Solid-State Refrigeration Research

During this research project, I engineered a solid-state refrigeration prototype that leveraged the magnetocaloric effect (MCE) in Ni-Mn-Ga Heusler alloys to achieve measurable cooling without harmful refrigerants. I began by synthesizing a full Heusler alloy through vacuum arc melting, using stoichiometric proportions of high-purity nickel, manganese, and gallium (Ni₅₀Mn₂₅Ga₂₅). The alloy was melted and homogenized in a tungsten-electrode vacuum chamber at up to 3000°C, ensuring purity and uniform composition. Once cooled and cast, the alloy was mounted between two N45-grade neodymium magnets (≈0.42 T field strength) affixed to a linear actuator assembly that modulated field exposure, emulating a magnetization–demagnetization cycle. To precisely monitor temperature fluctuations, I integrated K-type thermocouples with a VARTECH industrial-grade thermometer (accuracy ±0.1°C), enabling real-time data acquisition during repeated trials. Through iterative calibration of field alignment, actuator motion, and alloy positioning, I achieved a consistent 0.8 K temperature shift with a standard deviation of 0.05 K, validating the reproducibility of the MCE. The prototype’s design emphasized thermal isolation, field uniformity, and material integrity, while its modular configuration allowed systematic tuning of parameters like stroke length and magnetic field strength. Although not incorporating an active heat-exchange loop, the prototype served as a proof-of-concept for renewable-powered, eco-friendly solid-state refrigeration, demonstrating how Heusler alloys could replace hydrofluorocarbon-based systems in sustainable cooling applications.