Elastocaloric cooling exhibits extraordinary potential as an alternative cooling technology due to itsenvironmentally friendly nature. Previous studies have achieved highly efficient elastocaloric cooling byapplying compression or tension to Nickel Titanium alloy (Ni-Ti) and adopting active regeneration withwater as a heat transfer fluid (HTF) (Qian et al., 2016; Tušek et al., 2016). An active elastocaloricregenerator was developed in which cyclic tension loading was applied to bundles of Ni-Ti thin platesthat facilitated convective heat transfer (Tušek et al., 2016). However, insufficient structural fatiguelimits its application for long-term operation (Tušek et al., 2018). To improve the fatigue life,compression is identified as a promising alternative, and yet the integration of thermally efficientstructures with compressive loading mode is challenging due to material and structural instability. Theupgrading of the heat transfer component and its adequate coupling with the elastocaloric materials arerequired to achieve high cooling performance of compressive loaded elastocaloric cycles.The performance of an elastocaloric system is normally presented by specific cooling power (SCP).Numerical modelling of the elastocaloric system serves as a powerful tool to predict the thermodynamicefficiency and evaluate the system design. The state-of-the-art numerical models are based on relativelysimple structures, for instance, single or a bundle of tubes (Qian et al., 2017; Tušek et al., 2015). Here wepresent a quasi-1D model for an active elastocaloric regenerator system with efficient heat transfercomponents, aiming to achieve higher SCP without compromising the fatigue life of the elastocaloricmaterials in compressive loading cycles.As illustrated in Figure 1, a Ni-Ti tube is supported by mechanical structures inside the tube to avoidbuckling. The latent heat of the Ni-Ti tube is transferred by the structures surrounding the tube, whichinclude cupper enclosure and fluid passages. The fatigue of the design is not affected since the wholeheat transfer enhancement structure remains stress-free. In our simulations, we examined severaldesigns of fluid passages, e.g., porous medium, mini-channels, or thin film fins. With the heat transferarea extended by these structures, we expect that heat transfer by convection can be largely enhanced.The model is applicable for investigating the performance of different heat transfer enhancementstructures at various operating conditions including frequency, properties of heat transfer fluid, andtemperature difference, etc., as shown in Figure 2. The results demonstrate that these novel structuresare effective designs for enhancing the heat transfer efficiency and improving SCP of refrigerators. Thenewly developed model may provide us a useful tool to optimize and develop compressive elastocaloricrefrigerators.
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