Design And Optical Simulation Of A Beam-down Focal Fixed Dish Collector

With the emergence of environmental problems and the increasing depletion of fossil energy,people have gradually paid attention to the use of clean and renewable energy.As the world’s largest coal producer and consumer,China has entered a transitional stage from the era of traditional fossil energy utilization based on coal combustion to the era of clean and renewable energy utilization.In the current stage,on the one hand,it is necessary to strengthen the clean conversion of coal resources,on the other hand,renewable energy should be vigorously developed.Solar-coal thermochemical technology perfectly combines the needs of both aspects and is an excellent energy utilization program in this transitional stage.It is of great significance to promote the implementation of solar-coal thermochemical technology.In view of the fact that traditional solar collectors mostly provide heat sources for receivers that use fluid as the medium,the solar-coal thermochemical technology requires a reactor containing solid coal particles to realize the thermochemical reaction of coal.Since the solid coal particles are greatly affected by gravity,the solar collected is required to provide a high-temperature beam-down spot while maintaining the position of the spot fixed.Therefore,the focus of this study is to design a novel solar collector that can meet the requirements of solar-coal thermochemical technology on spot.Firstly,the design idea of the beam-down focal fixed dish collector is given.On the basis of the traditional dish solar collector,the method of tracking the sun by the novel collector is changed and the beam-down technology is combined so that the downward irradiated spot remains fixed in space.This idea not only retains the high concentration ratio of the traditional dish solar collector,but also meets the requirements of the solar-coal thermochemical technology for the beam-down spot with fixed position.Secondly,the beam-down technology is simulated based on a beam-down solar tower collector.Combined with the heliostat field generated by the campo code and the Monte Carlo ray tracing simulation method provided by the Soltrace,the optical efficiency and solar gathering characteristics of the beam-down solar tower constructed are studied,which will pave the way for the simulation of the beam-down focal fixed dish collector.Finally,based on the proposed design idea of the beam-down focal fixed dish collector,an optical model of the collector that meets the experimental needs of solar-coal thermochemical technology is constructed.The mirror model is built in the Solidworks and then imported into TracePro for optical simulation.The solar-collecting performance of the novel collector under three secondary reflection modes is studied,and the secondary reflection mirror is optimized.In addition,a comparative analysis is made between the novel collector and the solar furnace modified by optical path.The results show that the proposed beam-down focal fixed dish collector can provide a good spot for the experiment of solar-coal thermochemistry technology.