纳米流体为工质的直吸式太阳集热器性能研究

STUDY OF THE PERFORMANCE OF A DIRECT ABSORPTION SOLAR COLLECTOR USING NANOFLUIDS AS WORKING FLUIDS

搭建具有自动跟踪功能的直吸式太阳集热器实验系统,以Ti N-EG纳米流体为工质,采用菲涅尔透镜将太阳光聚焦到集热管上,集热管采用双层真空管。测量不同流量、辐照度时集热管内部及进出口处的流体温度;使用CFD软件得出集热管内的温度分布。通过分析管内的温度分布、进出口温差及集热器的热效率,对集热器的工作性能进行评价。结果表明:数值模拟与实验结果较吻合,集热器的热效率可达70%以上,出口处工质温度达到120℃以上,该集热器可工作于中温区域。

A direct absorption solar collector experimental system has been built. A Fresnel lens were used to concentrate solar radiation to an evacuated tube. TiN-EG nanofluids be applied as the working fluid. The solar collector can automatically track the sun. Fluid temperatures have been measured under different irradiation intensities and flow rates, and temperature distribution of the working fluid in the absorber tube and system thermal efficiency have been analyzed. A CFD software has been used to a build a three-dimensional model to conduct a simulation. Simulation results were compared with experimental measurements. Comparisons showed that the numerical simulation results agree well with the experimental results, confirming that the simulation method is reliable. Performance of the collector is good. The collector can be used in the medium temperature range. The fluid temperature at the outlet of the evacuated tube reaches up to 120 ℃ and the collector efficiency under different operating conditions are all higher than 70%.