Numerical investigation of thermal performance of heat loss of parabolic trough receiver

Abstract

Based on the analysis of computation methods and heat transfer processes of the parabolic trough receiver running in steady state, a two-dimensional empirical model was developed to investigate the thermal performance of heat loss of parabolic trough receivers under steady state equilibrium. A numerical simulation was conducted for the parabolic trough receiver involved in a literature. Comparisons between numerical and experimental results show that the empirical model is accurate enough and can be used to investigate the thermal performance of heat loss of parabolic trough receivers. The thermal performance of heat loss of UVAC3 and the new-generation UVAC2008 was investigated respectively. The simulation results show that selective coatings and annular pressure influence the thermal performance of heat loss of parabolic trough receivers greatly, wind velocity influences the thermal performance of thermal loss of parabolic trough receivers only a little in contrast with the emittance of selective coatings and air pressure in annular space. And the thermal performance of thermal loss of the new-generation parabolic trough receiver has been improved in a large amount.parabolic trough receiver, two-dimensional empirical model, thermal performance of heat loss, annular space, selective coating, wind velocity Citation:Xiong Y X, Wu Y T, Ma C F, et al. Numerical investigation of thermal performance of heat loss of parabolic trough receiver. Nomenclature col : q  total collector thermal energy output, W/m abs : q  absorbed thermal energy of HCE, W/m2 in : h enthalpy of heat transfer fluid in inlet of HCE, J/Kg out : h enthalpy of heat transfer fluid in outlet of HCE, J/Kg m : q mass flow rate of heat transfer fluid, kg/s heatsource : P power of heat source, W 56conv : q  convection heat transfer rate between outer surface of glass envelop and ambient air per meter receiver length, W/m 57rad : q  radiation heat transfer rate between outer surface of glass envelop and sky per meter receiver length, W/m 45cond : q  conduction heat transfer rate through glass envelop wall per meter receiver length, W/m 34conv : q  convection heat transfer rate between outer surface of steel absorber and inner surface of glass envelop per meter receiver length, W/m 34rad : q  radiation heat transfer rate between outer surface XIONG YaXuan, et al. Sci China Tech Sci February (2010) Vol.53 No.2 445 of steel absorber and inner surface of glass envelop per meter receiver length, W/m 23cond : q  conduction heat transfer rate through steel absorber wall per meter receiver length, W/m heatloss : q  total heat transfer rate between outer surface of glass envelop and ambient per meter receiver length, W/m 34 : h convection heat transfer coefficient of annulus gas at T 34 in annular space, W/m 2 K 1 56 : h convection heat transfer coefficient of air at T 56 around the horizontal glass envelop, W/m 2 K 1 D 2 : inside diameter of absorber pipe, m D 3 : outside diameter of absorber pipe, m D 4 : inside diameter of glass envelop, m D 5 : outs...

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