This paper presents a model of irreversible magnetic Stirling (MST) cryocooler using paramagnetic material as the working substance. The relation between optimal cooling load and the coefficient of performance (COP), the maximum cooling load and the corresponding COP, as well as the maximum COP and the corresponding cooling load of an irreversible MST cryocooler are derived.
Wu, F., Chen, L., Wu, C., Sun, F., & Zhu, Y. (2001). Optimization of irreversible magnetic Stirling cryocoolers. International Journal of Engineering Science, 39(4), 361–368. https://doi.org/10.1016/S0020-7225(00)00037-9