The purpose of the proposed research is to develop a magnetic refrigeration system that can operate in the range of ambient atmospheric temperatures and to determine the applicability of magnetic refrigeration to practical consumer refrigeration systems. The potential advantages of such a system are the prevention of environmental damage caused by harmful working fluids involved in existing systems and the reduction of energy consumption resulting from the significantly improved energy efficiency inherent in the utilization of the magneto-caloric effect. Magnetic refrigeration offers a significantly different thermodynamic approach than existing compression refrigeration systems since it does not depend upon a condensable working fluid. Successful application to automotive air conditioning would have an environmental benefit by reducing engine load and saving fuel while employing no environmentally damaging working fluids. The objective of this project is to investigate the system requirements for a magnetic refrigerator operating in the temperature range 0 to 40 degrees C and to produce an instrumented laboratory research test platform for a magnetic refrigerator. The magnetic field will be produced by an adjustable-field "magic ring" assembly made from commercial high-energy-product permanent magnets. The refrigerant will be a "superferromagnetic" nanocomposite, which has the potential of being designed to match the thermodynamic cycle being employed and which has no hysteretic losses. The heat transfer agent will be an environmentally safe fluid, such as an inert gas. A bellows is expected to provide the appropriate movement of the heat transfer fluid over the nanocomposite embedded in a porous material. In the course of this project, the choices of materials, heat exchange arrangements and fluids will be explored for the various applications of magnetic refrigeration.
