Proposal and analysis of different methodologies for the shading and blocking efficiency in central receivers systems. (1st March 2017)

• Record Type: Journal Article
• Authors: Ortega, Guillermo; Rovira, Antonio
• Is Part Of: Solar energy. Volume 144(2017)
• Page Start: 475
• Page End: 488
• Publication Date: 2017-03-01
• Subjects: Concentrated solar power -- Central receiver -- Heliostat field design -- Shading and blocking calculation; Solar energy -- Periodicals; Solar engines -- Periodicals; 621.47
• DOI: 10.1016/j.solener.2017.01.054
• Languages: English
• ISSNs: 0038-092X

Abstract

Highlights: Four methodologies for fast shading and blocking efficiency calculation. Comparison of the methods with a conventional Ray-tracing model. Suitable for heliostat layout optimization, especially homology and Boolean ones. Improvement of accuracy and reduction of computation time at low resolution rates. Simplified determination of potential heliostat for shading and blocking. Abstract: Nowadays, there are many simulation codes aimed at the simulation of the solar field performance and the optimization of the layout of central receivers systems. These codes should obtain fast and accurately the different efficiency factors of the solar field at different sun positions (representative of the yearly operation). Among these factors, the shading and blocking efficiency is maybe the most demanding one regarding the computational effort. In this paper four non-conventional methodologies are presented for the calculation of the shading and blocking efficiency. The codes have been developed with the ambition of decreasing the computational time without a significant accuracy drop. For that reason, they are suitable for optimization tools. Additionally, a new methodology for the determination of the subset of heliostats with potential for shading or blocking is presented. The performance of the methodologies is evaluated by means of a study of the errors and computational times, which are compared to those reached by a conventional Monte-Carlo ray tracing reference simulation. Results indicate that the proposed methodologies, particularly two of them, present good accuracy and a significant decrease of the computational time. The causes of the main errors of each methodology are also discussed.