Fluid choice and test standardization for magnetic regenerators operating at near room temperature

• Numerical study on a rotary magnetic refrigerator in room temperature.
• A two-dimensional porous medium numerical model has been established.
• The impact of different heat transfer fluid on magnetic refrigerators has been investigated.
• Three feasible types of test standards have been proposed.

Numerical simulations are performed to investigate the performance of an active magnetic regenerator (AMR) operating near room temperature. A two-dimensional porous model is established to analyze the impact different heat transfer fluids (HTFs) have on the performance of the AMR. The internal temperature distribution and cooling capacity of the system are analyzed and the influence of the HTF discussed. The simulation results show that when mercury is substituted in place of water as the HTF, the cooling capacity can be enhanced by nearly 600%. A fluid with high conductivity, high density, and low specific heat is most suitable for use as the HTF. Furthermore, as the environmental conditions have a great impact upon the performance of the AMR, three feasible methods of standardization testing are proposed. These involve: the evaluation index under fixed test environment conditions, a maximum exergy method, and a maximum specific exergy method around the Curie temperature.