| Solar dish thermal power generation system as an efficient way to use solar energy the collecting effect of the system will directly determine the power generation efficiency of Stirling engine.In order to find out the main factors which affecting the collecting effects, the light transmission path and the working principle of the system was analyzed, we found out the main factors including concentrator, frame, two-axis drives and reflection cone. Among them, the frame is the supporting part of the whole system Which used to control the mirror geometry and the receiver location, because of the weight of the system and the wind load frame will be deformed which reducing the system collecting efficiency. The double axis tracking device is the precise point of the system, But deviation of the system which caused by the actual manufacturing and installation process will directly affect the tracking accuracy of the system and reducing the collecting efficiency. The reflection cone is the basis of the flux distribution of the absorber and can be used to make full use of the light energy which is not used, the reflection cone will also reduce the collecting efficiency.So, Based on the above analysis, we take the 38 k W dish solar thermal power generation system as the object, By adopted the method of theoretical analysis and practical measurement to study the factors of dish solar thermal power system, The concrete research content includes:At first, the structural characteristics of the cavity absorber was analyzed and the parameter model of the absorber which variables for the secondary reflection cone was built. As the research object of the 38 k W dish stirling system, the Tracepro soft ware and Monte Carlo ray tracing method were employed to analyze the effects of different secondary reflection cone on the flux distribution of the cavity absorber. the results show that: two reflection cone can increasing the light energy utilization rate of the heat receiver, At the same time, the second reflection cone can improving the flow distribution of the absorber.Then, study the double axis tracking device error affecting the energy collecting of the solar dish system, the main source of the tracking device error was found, and then analyzed the main types of axis deviation.According to the need of axismeasurement of the double axis tracking device in the dish solar thermal power generation system, a method for measuring the position of the axis of the double axis tracking device was proposed which by using the total station instrument with 360 degree reflection prism. finally, the influence of axis deviation on the energy concentrating was analyzed. the measurement results show: the main axis deviation of dual axis tracking device was orthogonal deviation of the elevation axis, the deviation is 0.682° and with the increase of the elevation angle the the focal point is gradually deviated from the center position.Finally, according to the frame structure of 38 k W dish solar thermal power system, the Ansys software was used to analyze the frame deformation, which cased by gravity and wind. the displacement distribution of joint nodes on the frame was extracted. Using the formula derived the influence of the frame error on the energy distribution. On the basis of this, a method to measure the deformation of the frame is presented, the spatial coordinates of a large number of prism points fixed on the frame are measured by means of TS30 total station instrument and the influence of the deformation of the frame under different working conditions can be achieved which can provide reference for the field deformation measurement and optimization of the frame structure. |
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