Power generation by a thermomagnetic engine by hybrid operation of an electromagnetic generator and a triboelectric nanogenerator

This paper reports a thermomagnetic generator based on the magneto-caloric effect of Gadolinium to scavenge low-grade thermal energy and its eventual conversion into electrical energy. Gadolinium is one of the distinct materials whose Curie temperature is nearly room temperature. For this reason, a Gadolinium-based thermomagnetic engine offers enormous possibilities to harness available waste heat from the industries. In this work, the performance of an electromagnetic generator (EMG) coupled with a triboelectric nanogenerator (TENG) was experimentally investigated as it is driven by a thermomagnetic engine exploiting low temperature waste heat. At the temperature difference of 46.5°C between the hot and cold water jets, the thermomagnetic engine produced an average rotational speed of 263 ± 1.5% rpm and a mechanical output power of 76.38 ± 0.5% mW. At the aforementioned rotational speed, the hybrid generator delivered a rectified peak voltage of 15.34 V on an open-circuit, a short-circuit current of 20.1 mA, and the largest power output, 12.1 mW, at a 120 Ω load. It was demonstrated that the proposed energy harvester could light dozens of light-emitting diodes or power a digital thermometer. It is feasible that the proposed thermomagnetic generator can be utilized as an effective power source for various applications.