Study of Magnetocaloric Cooling for Thermal Management

Near room temperature magnetocaloric materials have attracted attention as a novel solid state thermal management technology as it has several advantages over conventional vapor compression systems. This effort is an investigation of the basic science of magnetocaloric materials wherein Fe, Co-based and Heusler alloys were used as replacements for gadolinium alloys. Findings from differential scanning calorimetry DSC and vibrating sample magnetometry VSM of Co substituted Ni-Mn-Sn Heusler melt spun ribbons show that the martensitic transition temperatures of Ni-Co-Mn-Sn decreased with increasing Co content. Co substitution resulted in a decrease in martensitic transition temperature by 25K per at. Co. The magnetocaloric effect MCE in Fe80-x B12Cr8REx RELa, Ce or Gd, x 1-15 alloys was also investigated. RE additions could be used to tune the Curie temperature TC TC could be adjusted near room temperature with relatively constant peak magnetic entropy change for Fe-B-Cr-Ce amorphous alloys. Construction of a magnetic cooling system was done which possessed an active magnetic double regenerator cycle AM2RC and control subsystems. An active transient cooling system was also developed.