An efficiency analysis of a novel thermal energy harvesting device

論文發表人：許晉睿 (加州大學洛杉磯分校機械與航太工程系博士班)

 

http://spie.org/smart-structures-nde.xml

 

我們針對一種獨特的熱磁集能元件進行基礎研究及效能分析。此元件係利用軟磁材料之熱磁能耦合效應進行集能，過程中此材料於鄰近居禮溫度範圍內進行熱循環，進而使得材料之磁透率在相同頻率下進行循環，最終使得材料與一永久磁鐵間產生週期性的磁力吸引。我們設計釓(一種於室溫範圍下發生二階相變之材料)之單一磁區奈米結構尺寸，並將其製造成奈米結構陣列來提高元件之集能轉換效率，而奈米結構之特性則以超導量子干涉儀及磁力顯微鏡進行量測。此分析結果可用來建立解釋巨觀(有磁壁)結構與微觀(無磁壁)結構間能量差異之理論模型。

 

We report on fundamental study and efficiency analysis of a unique thermomagnetic energy harvesting device. This system relies on the coupling effect between magnetic and thermal energy within a soft ferromagnetic working body to harvest energy. While in operation, the working body of this device is thermally cycled about its Curie point, such that its magnetic susceptibility is also cycled at the same frequency. The resulting phenomenon is a periodic magnetic force of attraction between the working body and a permanent magnet. Based on the geometric design of single domain nanostructure, we fabricate the Gadolinium (Gd) working body, which undergoing a second order phase transformation for energy harvesting in the room temperature range, into a nanostructure array to increase the conversion efficiency. Characterization of the nanostructures is performed using both a SQUID and a Magnetic Force Microscope (MFM). These data can be used to develop analytical models to explain the energy differences between macroscopic structures (with domain walls) and nanoscale structures (without domain walls).