Multicaloric Coupling Strategies in Ferroic Materials: Sequential vs. Simultaneous Activation for Solid-State Heat Pumping

Solid-state heat pumps based on caloric effects are emerging as a promising alternative to conventional vapor. compression systems owing to their use of solid refrigerants with zero global warming potential. However, single-effect caloric technologies are intrinsically limited by the temperature-dependent nature of the caloric response, which typically exhibits a peak adiabatic temperature change within a narrow temperature range. In this context, multicaloric approaches offer a promising pathway to enhance thermal performance by combining multiple external fields. This work focuses on the comparison between simultaneous and sequential (cascade) multicaloric operation, with particular attention to the interaction between field application and the temperature-dependent caloric behavior of the material. A finite element model is developed to investigate a multicaloric solid-state heat pump operating in the air conditioning temperature range. A representative material is considered: Mn0.6Ni0.6Fe0.4Co0.4Si0.95Ga0.05, characterized by distinct magnetocaloric and barocaloric responses occurring at different temperature ranges. The analysis explores different field application strategies, including both simultaneous and sequential configurations. The preliminary results suggest that simultaneous multicaloric operation enables a more effective exploitation of the caloric response by aligning the field activation with temperature regions closer to the corresponding peaks. In this framework, cascade strategies appear to offer additional flexibility in tuning system performance under realistic operating conditions. The proposed approach provides a new perspective for the design of multicaloric heat pumps, highlighting the potential role of thermodynamic matching between field activation and material response. Ongoing work is focused on further quantifying these effects and identifying optimal operating conditions.