Detailed optical and thermal analysis of trough-like concentrators using tubular absorbers

A detailed analysis for studying the optical and thermal properties of trough-like concentrators using tubular absorbers is presented. Effective emissivity as a function of number of reflections, acceptance angle, emittance from reflector and aperture, and wall angle has been evaluated. Effective emissivity ε_eff increases with an increase in the concentration factor. Angle factor as a function of wall angle has also been calculated. Variations of collector and thermal efficiencies with ε_eff have been predicted. The paper includes graphs to aid in the design of trough-like concentrators.