Highly efficient grooved NiTi tube refrigerants for compressive elastocaloric cooling

Zhang，Jiongjiong1,2; Zhu，Yuxiang1; Yao，Shuhuai1; Sun，Qingping1,3

2023-06-25

10.1016/j.applthermaleng.2023.120439

Applied Thermal Engineering   Impact Factor & Quartile

1359-4311

Elastocaloric (eC) cooling without environmental issues has been a promising substitute for the conventional vapor-compression refrigeration. Commercial superelastic NiTi shape memory alloy tubes show large elastocaloric cooling capacity and ultrahigh fatigue life under cyclic compression but suffer from the limited specific heat transfer area (A) and insufficient cooling performance. Up to now, compressive NiTi tube eC refrigerant with A larger than 1 m Kg has not been available due to the easy buckling problem. In this work, the buckling-free vertically and spirally grooved NiTi tubes (VGT and SGT) with A of 1.04 m Kg and 1.25 m Kg respectively are developed as the compressive eC refrigerants. The VGT and SGT are fabricated by the slow-feeding wire electric discharge machining based on the bared NiTi tubes. Then a compressive eC refrigeration prototype (ERP) is built to experimentally characterize the specific cooling power (SCP) and system temperature span (ΔT) of the grooved tubes. Under the regenerative flow configuration, the VGT and SGT achieve large zero-ΔT SCP of 2.18 W g and 2.61 W g at the operation frequency (f) = 0.5 Hz. Besides, the VGT and SGT produce maximum no-cooling-load ΔT of 25.2 K and 27.7 K respectively at f = 0.417 Hz. The experimental SCP and ΔT exceed most of the reported eC regenerators and there are still rooms for enhancing the cooling results by improving the ERP in future. Overall, the developed VGT and SGT with large A records and excellent cooling performance show big potentials of heat transfer structure design in developing highly efficient eC devices.

Cyclic compression Elastocaloric cooling Heat transfer enhancement NiTi tube Structure design

English

Corresponding

ENGINEERING

2-s2.0-85151898553

Scopus

1.Department of Mechanical and Aerospace Engineering,The Hong Kong University of Science and Technology,Clear Water Bay,Hong Kong
2.Department of Materials Science and Engineering,Southern University of Science and Technology,Shenzhen,China
3.HKUST Shenzhen-Hong Kong Collaborative Innovation Research Institute,Shenzhen,Guangdong,China

Zhang，Jiongjiong,Zhu，Yuxiang,Yao，Shuhuai,et al. Highly efficient grooved NiTi tube refrigerants for compressive elastocaloric cooling[J]. Applied Thermal Engineering,2023,228.

Zhang，Jiongjiong,Zhu，Yuxiang,Yao，Shuhuai,&Sun，Qingping.(2023).Highly efficient grooved NiTi tube refrigerants for compressive elastocaloric cooling.Applied Thermal Engineering,228.

Zhang，Jiongjiong,et al."Highly efficient grooved NiTi tube refrigerants for compressive elastocaloric cooling".Applied Thermal Engineering 228(2023).