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Geometrical and optical analysis of small-sized parabolic trough collector using ray tracing tool SolTrace

Singh Raman Kumar, Chandra Prakash

Archives of Thermodynamics

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2023

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Vol. 44, no 3

35--61

EN

The present work is aimed at geometrical optimization and optical analysis of a small-sized parabolic trough collector (PTC). Improving the performance of parabolic trough collectors can greatly justify the use of solar energy. An optimized curvature geometry, the location of the absorber tube, and the heat flux distribution along the circumference of the absorber tube are major features in the geometric optimization and optical modelling of parabolic trough collectors. Rim angle, aperture width, the diameter of the absorber tube, receiver position, and the optimum value of heat flux are the major parameters considered in this work for geometrical and optical analysis. The Monte Carlo ray tracing method has been adopted for analysis. The non-uniform heat flux distribution profile obtained from optical analysis of the proposed parabolic trough collector has been compared with the profile available in the literature, and good agreement has been obtained, which proves the feasibility and reliability of the model and method used for this study. An experimental new small-sized parabolic trough collector has been fabricated for the optimized rim angle of 90 deg after a successful laser light feasibility test. The effect of the absorber tube position along the optical axis on the heat flux profile was analysed and found to be substantial. Furthermore, the sensitivity analysis of the parabolic trough collector using the software applied has been discussed separately.

2

Heat transfer improvement using additive manufacturing technologies: a review

Byiringiro J., Chaanaoui M., Halimi M., Vaudreuil S.

Archives of Materials Science and Engineering

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2023

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Vol. 123, nr 1

30--41

EN

Purpose: To provide a comprehensive review of additive manufacturing use in heat transfer improvement and to carry out the economic feasibility of additive manufacturing compared to conventional manufacturing. Heat transfer improvement is particularly interesting for different industrial sectors due to its economic, practical, and environmental benefits. Three heat transfer improvement techniques are used: active, passive, and compound. Design/methodology/approach: According to numerous studies on heat transfer enhancement devices, most configurations with strong heat transfer performance are geometrically complex. Thus, those configurations cannot be easily manufactured using conventional manufacturing. With additive manufacturing, almost any configuration can be manufactured, with the added benefit that the produced parts’ surface characteristics can enhance heat transfer. It can, however, lead to a significant pressure drop increase that will reduce the overall performance. In the given article, a comparison of the capital cost of a 100 MW parabolic trough power plant has been carried out, considering two types of solar receivers; the first is manufactured using conventional methods, and the second uses additive manufacturing. The heat transfer of the new receiver configuration is investigated using computational fluid dynamics through ANYS Fluent. Findings: Although the cost of additive manufacturing machines and materials is high compared to conventional manufacturing, the outcome revealed that the gain in efficiency when using additive-manufactured receivers leads to a reduction in the number of receiver tubes and the number of solar collectors needed in the solar field It implies a considerable reduction of parabolic trough collector plant capital cost, which is 20.7%. It can, therefore, be concluded that, even if initial setup expenses are higher, additive manufacturing could be more cost- effective than traditional manufacturing. Practical implications: With the reduction of the parabolic trough collector plant capital cost, the levelized cost of electricity will eventually be reduced, which will play a role in increasing the use of solar thermal energy. Originality/value: No review studies discuss the manufacturing potential and cost- effectiveness potential of additive manufacturing when producing heat transfer improvement equipment, especially when producing long pieces. In addition, the paper uses a novel receiver configuration to investigate the economic aspect.

3

An experimental study on parabolic trough collector in simulated conditions by metal-halide solar radiation simulator

Stanek Bartosz, Bartela Łukasz, Węcel Daniel, Rulik Sebastian

Archives of Thermodynamics

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2022

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Vol. 43, no 3

47--61

EN

The utilization of solar radiation to obtain high-temperature heat can be realized by multiplying it on the illuminated surface with solar concentrating technologies. High-temperature heat with significant energy potential can be used for many technological purposes, e.g. the production of heat, cold or electricity. The following paper presents the results of the experimental study, on the operation of the parabolic linear absorber in the parabolic concentrator solar system. The parabolic mirror with an aperture of 1 m and a focal length of 0.25 m focuses the simulated radiation onto a tubular absorber with a diameter of 33.7 mm, which is placed in a vacuum tube. The length of the absorber is 1 m. The installation is illuminated by the solar simulator, which allows to carry out tests under constant and repeatable conditions. The simulator consists of 18 metal halide lamps, with a nominal power of 575 W each with a dimming possibility of up to 60%. The paper presents preliminary results of heat absorption by the analysed absorber, temperature increment, collected heat flux, and the pressure drop crucial for the optimization of the absorber geometry.

4

Enhancement of convective heat transfer in a parabolic trough collector using vibrations - an introductory numerical analysis

Grzywnowicz Krzysztof, Bartela Łukasz, Remiorz Leszek, Stanek Bartosz

Journal of Power Technologies

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2020

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Vol. 100, nr 4

291--300

EN

Energy generation systems based on renewable energy sources (RES) are rapidly gaining ground in the global power and heatmarket. Most of these systems are well-suited to distributed energy solutions, including distributed heat production. Individual users and local low-power plants can use solar thermal devices for the purpose of providing domestic hot water, heating and cooling. Nevertheless, the variability of solar irradiance can make it difficult to harvest energy efficiently all year round. Therefore, from the point of view of improving the overall, year-averaged operational parameters of a solar thermal device it isparamount to maximize the heat acquired from it at times ofhigh radiation flux. This paper discusses computational research on enhancing convective heat transfer in the absorber of a parabolic trough collector (PTC), through inducing vibrations of an immersed flat plate. The investigation identifies the influence of different amplitudes and frequencies of oscillatory motion on the absorber’s parameters, compares them with the construction of a classical absorber and considers flow turbulization. The results indicate there is only a limited application of vibrations to enhance operational parameters of solar thermal absorbers, with the best results obtained for thermal fluidflows of below 0.1 dms.