In this work, the effect of surface cavities on the concentrated solar receiver is studied experimentally. A parabolic dish solar concentrating collector is used to heat the receiver. A 15mm thick mild steel receiver plate is divided into four quadrants; three quadrants are formed with tapered surface cavities while the fourth quadrant is a flat surface. The effect of the cavity aspect ratio, wide/depth ratio, and taper angle on useful heat gain and heat losses has been determined. The cavity with a taper angle of 100° with an aspect ratio of 2.6 is revealed to be efficient. The cavity surface is observed with an instantaneous temperature of 100°C higher than that of the flat surface temperature.

solar receiver, parabolic dish, surface cavity, aspect ratio, heat absorption.