The Carnot Type Magnetic Refrigeration Below 4.2 K: Computer Simulation

Abstract

Presently, several investigation groups^1–5 are focussing on the magnetic refrigerator, especially in the temperature range from 20 K to 1.8 K because of its high efficiency. In this temperature range, the Carnot type magnetic refrigeration cycle usually has been selected because of the simplicity of the mechanical structure and its motion. However, in this type of magnetic refrigerator, refrigeration power is frequently limited by the heat transfer coefficient between the heat source and the magnetic working substance. A typical example of the low refrigeration power caused by a low heat transfer coefficient can be seen in the Carnot type magnetic refrigerator, operating from 4.2 K to 1.8 K made by the Grenoble group.³ The refrigeration power of this machine is mainly restricted by the heat transfer coefficient in the isothermal magnetization process at 4.2 K.