Improving Heat Generation
Among all possible demands for energy, heat is the highest end-use (including, for example, electricity transformed to heat). So it makes sense that decarbonization will only happen if heat generation is done in the greenest possible way, and very efficiently.
This is far from done, as fossil fuels account for 63% of global energy use for buildings-related heating, a decrease of only 4 percentage points since 2010.
Source: IEA
This is a major hindrance to any net-zero scenario, requiring at least as much effort as switching individual transportation methods to EVs.
For now, the main method has been to turn toward heat pumps, which, instead of burning things to produce heat, move it from one point to another.
Even if they are more efficient, heat pumps could still be improved. This is what researchers at the Ames National Laboratory (USA) and the Iowa State University are working on, with a new type of heat pump called “magnetocaloric heat pump”.
They recently published their latest results in the journal Applied Energy, under the title “Scalable and compact magnetocaloric heat pump technology”.
How Do Traditional Heap Pumps Work?
The key concept of a heat pump is to “grab” energy in one place, and carry it to another one.
Typically, it will extract heat from the environment around a house or other buildings and will inject it back inside.
Because no heat is actually generated, just moved around, it can display efficiency rates above 100% when measured in Watts-hours (Wh) of electricity consumed.
This system is also more polyvalent than a traditional heating system, as it can work in reverse as well. So in most cases, it can double as cooling as well during the summer months.
Source: The Heat Pump Warehouse
The typical heat pump uses a system of gas compression to move the heat, as gases absorb or release heat when they are compressed/decompressed.
Gas compression is the most commonly used method, because it is a very well-known technology, relying on valves, pipes, and compressors not so different from the one used decades ago.
This might, however, not be the best possible heat pump design, with magnet becoming a strong contender.
Types Of Heat Pumps
Different heat pump designs differ in several ways, including where they extract the energy, where they send it, and whether they are adapted to cold climates or not.
Energy Sources
- Ground Source: Also known as geothermal heat pumps, they harness heat from the ground and are known for their high efficiency.
- Air Source: The most common type, these extract heat from the air and are easier to install than ground-source pumps.
- Water Source: These use nearby water sources like lakes or wells for heat exchange.
Installation
- Ducted: Integrated into a home’s ductwork, these provide centralized heating and cooling.
- Mini-Split: Ideal for homes without ducts, these allow for individual control of room temperatures.
Climate
- Cold Climate: Specifically designed for regions with harsh winters, these heat pumps maintain efficiency even in extremely cold temperatures due to advanced features like variable-speed compressors.
- Normal Climate: Ideal for moderate climates, these are standard heat pumps suitable for typical heating and cooling needs.
Heat Transfer Method
- Gas compression: Works reasonably well, with simple, known technology.
- Magnets: A subset of the larger “solid-state” caloric heat pump, which requires no coolant.
Magnetocaloric Heat Pump (MCHP) Technology
MCHP uses the principles of magnetocaloric effects, or the cooling or heating of magnetic materials with the variation of an externally applied magnetic field.
Source: DST
In theory, this can be a much better system, as it removes the need for refrigerant materials, which are generally toxic and/or environmentally harmful, very often leaking from traditional heat pumps, especially when the equipment gets older.
Over the years, a lot of different designs for magnetocaloric heat pumps have been proposed using different setups:
- Different magnetic fields’ strength.
- Different magnetocaloric materials, like pure gadolinium, gadolinium alloys, and LaFeSi alloys (lanthanum-iron-silicon).
- Different shapes for the magnetocaloric material.
These systems have demonstrated efficiency higher than the best vapor-compression systems. Their temperature span and thermal power were also a good match.
However, it was yet to be demonstrated that these systems could as match traditional heat pumps regarding costs, mass, and size, all important considerations for potential commercial success.
Variable Performance
The researchers measured the System power density (SPD) of different MCHP proposed designs, or the thermal power in watts divided by device mass in kg.
The existing scientific literature shows a wide variety of SPD, ranging from ∼1 to 40 W/kg.
Interestingly, two of the designs with the highest SPD had completely different approaches: one used high magnetic fields at high frequencies, and one used low fields at low frequencies. So there are probably multiple approaches that are each technically viable.
Competing With Compressors
The researchers have investigated multiple ways to boost SPD, a venue of research neglected until now, with absolute efficiency and more the focus of material sciences researchers.
It is, however, SPD that will likely matter the most for mass adoption of such heat pumps, as no end users, both consumers and builders, will accept heat pumps the size of a full room or too heavy to be handled easily.
They used a variety of methods:
- Variation on the magnetic alloy used:
- The power per mass was 374 W/kg for gadolinium alone.
- It was 854 W/kg for LaFeSi-based materials alone.
- Different designs of the magnetic material, from plates to beads.
- Different magnetic impulses, varying in frequency and intensity.
Through this systematic testing, the researchers found that from a technical baseline of 5.9 W/kg, MCHP systems can be boosted up to 81.3 W/kg, or an almost 14x increase in system power density.
From these findings, it appears that MCHPs can nearly match the SPD of some currently used compressors-based heat pumps, especially for low or moderate cooling powers (
Magnetocaloric Heat Pump Companies
The next one does not seem to be a publicly-listed company yet currently selling MCHP. It is however a very active field with many startups, often spin-offs of cutting-edge research performed in top universities. For example:
So, while not very easy to access, it can be an interesting idea for people who are accredited investors and have access to such investments.
Gadolinium Company
Gadolinium is a rare earth, and 97% of global production (gadolinium dioxide) is produced by China.
Interestingly, the metal currently has little application besides niche usage like neutron absorption in some nuclear reactors or magnetic contrast agents for MRI, and would therefore be a perfect resource to utilize instead of polluting refrigerant currently used in heat pumps.
As the trade tensions between the USA & China have continuously risen since the first Trump presidency, it is likely that any Western investors willing to bet on rare earth, including gadolinium, will prefer alternative sources.
Such a potential company is Neo Materials.
Neo Materials specializes in rare earths and critical materials production. This includes gadolinium, but also currently critical other rare earths and materials, like hafnium, niobium, gallium, and rare earth magnets.
Source: Neo Materials
All of these products are critical for producing semiconductors, magnets of wind turbines, EVs, etc. And in most cases, supplied 90-99% by China.
The company is making most of its revenues from “Magnequench”: neodymium-iron-boron (NdFeB) magnetic powders and magnets used in electric motors (including EVs).
The second largest comes from Chemicals & Oxides used in petroleum and chemical catalysts, hybrid and EVs, water purification, high-efficiency displays, optical lenses, consumer electronics, etc.
Source: Neo Materials
Neo’s revenues are also very diversified geographically, making it safer from geopolitical storms than most companies in this sector. It manufactures some products in China and has even turned AsiaMag, a 2019 acquisition into the top 5 largest bonded magnet makers in China by increasing its sales volume 5-fold.
But it also diversifies its geographical risk. For example, the company will notably build in the EU (Estonia) the first outside of China sintered magnet plant for EVs, with the first production expected in 2025.
Source: Neo Materials
Overall, Neo Materials has the most integrated presence in the permanent magnet and rare earth value chain out of China, with only mining the raw ore not vertically integrated.
The company has also more rare earth advanced degrees and technical experts across rare earth magnetic products than any other company outside of China or Japan. And even in Japan, it can beat local competitors to sign contracts with companies like Honda or Daido Steel.
Source: Neo Materials
This strong presence in materials critical for the green transition, as well as many high-tech applications from semiconductor manufacturing to special alloys and catalysts, makes Neo a good stock pick for investors looking for exposure to the sector, with a potential upside in case of worsening trade wars.
