“…This is a reduction in temperature difference between T i and T a (temperature gradient) and forms a smaller value of the T* parameter, so solar collector efficiency increases 3 , 8 , 32 . A previous study by researcher Lyudmila Knysh on numerical method was conducted with MWCNT-water nanofluid and achieved nearly 10% improvement in the solar collector efficiency 33 . Figure 5 The influence of volume flow rates on solar parabolic collector efficiency ( a ), ( b ) & ( c ).…”
A limited experimental work was on multi-walled carbon nanotube (MWCNT)—water nanofluid with surfactant in the solar parabolic collector at low volume concentrations. At high-volume concentrated nanofluid, the pressure drop was more due to an increase in the viscosity of the working fluid and an increase in the nanoparticle cost; hence it is not economical. This report attempted to use Sodium Dodecyl Benzene Sulfonate (SDBS) surfactant in the low-volume concentrated MWCNT-water nanofluid to establish effective heat transfer in solar parabolic collector applications. The stable MWCNT-water nanofluid was prepared at 0.0158, 0.0238, and 0.0317 volume concentrations. The experiments were conducted from 10:00 to 16:00 at 6, 6.5 and 7 L/min flow rates concerning ASHRAE Standards. At the 7 L/min flow rate of the working fluid, having a minimum temperature difference between the working fluid and absorber tube leads to better heat transfer. The increased volume concentration of MWCNT in the water enhances the surface area interaction between water and MWCNT nanoparticles. This results in maximum solar parabolic collector efficiency at 0.0317 vol% with a 7 L/min flow rate and 10–11% higher than the distilled water.
“…This is a reduction in temperature difference between T i and T a (temperature gradient) and forms a smaller value of the T* parameter, so solar collector efficiency increases 3 , 8 , 32 . A previous study by researcher Lyudmila Knysh on numerical method was conducted with MWCNT-water nanofluid and achieved nearly 10% improvement in the solar collector efficiency 33 . Figure 5 The influence of volume flow rates on solar parabolic collector efficiency ( a ), ( b ) & ( c ).…”
A limited experimental work was on multi-walled carbon nanotube (MWCNT)—water nanofluid with surfactant in the solar parabolic collector at low volume concentrations. At high-volume concentrated nanofluid, the pressure drop was more due to an increase in the viscosity of the working fluid and an increase in the nanoparticle cost; hence it is not economical. This report attempted to use Sodium Dodecyl Benzene Sulfonate (SDBS) surfactant in the low-volume concentrated MWCNT-water nanofluid to establish effective heat transfer in solar parabolic collector applications. The stable MWCNT-water nanofluid was prepared at 0.0158, 0.0238, and 0.0317 volume concentrations. The experiments were conducted from 10:00 to 16:00 at 6, 6.5 and 7 L/min flow rates concerning ASHRAE Standards. At the 7 L/min flow rate of the working fluid, having a minimum temperature difference between the working fluid and absorber tube leads to better heat transfer. The increased volume concentration of MWCNT in the water enhances the surface area interaction between water and MWCNT nanoparticles. This results in maximum solar parabolic collector efficiency at 0.0317 vol% with a 7 L/min flow rate and 10–11% higher than the distilled water.
“…In this paper, the coefficient K was introduced, which shows the degree of aberrations of the concentrator surface, which cause the deviation of the reflected beam of rays from its ideal direction. The root-mean-square deviation of the angular errors σ γ C was calculated in fractions of the magnitude of the opening angle of the Sun σ ψ γ C K S = [20,21]. Stu dies [1] were continued in work [2], where flat angles μ and λ were introduced, which characterize the deviation of the beam of rays reflected from the concentrator, which occurs in the process of defocusing the concentrator relative to the direction to the Sun.…”
Section: Verification Of the Results Obtained Using The Monte Carlo M...mentioning
The object of research is the processes of radiation transfer in the «Sun – paraboloid concentrator – heat receiver» system. There are many factors that affect the value of the density of the concentrated heat flux that reaches the surface of the heat sink. The study of the influence of these factors on the overall energy indicators of the system is an important scientific problem that was solved in this work. To solve this problem, a generalized mathematical model of the radiation transfer process in the «Sun – concentrator – heat receiver» system was built, which was adapted for a paraboloid concentrator. The constructed mathematical model was solved by an approximate analytical method, which took into account the integral and discrete parameters of the system, as well as the probability distribution of aberrations of the concentrator surface, its defocusing, and other random influences. The dimensionless density of the heat flux on the surface of the heat sink for a mathematically ideal and real paraboloid concentrator of a fixed geometry was determined. Using the found analytical solution, the results obtained on the basis of the Monte Carlo method were verified. Analytical and numerical results for a mathematically ideal and a real concentrator with minor aberrations and a clear orientation to the Sun agree within the permissible error. For a real concentrator with defocusing, a deviation of numerical data from analytical data was observed. The presence of deviations is associated with a simplification in the interpretation of the analytical probability distribution, in which it is impossible to take into account each influence separately. The obtained analytical results will be useful in the development of real power plants and can be used practically at the stage of checking the adequacy of the system model
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
