High Temperature Magnetocaloric Refrigeration

The magnetocaloric effect is a magneto-thermodynamic phenomenon in which a reversible change in temperature of magnetic materials occurs with a magnetization/demagnetization process. By cycling the material through these hot and cold states and exchanging heat through a fluid media, the system can generate an overall cooling effect. Research efforts in the last 10 years resulted in the discovery of materials with a giant magnetocaloric effect around room temperature and also proved that magnetic refrigeration technology based on materials that exhibit magnetocaloric effect offers great potential improvement in energy efficiency of up to 60% of a Carnot cycle. This work proposes the proof of feasibility (in Phase I) and development (in Phase II) of high temperature magnetocaloric materials and compact, low weight magnetic refrigerators that can provide hundreds of watts of cooling with efficiency greater than 50% of a Carnot cycle, and can operate in the temperature range of 200500C. The overall technical approach of the research effort in Phase I consists of (i) synthesis and study of crystalline and non-crystalline materials with substantial magnetocaloric effect above 200C, (ii) refrigerator system modeling based on specific parameters,  and (iii) conceptual refrigerator design that can operate in the temperature range of 200-500C. BENEFIT: Magnetic refrigeration at elevated temperatures (> 200C), is an attractive technology for cooling high power density rotating machines and electronic devices with both military and commercial applications. Development of such systems would offer the opportunity to replace the current hydraulic cooling loops with a more local, and more efficient cooling system, which would greatly increase device lifetime. Commercial systems would include oil drilling and data logging equipment and instrumentation where temperatures are in excess of 200C; very deep reserves are being pursued aggressively due to the elevated demand and high oil prices which will last for the foreseeable future.