Continuous rotating bending NiTi sheets for elastocaloric cooling: Model and experiments

Cheng, Siyuan; Xiao, Yinan; Li, Xueshi; Lin, Hongyang; Hua, Peng; Sheng, Liyuan

doi:10.1016/j.ijrefrig.2022.11.020

Cited by 13 publications

(3 citation statements)

References 44 publications

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“…Elastocaloric cooling/heat pumping does not contribute to greenhouse substance emissions in its operation and demonstrates considerable potential for energy conservation; thereby, it has attracted significant attention from researchers recently. [1][2][3][4][5][6] Recent endeavors have yielded diverse prototypes for elastocaloric cooling and heat pumping, [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26] and a lot of materials have been scrutinized for their efficacy as solid-state elastocaloric refrigerants. Among the developed elastocaloric coolers and heat pumps, the ones based on the NiTi shape memory alloy (SMA) tubular structures under compression have emerged as highly promising candidates due to their commendable long-term durability.…”

Section: Introductionmentioning

confidence: 99%

Characterization of the temperature-dependent superelastic and elastocaloric effects of a NiTi tube under compression at 293–330 K

Cheng,

Yan,

et al. 2024

AIP Advances

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Comprehensive characterizations of the superelastic and elastocaloric effects of NiTi and NiTi-based shape memory alloys (SMA) in the operation temperature region are highly desirable for using them in elastocaloric coolers with a large temperature lift. In this article, we report the superelastic and elastocaloric effects of a commercially available superelastic polycrystalline NiTi SMA tube with an outer diameter of 5 mm and a wall thickness of 1 mm between 293 and 330 K. The NiTi tube sample was subjected to a training of 250 cycles to stabilize its superelastic and elastocaloric effects. We observed that temperature dependencies existed for both superelastic and elastocaloric effects of the NiTi tube, and stress–strain curves differed much between isothermal and adiabatic loading conditions. The largest temperature rise and temperature drop measured at 293 K under an applied strain of 3.66% and a strain rate of 0.1 s−1 during loading and unloading were 21 and 11 K, respectively. The loading conditions (loading function and holding time) also impacted the superelastic effect of the NiTi tube. We identified two major reasons for the irreversibility of the adiabatic temperature change: the hysteresis heat dissipation and the temporary residual strain after unloading, and they affected the cooling performance of the elastocaloric cooler in different ways. We investigated the dependencies of the superelastic and elastocaloric effects on the maximum applied strain and the temperature distribution on the NiTi tube during loading and unloading. The results are beneficial to the modeling of elastocaloric coolers with large temperature lifts.

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Section: Introductionmentioning

confidence: 99%

Characterization of the temperature-dependent superelastic and elastocaloric effects of a NiTi tube under compression at 293–330 K

Cheng,

Yan,

et al. 2024

AIP Advances

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“…Elastocaloric cooling and heat pumping is an alternative cooling technology to current vapor-compression systems that has the potential to be efficient and environmentally friendly [1][2][3][4]. Researchers and engineers among the world have been actively developing tensile [5][6][7][8][9][10][11][12][13][14][15][16], compressive [17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33], bending [34][35][36], and twisting [37] elastocaloric cooling and heat pumping prototypes recently, and a high fatigue life have been demonstrated for compressive elastocaloric prototypes utilizing NiTi shape memory alloys as solid-state refrigerants [28,30,31,33,[38][39][40][41]. Development of an efficient operation strategy, including achieving a large temperature span, specific cooling power, and coefficient of performance for compressive el...…”

Section: Introductionmentioning

confidence: 99%

A single long NiTi tube compressive elastocaloric regenerator: experimental results

Cheng

2023

Phys. Scr.

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Elastocaloric cooling is an environmentally friendly alternative to the current vapor-compression refrigeration technology, and the development of an efficient operation strategy is significant for its commercialization. In this article, the cooling performance including the temperature span, specific cooling power, and coefficient of performance for a novel single long NiTi tube compressive elastocaloric regenerator (tube outer diameter 5 mm, wall thickness 1 mm, and initial length 305 mm) was comprehensively characterized under different operation parameters (operation cycle time, loading/unloading time, heat transfer fluid timing, flow time, and utilization). The single long NiTi tube compressive elastocaloric regenerator achieved maximum temperature span, specific cooling power, and coefficient of performance of 5.7 K, 135 W∙kg−1, and 4.7, respectively under an applied strain of 2.5%. It was found that the most important factors for obtaining a good cooling performance of the single long NiTi tube compressive elastocaloric regenerator were a short operation cycle time, a proper heat transfer fluid timing, and a proper heat transfer fluid utilization. The dependences of the temperature span on the cycle time and heat transfer fluid utilization factor were in agreement with the existing experimental data for a parallel plate tensile elastocaloric regenerator. A thinner tube wall thickness and advanced cross-section geometry for the regenerator may further improve the cooling performance of the compressive elastocaloric regenerator.

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“…Over the past decade, there have been substantial advancement in the development of SMA-based elastocaloric cooling prototypes. These prototypes have utilized various driving modes and refrigerant structures, including compression-based thin-walled tubes 24 – 32 , topology-designed tubular structures 33 – 35 , tension-based wires 23 , 36 – 39 and sheets 40 – 44 , bending-based wires 45 – 47 and sheets 48 , 49 , and torsion-based wires 50 (Supplementary Note S 10 and Table S6 ). Commercial air conditioning systems require compact size, high safety, and high energy efficiency.…”

Section: Introductionmentioning

confidence: 99%

Continuous and efficient elastocaloric air cooling by coil-bending

Li,

Hua,

Sun

2023

Nat Commun

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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−1 at a low specific driving force of 26 N g−1. 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 cm2 g−1) and the constant cold zone of NiTi wires. Our coil-bending system exhibits a competitive performance among caloric air coolers.

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Continuous rotating bending NiTi sheets for elastocaloric cooling: Model and experiments

Cited by 13 publications

References 44 publications

Characterization of the temperature-dependent superelastic and elastocaloric effects of a NiTi tube under compression at 293–330 K

Characterization of the temperature-dependent superelastic and elastocaloric effects of a NiTi tube under compression at 293–330 K

A single long NiTi tube compressive elastocaloric regenerator: experimental results

Continuous and efficient elastocaloric air cooling by coil-bending

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