Origin and avoidance of double peaks in the induced voltage of a thermomagnetic generator for harvesting low-grade waste heat

Thermomagnetic harvesting is an emerging approach used to convert low-grade waste heat to electricity, which recently obtained a boost due to the development of both more efficient functional materials and innovative device concepts. Here, we examine a thermomagnetic generator which utilizes gadolinium as the thermomagnetic material and report on the double peaks of the induced voltage. Using a combination of experiments and theory we show that these double peaks originate from the interaction between an asymmetric magnetization curve and a pretzel-like magnetic field topology. Double peaks are detrimental for the output power and can be avoided by matching the magnetization change by adjusting the cold and hot fluid flow.

Automated summary

Thermomagnetic harvesting converts low-grade waste heat to electricity using thermomagnetic materials. This study discovers the double peaks in the induced voltage, which negatively affect the output power. The avoidance of double peaks can be achieved by adjusting the flow of the cold and hot fluids.