| Solar energy is the most widespread renewable energy almost in every corner of the world.It can be accessed to conveniently and always has abundant reserves.So solar energy is bound to play an important role in the future energy structure.This paper aims to design a model to do the feasibility study of using solar power in solar-heat-mechanical energy's way.Use flat-point-focusing Fresnel lens to concentrate solar power and transform it into heat by refracting light.Using two-cylinder ? type Stirling engine as the prime motor to turn heat into mechanical energy.Meanwhile,also design the Sun tracing system and auxiliary heating device to improve the solar efficiency.If the plant is feasible,it will have great market in the area of offshore islands or marine structures.Based on the unified design formula,derive flat-point-focusing Fresnel lens design formula to calculate the height angle of each lens ring edge.Then use the formula derived from the direct way to check the data.Use Trace Pro to simulate and emulate the lens and get the best ring distance,focal length/diameter and light injection angle.According to the conclusions,design a diameter of 360 mm,a focal length of 400 mm,a ring distance of 0.5mm Fresnel lens as a solar collector,and simulate and emulate it again to get the conclusion: In real-world applications,It should be possible to ensure that sunlight incident on the mirror vertically,while selecting the focal point of the lens as a thermal energy utilization point.Based on the principle of Stirling engine,design a tow-cylinder? type Stirling engine as the prime moter,using center-crank linkage mechanical to output mechanical power.Design a Sun tracing system which is inclined arrangement(manual adjustment)in north-south direction,automatic tracking(tracking photovoltaic)in east-west direction,including:(1)Rationally design the mounting position and structure of heat accumulating bracket,so that the trajectory of the center of the lens nearly like the sphere which uses focus point as the center,focusing length as the radius,to ensure the sunlight incidents vertically,and at the same time,the focus point remains unchanged.(2)The sunlight tracing in east-west direction,chose photodiodes as light sensors to convert light into optical signals,and rationally design track sensor unit structure to ensure the ability to accurately sense the changes in the angle of incidence of light.(3)Control unit is mainly set up by AT89C51 MCU and LM324 chip.Use the operational amplifiers in LM324 to complete and judgment the comparison of signals under different light conditions.Use PNP transistor to control opening and closing of the electromagnetic relay,and thus controls the rotation of the motor.Design control strategies,and use the C51 programming language to complete the preparation procedures code.Design an auxiliary heating device,in low light intensity,continues to drive the Stirling engine work.Use magnesium sulfate-zeolite mixture which's mass fraction of magnesium sulfate is 15%,as heat-chemical energy storage material to save burning energy.A small DC generator driven by Stirling engine flywheel,use a voltmeter and ammeter power generation.Due to time constraints,only produced a Fresnel lens and a Stirling engine model to do the experimental tests,and calculate the solar energy utilization. |
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