Experimental investigation on paraboloid solar concentrator with a conical secondary concentrator

Abstract

Material removal through ablation caused by concentrated solar thermal power is investigated. Experiments are conducted using a mirror-finish electroplated paraboloid along with a conical secondary concentrator in both fall and summer months in Al Ain city, UAE. Data collection for melting of aluminum shims facilitated the assessment of the feasibility of utilizing the available solar irradiance after the two-stage concentration. A geometric concentration factor of over 2800 is achieved for the first stage of power concentration with the current installation that also has a two-axis sun tracking system and a built-in pyrheliometer. The results confirm the feasibility of the approach, as the available power for ablation around solar noon is order of magnitudes higher than the power needed for the task, for the aluminum shim used. The main aim of the study is to hone the process to the power and precision of continuous pulse laser material removal, notably CO2 lasers, as challenges further reduction of the concentrated solar beams to acceptable tolerances remain to be successfully resolved. Copyright © 2014 John Wiley & Sons, Ltd.