Parametric study of an active magnetic refrigeration (AMR) system on exergy efficiency and temperature span with Gadolinium

Magnetic cooling at room temperature is one of the world’s newest technologies that can be considered as an alternative for vapor compression refrigeration systems. Magnetic cooling follows the magnetocaloric effect (MCE) phenomenon, which is justified by the change in entropy with respect to magnetic flux changes. In this research, a computational fluid dynamic (CFD) simulation of the magnetic refrigeration system is conducted in COMSOL Multiphysics 5.5 software with the geometry of sandwiched gadolinium layers and water channels. The magnetic cooling system can be analyzed in two aspects i.e. constant cooling load and zero cooling load. For this purpose, two performance indicators including the exergy efficiency and the minimum achievable temperature, can be defined for constant and zero cooling loads, respectively. Sensitivity analysis is used as a tool to understand the importance of operating parameters such as frequency, passing fluid’s velocity, cold heat exchanger temperature, magnetization, or demagnetization time. The parametric study of the zero cooling load simulation reveals that high operating frequency (f=0.5Hz\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$f = 0.5\;{\mathrm{Hz}}$$\end{document}) besides low fluid velocity (V=0.05ms-1\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$V = 0.05 \;{\mathrm{m}}\;{\mathrm{s}}^{ - 1}$$\end{document}) results in a 51 °C temperature span. In addition, the exergy efficiency can reach the maximum value of 30 percent with respect to various velocity and frequency variables for laminated geometry.