Estimation of convective and radiative heat losses from an inverted trapezoidal cavity receiver of solar linear Fresnel reflector system

Solar linear Fresnel reflector (LFR) system is simple in design and cost effective technology for medium temperature (400 degrees C) applications. In this article, convective and radiative heat losses from the inverted trapezoidal cavity receiver for solar linear Fresnel reflector are estimated using a two dimensional (2-D) numerical model. The 2-D numerical simulation of trapezoidal cavity receiver is carried out by considering the receiver surface as isothermal conditions. The heat loss analysis is carried out for various receiver geometric and operating parameters viz, thickness of the insulation (t(ins)), aspect ratio (A(s)), cavity depth (D-c), cavity width (w), operating temperature (T-r), cavity cover emissivities (epsilon(cc)), and wind speed (V-w). Based on the numerical simulation of the receiver, an optimum configuration of trapezoidal cavity receiver is obtained with t(ins) = 300 mm, D-c = 300 mm and A(s) = 2. The total heat losses varies from 663.47 W/m to 1046.3 W/m for w of 300 mm-800 mm at T-r = 500 degrees C, epsilon(cc) = 0.5, V-w = 2.5 m/s. The effect of cavity cover emissivity on total heat losses is found to be less significant when compared to that of other cavity parameters. The optimum receiver configuration of the inverted trapezoidal cavity receiver can be used in solar LFR system with minimum heat losses. (C) 2014 Elsevier Masson SAS. All rights reserved.