HKUST develops sub-zero freezer using elastocaloric technology for zero-emission cooling.
The sub-zero elastocaloric freezer by HKUST offers zero-emission cooling at -12℃.
Photo Credit: Nature
The first sub-zero elastocaloric freezer in the world that can achieve a temperature below minus 12 degrees Celsius, leading to a greener, more sustainable cooling solution, has been developed by researchers from the Hong Kong University of Science and Technology (HKUST). The system operates by effecting cooling with memory shape alloys and without using greenhouse gases and offers a sustainable solution to the freezing requirements of markets worldwide. In outdoor tests, it cooled an insulated chamber to a temperature of minus 4℃ within one hour and froze water in two hours, showing practical effectiveness. Experts say the innovation has the potential to significantly reduce emissions from sub-zero freezing while also enabling more energy-efficient refrigeration for facilities in different industries.
According to a Nature report, the system uses a high-nickel nickel-titanium alloy and a calcium chloride heat transfer fluid. Its cascaded tubular design and Brayton cycle operation provide a temperature lift of 36℃ from room temperature. The freezer exhibited a cooling power of 1.43 W g⁻¹ and a coefficient of performance of up to 3.4, indicating the high energy efficiency and running with no emissions.
The technology is aimed at conventional freezers containing high-GWP refrigerants, which release around 330 million tonnes of CO₂ each year in sub-zero applications. The technology is ready for industrial expansion and its optimisation, stated Prof. Sun Qingping, and Prof. Lu Mengqian highlighted that it has a global remark as a green and carbon-neutral cooling solution.
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