Research On Concentrating Solar Air Collector Of Concentric Sleeve

Solar energy as a renewable energy most abundant energy,development and utilization of solar energy resources is an important measure of sustainable development and coordination of economic environment.The solar energy resources can be collected and utilized by the solar collector,and can be transferred to the working medium for people to use.This paper presents a concentrating solar air collector of concentric sleeve,the CPC concentrator,vacuum tube,and concentric sleeve air collector are organically combined.The device uses the CPC concentrator to converge the sun’s rays and collect radiant energy to heat the flowing medium air.At the same time,the vacuum tube and the concentric sleeve air heat collection device form a series flow channel,which increases the heat exchange time of the air inside the experimental device and improves the heat collection effect.In this paper,cabinet exhaust is used as device air intake.Experiments have been conducted to test the heat collection performance of the device under different working conditions before and after the CPC condenser is installed,changing the air inlet temperature(30 ℃,40 ℃,45 ℃,50 ℃),and changing the air flow rate(0.5 m/s,0.6 m/s,0.7 m/s,1.0 m/s).This is the engineering application and further improvement of the device.By experimental tests,this paper obtained the following results:After the installation of the CPC concentrator in the experimental device,through comparative experiments,the overall heat collection performance and efficiency of the experimental device is better than that of the heat collection device without a condenser.Air flow rate at different conditions were 0.5 m/s,0.6 m/s,0.7 m/s,1.0 m/s,and the air condenser installation CPC improved the average temperature rise were 79.5%,74.6%,88.3%,29.6%;the total heat collection efficiency has increased by 24.2%,22.7%,40.6%,and 29.2%;the average heat collection has increased by 79.6%,60.1%,91.9%,and 29.3%.Experimental apparatus internal air flow rate is kept constant,the temperature of air inlet collector is a major factor in the performance and efficiency of the experimental device and heat collection unit at all levels.Under the test conditions where the air inlet temperature increased by 23 ℃,19.5 ℃,24.5 ℃,16.8 ℃ in the experimental device,the average air temperature rise decreased by 19.9 ℃,11.3 ℃,15.8 ℃,8 ℃,the average heat collection is reduced by 107.3 W,78.9 W,127.5 W,93.9 W,and the total heat collection efficiency decreased by 13.7℃.%,11.6%,25.5%,17.7%.Air flow rate is kept constant,increasing the air inlet temperature conducive to raise the temperature of each collector unit;inlet air temperature is higher,the lower the average efficiency of the collector unit of the collector.Experimental device for air inlet temperature is maintained constant,the air flow rate is a major factor affecting the performance of the collector and the collector efficiency and levels of experimental units.At inlet temperatures of 30 °C and 50 °C conditions,with the air flow rate increases,the average air temperature increases,the overall collection efficiency is increased.At inlet temperatures of 40 °C and 45 °C conditions,with the air flow rate increases,the average air temperature decreases,the overall collection efficiency is increased.In the experimental device,the average heat collection increased by 130.3 W,122.3 W,145.9W,and 107.8 W under test conditions with air flow rates of 0.5 m/s,0.6 m/s,0.7 m/s,and 1.0m/s.The total heat collection efficiency has increased by 30.3%,25.6%,28.5% and 20.4%.The higher the air velocity of the experimental device,the lower the temperature of each heat collection unit,and the higher the average heat collection efficiency of the unit.In addition to the experimental tests,this paper has carried out a numerical simulation analysis on the concentrating solar air collector of concentric sleeve.Analyze and design the thermal boundary conditions of the numerical simulation based on the content of geometric optics,simulate and calculate the model with non-uniform heat flow boundary conditions,and restore the experimental conditions well.The average relative error between the experimental results and the simulated results is controlled within 10%.