3 Key Takeaways:
1. The new elastocaloric cooling technology developed at HKUST achieves record-breaking efficiency with a 75 K temperature lift, offering a sustainable alternative to traditional refrigeration systems.
2. By utilizing solid-state shape memory alloys (SMAs) that are 100% recyclable and free of greenhouse gases, this technology significantly reduces the environmental impact of cooling.
3. The innovation paves the way for next-generation energy-efficient cooling and heating solutions, crucial for meeting global decarbonization goals and rising electricity demand.
Why Is This a Groundbreaking Technology?
The unique aspect of this technology lies in its use of solid-state elastocaloric cooling, which leverages the latent heat from the cyclic phase transition of shape memory alloys (SMAs) to achieve high-efficiency, eco-friendly refrigeration. Unlike traditional systems that rely on refrigerants with high global warming potential, this device uses 100% recyclable SMAs, eliminating greenhouse gas emissions. The innovative multi-material cascading design expands the temperature range and boosts cooling efficiency, setting a new world record and paving the way for more sustainable cooling and heating solutions.
How Does Pioneering Elastocaloric Technology Redefine Sustainable Refrigeration?
Researchers at the Hong Kong University of Science and Technology (HKUST) have developed an eco-friendly refrigeration device that has shattered previous records for cooling performance. This groundbreaking technology is poised to revolutionize industries that rely on cooling systems while significantly reducing global energy consumption. With an impressive 48% increase in efficiency, this new elastocaloric cooling technology offers a promising pathway to commercializing a disruptive innovation that could address the environmental challenges posed by traditional refrigeration methods.
Traditional vapor compression refrigeration systems depend on refrigerants with high global warming potential, contributing to environmental degradation. In contrast, solid-state elastocaloric refrigeration leverages the latent heat generated during the cyclic phase transition of shape memory alloys (SMAs), offering an environmentally friendly alternative. SMAs are not only free of greenhouse gases but are also 100% recyclable and highly energy-efficient. However, the limited temperature lift of 20 to 50 K—a key measure of a cooling device’s capacity to transfer heat from a cooler source to a warmer sink—has been a major obstacle to the widespread adoption of this technology.
To overcome this challenge, a research team led by Professors Qingping Sun and Shuhuai Yao from the Department of Mechanical and Aerospace Engineering at HKUST has developed a multi-material cascading elastocaloric cooling device. This innovative device, made from nickel-titanium (NiTi) shape memory alloys, has set a new world record for cooling performance.
The team strategically selected three different NiTi alloys, each with distinct phase transition temperatures, to operate at the cold, intermediate, and hot ends of the device. By aligning the operating temperatures of each unit with its corresponding phase transition temperature, they expanded the device’s superelastic temperature range to over 100 K. This optimization allowed each NiTi unit to function within its ideal temperature range, significantly boosting overall cooling efficiency.
The resulting multi-material cascading elastocaloric cooling device achieved a remarkable temperature lift of 75 K on the water side, surpassing the previous world record of 50.6 K. This breakthrough, detailed in their study titled “A Multi-Material Cascade Elastocaloric Cooling Device for Large Temperature Lift,” was recently published in Nature Energy, one of the leading journals in the field.
This achievement not only advances the commercialization of elastocaloric cooling but also marks a significant step toward more sustainable and energy-efficient refrigeration technologies, aligning with global efforts to mitigate climate change.
Building on their success in developing elastocaloric cooling materials and innovative architectures, the research team at the Hong Kong University of Science and Technology (HKUST) is setting its sights on new frontiers. With numerous patents and publications in leading journals, the team now aims to advance high-performance shape memory alloys and devices specifically designed for sub-zero elastocaloric cooling and high-temperature heat pumping applications. Their ongoing work focuses on optimizing material properties and enhancing energy-efficient refrigeration systems, with the ultimate goal of driving the commercialization of this cutting-edge technology.
Space cooling and heating currently account for 20% of the world’s total electricity consumption. By 2050, these systems are projected to become the second-largest source of global electricity demand. Given these trends, the need for more sustainable and energy-efficient solutions is becoming increasingly urgent.
“In the future, with the continuous advancement of materials science and mechanical engineering, we are confident that elastocaloric refrigeration can provide next-generation green and energy-efficient cooling and heating solutions to meet the enormous global demand,” said Professor Qingping Sun. “This technology will be crucial in addressing the urgent tasks of decarbonization and mitigating global warming.”
The research was led by Professors Qingping Sun and Shuhuai Yao, with significant contributions from Postdoctoral Research Associate and PhD graduate Dr. Zhou Guoan (the study’s first author), PhD student Li Zexi, PhD graduates Zhu Yuxiang and Hua Peng, and a collaborator from Wuhan University.