The Dust Removal Method Of Fresnel HCPVT System And Its Cleaning Effect Analysis

In order to solve the problem of dust on the surface of the concentrator caused by climate,emissions and other factors in Hohhot.For the Fresnel concentrated photovoltaic photothermal system(HCPVT),the dust removal effect of the nozzle under different working conditions was simulated and analyzed.Through experimental testing,the optical performance,energy flow distribution and thermoelectric output of the system under the influence of high-frequency airflow dust removal are analyzed.The BP neural network model optimized based on genetic algorithm was used to predict and analyze the change law of system electrical power under the influence of single factor.Firstly,in order to analyze the influence of mirror area dust on the overall transmittance of Fresnel lens,and at the same time facilitate the analysis of the change law of lens transmittance before and after dust removal,an integrating box test platform is built based on the integrating sphere principle.Within 30 days of exposure,the average transmittance of Fresnel lens decreased by 12.04%,which showed the law of rapid decline in the early stage of dust accumulation and gradual flattening in the later stage.After testing the small samples with the same dust accumulation location and dust accumulation time with UV-3600 spectrophotometer,the average value of the data difference between the two was maintained at about 1.3%,so it was considered that the test error of the integrating box test platform met the requirements.Secondly,the internal flow characteristics of the air knife nozzle and the simulation of the high-frequency airflow dust removal process are analyzed,and the applicable working conditions and dust removal effects of high-frequency airflow dust removal are compared and analyzed by setting different inlet flow rates,nozzle angles and particle parameters.The results showed that for every 1m/s increase in the average inlet flow rate,the outlet flow rate of the nozzle increased by 1.19m/s,and the turbulent kinetic energy at the outlet increased by 15.2m~2/s~2.Thirdly,in order to analyze the influence of high-frequency airflow dust removal on the optical,energy flow and thermoelectric properties of Fresnel HCPVT system,a high-frequency airflow dust removal system was built and dust removal tests were carried out.After high-frequency airflow dust removal of the lens with an exposure time of 21days,the dust accumulation density decreased by 0.83g/m2,the average transmittance increased by 7.1%,the reflectivity decreased by 5.8%,the average energy flow in the center of the focal spot increased by 62k W/m~2,the battery temperature rise increased by3.02°C,and the current increased by 0.84A.Overall,the longer the exposure time,the greater the system performance improvement after dust removal.Finally,the BP neural network model optimized based on genetic algorithm is used to predict the system electrical power data under the influence of dust density,solar irradiance,cooling water temperature and battery temperature,and the remaining influencing factors are unified in the prediction data and single-factor analysis is carried out.Under the influence of dust density,the electrical power improvement before and after dust removal based on the prediction model in the three dust removal days was 1.24W,2.21W and2.31W,and the test improvement data were 1.24W,2.59W and 2.46W.The difference in the data is due to other factors in the experimental data.