Modelling an active magnetic refrigeration system: A comparison with different models of incompressible flow through a packed bed

Active Magnetic Regenerative refrigeration system (AMR) is an environmentally attractive refrigeration alternative to vapour compression plants. A magnetic refrigerator is composed of a regenerator that is a solid packed bed made of a magnetic material and a secondary heat transfer fluid flowing in the porous matrix. The secondary fluid can be a liquid (water or water anti-freezing mixture). Modelling is a particularly cost-effective method for studying, designing and optimizing a magnetic refrigeration system. In this paper a comparison between three different models to simulate the thermo-fluidodynamic behaviour of an AMR cycle is carried out. Each model simulates both the magnetic material and the secondary fluid of an AMR operating in conformity with a Brayton regenerative cycle. In the reported models GdxDy1−x alloys are the constituent materials for the regenerator over the temperature range 260–280 K. The heat transfer medium is a water-glycol mixture (50% by weight).With these models, the refrigeration capacity, the power consumption and consequently the coefficient of performance of the cycle can be predicted.