What is Magnetic Air Conditioning?
Arlington, TX – Magnetic air conditioning also known as magnetocaloric air conditioning is a new high-tech method for keeping cool. These AC systems operate by utilizing a phenomenon known as the magnetocaloric method. First discovered by a German physicist around the same time as the beginning of the industrial revolution. This makes it almost as old as electricity itself so maybe it’s not quite that new after all.
What is the Magnetocaloric Method?
As stated above the magnetocaloric method is a thermodynamic phenomenon that can change the temperature of a suitable material. It accomplishes this by exposing that material to an alternating magnetic field. To phrase this another way, the material will heat up when it is exposed to a magnet. That same material will cool down when the magnetic field is removed. For a more complex explanation, you can read about the effect here.
When this phenomenon was first observed, the temperature change was so subtle that it did not have any practical purposes. In recent years through research and experiment, this has changed. There are newly developed metal alloys that have been created that have a significantly greater magnetocaloric effect at room temperature.
How long has Magnetic AC Been Around?
The concept of magnetic ac is not new. As stated above, it was first observed in 1881. Additionally, a magnetic refrigerator was first demonstrated in 1933. After that, many laboratories across the world have utilized magnetic refrigerators. The path of Magnetic AC / Refrigeration has been a long and lonely one since most people have never even heard of it.
In 1991, Ames laboratory produced materials that were 10 – 30% more efficient than those that were currently in use with magnetic refrigeration. In 1996, Aeronautics demonstrated a working prototype based on Ames Labs’ work. The next breakthrough was in 1997 when Ames found that the magnetocaloric method in gadolinium was 2 to 10 times larger than with existing alloys. However, it required expensive high-purity gadolinium and resulted in small quantities. Eventually, Ames Labs was able to optimize the less expensive commercial-grade gadolinium to achieve nearly the same results. This paved the road for smaller applications outside of laboratories such as residential homes and automotive air conditioning.
When Will Magnetic AC be commercially Available?
After the turn of the century, magnetic ac basically went dark. I really could not find any advancements. After, the successes in 1997 you would think it should have been commercially available by 2010 and would already be heavily deployed in residential and automotive applications in the present day. However, it is not. I came across an article from 2016, that touted a company called Cooltech was releasing a magnetic Refrigerator for residential/commercial use. Did it come to fruition? Apparently not. When I looked for Cooltech’s website, instead I found Uniblue.
When I looked at Uniblue’s product offerings I was met with a blank page. With further research, I found that Uniblue purchased the patents from Cooltech and supposedly offers modules of 2KW, 20KW, and 100KW right now. They plan on being ready for small-scale serial production by 2022 or 2023.
Cooltech’s Refrigerators use gadolinium alloy and are claimed to have achieved an energy savings of 30 – 40% compared to current R404A systems. Other than Cooltech, other companies working on commercializing magnetocaloric cooling include Ames Laboratory, Astronautics, BASF, Vacuumschmelze, and Haier. However, if I remember correctly, there are others such as GE, Toshiba, and I am sure plenty of other companies in the AC & Refrigeration field are working on it as well.
How will a Magnetic Air Conditioner Work?
First, let’s review how traditional air conditioning technology works. HVAC units operate by converting a liquid refrigerant into a gas that absorbs heat from the outside air. Next, the refrigerant in its gas state passes through the compressor. While the gas is in the compressor it cools down returning to its liquid state. Finally, the process begins anew and repeats itself.
Magnetic air conditioners have no need for compressors or refrigerants. Instead, they will use magnets and water. It accomplishes this by placing a magnetocaloric alloy in an insulated environment.
The first step in the process known as adiabatic magnetization is heating the magnetocaloric alloy. Water will then transfer the heat from the alloy. The next process known as isomagnetic enthalpic transfer prevents the alloy from reabsorbing the heat since the magnetic field is still on. The third process, known as adiabatic demagnetization involves reducing the magnetic field. The last process known as isomagnetic entropic transfer prevents the alloy from reheating by keeping the magnetic field constant. This is where the magic happens and once the alloy and the environment are in equilibrium, the cycle repeats itself.
What Materials are Magnetocaloric?
The magnetocaloric material used for magnetic AC could vary because there are multiple rare-Earth alloys that work well with it. However, some of these alloys will most likely need optimization before we see them in widespread residential applications. One such magnetocaloric alloy that works well is gadolinium. Of course, the problem with gadolinium is it is a rare-Earth material and therefore may not be a very good candidate for cooling future homes worldwide. Currently, gadolinium averages $19,700 per metric ton. Applications, where gadolinium is currently in use, are with MRIs and as fuel rods in Nuclear power plants.
Furthermore, residential applications could drive the costs of gadolinium higher. If it rose to 100K then that would be around $45 per pound. This could very well make it a very expensive component in next-generation AC systems. How much would be needed? I don’t have the foggiest idea. However, let’s assume that the answer is a 25-pound wheel. That would mean the wheel could run upwards of up to $1,125 just for the raw material. Forged, packaged, and marketed you could see it double in cost by the time it reaches retail. Here’s hoping it stays relatively around current prices, and if so, then that same 25-pound wheel would run around $500 retail instead.
Other Materials
However, there appear to be other magnetocaloric alloys that could be more promising than gadolinium. One such material is Holmium oxide, which currently runs for around $18 per pound. This is more expensive than gadolinium, however, holmium only requires a small magnetic field to achieve an entropy change, whereas gadolinium requires a high magnetic field. Therefore, holmium as a magnetocaloric alloy could very well be much more energy-efficient than gadolinium.
Environmentally Friendly
Since magnetic air conditioning can use water instead of hydrochlorofluorocarbons it makes it a very environmentally friendly air conditioning system. On top of that, the energy requirements for magnetic AC are exponentially lower than traditional AC. How much more efficient is kind of up in the air though. There have been a few sources that generically speak about magnetic AC being around two-thirds cheaper than traditional AC. Magnetic air conditioning could very well be around 50 – 60% more efficient than current AC tech by the time it hits consumer level. Whenever that is only the crystal ball knows. However, I expect we will be hearing a lot more about it in the coming year.
