Simulation Analysis of Thermal Losses of Parabolic trough Solar Collector in Malaysia Using Computational Fluid Dynamics

Abstract

The increase trend in fuel price coupled with escalating carbon dioxide concentration and energy security have encouraged the world to shift towards renewable energy sources. Parabolic trough collector is the most proven technology for indirect steam generation in solar thermal power plants. Since the annual average daily solar radiation for Malaysia are from 4.21 KWh/m2 to 5.56 KWh/m2 and sunshine duration is more than 2200 hours per year, parabolic trough solar collector is a very promising technology in the renewable energy field. The purpose of this paper is to simulate and describe the heat losses (radiation and convection) associated with heat collection element (HCE) of Solar Parabolic Trough Collector (PTC), the effect of different wind speeds and mass flowrate of the heat transfer fluid (HTF) on thermal losses were investigated. The receiver of the parabolic trough is modeled in CFD code ANSYS Fluent environment and the geometry is similar to that of LS-2 parabolic trough solar collector. Some assumptions have been made to ease and simplify the simulation. Solar radiation flux profile around the absorber tube is assumed uniform and the radiation flux is treated as heat flux wall boundary condition for the absorber tube. Heat loss model was simulated by employing the Surface – to – Surface (S2S) radiation model to account for the radiation exchange in an enclosure (vacuum annulus gap) of gray – diffuse surfaces. It resulted in a favorably low temperature of the glass envelope as compared to the temperature of the absorber. The convection and radiation heat loss to the surrounding was calculated by the resulting temperature of the glass envelope from the simulation model.