a b s t r a c tThe present paper gives a numerical investigation of the effect of mirror curvature on optical performance of a Linear Fresnel Reflector solar field installed recently in Morocco. The objective is to highlight and discuss the effect of mirror curvature on the flux density distribution over the receiver and the system optical efficiency. For this purpose, a Monte Carlo-ray tracing simulation tool is developed and used to optimize the optical design taking into account the curvature degree of the heliostat field. In order to assess the accuracy of the numerical code developed and the validity of simulation results, a set of verification tests were developed and detailed within this article. Then, the optical performance of the system is evaluated as a function of mirror curvature and receiver height. The major challenge of this study is to find a trade-off between heliostat curvature and receiver height since lower and smaller receivers may reduce the system cost. It has been found that the flux distribution over the receiver and the optical efficiency of the system are relatively sensitive to the mirror curvature. We have demonstrated quantitatively how the use of curved mirrors can enhance the optical performance and reduce the required receiver size.

The work presented in this paper belong to CHAMS-1 project supported by the IRESEN (Institute of Research on Solar and New Energy-Morocco). Its scientific and technological aim is to develop a new generation of Concentrating Solar Power plant (CSP) suitable for a medium concentrating solar thermal electricity generation closed to the grid parity. The originality of this project lies on using a new generation of a linear Fresnel concentrating thermal solar field for thermal applications taking into account cost reduction, material enhancement and efficiency gain. To attempt this goal, a preliminary Monte-Carlo Ray Tracing model was developed that will be used to analyze, optimize and design solar concentrating linear Fresnel optical systems. The code consists of a detailed three dimensional geometrical model for the optical solar field behavior. In this paper, technical approach used to model optically and geometrically an optical system is presented. Preliminary results are presented for a simplified configuration of an optical system and for a Linear Fresnel solar field.

No abstract

The work presented in this paper is carried out in the frame of the research project called CHAMS-I, supported by IRESEN (Institute of Research on Solar and New Energy Morocco). The main objective of this work is to develop a numerical tool for scientific computing that enables the design and optimization of a new low cost CSP system based on a new generation of linear Fresnel technology. To model incident rays coming from the solar disk and interacting with different components of the solar field, we have used the ray-tracing Monte-Carlo algorithm. Preliminary results are presented for a Linear Fresnel solar field.

Recently, linear Fresnel reflectors (LFR) arouse an increasing interest by the scientific and industrial community and have had a really fast development in the domain of concentrated solar power (CSP). LFR is considered as a promising technology which could produce an optical performance lower than those of parabolic trough collector, but its component simplicity would allow high cost reductions in its manufacturing compared to high investment costs of parabolic troughs. The purpose of this paper is to analyze the optical performances of an LFR prototype developed in the framework of CHAMS project, Morocco. The development of this prototype comes to supply industrial applications needing heat at small to medium temperature levels. To achieve this objective, an optical code based on the Monte Carlo (MC) ray tracing technique was developed for optical optimization purposes. The developed code identifies geometrical parameters that have a greater influence on optical efficiency of the LFR system as the mirror spacing arrangement, the receiver height, the receiver geometrical configuration taking into account the secondary reflector shape, and the absorber tube diameter. An analysis is conducted to identify the contribution of each mode of optical losses (blocking, shading, cosine…) in the optical efficiency of the system. Then, an optimization procedure is applied to enhance the optical performances of the prototype.