THERMAL AND OPTICAL CONSEQUENCES OF THE INTRODUCTION OF BAFFLES INTO COMPOUND PARABOLIC CONCENTRATING SOLAR-ENERGY COLLECTOR CAVITIES

A theoretical and experimental investigation into the modifications in optical and thermal performance resulting from the introduction of a baffle into the cavity of a compound parabolic concentrating solar energy collector has been performed. Results are presented in the form of velocity vector diagrams and isothermal plots. A comparison is made of the collector loss coefficient and Hottel-Whiller-Bliss graphs are produced for cavities with and without a baffle present. The introduction of a baffle reduces internal convection thereby reducing heat losses. The associated reduction in optical efficiency is small.