Proof-of-Concept Static Thermomagnetic Generator Experimental Device

Abstract

A thermomagnetic power conversion device is constructed using water flows with very low caloric energy. The device has two active regenerators built from (Mn,Fe)2(P,As) materials suspended in a magnetic circuit as proposed by Brillouin and Iskenderian. The final magnetic circuit design was further optimized with finite-element simulations. The permanent magnet acting as field source was 1.4 kg of NdFeB alloy. The active part of the generator consists of 48 disks of (Mn,Fe)2(P,As) material with four different Curie temperatures of 300 K, 304 K, 307 K, and 310 K (27 °C, 31 °C, 34 °C, and 37 °C) measured in 1 T. Into each plate, microchannels are laser cut. By stacking these plates in series, two regenerators with a gradient temperature span are built. Both generators have an exact weight of 26.9 g. The material was cycled at different speeds to find the maximum power output at the optimum frequency. Critical to a better design is a more tapered design and different materials. The tapered design ensures a greater external field and a larger external field change across the material. The materials for devices that use water as heat-transfer fluid in combination with this type of regenerator design should have a lower latent heat while maintaining their magnetic properties. This will increase the cycling speed and improve the power output of this type of device.