Diagram of a six-stage cooling cycle for magnetic shape-memory alloys developed by researchers at the TU Darmstadt and the HZDR. Illustration: Alexey Karpenkov
As a result of climate change, population growth, and rising expectations regarding quality of life, energy requirements for cooling processes are growing much faster worldwide than for heating. Another problem that besets today’s refrigeration systems is that most coolants cause environmental and health damage. A novel technology could provide a solution: refrigeration using magnetic materials in magnetic fields.
Researchers at the Technische Universität Darmstadt and the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) have developed the idea of a cooling cycle based on the ‘magnetic memory’ of special alloys. Relevant initial experimental results have now been published in the journal ‘Nature Materials’ (DOI: 10.1038/s41563-018-0166-6). The project is funded by the European Research Council (ERC).The magnetic properties of metals can change when they are heated or cooled. “Iron, for example, is only ferromagnetic below 768 degrees Celsius; nickel’s transformation temperature is 360 degrees Celsius,” says Oliver Gutfleisch, Professor of Functional Materials at the TU Darmstadt. “Conversely, some alloys become ferromagnetic when they warm up. This phase transition is connected with the so-called magnetocaloric effect: when these shape-memory alloys are placed in an external magnetic field just below their transformation temperature, they spontaneously jump to their magnetic order and simultaneously cool down,” explains Gutfleisch. “The stronger the magnetic field, the more they cool.”Dr. Tino Gottschall, who is now researching at the HZDR’s Dresden High Magnetic Field Laboratory (HLD), and his colleagues have studied different shape-memory alloys and their properties in minute detail: “The application of a magnetic field can also change other properties, for example density – which is why some alloys increase their volume.” The physicists discovered that externally applied pressure can indeed reverse the magnetization process, causing the alloy to heat up.Together with Prof. Antoni Planes and Prof. Lluís Mañosa from the University of Barcelona, the scientists succeeded in providing experimental proof: “We used an alloy of nickel, manganese, and indium for our experiments because its conversion can be triggered at room temperature”, says Gottschall. The researchers generated the magnetic field using the strongest permanent magnets known to date – containing the rare-earth metal neodymium in addition to iron and boron. They can generate magnetic fields up to a flux density of 2 tesla – that is 40,000 times stronger than the Earth’s magnetic field. “Under such conditions, our alloy cools down by several degrees,” explains Gottschall. “Measurements we have made at the HLD have shown that a millisecond in the magnetic field is already enough for permanent transformation.”
Slight pressure – big impact
In the next step of the six-step cycle, the researchers removed the cooling element from the magnetic field, which retained its magnetization. In step three, the heat sink comes into contact with goods to be cooled down and absorbs its heat. The alloy even remains magnetic if the material returns to its original temperature. This can be remedied by mechanical pressure: in step four, a roller compresses the shape memory alloy. Under pressure, it switches to its denser, non-magnetic form and heats up in the process. When the pressure is removed in step five, the material retains its state and remains demagnetized. In the final step, the alloy releases heat into the environment until it has returned to its initial temperature and the cooling cycle can recommence.
“Just a few years ago, alloys with a magnetic memory were regarded as unusable because they can only be cooled in the magnetic field once,” explains Gutfleisch. “Global research, therefore, focused on materials that have no memory effect. However, refrigerators produced according to this principle come at a price.” The largest item in the manufacturing costs are the necessary permanent magnets: “In the case of reversible magnetization, the cooling effect only lasts as long as the cooling element is exposed to the magnetic field. Even in the best-case scenario, half of the coolant must be placed between the magnets. This means that you need four times as much permanent magnet as cooling medium.” Neodymium magnets are the most effective, but they are also the most expensive on the market. In addition, the rare-earth metal is a critical raw material, and considerable amounts of it are needed. The largest known deposits are in China, and its extraction causes considerable environmental pollution.Electromagnets cannot be used for magnetic cooling. For physical reasons, the level of efficiency would be lower than with vapor compression, which is used in billions of refrigerators and air conditioners. However, the researchers are convinced that this cooling technology no longer has a future: “There are simply no suitable cooling liquids,” says Gottschall. “The coolants commonly used today are highly effective as heat-transfer media, but their greenhouse impact is a thousand times greater than that of carbon dioxide. The production licenses for most of them in Europe will expire in the near future. Propane or butane are effective coolants, but form highly explosive mixtures in contact with the air. Ammonia is toxic and corrosive. Carbon dioxide is not especially efficient as a coolant.”
Using rare earths sparingly
Oliver Gutfleisch is also convinced that the future belongs to solid coolants. “We have been able to show that shape-memory alloys are highly suitable for cooling cycles,” says the functional materials expert: “We need far fewer neodymium magnets but can nevertheless generate stronger fields and a correspondingly greater cooling effect.” By 2022, he intends to build a demonstrator at the TU Darmstadt that makes it possible to estimate both the actual cooling capacity under real-life conditions and the energy efficiency of the process. For this, he has received an ERC Advanced Grant from the European Research Council worth a total of 2.5 million euros over five years.
Learn more: Researchers develop magnetic cooling cycle
The Latest on: Magnetic refrigeration
Market Insights of Magnetic Refrigeration Market by Major Competitor, Size, Subdivision, Market Dynamics Forces - Markets Pioneer
February 19, 2019 - Market Insights of Magnetic Refrigeration Market by Major Competitor, Size, Subdivision, Market Dynamics Forces Markets PioneerMagnetic Refrigeration market reports provides a comprehensive overview of the global market size and share. Magnetic Refrigeration market data reports also ...
Global Magnetic Refrigeration Market Insight Report 2018 – Samsung Electronics, Eramet, Whirlpool Corporation, Cooltech Applications - Industry News Network
February 15, 2019 - Global Magnetic Refrigeration Market Insight Report 2018 – Samsung Electronics, Eramet, Whirlpool Corporation, Cooltech Applications Industry News NetworkThe Market Research Store report is a collective informative report that goes through the fundamental characteristics of the Market Research Store, essential to ...
Global Magnetic Refrigeration Market Research Report Growing at a CAGR of 98.8% by 2024 With Vendors Analysis like Sigma-Aldrich, VACUUMSCHMELZE Gmbh & Co. KG, Toshiba, Samsung Electronics, Eramet, BASF, Qingdao Haier Co., Ltd., Whirlpool Corporation - Wise Awareness
February 1, 2019 - Global Magnetic Refrigeration Market Research Report Growing at a CAGR of 98.8% by 2024 With Vendors Analysis like Sigma-Aldrich, VACUUMSCHMELZE Gmbh & Co. KG, Toshiba, Samsung Electronics, Eramet, BASF, Qingdao Haier Co., Ltd., Whirlpool Corporation Wise AwarenessGlobal Magnetic Refrigeration Market accounted to USD 6 billion in 2016 growing at a CAGR of 98.8% during the forecast period of 2017 to 2024.
Magnetic Refrigeration Market by Economic/Political Environmental Change, Production and Revenue and Price Forecast by Type 2019-2025 - Herald News Press
February 17, 2019 - Magnetic Refrigeration Market by Economic/Political Environmental Change, Production and Revenue and Price Forecast by Type 2019-2025 Herald News PressMagnetic Refrigeration Market report provides featured analysis that will drive your business to the next level. It overview including growth factors, market ...
Magnetic Refrigeration System Market Development and Growth by Regions to 2025 - Crypto News
February 11, 2019 - Magnetic Refrigeration System Market Development and Growth by Regions to 2025 Crypto NewsGlobal Magnetic Refrigeration System Market is expected to strongly dominate the global economy with a substantial growth rate in upcoming years. Rapidly ...
Sustainable Growth Study of Magnetic Refrigeration System Market 2019-2025 Revenues, with Incarporated key Players like Cooltech Applications, Camfridge Ltd, Astronautics Corporation of America, Whirlpool Corporation, Haier Co., Ltd - Industry Chronicles
February 7, 2019 - Sustainable Growth Study of Magnetic Refrigeration System Market 2019-2025 Revenues, with Incarporated key Players like Cooltech Applications, Camfridge Ltd, Astronautics Corporation of America, Whirlpool Corporation, Haier Co., Ltd Industry ChroniclesUpMarketResearch offers a latest published report on “Global Magnetic Refrigeration System Market Analysis and Forecast 2019-2025” delivering key insights ...
Global Magnetic Refrigeration Market 2019 – Cooltech Applications (France), Camfridge (UK), Astronautics Corporation of America (US) - Bitcoin Journal
February 13, 2019 - Global Magnetic Refrigeration Market 2019 – Cooltech Applications (France), Camfridge (UK), Astronautics Corporation of America (US) Bitcoin JournalThe report gives the research-based overview of Global Magnetic Refrigeration Market 2018 and estimates future industry trends throughout the forecast period ...
Magnetic Refrigeration System Market Research By Key Players And Technological Advancements & Competitive Insights To 2023 - Honest Version
January 31, 2019 - Magnetic Refrigeration System Market Research By Key Players And Technological Advancements & Competitive Insights To 2023 Honest VersionMagnetic Refrigeration System Market Report Provided Full Details of Executive summary Scope of the report Research Methodology Introduction 2017 Market ...
Global Magnetic Refrigeration Market Research Report | Size, Share and Forecast : Cooltech Applications (France), Camfridge (UK) and Astronautics Corporation of America (US) - Honest Journalist
February 4, 2019 - Global Magnetic Refrigeration Market Research Report | Size, Share and Forecast : Cooltech Applications (France), Camfridge (UK) and Astronautics Corporation of America (US) Honest JournalistGlobal Magnetic Refrigeration Market report details the competitive marketplace scenario based on manufacturing quantity, earnings, sales and size from ...
Magnetic Refrigeration Market Overview, Technology Progress (2018-2025) - Global News Tribune
January 21, 2019 - Magnetic Refrigeration Market Overview, Technology Progress (2018-2025) Global News TribuneMagnetic Refrigeration Market Report (Request for Sample Report Here) covers elaborate competitive outlook including the market share and company profiles ...
via Google News
The Latest on: Magnetic refrigeration
via Bing News