Designing the most efficient parabolic trough solar collector (PTSC) is still a demanding
and challenging research area in solar energy systems. Two effective recommended methods for
this purpose that increase the thermal characteristics of PTSCs are adding turbulators and
nanofluids. To study the effects of the two approaches on the energy efficiency of PTSCs, a stainless
steel turbulator was used and solid nanoparticles of Cu/SBA‐15 were added to the water with the
volume concentrations of 0.019% to 0.075%. The generated turbulence in the fluid flow was modeled
by the SST k–ω turbulent model. The results in daylight demonstrated that energy efficiency
increases steadily by 11:30 a.m., and then, starts to drop gradually due to more irradiations at noon.
It was observed that applying the turbulator to the studied PTSC has a significant influence on the
enhancement of energy efficiency. Adding the nanoparticles augmented the average Nusselt
number inside the solar collector in various studied Reynolds numbers. It was also found that the
increase in volume concentrations of nanoparticles enhances heat transfer regularly.