Continuous and efficient elastocaloric air cooling by coil-bending.

Li, Xueshi; Hua, Peng; Sun, Qingping · Nat Commun · 2023

basic_science · Level V

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Abstract

Elastocaloric cooling has emerged as an eco-friendly technology capable of eliminating greenhouse-gas refrigerants. However, its development is limited by the large driving force and low efficiency in uniaxial loading modes. Here, we present a low-force and energy-efficient elastocaloric air cooling approach based on coil-bending of NiTi ribbons/wires. Our air cooler achieves continuous cold outlet air with a temperature drop of 10.6 K and a specific cooling power of 2.5 W g<sup>-1</sup> at a low specific driving force of 26 N g<sup>-1</sup>. Notably, the cooler shows a system coefficient of performance of 3.7 (ratio of cooling power to rotational mechanical power). These values are realized by the large specific heat transfer area (12.6 cm<sup>2</sup> g<sup>-1</sup>) and the constant cold zone of NiTi wires. Our coil-bending system exhibits a competitive performance among caloric air coolers.