The effect of receiver geometry on the optical performance of a small-scale solar cavity receiver for parabolic dish applications

Daabo, Ahmed M.; Mahmoud, Saad; Al-Dadah, Raya

doi:10.1016/j.energy.2016.08.025

Cited by 143 publications

(57 citation statements)

References 37 publications

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“…Many studies focused on the effects of the cavity geometry shape, [8][9][10][11][12] installation location, 8,9 geometry size, 13,14 and cavity wall materials (ie, absorptivity) 13,15 of the cavity receiver on the optical performance of dish concentrator/cavity receiver system. Daabo et al 8,9 systematic studied the optical performance of the cavity receiver with a cylindrical, conical, and spherical geometries using an advanced ray-tracing OptisWorks software base on Monte Carlo ray-tracing method (MCRT). Considering the effects of the absorptivity and installation location of the cavity receiver.…”

Section: Discussionmentioning

confidence: 99%

“…23,24 For the Monte Carlo ray-tracing method, first, through the discretization of the reflection mirror of the solar concentrator, solar incident cone and cavity receiver surface, then simulating the reflection of each solar incident ray on the mirror surface of the solar concentrator, and the multiple reflection and absorption processes after the solar ray entering the cavity receiver, finally, count the solar radiation energy received by each element of the receiver surface and obtain the flux distribution on the cavity receiver. 8,9,22,25 With the increase of the new features in OptisWorks 2012 software, especially the 3-dimensional (3D) detector technologies, the software is capable of seeing exactly what is going on inside the geometry of the cavity receiver and how the reflected flux is distributed on the cavity walls.…”

Section: Methodology Description and Validationmentioning

confidence: 99%

“…The OptisWorks 2012 software has been widely used in the fields of the solar optical application. 8,9,22,25…”

Section: Methodology Description and Validationmentioning

confidence: 99%

“…From Figure 15, the heat flux of the part III area (within 183-230 mm) increases with the increase of f, but the size and position of the peak heat flux of part III area are small changes. 9 The variations of uniformity factor of the flux distribution on the absorber surface and optical efficiency of the cavity receiver with the focal length f and aperture radius R 1 of the dish concentrator are shown in Figures 16 and 17, respectively. The reasons for these laws generated the following: The part 1 mirror area in the dish concentrator increases with the increase of f, so that more sunlight hits the reflecting cone surface first and is absorbed or reflected, and then the reflected sunlight would hit the part III area and increase the heat flux in this area.…”

Section: Flux Distribution Uniformity Factor and Optical Efficiencymentioning

confidence: 99%

“…The formula of the uniformity factor UF is shown in Equation 9. 9 The variations of uniformity factor of the flux distribution on the absorber surface and optical efficiency of the cavity receiver with the focal length f and aperture radius R 1 of the dish concentrator are shown in Figures 16 and 17, respectively. From Figure 16, it can be seen that the uniformity factor decreases with the increase of f when R 1 is fixed.…”

Section: Flux Distribution Uniformity Factor and Optical Efficiencymentioning

confidence: 99%

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Effects of geometrical parameters of a dish concentrator on the optical performance of a cavity receiver in a solar dish-Stirling system

2018

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Summary Dish‐Stirling concentrated solar power (DS‐CSP) system is a complex system for solar energy‐thermal‐electric conversion. The dish concentrator and cavity receiver are optical devices for collecting the solar energy in DS‐CSP system; to determine the geometric parameters of dish concentrator is one of the important steps for design and development of DS‐CSP system, because it directly affects the optical performance of the cavity receiver. In this paper, the effects of the geometric parameters of a dish concentrator including aperture radius, focal length, unfilled radius, and fan‐shaped unfilled angle on optical performance (ie, optical efficiency and flux distribution) of a cavity receiver were studied. Furthermore, the influence of the receiver‐window radius of the cavity receiver and solar direct normal irradiance is also investigated. The cavity receiver is a novel structure that is equipped with a reflecting cone at bottom of the cavity to increases the optical efficiency of the cavity receiver. Moreover, a 2‐dimensional ray‐tracking program is developed to simulate the sunlight transmission path in DS‐CSP system, for helping understanding the effects mechanism of above parameters on optical performance of the cavity receiver. The analysis indicates that the optical efficiency of the cavity receiver with and without the reflecting cone is 89.88% and 85.70%, respectively, and former significantly increased 4.18% for 38 kW XEM‐Dish system. The uniformity factor of the flux distribution on the absorber surface decreases with the decreases of the rim angle of the dish concentrator, but the optical efficiency of the cavity receiver increases with the decreases of the rim angle and the increase amplitude becomes smaller and smaller when the rim angle range from 30° to 75°, So the optical efficiency and uniformity factor are conflicting performance index. Moreover, the unfilled radius has small effect on the optical efficiency, while the fan‐shaped unfilled angle and direct normal irradiance both not affect the optical efficiency. In addition, reducing the receiver‐window radius can improve the optical efficiency, but the effect is limited. This work could provide reference for design and optimization of the dish concentrator and establishing the foundation for further research on optical‐to‐thermal energy conversion.

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Section: Discussionmentioning

confidence: 99%

Section: Methodology Description and Validationmentioning

confidence: 99%

“…The OptisWorks 2012 software has been widely used in the fields of the solar optical application. 8,9,22,25…”

Section: Methodology Description and Validationmentioning

confidence: 99%

Section: Flux Distribution Uniformity Factor and Optical Efficiencymentioning

confidence: 99%

Section: Flux Distribution Uniformity Factor and Optical Efficiencymentioning

confidence: 99%

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Effects of geometrical parameters of a dish concentrator on the optical performance of a cavity receiver in a solar dish-Stirling system

2018

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Performance evaluation and optimization of solar dish concentrator in the upper Egypt region

Mohammed,

Shmroukh,

Ghazaly

et al. 2023

Env Prog and Sustain Energy

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The goal of this study is to optimize and examine the effect of different rim angles and focus lengths on the performance of a solar parabolic dish. To achieve these goals, a solar parabolic dish concentrator was constructed with different focus point positions and tested under the climatic conditions of the Upper Egypt region in Qena city, with the location of (Latitude: 26.16°, Longitude: 32.71°). The preliminary experimental days started on 18th and lasted on 20th of September 2022, and the tested rim angles were 70°, 80°, and 60°. The results showed that the performance of the proposed solar parabolic dish concentrator was enhanced when the rim angle was between 60° and 70°, otherwise, the performance was regressed when the rim angle was between 70° and 80°. To optimize the rim angle, another available rim angle was selected to increase the performance of the solar dish fixed at 65°, and this angle was tested on 21st of September 2022. The results demonstrated that the thermal efficiency of the solar parabolic dish with rim angle of 65° was higher than that of 70°, 80°, and 60°, and the recorded thermal efficiency reached up to 79.5%, 39.4%, 5.84%, and 28.4%, respectively, under the tested rim angles.

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Mirror rearrangement optimization for uniform flux distribution on the cavity receiver of solar parabolic dish concentrator system

2018

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Summary The nonuniform and high‐gradient solar radiation flux on the absorber surface of solar dish concentrator/cavity receiver (SDCR) system will affect its operational reliability and service lifetime. Therefore, homogenization of the flux distribution is critical and important. In this paper, 2 mirror rearrangement strategies and its optimization method by combining a novel ray tracing method and the genetic algorithm are proposed to optimize the parabolic dish concentrator (PDC) so as to realize the uniform flux distribution on the absorber surface inside the cavity receiver of SDCR system. The mirror rearrangement strategy includes a mirror rotation strategy and mirror translation strategy, which rotate and translate (along the focal axis) each mirror unit of the PDC to achieve multipoint aiming, respectively. Firstly, a correlation model between the focus spot radius and mirror rearrangement parameters is derived as constraint model to optimize the PDC. Secondly, a novel method named motion accumulation ray‐tracing method is proposed to reduce the optical simulation time. The optical model by motion accumulation ray‐tracing method and optimization model of SDCR system are established in detailed, and then, an optimization program by combining a ray‐tracing code and genetic algorithm code in C++ is developed and verified. Finally, 3 typical cavity receivers, namely, cylindrical, conical, and spherical, are taken as examples to fully verify the effectiveness of these proposed methods. The results show that the optimized PDC by mirror rearrangement strategies can not only greatly improve the flux uniformity (ie, reduce the nonuniformity factor) and reduce the peak local concentration ratio of the absorber surface but also obtain excellent optical efficiency and direct useful energy ratio. A better optimization results when the PDC is optimized by mirror rotation strategy at aperture radius of 7.0 m, focal length of 6.00 m, and ring number of 6; the nonuniform factor of the cylindrical, conical, and spherical cavity receivers is greatly reduced from 0.63, 0.67, and 0.45 to 0.18, 0.17, and 0.26, respectively; the peak local concentration ratio is reduced from 1140.00, 1399.00, and 633.30 to 709.10, 794.00, and 505.90, respectively; and the optical efficiency of SDCR system is as high as 92.01%, 92.13%, and 92.71%, respectively. These results also show that the dish concentrator with same focal length can match different cavity receivers by mirror rearrangement and it can obtain excellent flux uniformity.

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The effect of receiver geometry on the optical performance of a small-scale solar cavity receiver for parabolic dish applications

Cited by 143 publications

References 37 publications

Effects of geometrical parameters of a dish concentrator on the optical performance of a cavity receiver in a solar dish-Stirling system

Effects of geometrical parameters of a dish concentrator on the optical performance of a cavity receiver in a solar dish-Stirling system

Performance evaluation and optimization of solar dish concentrator in the upper Egypt region

Mirror rearrangement optimization for uniform flux distribution on the cavity receiver of solar parabolic dish concentrator system

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