Intercept Factor for a Beam-Down Parabolic Trough Collector

2021 ◽  
Vol 143 (6) ◽  
Author(s):  
Muhammad Uzair ◽  
Naveed ur Rehman
Keyword(s):  
Ray Tracing ◽  
Concentration Ratio ◽  
Design Parameters ◽  
Two Dimensional ◽  
Parabolic Trough ◽  
High Concentration ◽  
Angular Misalignment ◽  
Online Tool ◽  
Parabolic Trough Collector

Abstract This paper presents a method for evaluating the intercept factor (γ) of a beam-down parabolic trough collector (BDPTC), accounting for collector design, solar cone, and shading on the aperture due to secondary reflectors. A numerical ray-tracing technique was developed and used for the purpose. Validation was performed by comparing the results with rays traced in a two-dimensional drafting program. The effects of changing the rim-angle and angular misalignment associated with the primary and secondary concentrators for various designs are presented and discussed in detail. The optimum values of the design parameters for low, medium, and high concentration ratio BDPTCs are reported. An online tool for quickly estimating γ is also launched in this paper.

EFFECTS OF RECEIVER MISALIGNMENT ON THE INTERCEPT FACTOR OF PARABOLIC TROUGH COLLECTORS

2021 ◽  
pp. 1-22
Author(s):  
Muhammad Uzair ◽  
Naveed Rehman ◽  
Muhammad Asif
Keyword(s):  
Concentration Ratio ◽  
Latin Hypercube Sampling ◽  
Design Parameters ◽  
Optical Performance ◽  
Parabolic Trough ◽  
Online Tool ◽  
Contour Plots ◽  
Aperture Width ◽  
Parametric Analyses ◽  
Tracing Method

Abstract This study developed a methodology for determining the intercept factor (γ) and reports the effects of varying the design parameters, within realistic ranges, on the optical performance of parabolic trough collectors (PTC). The design equations account for the aperture width of the concentrator, the geometric concentration ratio, rim-angle and misalignment of the receiver, characterized by the radial and angular offsets. The Latin Hypercube Sampling (LHS) based ray-tracing method was used. Validation of the method was performed by comparing the results obtained by tracing a single ray with measurements obtained in a 2D drafting program. Then, parametric analyses were performed to determine the effects of changing the radial and angular offset, geometric concentration ratio and rim-angle on the percentage change in intercept factor (γΔ) with respect to the γ of a PTC with a perfectly aligned receiver. Finally, contour plots depicting the γ of various standard troughs over the range of radial and angular offsets were plotted, compared and discussed. An online tool is also presented to help designers and researchers analyze these effects quickly by providing the design parameters.

Optimization of Parabolic Trough Collector Design for Varying Manufacturing Tolerances Using a Closed-Form Expression for Intercept Factor

1994 ◽  
Vol 116 (3) ◽  
pp. 164-166 ◽  
Author(s):  
H. M. Gu¨ven
Keyword(s):  
Closed Form ◽  
Optical Design ◽  
Computer Code ◽  
Closed Form Expression ◽  
Design Parameters ◽  
Parabolic Trough ◽  
Form Expression ◽  
Parabolic Trough Collector ◽  
Manufacturing Tolerances ◽  
Ray Trace

In this paper, a closed-form expression for intercept factor is used to carry out the optimization of parabolic trough collector geometry (rim angle and concentration ratio). It is shown that the presented closed-form expression eliminates the need for a detailed ray-trace computer code and facilitates optimization of the collector optical design parameters.

Experimental Study on Thermal Efficiency of Parabolic Trough Collector (PTC) Using Al2O3/H2O Nanofluid

2015 ◽  
Vol 787 ◽  
pp. 192-196
Author(s):  
E. Siva Reddy ◽  
R. Meenakshi Reddy ◽  
K. Krishna Reddy
Keyword(s):  
Experimental Study ◽  
Solar Energy ◽  
Thermal Efficiency ◽  
Base Fluid ◽  
Concentration Ratio ◽  
Volume Fraction ◽  
Nano Particles ◽  
Parabolic Trough ◽  
Flow Rates ◽  
Parabolic Trough Collector

Dispersing small amounts of solid nano particles into base-fluid has a significant impact on the thermo-physical properties of the base-fluid. These properties are utilized for effective capture and transportation of solar energy. This paper attempts key idea for harvesting solar energy by using alumina nanofluid in concentrating parabolic trough collectors. An experimental study is carried out to investigate the performance of a parabolic trough collector using Al2O3-H2O based nanofluid. Results clearly indicate that at same ambient, inlet temperatures, flow rate, concentration ratio etc. hike in thermal efficiency is around 5-10 % compared to the conventional Parabolic Trough Collector (PTC). Further, the effect of various parameters such as concentration ratio, receiver length, fluid velocity, volume fraction of nano particles has been studied. The different flow rates employed in the experiment are 2 ml/s, 4 ml/s and 6 ml/s. Volumetric concentration of 0.02%, 0.04% and 0.06% has been studied in the experiment. Surfactants are not introduced to avoid bubble formation. Tracking mode of parabolic trough collector is manual. Results also reveal that Al2O3-H2O based nanofluid has higher efficiency at higher flow rates.

Thermal Performance of a Receiver Tube for a High Concentration Ratio Parabolic Trough System and Potential for Improved Performance With Syltherm800-CuO Nanofluid

2015 ◽  
Author(s):  
Aggrey Mwesigye ◽  
Zhongjie Huan ◽  
Josua P. Meyer
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Thermal Performance ◽  
Thermal Efficiency ◽  
Concentration Ratio ◽  
Low Flow ◽  
Fluid Temperature ◽  
Parabolic Trough ◽  
High Concentration ◽  
Flow Rates

In this paper, the thermal performance of a high concentration ratio parabolic trough system and the potential for improved thermal performance using Syltherm800-CuO nanofluid were investigated and presented. The parabolic trough system considered in this study has a concentration ratio of 113 compared with 82 in current commercial systems. The heat transfer fluid temperature was varied between 350 K and 650 K and volume fractions of nanoparticle were in the range 1–6%. Monte-Carlo ray tracing was used to obtain the actual heat flux on the receiver’s absorber tube. The obtained heat flux profiles were subsequently coupled with a computational fluid dynamics tool to investigate the thermal performance of the receiver. From the study, the results show that with increased concentration ratios, receiver thermal performance degrades, with both the receiver heat loss and the absorber tube circumferential temperature differences increasing, especially at low flow rates. The results further show that the use of nanofluids significantly improves receiver thermal performance. The heat transfer performance increases up to 38% while the thermal efficiency increases up to 15%. Significant improvements in receiver thermal efficiency exist at high inlet temperatures and low flow rates.

scholarly journals Analysing the Material Suitability and Concentration Ratio of a Solar-Powered Parabolic trough Collector (PTC) Using Computational Fluid Dynamics

Energies ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 5479
Author(s):  
Mohammad Akrami ◽  
Husain Alsari ◽  
Akbar A. Javadi ◽  
Mahdieh Dibaj ◽  
Raziyeh Farmani ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Production Rate ◽  
Water Scarcity ◽  
Concentration Ratio ◽  
Parabolic Trough ◽  
Parabolic Trough Collector ◽  
Maximum Production ◽  
Solar Powered ◽  
Maximum Production Rate

Solar-powered desalination is a sustainable solution for countries experiencing water scarcity. Several studies have presented different solutions to provide cleaner production in desalination systems. Parabolic trough collector (PTC) is one of these solutions that has proven to be superior among solar concentrators. Furthermore, a number of studies have investigated the use of PTC for distillation of saline water in response to water scarcity. In this study, a modified PTC model was developed, in which the heat exchanger was replaced by a condensation tube to reduce the energy consumption, and a black layer was introduced to the surface of the receiver to enhance its absorptance. As a reference case, the system productivity according to average solar intensities in Zagazig, located at 30°34′N 31°30′E in the North East of Egypt, is estimated. The results indicated that the maximum production rate that can be attained is 1.72 kg/h. Then, the structure of the system is evaluated with the aid of Computational Fluid Dynamics (CFD) modelling, in order to enhance its productivity. Many materials are examined and the results recognised copper as the most suitable material amongst marine grade metals (i.e., aluminium, galvanised steel and stainless steel) to construct the receiver tube. This is due to its superior thermal performance, satisfactory corrosion resistance, and acceptable cost. Afterwards, the selected receiver tube was employed to identify the optimal Concentration Ratio (CR). Consequently, a CR of 90.56 was determined to be the optimum value for Zagazig and regions with similar solar radiation. As a result, the system’s productivity was enhanced drastically, as it was estimated that a maximum production rate of 6.93 kg/h can be achieved.

scholarly journals Performance analysis and modeling of parabolic trough based concentrated solar facility using different thermal fluid mediums

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Ahmed Ullah ◽  
◽  
Asim Mushtaq ◽  
Rizwan Ahmed Qamar ◽  
Zaeem Uddin Ali ◽  
...  
Keyword(s):  
Solar Energy ◽  
High Efficiency ◽  
Solar Power ◽  
Operating Conditions ◽  
Design Parameters ◽  
Small Scale ◽  
Concentrated Solar Power ◽  
Parabolic Trough ◽  
Parabolic Trough Collector ◽  
Thermal Fluids

The significance of sustainable power source has expanded because of environmental change and worldwide cautioning concerns because of its renewing quality. Solar energy is the focal point of numerous examinations due to modern industrial applications and small scale local applications in emerging nations. Solar energy is being bridled, either specifically utilizing photovoltaic or secondarily utilizing concentrated solar power. This study aims to design and fabricate a small scale concentrated solar power (CSP) plant using linear parabolic trough. Linear parabolic trough collector is used because of high efficiency and exceedingly prescribed kind of CSP. The scope of this study is to develop a CSP plant and also study the properties of various thermal fluids and expect the best transfer medium. The study done in this research is based on carrying out a detailed energy balance scheme for a linear parabolic trough collector while observing twenty-six vital design parameters, including the geometric measurements and material properties of concentrator and receiver pipe, thermal fluids properties, and operating conditions. Modeling of the system is carried out for different thermal fluids that are deemed viable for use. It was found that the results obtained from the fabricated parabolic trough CSP were used to verify the model and compare with the theoretical results. The conclusions deduced from this study will help design both small and large scale applications of linear parabolic troughs.

scholarly journals Finite Element Modeling and Ray Tracing of Parabolic Trough Collectors for Evaluation of Optical Intercept Factors With Gravity Loading

2011 ◽  
Author(s):  
Joshua M. Christian ◽  
Clifford K. Ho
Keyword(s):  
Finite Element ◽  
Ray Tracing ◽  
Finite Element Models ◽  
Optical Performance ◽  
Parabolic Trough ◽  
Parabolic Trough Collector ◽  
Error Distributions ◽  
Slope Error ◽  
The Impact ◽  
Reflective Surfaces

Predicting the structural and optical performance of concentrating solar power (CSP) collectors is critical to the design and performance of CSP systems. This paper presents a performance analysis which utilizes finite-element models and ray-tracing of a parabolic trough collector. The finite-element models were used to determine the impact of gravity loads on displacements and rotations of the facet surfaces, resulting in slope error distributions across the reflective surfaces. The geometry of the LUZ LS-2 parabolic trough collector was modeled in SolidWorks, and the effects of gravity on the reflective surfaces are analyzed using SolidWorks Simulation. The ideal mirror shape, along with the 90° and 0° positions (with gravity deformation) were evaluated for the LS-2. The ray-tracing programs APEX and ASAP are used to assess the impact of gravity deformations on optical performance. In the first part of the analysis, a comprehensive study is performed for the parabolic trough to evaluate a random slope error threshold (i.e., induced by manufacturing errors and assembly processes) above which additional slope errors caused by gravity sag decrease the intercept factor of the system. The optical performance of the deformed shape of the collector (in both positions) is analyzed with additional induced slope errors ranging from zero up to 1° (17.44 mrad). The intercept factor for different solar incident angles found from ray-tracing is then compared to empirical data to demonstrate if the simulations provide consistent answers with experimental data.

Sign in / Sign up

Export Citation Format

Share Document