(350c) Simulation of Self-Heat Recuperation Using Magnetocaloric Effect

The reduction of carbon dioxide (CO₂) and the fossil fuel consumption has been one of our major concerns over past few decades. In chemical processes that involve heating, heat is mainly provided by fossil fuel combustion associated with great exergy loss. Recently, self-heat recuperation technology based on the exergy recuperative heat utilization principle has been developed, which can recirculate all heat of the process stream by providing work instead of heat generated by fuel combustion. By compressing gas at its highest temperature in the process for heat elevation, the energy consumption for heating can be reduced drastically compared to conventional heat-recovery technology.

A novel magnetic heat circulator for thermal process based on self-heat recuperation technology is proposed. In magnetic heat circulator, process heat is recirculated by magnetocaloric effect of ferromagnetic materials through cyclic magnetization and demagnetization. The ferromagnetic material is adiabatically magnetized/demagnetized at the highest/lowest temperature of the process to create a temperature difference required for heat exchange. All heat is recirculated inside the system without heat addition. The theoretical energy consumption of magnetic heat circulator was calculated in terms of the temperature-entropy diagram. The simulation result shows large potential for energy saving in thermal processes.

 In this research, because the magnetic heat circulator poses a complex problem of heat transfer, magnetic field, and physical properties of ferromagnetic material, a numerical 1D model of magnetic heat circulator has been constructed. The magnetocaloric effect (MCE), varying magnetic field, thermal conduction and heat transfer has been implemented in the governing equation.