The primary objective of this study is to discuss the optimum operating conditions of magnetocaloric heat pumps according to the fundamental heat transfer characteristics of an active magnetic regenerator (AMR) bed. The AMR cycle has four sequential processes: magnetization, heat exchange fluid flow, demagnetization, and heat exchange fluid blow. The fundamental heat transfer characteristics of each process of the AMR cycle is investigated minutely. Moreover, the cooling power and the overall system performance are evaluated when the system is running continuously.
In addition to the aforementioned investigation, we have developed a prototype rotational magnetocaloric heat pump having a compact component arrangement and an uncomplicated control system. A performance evaluation has been conducted to obtain the optimum conditions for practical operation. The operation parameters such as the heat transfer fluid flow rate, rotational frequency, and initial temperature of the heat transfer fluid are examined, and the variations of the maximum temperature span between the inlet and outlet for the heat transfer fluid are discussed. As a result, the values of the optimum rotational frequency and flow rate are obtained to obtain the maximum temperature span between the inlet and outlet of the present magnetocaloric heat pump.