Simulation of magnetic refrigeration systems with thermal diodes and axial conductive heat transfer.

In conventional magnetic refrigeration cycles with heat transfer fluid, the achievable cycle frequency, and therefore, specific cooling capacity is limited. Furthermore, ineffective use of magnet in low frequency devices makes them expensive. In this work, as an alternative technique, utilizing conductive heat transfer controlled by two different types of thermal diodes, gas-liquid and contact-break diodes, is investigated. For that purpose two software models are made to simulate the performance of a magnetic refrigerator with each of the diodes. The results of simulations are presented and comparison is made between these results and
the results of older studies which used ideal properties. According to the results, due to the limited thermal conductivity of the magnetocaloric materials, the increase in the capacity becomes small with too high frequencies. Among the thermal diodes and materials studied, the liquid metal Galinstan as the conducting fluid in an active diode gave the best results.