20.500.12556/RUL-142646 From the elastocaloric effect towards an efficient thermodynamic cycle In recent years, the elastocaloric cooling technology has been considered as one of the most promising alternatives to the vapor compression technology. Given that the elastocaloric technology is only in the early stage of development, a uniform method for evaluating the elastocaloric effect has not yet been established and the thermodynamics of different elastocaloric cooling cycles have not yet been studied in detail. Therefore, the main goal of this work is to investigate these two important areas. Here, multiple thermodynamic cycles were studied, focusing on the parameters of the holding period of the cycle, which is essential for heat transfer between the elastocaloric material and the heat sink/source. The cycles were applied to commercially available superelastic thin-walled NiTi tubes under compressive loading and a thin NiTi wire under tensile loading. Isostress cycles with constant stress throughout the holding period, isostrain cycles with constant strain throughout the holding period and no-hold cycles (without a holding period) were studied across multiple stress/strain range. Based on the experimental results, a previously developed phenomenological model was applied to better understand and further evaluate the different cycles. The results revealed that the applied thermodynamic cycle significantly affects the thermomechanical response and thus the cooling/heating efficiency of the elastocaloric material. We show that by using the isostress cycles and partial transformation, a Carnot-like thermodynamic cycle with improved heating/cooling efficiency can be generated. By applying the isostress cycles, an adiabatic temperature change of 30.2 K was measured, which is among the largest directly measured reproducible adiabatic temperature changes reported for any caloric material to date. Ultimately, this study intends to serve as a basis for establishing a uniform method for evaluating the elastocaloric effect in different materials that would allow for reliable and accurate one-to-one comparison of the reported results in the rapidly growing field of elastocalorics. elastocaloric effect shape memory alloys thermodynamic cycle Carnot Brayton efficiency phenomenological modeling elastokalorični učinek zlitine z oblikovnim spominom termodinamični cikel Carnot Brayton učinkovitost true false true Angleški jezik Slovenski jezik Članek v reviji 2022-11-17 14:45:14 2022-11-17 14:45:20 2024-02-02 03:56:06 0000-00-00 00:00:00 2022 0 0 22 str. no. 4, art. 044009 Vol. 4 2022 0000-00-00 Zaloznikova Objavljeno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 539.3 2515-7655 10.1088/2515-7655/ac92a5 122613251 Kabirifar_2022_J._Phys._Energy_4_044009.pdf Kabirifar_2022_J._Phys._Energy_4_044009.pdf 1 57BA373C509663861F0EEF5725428E9A 0cd1808540523f3229a1604bb4c25bc93488e4d007376f4670afd4313678142b 443ca1dc-c0d6-11ee-9ffb-0050569b8976 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=180453 https://iopscience.iop.org/article/10.1088/2515-7655/ac92a5 1 f6f0553e-667d-11ed-9c94-00155dcfd717 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=164091 Fakulteta za strojništvo 0 0 0