Thermomagnetic motors (also known as Curie wheels,[1] Curie-motors[2][3] and pyromagnetic motors[4]) convert heat into kinetic energy using the thermomagnetic effect,[5] i.e., the influence of temperature on the magnetic material magnetization.
[6] This technology dates back to 19th century, when a number of scientists submitted patents on the so-called "pyro-magnetic generators".
[7] These systems operate in a magnetic Brayton cycle, in a reverse way of the magnetocaloric refrigerators.
[8] Experiments have produced only extremely inefficient working prototypes,[9][10][11] however, thermodynamic analysis indicate that thermomagnetic motors present high efficiency related to Carnot efficiency for small temperature differences around the magnetic material Curie temperature.
[8][5][12] The thermomagnetic motor principle has been studied as a possible actuator in smart materials,[13] being successful in the generation of electric energy from ultra-low temperature gradients.