Research On The Key Technologies And Operational Characteristics Of Parabolic Trough Solar Power Plant

With the rapid development of economy and society, the dual pressures of energy crisis and environmental pollution have promoted the transformation of energy production and consumption patterns to renewable energy in the world. Concentrating solar power (CSP) technology as one of emerging technologies for sustainable use of coal for power generation is widely concerned in the world. With the recent introduction of a series of relevant national policies,Concentrating solar power as a new form of renewable energy power generation ushered in the development period in China . Key Technologies of concentrating solar power such as parabolic trough solar concentratoris, solar receiver, control technology and plant modeling are studied in depth in this paper.Aiming at the solar concentrator and solar receiver in parabolic trough solar power plants, solar concentrator theory was studied, the influence of the error on the intercept factor and random error on the energy flux density distribution of solar receiver was calculated and analyzed. The modeling of parabolic trough solar field was presented in this paper. The key characteristics of parabolic trough solar field such as collector geometrical end losses, cosine factor, solar shading, solar field efficiency and others can be calculated using this model. The results of the efficiency analysis show that the average annual efficiency of the north-south arrangement is higher than that of the east-west arrangement, the average annual efficiency of the north-south arrangement is 0.473 and the average annual efficiency of the east-west arrangement is 0.398. The cosine of the sun’s incident angle and incident angle modifier are the main factors that affect parabolic trough solar field efficiency by calculating the results of the analysis.The influence of solar shading and end losses on the efficiency is relatively small. The heat transfer of solar receiver’s model and the dynamic model of the outlet temperature were established in this paper. The instantaneous thermal efficiency of the solar receiver decreases with the increase of the average temperature of the heat transfer fluid and increases with the increase of direct normal radiation by using this mathematical model.The difference between the instantaneous thermal efficiency calculated by the model and the NREL test results is less than 3%. The model of parabolic trough solar field and the solar receiver can effectively predict the main characteristic parameters of parabolic trough solar field in different conditions, which can provide an important theoretical basis for the optimal design and efficient operation of parabolic trough solar field by using oil as heat transfer fluid.A model of a 35MW parabolic trough solar power plant was established in this paper.The dynamic performance analysis of the parameters such as heat transfer fluid flow rate, the efficiency of solar energy into heat and heat into electrical energy, the efficiency of parabolic trough solar field and power cycle were studied. The model can be used to simulate in different regions of China and can effectively evaluate the output power and efficiency of the parabolic trough solar power plant under different working conditions in time and space dimension. It can be used for the location, design,parabolic trough solar power plant operation analysis and investment decision to provide theoretical basis.An outlet temperature control strategy for parabolic trough solar receiver based on internal model control theory is proposed, which can effectively control the outlet temperature for time-delay and time-varying characteristics. This control strategy is superior to the traditional PID control strategy from the dynamic error, static error, anti-perturbation and other control performance aspects by simulation comparison. The control strategy can provide some reference for the temperature control of parabolic trough solar power plant in China.A solar tracking system for parabolic trough solar field was designed in this paper,which fully automatic, high precision, low cost as its performance characteristics.The solar tracking system adopts the active tracing strategy of astronomical algorithms. The system can calculate the rotation angle of parabolic trough solar concentrator to track the sun and use the angle to generate the control command to drive the hydraulic cylinder,which can realize the accurate solar tracking of parabolic trough solar concentrator with various arrangement modes. Experiments show that the error of the solar tracking system is within 0.5°, which can meet the requirements of solar tracking for parabolic trough solar concentrator.