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

• Published in: International journal of thermal sciences Vol. 80; no. 80; pp. 48 - 57
• Main Authors: Reddy, K.S., Kumar, K. Ravi
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Masson SAS 01.06.2014; Elsevier
• Subjects: Applied sciences; Aspect ratio; Cavity receiver; Computer simulation; Direct current; Energy; Exact sciences and technology; Fresnel reflectors; Heat loss; Holes; Linear Fresnel reflector; Mathematical models; Natural energy; Optimization; Receivers; Solar collectors; Solar energy; Solar thermal conversion; Cavity receiver; Heat loss; Aspect ratio; Solar energy; Linear Fresnel reflector; Geometrical shape; Solar collector; Fresnel reflectors; Cavity receivers; Modeling; Collector concentrator; Numerical simulation; Heat transfer
• ISSN: 1290-0729; 1778-4166
• DOI: 10.1016/j.ijthermalsci.2014.01.022

Solar linear Fresnel reflector (LFR) system is simple in design and cost effective technology for medium temperature (400 °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 (tins), aspect ratio (As), cavity depth (Dc), cavity width (w), operating temperature (Tr), cavity cover emissivities (εcc), and wind speed (Vw). Based on the numerical simulation of the receiver, an optimum configuration of trapezoidal cavity receiver is obtained with tins = 300 mm, Dc = 300 mm and As = 2. The total heat losses varies from 663.47 W/m to 1046.3 W/m for w of 300 mm–800 mm at Tr = 500 °C, εcc = 0.5, Vw = 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. •Design of cavity receiver for linear Fresnel reflector system.•Convective and radiative heat loss analyses for linear Fresnel reflector system.•Heat loss analysis of cavity receiver using non-Boussinesq approximation.•Heat loss analyses for different cavity receiver width, temperature and velocity.