The impact of using Curved heliostats on a Linear Fresnel reflector (LFR) has been investigated.
The Curved LFR (CLFR) allows better performances than a LFR concentrator in terms of optical efficiency and flux density over the receiver.
Low receiver heights are favored while using CLFR systems, which would decrease related system manufacture cost.
The new CLFR geometrical configuration found allows using reduced receiver size which may minimize thermal losses and enhance the thermal efficiency of the device.
The 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.
- Concentrating solar power;
- Linear fresnel reflector;
- Monte Carlo method;
- Heliostat curvature
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