Abstract
A magnetohydrodynamic (MHD) generator is a device that generates electrical energy through the interaction between a conductive fluid and a magnetic field. This method of direct energy conversion allows the use of a renewable energy source such as solar energy and represents an alternative to tackle the greenhouse effect. This paper presents the development of an MHD solar generator, which is constituted by a solar thermal system and an MHD cell. The solar thermal system consists of a set of tubes with copper fins, connected in parallel and placed inside of a 1 m2 panel. In which, an electrolytic mixture of H2O and NaCl at 20% vol. was introduced as a working fluid. In order to increase the kinetic energy of the fluid, the panel was exposed to solar radiation, where it reached temperatures above 373 K and pressures above 96 kPa. This solar thermal system operates in closed cycle conditions by including a check valve in its inlet–outlet junction; in this way, the fluid travels through the MHD generator. The MHD cell was composed of a block of polytetrafluoroethylene, two cylindrical stainless-steel electrodes, and four neodymium magnets. For simulation purposes, comsol multiphysics was used to reproduce the current density produced by the MHD solar generator. Pressure and temperature quantities obtained experimentally in the MHD cell were employed as boundary conditions. The experimental maximal current density obtained corresponds to 4.30 mA/m2, and the comparison between theoretical and experimental results shows that the model fits fairly well.
