Parametric analysis of fatigue-resistant elastocaloric regenerators

Tensile vs. compressive loading

Žiga Ahčin (Author), Jaka Tušek (Author)

Abstract

Elastocaloric cooling has recently shown high potential as an environmentally friendly alternative to vapor-compression technology. Here, we have studied and analyzed the geometric characteristics of two active elastocaloric regenerators (AeCRs) that were proved to have high application potential, i.e., a shell-and-tube AeCR loaded in compression and a parallel-plate AeCR loaded in tension, with the goal of maximizing their cooling performance. For this purpose, a previously developed and experimentally verified 1D numerical model was used. We focused only on the geometries and operating conditions that allow for durable, i.e., buckling-free operation in compression and fatigue-resistant operation in tension. The results show that although the applied strain of the parallel-plate AeCR loaded in tension needs to be limited (below 2%) to ensure fatigue-resistant operation, it outperforms (in terms of cooling power and COP at 15 K of temperature span) the shell-and-tube AeCR, which due to buckling issues suffers from a poorer heat-transfer geometry, but can withstand higher strains due to compressive loading. At the maximum strain of 2%, the optimum parallel-plate AeCR can generate a maximum cooling power of 1825 W (corresponding to 7075 W kg−1 of elastocaloric material) and a COP of 9.15 at a zero-temperature span. On the other hand, due to a higher applied strain (3%) the optimum shell-and-tube AeCR can generate a higher maximum temperature span at zero cooling power (up to 50 K) but has limited cooling performance at lower temperature spans. In addition, the layering of the shell-and-tube AeCR was investigated for the first time to improve its performance. This study shows the crucial impact of the heat-transfer geometry (heat-transfer area and hydraulic diameter), which needs to be further improved in compression-loaded AeCRs to improve their efficiencies (without compromising the buckling stability). The study also shows the importance of the applied strain, which needs to be at least 2% or more to achieve a high cooling performance of the AeCR. The obtained results should serve as guidelines for designing powerful and efficient AeCRs in the future.

Keywords

elastocaloric effect;caloric cooling;Ni-Ti;regenerators;parametric analysis;

Data

Language:	English
Year of publishing:	2023
Typology:	1.01 - Original Scientific Article
Organization:	UL FS - Faculty of Mechanical Engineering
UDC:	519.876.5:621.57
COBISS:	157626371
ISSN:	1359-4311
Views:	170
Downloads:	37
Average score:	0 (0 votes)
Metadata:

Other data

Secondary language:	Slovenian
Secondary keywords:	elastokalorični učinek;kalorično hlajenje;Ni-Ti;regeneratorji;parametrična analiza;
Type (COBISS):	Article
Pages:	str. 1-13
Issue:	ǂVol. ǂ231
Chronology:	Aug. 2023
DOI:	10.1016/j.applthermaleng.2023.120996
ID:	19469792