Scientists at the Hong Kong University of Science and Technology (HKUST) have created a special metal that could revolutionize the way we heat and cool our homes, buildings, and industrial equipment.
This new elastic alloy, called Ti₇₈Nb₂₂, can heat up or cool down 20 times more than ordinary metals when stretched or compressed—and it does so with energy efficiency close to the theoretical limit.
This discovery offers a cleaner alternative to traditional heating and cooling systems, which mostly rely on burning fossil fuels or using chemical refrigerants that harm the environment.
Today, nearly half of the world’s energy is used just for heating, whether it’s warming homes or powering industrial processes.
Most of this energy comes from fossil fuels, which release greenhouse gases and accelerate climate change.
The new alloy, developed by Professor Sun Qingping and Research Assistant Professor Li Qiao from HKUST’s Department of Mechanical and Aerospace Engineering, makes use of a phenomenon called the thermoelastic effect.
This effect, known since the 1800s, describes how materials can change temperature when they are stretched or compressed. Until now, it was thought to be too weak for real-world applications.
But the research team found that their new alloy responds very differently.
By shaping the alloy in a special way (known as [100]-texturing), they were able to make it change temperature by 4 to 5 degrees Celsius with simple elastic stretching.
That’s 20 times more than what most metals can achieve under the same conditions. In some versions of the alloy, temperature changes of up to 22 degrees could be possible.
Most importantly, this heat-pumping method operates with around 90% of the maximum efficiency allowed by physics—the so-called Carnot limit. That makes it more efficient than many current heat pump systems that use gas compression and liquid refrigerants.
This approach doesn’t rely on chemical reactions or phase transitions like many other solid-state heat pumps.
Instead, it uses just mechanical stress—stretching and relaxing the alloy—to generate heating or cooling. That means fewer moving parts, no harmful chemicals, and potentially longer-lasting systems.
Professor Sun says the breakthrough challenges a long-standing belief that the thermoelastic effect is too weak to be practical. Dr. Li adds that the team is now building prototypes of this new type of heat pump for industrial use.
This discovery offers a powerful new tool for reducing our dependence on fossil fuels and cutting greenhouse gas emissions—one elastic stretch at a time.
