Research On Heat Loss Test Method Of Solar High Temperature Vacuum Collector

With the massive exploitation and forthputting of fossil fuels such as oil and natural gas,the global environmental pollution problem has become more and more serious,and fossil fuels are non-renewable resources,it will be exhausted one day as a result of uncontrolled exploitation of human beings.As an inexhaustible source of clean energy,solar energy has unique advantages in all aspects and is favored by energy organizations all over the world.As an effective form of solar energy utilization,CSP has been highly valued by experts from all over the world.Vacuum collector tubes are the key components of trough solar power system and linear Fresnel CSP systems,and their thermal performance directly affects the power generation efficiency of the entire system.Therefore,it is necessary to carry out research on the thermal performance test platform of vacuum collector tubes.Based on above problems,this paper studies the thermal performance test platform of vacuum collector tubes.The main research contents are as follows:(1)Investigate the methods and principles used in relatively mature thermal performance test systems abroad.The main methods are steady state test method and dynamic test method.The different principles and test procedures of the two test methods are introduced.The thermal performance test method based on heat balance method is selected for further study.The main factors affecting the final test results are analyzed: heat loss at the end of the collector tube,temperature field distribution in the collector tube,and temperature control accuracy,and put forward the corresponding solution.(2)The hardware of the whole heat collecting tube heat loss test platform is built.The platform is controlled by the industrial computer which mainly includes the temperature collecting module,the power collecting module,the temperature control module and the end compensation unit,and the functions and device selection of each module are introduced.The upper monitoring software was programed by visual basic6.0,which realized the functions of uploading heat collector temperature,historical data storage and export,historical curve display,power collection and calculation,intelligent control algorithm,heating control algorithm,etc.The main considerations in the use of the software are described in detail.(3)Aiming at the temperature control part which seriously affects the heat loss test results of collector tube,the traditional algorithm of temperature control is studied.After analyzing the advantages and disadvantages of traditional algorithm,the PID control strategy of hybrid particle swarm optimization parameters is proposed.The control effect is verified by simulation comparison.(4)On the previously established test platform,the thermal performance of 4060 mm class and 90 mm solar vacuum collector tube was tested by traditional algorithm and optimization algorithm.The temperature of the collector tube was tested from 100°C to 550°C every 50°C.The heat loss value of each point is plotted,and the thermal performance curve is drawn.By comparing the determination coefficients of the thermal performance fitting curves of two control algorithms,the determination coefficient of the fitting curve of the optimization algorithm is closer to 1,and the fitting effect is better,indicating that the optimized algorithm test results have higher credibility.