Characteristic Analysis And Modeling Research Of Tower Solar Thermal Power Generation Heating System

Tower solar thermal power generation technology has the advantages of large-scale capacity,low cost,large-scale thermal storage,and is an important form of large-scale grid-connected solar thermal power generation.In this paper,the calculation model of solar altitude angle and azimuth angle is established,and the sun position tracking method of azimuth-elevation angle of heliostat in the field coordinate system of concentrator is studied,and the factors affecting the concentrating efficiency are analyzed.It is found that compared with winter,the northern hemisphere has larger solar altitude angle,stronger radiation energy and higher concentration efficiency in summer.Cosine efficiency is about0.7-0.8,which accounts for the largest proportion,and is affected by season and tower height.In summer,the sun has a high altitude angle and high cosine efficiency.Within a certain range,the tower height increases from 50m to 150m,the cosine efficiency increases by 0.4 on average,and the concentrating efficiency improves.Based on the analysis of the structure and principle of cavity heat absorber,a concentrating model of 10MW water/steam working fluid cavity heat absorber is established.The results show that when the solar radiation intensity decreases by 10%step disturbance,the drum outlet temperature decreases by 8.5?on the basis of 327?and tends to be stable.The drum outlet pressure decreases by 1.3 MPa on the basis of 12 MPa and tends to be stable.When the solar irradiation intensity decreases by 20%and 30%step disturbance,the larger the disturbance amplitude is,the larger the temperature and pressure of steam at the drum outlet decrease,and the change direction is consistent with the disturbance change direction.Based on the analysis of cloud transmittance,height and shape distribution,a cloud classification method representing different weather types is designed.The transmittance ranges from 0.29 to 0.89.The step disturbance,continuous disturbance and complex random disturbance of mirror field energy caused by cloud movement are simulated.When the cloud transmittance changes from 100%,92%to 85%,the steam pressure at the outlet of the drum decreases by 0.78 MPa and the steam temperature at the outlet of the drum decreases by 11.13?,but the system remains stable,with the error less than 4%,which meets the design requirements.The influence of wind speed on cloud shadow movement is analyzed.When the period of wind speed change is T=20s,the wind speed is slow,the radiation intensity of the sun varies randomly in the range of 1000W/m~2:±40W/m~2,the drum temperature fluctuates in the range of 320?:±8?,and the drum pressure fluctuates in the range of12MPa:±1.5MPa.When the wind speed changes in the period T=2s,the wind speed is fast,the solar irradiation intensity fluctuates irregularly and rapidly,the drum temperature fluctuates in the range of 320?:±2?,the drum pressure fluctuates in the range of 12MPa:±0.4MPa,the fluctuation speed is fast but the overall amplitude is small.It can be seen that the faster the period of wind speed change,the smaller the impact of light on the system.