Parabolic trough collectors (PTCs) are highly sensitive to receiver positioning accuracy; however, most existing studies report optical efficiency degradation without formally defining alignment tolerance limits. This study proposes a tolerance-based thermo-optical risk framework to quantify allowable receiver misalignment envelopes for reliable PTC operation. A Monte Carlo Ray Tracing (MCRT) methodology is employed to evaluate the impact of angular receiver misalignment on optical efficiency and circumferential heat flux redistribution. Beyond conventional efficiency metrics, normalized flux-based thermal non-uniformity indicators are introduced to assess thermo-mechanical risk without requiring full thermo-fluid modeling. The results reveal a nonlinear decoupling between optical acceptability and thermal safety. While optical efficiency remains above 0.80 up to approximately ±6°, pronounced flux localization and rapid growth of thermal stress indicators occur beyond ±4°, marking the onset of thermally critical behavior. The identified ±4° threshold corresponds to approximately twice the collector half-acceptance angle (θ(crit)/δ ≈ 2), demonstrating geometry-dependent scaling characteristics. The proposed framework formalizes the optical–thermal decoupling phenomenon and transforms conventional efficiency-based evaluation into a reliability-informed alignment tolerance assessment tool applicable to manufacturing precision, installation control, and operational quality management in CSP systems.
116Comparison of Medium-size Concentrating Solar Power Plants based on Parabolic Trough and Linear Fresnel Collectors
Comparison of Medium-size Concentrating Solar Power Plants based on Parabolic Trough and Linear Fresnel Collectors
6An On-site Test Method for Optical Efficiency of Large-size Parabolic trough Collectors
An On-site Test Method for Optical Efficiency of Large-size Parabolic trough Collectors
191Study on optical and thermal performance of a linear Fresnel solar reflector using molten salt as HTF with MCRT and FVM methods
Study on optical and thermal performance of a linear Fresnel solar reflector using molten salt as HTF with MCRT and FVM methods
Read more5Wind-induced torsion of parabolic trough collectors in operation
Wind-induced torsion of parabolic trough collectors in operation
1Optical Efficiency of Semi-parabolic Linear Fresnel Reflector System “SPLFR”
One of the developed technologies in the solar energy field is Concentrated Solar thermal (CST) which is favorable to be deployed in Tunisia. Although Parabolic Trough Collector (PTC) is the most advanced, reliable and extensively used technology, Tunisia faces challenges to put it into use due to its expensive cost. Manufacturing a conventional PTC system locally requires a high-tech for float glass mirrors. There are numerous studies which investigate alternative designs for different PTC configurations, in order to have an acceptable optical and thermal efficiency and a reduction in the manufacturing cost via local construction. The used optical modification on PTC reflector, based on shaped strip mirrors on a discretized parabola, leads to a Semi Parabolic Linear Fresnel Reflector (SPLFR) design. The aim of this paper was to perform an optical design for an SPLFR to be set up in Tunisia and compared to a classic PTC with an inox sheet reflector using geometrical and ray tracing techniques. The findings show that stretched-shape of strip mirrors is more affected by conventional errors specially tracking ones. Nevertheless, this model provides an acceptable optical efficiency at a low cost, simple and locally manufactured.
Read more413D Thermal-structural Analysis of an Absorber Tube of a Parabolic Trough Collector and the Effect of Tube Deflection on Optical Efficiency
3D Thermal-structural Analysis of an Absorber Tube of a Parabolic Trough Collector and the Effect of Tube Deflection on Optical Efficiency
Read more39Optical and structural optimization of a large aperture solar parabolic trough collector
Optical and structural optimization of a large aperture solar parabolic trough collector
48Numerical investigation of efficiency enhancement in a direct absorption parabolic trough collector occupied by a porous medium and saturated by a nanofluid
In this study, a numerical investigation of the solar parabolic trough collector with an area of 0.856 m2 by combination of Monte Carlo Ray‐Trace (MCRT) and finite volume method (FVM) has been carried out using the FLUENT software. The purpose of this study is to investigate the effect of metal foams and nanofluids on the thermal performance of a direct absorption parabolic trough collector (DAPTC). For this purpose, three‐dimensional fully developed laminar convection heat transfer of Al2O3 and TiO2/water nanofluids is examined by 0.1, 0.2, and 0.3 vol %. Furthermore, 64 cm copper‐filled porous media in a volumetric absorbent tube are applied. The obtained results of numerical simulations are compared with the experimental data. The results demonstrate a good agreement between the numerical simulations and experimental data. The results indicate that the maximum efficiency was 34.51% for TiO2/water at 0.3 vol %. Furthermore, using porous media with high absorption coefficient and scattering coefficient that could absorb more incoming radiation and transfer to heat transfer fluid can result in increasing the efficiency of the collector. © 2018 American Institute of Chemical Engineers Environ Prog, 38: 727–740, 2019
Read more83A detailed parameter study on the comprehensive characteristics and performance of a parabolic trough solar collector system
A detailed parameter study on the comprehensive characteristics and performance of a parabolic trough solar collector system
Read more355Comparison of Linear Fresnel and Parabolic Trough Collector power plants
Comparison of Linear Fresnel and Parabolic Trough Collector power plants
14Optical performance study of different shapes of solar cavity receivers used in central receiver system plant
In the current study, we present the optical efficiency of six different shapes of cavity receivers that are mostly used in solar power tower systems. This study was conducted in applied research unit for renewable energies (URAER) at Ghardaïa province, Algeria. Each heliostat reflects the sunray into the centre point of the cavity aperture situated at 7.4 m on the top tower. In order to find the orientation of each heliostat, several parameters relating the position of the sun and heliostat tower system are estimated. Optical simulation was performed by means of TracePro® 2013 ray tracing software using the MCRT (Monte Carlo ray trace) method. The results show that conical and trapezoidal shapes perform better than other studied cavities. They mostly exhibit the highest optical efficiency reaching 92.65%, 91.81% at absorptivity 85% and an optical efficiency of 90.88% and 89.30% at absorptivity 75%.
Read more6Two new methods used to simulate the circumferential solar flux density concentrated on the absorber of a parabolic trough solar collector
The optical efficiencies of a solar trough concentrator are important to the whole thermal performance of the solar collector, and the outer surface of the tube absorber is a key interface of energy flux. So it is necessary to simulate and analyze the concentrated solar flux density distributions on the tube absorber of a parabolic trough solar collector for various sun beam incident angles, with main optical errors considered. Since the solar trough concentrators are linear focusing, it is much of interest to investigate the solar flux density distribution on the cross-section profile of the tube absorber, rather than the flux density distribution along the focal line direction. Although a few integral approaches based on the "solar cone" concept were developed to compute the concentrated flux density for some simple trough concentrator geometries, all those integral approaches needed special integration routines, meanwhile, the optical parameters and geometrical properties of collectors also couldn't be changed conveniently. Flexible Monte Carlo ray trace (MCRT) methods are widely used to simulate the more accurate concentrated flux density distribution for compound parabolic solar trough concentrators, while generally they are quite time consuming. In this paper, we first mainly introduce a new backward ray tracing (BRT) method combined with the lumped effective solar cone, to simulate the cross-section flux density on the region of interest of the tube absorber. For BRT, bundles of rays are launched at absorber-surface points of interest, directly go through the glass cover of the absorber, strike on the uniformly sampled mirror segment centers in the close-related surface region of the parabolic reflector, and then direct to the effective solar cone around the incident sun beam direction after the virtual backward reflection. All the optical errors are convoluted into the effective solar cone. The brightness distribution of the effective solar cone is supposed to be circular Gaussian type. Then a parabolic trough solar collector of Euro Trough 150 is used as an example object to apply this BRT method. Euro Trough 150 is composed of RP3 mirror facets, with the focal length of 1.71m, aperture width of 5.77m, outer tube diameter of 0.07m. Also to verify the simulated flux density distributions, we establish a modified MCRT method. For this modified MCRT method, the random rays with weighted energy elements are launched in the close-related rectangle region in the aperture plane of the parabolic concentrator and the optical errors are statistically modeled in the stages of forward ray tracing process. Given the same concentrator geometric parameters and optical error values, the simulated results from these two ray tracing methods are in good consistence. The two highlights of this paper are the new optical simulation method, BRT, and figuring out the close-related mirror surface region for BRT and the close-related aperture region for MCRT in advance to effectively simulate the solar flux distribution on the absorber surface of a parabolic trough collector.
Read more10Towards standardization of in-site parabolic trough collector testing in solar thermal power plants
This paper presents a summary of the testing procedure and a validation of the methodology of parabolic trough collector in solar thermal power plants. The applied testing methodology is the one proposed within the Spanish standardization sub-committee AEN/CTN 206/SC117 working group WG2 related to the components for solar thermal power plants. This methodology is also proposed within the international committee IEC TC 117 (Standard draft IEC 62862-3-2 Ed. 1.0). This study is done at Plataforma Solar de Almería (PSA) in Almeria within the European project STAGE-STE. This paper presents the results of the optical and thermal efficiency of a large-size parabolic trough collector. The obtained values are similar to the previous analysis on this collector by PSA. The results of the tracking system have a good accuracy compared to the acceptance angle of the concentrator.
Read more15Optimum geometry of parabolic trough collectors with optical and thermal criteria
The objective of this work is to investigate the impact of the geometric dimensions of parabolic trough collector (PTC) in the optical, energetic and exergetic efficiency. The module of the commercial LS-3 PTC is examined with SOLIDWORKS FLOW SIMULATION in steady-state conditions. Various combinations of reflector widths and receiver diameters are tested. The optical and the thermal performance, as well as the exergetic performance are calculated for all the examined configurations. According to the final results, higher widths demands higher receiver diameter for optimum performance. For inlet temperature equal to 200 °C, the optimum design was find to be 3000 mm width with 42.5 mm receiver diameter, with the focal length to be 1840 mm (this is kept constant in all the cases). The results of this work and the presented methodology can be used as guidelines for the design of optimum PTC in the future.
Read moreEnhancing parabolic trough collector thermal efficiency: Experimental investigation of hybrid nanofluid
This study examines the performance of parabolic trough collectors (PTCs) in series with a hybrid nanofluid consisting of multi-walled carbon nanotubes (MWCNT) and cobalt (III) oxide nanoparticle (Co2O3). In this study, distilled water sourced from Amman, Jordan, was used as the working fluid, while gum arabic served as the surfactant. Initially, the flow rate was 1 L min−1, and water was used as a thermal medium to join two identical PTC devices in a sequence. Subsequently, a hybrid-type nanofluid with different volume concentrations was used for experiments namely; 0.01%, 0.04%, and 0.1%. All tests were conducted between 10 a.m. and 2 p.m. on different days, equipping both collectors with a digital tracking system. After the nanofluid was prepared and tested, the heat-handling performance of the PTCs was evaluated at different concentrations of MWCNT and Co₂O₃, and the results were compared to those of pure water. In the tests, the best thermal efficiency (17.84%) was achieved when the hybrid nanofluid was used at a concentration of 0.1%. The MWCNT and Co2O3 nanofluids with concentrations of 0.04% and 0.01% obtained thermal efficiency of 17.6% and 17.02%, respectively, while water obtained 15.07%. By increasing the concentration to 0.1%, a peak optical thermal efficiency of 18.38% was achieved.
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