Utilization of Nanofluids Potency as Advanced Htfs on Solar Parabolic Trough Collector Evacuated Tube Receiver

Abstract

Abstract

An experimental investigation has been performed to study thermal performance of TiO /distilled water nanofluid in an evacuated tube receiver model with titania nanoparticles concentration of 0.1 vol.%. In the solar parabolic trough collector system, an evacuated tube receiver usually is employed to efficiently absorb the radiation reflection from the parabolic collector. In the present work, the uniform heat flux is generated by variac transformer for a fix magnitude instead of daily solar radiation. The results of this investigation show that the applied heat flux has just affected on outlet temperature of nanofluids but it does not influence on dimensionless number (Nusselt number). The result also indicates that the friction factor of the observed nanofluid is higher than that of the base fluid. For thermal performance, the average Nusselt number enhancement between non-evacuated and evacuated condition yields 17.9% and 21.7% for water and nanofluid, respectively. Due mainly to adding nanoparticles into base fluid, the changes of the thermophysical properties of nanofluid and thermal boundary layer at the inside pipe wall play an important role in heat transfer enhancement. With applying an evacuated condition application into receiver tube, thermal performance of Nano fluids is more efficient than that of non-evacuated condition.