Solar LFR system with new cavity reflector employing DO model

Abstract

AbstractIn current context, to achieve lower heat loss in Linear Fresnel reflector (LFR) unit, innovative configuration for cavity has been offered. This cavity consists of one hot circular wall and two inclined adiabatic walls. The below wall is made of glass and connect with outside air flow. The operating fluid is air and its features were temperature dependent. Inclination angle (θ), wind speed and circular wall temperature are variable factors. Both thermal and irreversibility behavior were analyzed in outputs. Finite volume method (FVM) was utilized for such 2D problem involving radiation source term. The incident radiation contours were reported which were obtained by implement of discrete ordinates (DO) model. Verification was done with comparing data with that of previous numerical publication. Stream function augments about 87.5% with augmentation of θ while changing the hot temperature cannot affect the strength of the eddy. Radiation mode is directly relevant to temperature difference, so lower glass temperature provides lower incident radiation. At lowest Th, augment of θ offers reduction in glass temperature and incident radiation about 2.27% and 12.94%. Given θ = 120o, reduce of Tr makes cold temperature to increase about 20.59%. Owing to augmentation of heat loss with rise of Th, θ and wind speed; all factors have direct relation with Nu and Nur. Temperature of circular wall has highest influence on Nu. With assumption of minimum values of other factors, Nu augments 19.63% and 65.07% with rise of hext and θ while it declines about 89.59% with increase of Tr. Irreversibility decreases about 86.38% with rise of Tr when θ = 120o, hext = 20. Given Th = 673 K, hext = 20, total entropy augments about 6.75% with employing greater angle.