Performance optimization of irreversible ferromagnetic Stirling heat pumps

An irreversible Stirling heat pump cycle using ferromagnetic materials as a cyclic working substance is established. The influences of finite-rate heat transfer, heat leak, regeneration time, regenerative loss and the internal irreversibility on the cyclic performance of magnetic heat pumps are taken into account. On the basis of the thermodynamic properties of ferromagnetic materials, the performance characteristic of the ferromagnetic Stirling heat pump cycle is investigated. Also, by applying the optimization technology, the relation between the optimal heating load and the coefficient of performance (COP) is derived. Furthermore, the maximum heating load and the corresponding COP as well as the maximum COP and the corresponding heating load are determined and discussed in detail. The results obtained in the present paper may provide some new information for the optimal design and the development of real magnetic heat pumps.