Researchers have created a groundbreaking refrigeration device that is environmentally friendly and boasts exceptional cooling performance, poised to revolutionize industries that depend on cooling and lessen global energy consumption. This innovative elastocaloric cooling technology has improved efficiency by over 48%, paving the way for its commercial use and tackling the environmental issues linked to conventional cooling systems.
Researchers at the School of Engineering of the Hong Kong University of Science and Technology (HKUST) have developed an eco-friendly refrigeration device with record-breaking cooling performance in the world, set to transform industries reliant on cooling and reduce global energy use. With a boost in efficiency of over 48%, the new elastocaloric cooling technology opens a promising avenue for accelerating the commercialization of this disruptive technology and addressing the environmental challenges associated with traditional cooling systems.
Conventional vapor compression refrigeration relies on refrigerants that contribute significantly to global warming. In contrast, solid-state elastocaloric refrigeration draws on the latent heat of shape memory alloys (SMAs) during their phase changes, offering a greener alternative. This technology is free from greenhouse gases, fully recyclable, and energy-efficient. However, the limited temperature lift of 20 to 50 K, which is vital for the ability of the cooling device to move heat from cooler to hotter areas, has been a barrier to its commercialization.
To tackle this issue, a research team led by Professors SUN Qingping and YAO Shuhuai from the Department of Mechanical and Aerospace Engineering has designed a multi-material cascading elastocaloric cooling device using nickel-titanium (NiTi) shape memory alloys and has succeeded in achieving a world record in cooling performance.
By selecting three different NiTi alloys, each with its own phase transition temperatures to operate at the device’s cold, intermediate, and hot ends, the researchers enhanced the superelastic temperature range of the device to over 100 K. Each NiTi component was optimized for its specific temperature range, significantly boosting overall cooling efficiency. Their multi-material cascading elastocaloric cooling device managed an impressive temperature lift of 75 K on the water side, which eclipses the previous world record of 50.6 K. This significant breakthrough was documented in the prestigious journal Nature Energy.
Following their successful development of elastocaloric cooling materials and structures, supported by numerous patents and research papers, the team is looking to advance the creation of high-performance shape memory alloys and devices for applications requiring sub-zero elastocaloric cooling and high-temperature heat pumping. They aim to keep improving the materials and design energy-efficient refrigeration systems to promote the commercialization of this novel technology.
Heating and cooling spaces contribute to 20% of total electricity use globally and are expected to become the second-largest source of electric demand by 2050, according to industry forecasts.
Prof. Sun expressed optimism about the future, stating, “With continuous advancements in materials science and mechanical engineering, we believe elastocaloric refrigeration will offer next-generation green and energy-efficient cooling and heating solutions to meet the vast global refrigeration market, addressing the critical challenges of decarbonization and combating climate change.”
This research was conducted by Professors Sun and Yao (both served as corresponding authors), along with Dr. ZHOU Guoan (first author, Postdoctoral Research Associate and PhD graduate), PhD student LI Zexi, and PhD graduates ZHU Yuxiang and HUA Peng, along with a collaborator from Wuhan University.
