Design of wall-mounted solar collector with concentration by a parabolic mirror

Abstract

The objective of this study is to evaluate the performance of vertically mounted solar collector with a parabolic mirror for solar concentration to boost the energy density. A flat absorber is attached to the bottom of the parabolic mirror. Ray-tracing simulation was employed to estimate the recovery of solar irradiation and to find out the optimal settings of the geometrical parameters of parabola shape such as the focal length and the inclined angle. The system is assumed to be within the depth of 100 mm for being mounted on a wall. The objective function to be maximized was the energy intensity of solar irradiation captured on the absorber in winter season, i.e. from November until February. It was derived from the sensitivity analysis of the design parameters that the focal length of 95 mm and the angle of 25 degree would be optimal. The parabolic mirror effectively collects the sunlight so that the reflected sunlight contributes to 74-79 % of the solar intake every month. From the viewpoint of annual performance, it was predicted that the proposed system would provide quite high energy density in winter while very small one in summer, which is considered preferable because the behavior is in accordance with the change of heat load for residential buildings during a year.