Design and Construction of a Solar Electric Plastic Extruder Machine Based on a Parabolic Trough Collector

Plastics can be recycled by extrusion using an extruder machine that melts and transforms the material into a new product. This paper proposes the design, construction and thermal characterization of a horizontal extruder machine integrated with a parabolic trough concentrator with a one-axis solar tracking system, in which hybrid heating is performed by means of an arrangement of electrical resistances and by the concentration of direct normal irradiance. The optical simulation and the design of the proposed extruder are presented; as well as its integration with the parabolic trough concentrator. Experimental tests were performed in a real environment and the temperatures reached in three cases of heating by electrical resistance, solar radiation, and hybrid (electrical resistance plus solar radiation) were compared. The objective is to reach a temperature of 200 degrees C in the barrel, for which an analysis of the experimental thermal performance of the proposed extruder is presented. The heating by electrical resistances took from 77 to 95 min to reach 200 degrees C, while the hybrid system only took 25 to 57 min, reducing the times between 25.97 and 73.68% and, consequently, reducing the consumption of resistor current. In hybrid mode, at one point in the barrel, temperatures higher than 260 degrees C were reached, providing the possibility of instantly turning off some electrical resistances to save energy.