articles by Darren Quick
16 Comments

These new fridge magnets are also 35% more efficient at keeping your reminder notes and postcards stuck to door.

davem2
14th February, 2014 @ 12:24 am PST

you should use Kelvin when you talk about temperature differences

MG127
14th February, 2014 @ 01:14 am PST

I wonder why they have used solid magnets that they have to oscillate in preference to coils fed with AC current, which, unlike the oscillating solid magnet components, will not wear out.

If they can get it down in size to that shown at the end of the video, then all well and good. Failing that, there is no reason why something too big for the kitchen should not be located in the cellar and plumbed in to a kitchen fridge cabinet.

Also, there are the obvious heat pump applications of domestic heating and cooling. If the kitchen unit is plumbed in, these could be combined with the fridge application into one unit that extracted waste heat from the sink and bathroom, etc. as well as from ground water in order to heat the house or in air conditioning mode, the domestic hot water tank.

Mel Tisdale
14th February, 2014 @ 04:09 am PST

I agree wilth Mel RE, the application of this technology to AC for a small home or apt where only a 20 F difference between I/O of air flow works to cool a dwelling. There is still the cost of moving a volumn of air through the system.

Philip M. Fortman
14th February, 2014 @ 08:29 am PST

MG127:

1 degree C = 1 degree K, so the temperature difference is the same in Kelvin and C.

David Charles Leithauser
14th February, 2014 @ 09:14 am PST

So if I understand this correctly we still need a heat transfer fluid, but it does not have to be one that changes phases under pressure and heat - as the magnets are replacing this step and doing the cooling. Sounds good.

myale
14th February, 2014 @ 09:14 am PST

I see opportunities all over the place. In heating and cooling homes, in heating hot water. Why not standardize the fittings and make heat exchangers that can be used in ventilation ducts for heating and cooling, and for domestic hot water, as well as a refrigerator? Maybe even a stove? Think big guys, this is great work, and the opportunities abound if the energy savings and capacities can be realized!

Congratulations. Time to cool a Champaign bottle!

ADVENTUREMUFFIN
14th February, 2014 @ 03:09 pm PST

There was no mention of the energy used, compared to a standard refrigerator. The same principal can be used with a propane flame, microwave or the standard compressor. It still takes energy to create heat. They are merely using the magnetic eddies to generate heat and alloys to cool down.

I just loved the wash machine sound!

donwine
14th February, 2014 @ 06:35 pm PST

The GE presenter did a great job making the material easy to understand. I like his speech patterns and the mood and tone of his delivery.

ralph.dratman
15th February, 2014 @ 07:36 am PST

Donwine,

It's right there in the first paragraph. "...predicted to be 20 to 30 percent more efficient that current technology."

Gadgeteer
15th February, 2014 @ 10:14 am PST

It appears that this is maturing pretty much at the same pace as Aerogels.

Aerogels sturdy enough to be used as clothing insulation but with R40 at a 1/4 inch thick would give such a fridge or freezer far better insulation than is used today, have far thinner walls, be very durable, and hopefully, not cost too much. A fridge or freezer so equipped would not need as large a cooling unit.

StWils
15th February, 2014 @ 10:46 am PST

This technology has a great future cooling Dwave processors, you thought over $8 million for a quantum annealing processor was expensive, until you saw what boiling off Helium costs as coolant.

L1ma
15th February, 2014 @ 02:14 pm PST

I don't get it. This is a heat pump. It makes no difference if you get the heat from compression, magnets, sun, flame, whatever - the only thing that counts is how much energy it takes to cool... and since there was zero mention of that, it's obviously nowhere near as efficient as current tech.

christopher
16th February, 2014 @ 08:16 pm PST

Christopher, you don't get it because you don't understand what a heat pump is really. Heat pumps don't get heat from stuff to cool, they use energy to move the heat from one place to another.

To answer the question of why they are not using AC electromagnets instead of permanent magnets is pretty obvious too. In an electromagnet the field would be changing sixty times a second which is too fast for the heat to transfer from the metal that is cooled or heated using the magnetocaloric effect. An electromagnet only generates a magnetic field for a short time, depending on the amount of iron inside the field. The field would collapse well before the "moment of heat" is satisfied. "Moment of heat" is how many calories it takes to change the temperature of a substance, in this case the special alloy rod they are using to make all this possible. If they could get the two values closer, then maybe they could use an electromagnet with no moving parts, but you have to increase the amount of iron which makes the thing heavier and expensive. Remember this is a prototype and if they can later tweak the physics to work, then sure, use an electromagnet if it is cheaper to build and run. I suspect any market ready unit would have a rotary setup for the magnets no matter what kind they are because it is cheaper and quiet.

Paul Montgomery
17th February, 2014 @ 12:27 am PST

also at the AC current comment... it's a pick your poison situation - electronic components will also wear out, though we don't usually think of them doing that. Switching components will degrade as semiconductor interfaces change with localized heating, thermal stresses and electric field stresses. That said, one will be more reliable, or convenient to fix and it may well be the electronically switched version. But it won't be line frequency switched at 60 Hz, as Paul mentioned above unless it just uses the 60 Hz as a reference and counts to switch at a lower freq.

joez
18th February, 2014 @ 10:39 am PST

Paul Montgomery,

.

If you are going to accuse someone of not knowing what they are talking about, it would be wise to limit your own claims...to things you know about.

.

While, 'Heat of the Moment' is the 1982 hit single from progressive rock band, Asia; 'Moment of Heat' isn't a term in wide use (even thermodynamics geek out sessions).

What you are describing is properly called 'heat capacity'. It might be molar heat capacity, volumetric heat capacity, or specific heat capacity or some derivative thereof, depending on whether your metric was per mole, volume, mass or some derivative thereof.

.

Iron is not an absolute requirement of an electromagnet, and neither is a 60 hz frequency (even if that is what local power is supplied at). If you need verification, you shouldn't have trouble constructing a fairly steady (non-pole-reversing) iron free magnet with just a few loops of wire and a DC current.

BGriffin
1st March, 2014 @ 02:45 pm PST
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