Development of the tandem reciprocating magnetic regenerative refrigerator and numerical simulation for the dead volume effect

• Numerical modeling is used to analyze the dead volume effect.
• Numerical results indicate that the dead volume effect degrades the performance.
• The design and the performance of a room-temperature AMR are explained.
• The compact heat exchangers are employed to reduce dead volume in the AMR system.

In this paper, the development of the tandem reciprocating room-temperature active magnetic regenerative refrigerator and the numerical simulation for the effect of the dead volume are presented. The dead volume effect is analyzed by establishing a one-dimensional time-dependent model for the active magnetic regenerator (AMR). The cooling power at the mass flow rate of 5 g s−1 water and a temperature span of 20 K is reduced from 4 W to 2 W when the length of the dead volume (DDV = 12 mm) is increased from 15 mm to 30 mm. The numerical results indicate that the minimization of dead volume facilitates the improvement of the AMR performance. In particular, the components and the parameters of AMR system are demonstrated. The printed circuit heat exchangers (PCHEs) are employed as the warm end heat exchangers in order to minimize the dead volume of the system. The experimental apparatus includes two active magnetic regenerators containing 186 g of Gd spheres. The maximum no-load temperature span of 26.8 K and a maximum cooling power of 33 W at a zero temperature span were obtained with the frequency of 0.5 Hz under the maximum field of 1.4 T.