Optimization of Multi-layer Active Magnetic Regenerator towards Compact and Efficient Refrigeration

Magnetic refrigerators can theoretically be more efficient than current vapor compression systems and use no vapor refrigerants with global warming potential. The core component, the active magnetic regenerator (AMR) operates based on the magnetocaloric effect of magnetic materials and the heat regeneration processes of periodic fluid blows. Magnetocaloric materials with a first order phase transition (FOPT) are suitable to realize a higher cooling capacity than commonly used gadolinium, but layering such materials is necessary, due to a large isothermal entropy change (Δ푆_푚) in a narrow region around their Curie temperature. Simulations are implemented to investigate how to layer the FOPT materials for obtaining higher cooling capacity. Moreover, based on entropy generation minimization, optimization of the regenerator geometry and related operating parameters is presented for improving the AMR efficiency. In addition, simulations are carried out to investigate the potential of applying nanofluid in future magnetic refrigerators.