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 thermofluidodynamic 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. (C) 2011 Elsevier Ltd. All rights reserved.