Solar energy application for LFR unit with trapezoidal cavity receiver considering radiative mode

Abstract

Abstract In current article, influence of radiation and convection modes on behavior of air inside an absorber in trapezoidal shape has been investigated. Such cavity is part of Linear Fresnel Reflector (LFR) unit and it is important to analyze such geometry to reach higher performance. Properties of carrier fluid were assumed as function of temperature. To involve radiation effect, discrete ordinates model was implemented. Influences of external convective factor (hext), Angle of adiabatic wall (θ), temperature ratio (Tr) on irreversibility and heat transfer were depicted in outputs. Augment of Tr, θ and hext cause incident radiation to decline about 85.95%, 20.97% and 20.68% with assuming lowest values of other factors. Strength of eddy, temperature difference augments about 180% and 9.77% when θ enhances at Tr = 0.8. With considering highest level of other factors, as values of wind speed and θ intensify, Nu enhances 9.28% and 17.36% while it declines about 52.2% with rise of Tr. Given minimum values of other parameters, irreversibility intensifies about 45.45% and 8.3% with augment of hext and θ but it declines about 84.44% with augment of Tr.