{"id":671576,"date":"2025-05-27T01:10:23","date_gmt":"2025-05-26T22:10:23","guid":{"rendered":"https:\/\/en.buradabiliyorum.com\/novel-elastic-alloy-achieves-20x-temperature-change-and-90-carnot-efficiency-in-solid-state-heat-pumping\/"},"modified":"2025-05-27T01:10:23","modified_gmt":"2025-05-26T22:10:23","slug":"novel-elastic-alloy-achieves-20x-temperature-change-and-90-carnot-efficiency-in-solid-state-heat-pumping","status":"publish","type":"post","link":"https:\/\/buradabiliyorum.com\/en\/novel-elastic-alloy-achieves-20x-temperature-change-and-90-carnot-efficiency-in-solid-state-heat-pumping\/","title":{"rendered":"Novel elastic alloy achieves 20x temperature change and 90% Carnot efficiency in solid-state heat pumping"},"content":{"rendered":"
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\n Key idea and candidate materials for large thermoelastic effect (TeE). Credit: HKUST
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Researchers at the School of Engineering of the Hong Kong University of Science<\/a> and Technology<\/a> (HKUST) have developed a novel elastic alloy called Ti78<\/sub>Nb22<\/sub>, which achieves remarkable efficiency for solid-state heat pumping and exhibits a reversible temperature change (\u0394T) ability that is 20 times greater than that of conventional metals when stretched or compressed, offering a promising green alternative to traditional vapor-compression heating and cooling technologies.<\/p>\n

The study is published<\/a> in Nature Communications<\/i>, in a paper titled “Large thermoelastic effect in martensitic phase of ferroelastic alloys for high efficiency heat pumping”.<\/p>\n

Nearly half of the world’s energy is consumed for heating, including district heating in the building sector and process heating in various industrial sectors.<\/p>\n

Currently, global heat demand is primarily supplied by burning fossil fuels, which produce a large amount of greenhouse gases and consume significant energy. Using heat pumps based on solid-state phase transitions is a more eco-friendly app<\/a>roach, but their energy efficiency remains only 50\u201370% of the Carnot limit. Achieving more efficient and eco-friendly heat pumping remains a global challenge.<\/p>\n

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\n Prof. Sun Qingping (left) and Research Assistant Prof. LI Qiao (right), both from the Department of Mechanical and Aerospace Engineering at HKUST, demonstrate their newly developed Ti\u2087\u2088Nb\u2082\u2082 elastic alloy. Credit: HKUST
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To address this challenge, Prof. Sun Qingping from the Department of Mechanical and Aerospace Engineering (MAE)’s research team has proposed a novel heat-pumping approach that utilizes heat generated by elastic deformation, known as the thermoelastic effect (TeE).<\/p>\n

Although TeE was discovered by scientists Kelvin, Joule, and Duhamel in the 19th century, it was long considered too weak for practical applications.<\/p>\n

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Prof. Sun’s team then fabricated a [100]-textured Ti78<\/sub>Nb22<\/sub> martensitic polycrystal, which, when subjected to linear elastic deformation for heat pumping, exhibits a reversible temperature change (\u0394T) of 4\u20135 K\u201420 times greater than conventional metals, which typically change only about 0.2 K.<\/p>\n

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\n Predicted absolute temperature change in different martensitic single crystals. Credit: HKUST
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Remarkably, this alloy achieves approximately 90% of the Carnot efficiency limit in a heat-pumping cycle, making it highly competitive with refrigerants used in commercial vapor-compression heat pumps.<\/p>\n

Furthermore, the team’s research indicates that certain ferroelastic alloys could be developed with even higher thermal expansion, achieving temperature changes of up to 22 K. This work provides a promising opportunity for the green heat pumping industry and presents the first non-phase-transition-based solution for eco-friendly, high-efficiency heat supply.<\/p>\n

Prof. Sun said, “This discovery changes the long-standing and well-established perception that the thermoelastic effect is too weak to be useful. Our research demonstrates that linear elastic deformation alone can be used for highly energy-efficient heat pumping.”<\/p>\n

Dr. Li Qiao, the first author of this study and Research Assistant Professor from the same department, added, “As global decarbonization efforts intensify, this technology provides a transformative solution for replacing fossil fuel-based heating. We are currently developing prototype heat pumps using the alloy for industrial applications.”<\/p>\n

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More information:<\/strong>
\n\t\t\t\t\t\t\t\t\t\t\t\tQiao Li et al, Large thermoelastic effect in martensitic phase of ferroelastic alloys for high efficiency heat pumping, Nature Communications<\/i> (2025). DOI: 10.1038\/s41467-025-59720-3<\/a><\/p>\n<\/p><\/div>\n

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\n Hong Kong University of Science and Technology
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\n Citation<\/strong>:
\n Novel elastic alloy achieves 20x temperature change and 90% Carnot efficiency in solid-state heat pumping (2025, May 26)
\n retrieved 26 May 2025
\n from https:\/\/techxplore.com\/news<\/a>\/2025-05-elastic-alloy-20x-temperature-carnot.html\n <\/p>\n

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