Parabolic trough collector with rhombus tube absorber for higher concentration ratio

In the present study, the concentration ratio of the parabolic trough collector using rhombus tube absorber has been estimated. An analytical technique has been developed to determine the optimum size of the rhombus tube absorber for given trough dimensions. The optimum size of the rhombus tube absorber is 13.8% smaller than the circular tube absorber for the LS3 trough with no change in intercept factor. The maximum improvement in the concentration ratio is found to be 31.5% for the troughs with rim angle 90° in comparison to circular tube absorber. Results also indicate that rhombus tube absorber can be employed for a range of rim angle 75 to 90 degree.

Abbreviations: CR: concentration ratio; CSP: concentrated solar power; MCRT: Monte Carlo ray tracing; PTC: parabolic trough collector     

塔式光热电站吸热器的壁面热流分布

为深入研究塔式光热电站吸热器壁面的热流密度分布,基于赤道聚光策略和基本光路原理,利用光学仿真分析软件SolTrace对西班牙Gemasolar塔式光热电站系统进行几何与光学建模.通过结果敛散性判断,确定采用5 000 000条射线进行模拟研究;模拟结果与文献研究结果符合良好,证明模型准确可靠.采用夏至日设计点标准状况下的太阳光入射辐射,通过射线追踪的方法,模拟获得外露管式吸热器壁面上的热流密度分布,发现不同吸热管壁面接收的太阳辐射热流密度变化规律与定日镜场环形分布方式有关;单根吸热管时壁面热流密度分布不均匀.分析冬至日午时吸热管的热流密度分布,对比吸热管壁面热流分布的模拟结果与相应的近似高斯分布,发现近似处理与模拟结果差异较大.研究结果表明,对于塔式吸热器壁面热流分布,采用SolTrace仿真分析比用近似高斯分布更具有实际指导意义.