DEVELOPMENT OF A CYLINDRICAL-PARABOLIC SOLAR CONCENTRATOR TO HEATING’S FLUIDS

Abstract

We design, calculated numerically and compare experimental data of temperature with values obtained from modeling of a cylindrical-parabolic solar concentrator for heating fluid, which consists of a stainless steel plate formed into a parabolic structure with the copper tube along the focus serving as absorber and a monitoring mechanism that always directs the concentrator to the sun so that solar rays focus perpendicularly to its aperture area "seen by the sun." Inside the tube is passed the fluid to be heated. In this study, we defined initially geometric parameters from a developed equation that relates them, so as to increase efficiency and concurrently in order to not compromise the joint's mobility at the monitoring of the sun's apparent movement. To model the system, differential equations were developed that take into account the physical parameters (absorptivity of the receiver tube, the mirror reflectivity, conductivity and thermal capacity of the materials involved, heat transfer by conduction and radiation) and geometric (concentration of the incident energy in focal region) of the hub. These equations were implemented in a computer program that calculates, based on input parameters, the temperature in the tube at any time, using the equations of the model and gives us the temporal evolution of temperature. To prove the validity of the theoretical model a solar collector was built according to the dimensions used in theoretical calculations and then comparing to the obtained results by both methods. It will be presented graphs showing the temporal evolution of temperature, energy losses, possible ways to mitigate losses and finally the thermal efficiency of the cylindrical-parabolic solar concentrator built.