Performance evaluation of a magnetic refrigeration system

This work presents an evaluation of the thermodynamic performance of a magnetic refrigerator prototype developed at the Federal University of Santa Catarina. Experiments were carried out to determine the power consumption of the system as a whole, and of its main components (sub-systems) individually. The transmission powers associated with the system components were computed from the torques required to drive each sub-system at frequencies between 0.2 and 1.6 Hz. Thermodynamic efficiency parameters, namely the coefficient of performance and the second-law efficiency were computed. Maximum values of the coefficient of performance and second-law efficiency of 2.5 and 3.7%, respectively, were obtained at system temperature spans of 4 and 6 K. The maximum zero-span cooling capacity was approximately 150 W. The major limitations to enhancing the system performance were the losses in the flow management sub-system (pumping power and valve losses). Improving the operation of the components in this system would lower their power requirements for a given fluid flow rate, which would increase the overall efficiency of the system.