Cleber S. Alves, Flavio C. Colman, Gabriel L. Foleiss, Wesley Szpak, Gabriel T. Flores Vieira e Antonio C. Bento
International Journal of Refrigeration – Volume: 37; Pages: 215–222; DOI: 10.1016/j.ijrefrig.2013.09.031
The increasing demand for energy has driven society to explore different sources of energy, seeking to achieve sustainability. In this sense, we designed a thermal machine whose energy source is solar, which was based on the working principle of the Curie thermomagnetic motor. Thus this paper describes the modeling and simulation of a Curie wheel. Two materials were analyzed for the rotor, 30% NiFe alloy and Gd. The heat transfer inherent to the conversion process of solar energy and natural convection were studied, utilizing a one-dimensional finite difference model linked with the rotor magnetization in the magnetic circuit. We verified that for both materials the best performance was achieved with a convection coefficient of 10 W m−2 K−1. Furthermore, Gd offers about one order of magnitude greater efficiency when compared to the 30% NiFe alloy, but unfortunately the actual value is still too small to be commercially implementable. Nevertheless, this result indicates that better magnetic materials with Curie temperatures slightly above ambient are the key to achieving higher efficiencies, and, accordingly, magnetocaloric materials research has much to add.