01644nas a2200169   4500008004100000022001400041245009500055210006900150300001600219490000700235520106600242653003201308100002401340700001801364700002101382856007101403       2012                        eng d  a0038-092X00aAnalysis of heat losses from a trapezoidal cavity used for Linear Fresnel Reflector system0 aAnalysis of heat losses from a trapezoidal cavity used for Linea  a1313 - 13220 v863 aA Computational study to investigate the heat loss due to radiation and steady laminar natural convection flow in a trapezoidal cavity having eight absorber tubes for a Linear Fresnel Reflector (LFR) solar thermal system with uniformly heated tubes and adiabatic top wall and side walls has been performed. The losses due to convection and radiation were considered from the bottom glass cover. The results are validated with experimental data. Radiative component of losses from the cavity was found to be dominant which contributes around 80–90%. Heat loss characteristics have been studied for cavities of different depths. Simulations have been carried out for various values of heat transfer coefficient based on the wind speed below the glass surface. Effect of emissivities of the tubes on the heat loss has also been simulated. Flow pattern and isotherms inside the cavity for various depths have been analyzed. Finally, the correlation between the total average Nusselt number and its influencing parameters has been obtained for the proposed cavity.10aNusselt number correlations1 aSahoo, Sudhansu, S.1 aSingh, Suneet1 aBanerjee, Rangan  uhttp://www.sciencedirect.com/science/article/pii/S0038092X12000394