Thermodynamic modeling, material selection, and new dimensioning of a multilayer regenerator for a magnetic refrigeration system

The present work aimed to model magnetic entropy and deduce the magnetocaloric effect of materials for different temperature ranges. This modeling was based on thermodynamic and statistical approaches. Five expressions of magnetic entropy for temperatures far below, below, equal to, above, and far above the Curie temperature (T-c) were determined. Comparison with experimental values shows that three models for temperatures far below, above, and far above T-c are valid. For temperatures below T-c, we verified that a semi-empirical equation was the most appropriate. And for temperatures such as T approximately equal to T-c, a theoretical model-the Oesterreicher and Parker equation-is the most appropriate, provided that the T-c of the material is close to room temperature and the magnetic field is relatively low. The exploitation of these models and their substitutions in other theoretical equations allowed us to determine the maximum magnetocaloric effect and the T-c of Gd & alpha;R(1-& alpha;) alloys as a function of gadolinium & alpha; concentration. Based on these parameter models, which are the most pertinent for a magnetic regenerator, we developed a new method for choosing the right material to use in a magnetic refrigeration system and presented its flowchart. Finally, an original method for sizing a multilayer magnetic refrigeration system, which takes into account thermal, fluidic, and calorimetric properties and thermodynamic cycles according to a given specification, is detailed, and its steps are presented in a flowchart.

Automated summary

This study aimed to model magnetic entropy and determine the magnetocaloric effect of materials across different temperature ranges using thermodynamic and statistical approaches. Several models were developed and validated, allowing for the determination of maximum magnetocaloric effect and Curie temperature, and providing a new method for selecting materials in magnetic refrigeration systems.