Experimental Study on Refrigeration Performance Optimisation of Reciprocating Room Temperature Magnetic Refrigerator

In this paper, the effects of operating conditions on the energy efficiency of a reciprocating room temperature magnetic refrigerator were experimentally investigated in order to optimise its refrigeration performance. An experimental setup of a magnetic refrigerator allowing the thermal characterisation of an active magnetic regenerator, with gadolinium particles (diameter 0.3 mm) used as a magnetocaloric material and water used as a working fluid, was developed. The effects of the magnet velocity (0.04-0.16 m.s −1 ), the water filling ratio (2.985.96) and the room temperature (14.5-18.1 ◦ C) on the cold end temperature of the active magnetic regenerator were determined and analysed. An optimal operating point of the magnetic refrigerator was found for a magnet velocity of 0.16 m.s −1 , a water filling ratio of 5.21 and a room temperature of 18.1 ◦ C, for which a characteristic time of 70 s, a maximum cold end temperature variation of 12.4 ◦ C, a cold power of 1450 W and a coefficient of performance of 6.7 were obtained. A synthesis on the suitable choice of the magnetic refrigerator operating conditions is given in order to optimise its refrigeration performance