Characteristics of Solar Radiation Reception by Solar Wing Based on Congruent Concentrating Surface
Objective The growing emphasis on renewable energy sources in sustainable societies is evident,indicating a shift towards cleaner energy solutions.Solar photovoltaic modules harness solar radiation to generate electricity and meet the power requirements for the normal operation of instruments and devices.Typically,there are two primary approaches to increasing electricity generation,including using high-efficiency solar panels and expanding the deployment areas of solar arrays.However,the former approach has limitations in improving efficiency,while the latter significantly increases the satellite launch cost.Non-imaging solar compound parabolic concentrators have caught considerable attention due to their efficient and stable operation,easy construction,and compatibility with satellite systems for reducing energy costs and improving the effective payload capacity of satellites.The utilization of solar concentrators in satellite systems enhances sunlight capture by solar wings,thus increasing energy output,reducing weight and volume,improving the stability and durability of solar panels,and expanding the application range of concentrators.Taking these advantages into account,we design a truncated compound planar concentrator for the operational characteristics of solar wings.Coupled with real-time sun-earth distance,earth-satellite space relationships,and solar radiation theory,a model for receiving solar radiation by solar wings is developed.The findings provide valuable insights for the structural design and optimization of solar wings.Methods First,via carefully analyzing the shortcomings of traditional S-CPC systems,a TMS-CPC surface structure is designed based on the edge-ray tracing principle,and its three-dimensional geometry is modeled by software.Meanwhile,a scaled-down model is built using 3D printing technology to verify the focusing performance of the constructed TMS-CPC.In the ground laboratory,parallel lasers are employed to simulate sunlight and enable visual ray tracing of the coupled TMS-CPC system.This allows for observing and recording the concentration process and characteristics of TMS-CPC on"solar rays".Simultaneously,optical simulation software is adopted for ray tracing simulations,and the obtained experimental values are compared and analyzed against the simulated values to validate the model reliability.Secondly,by considering the spatial relationships among the sun,the earth,and the satellite,a real-time distance model is built.The solar radiation amount received by the solar wing can be calculated via spatial radiation theory.Simulations and analyses are conducted using the Satellite Tool Kit(STK)to study the characteristics of solar wing reception of solar radiation based on a congruent concentrating surface.Results and Discussions During the laser validation experiment of the solar wing TMS-CPC,factors such as the laser divergence angle,high reflectivity of the flexible reflective membrane,and manufacturing errors associated with 3D printing all affect the experimental results.However,in this scenario,the simulated values of the concentrating performance of the solar wing TMS-CPC tend to align with the experimental values,with a maximum average absolute error of 1.49 mm and a minimum of 0.75 mm(Fig.3).When the incident angle of the light exceeds 6°,optical efficiency decreases within the TMS-CPC system(Fig.4).A comparison between the theoretical and simulation values of solar radiation on the solar wing,along with the satellite exposure characteristics,reveals an average absolute error of only 0.04 W/m2 in the radiation model calculation values and 18.2 s in satellite exposure characteristics(Fig.7 and Table 1).During variation analysis in energy flux density on the solar surface with different incident angles of sunlight,it is observed that in the constructed solar wing TMS-CPC system,when sunlight is incident vertically(at an angle of 0°),the energy flux density on the surface of the solar panels is symmetrically distributed on both sides of the central axis.However,when sunlight is incident at angles within the acceptance half-angle(0°,1°,and 2°),the peak energy flux density increases with the rising incident angle,while the average energy flux density remains constant(Fig.8).The closer distance of the incident angle to the acceptance half-angle leads to more uniform distribution of energy flux density on the solar panel surface(Fig.9).Theoretical peak power generation with the solar wing TMS-CPC is approximately 87％higher than that of traditional solar wings.However,there is a reverse trend in power generation with variations in sun-satellite distance(Fig.10).Conclusions Our study is based on the edge-ray tracing principle to construct a truncated structure compound planar concentrator TMS-CPC,and incorporates real-time sun-earth distance calculations,earth-satellite spatial relationships,and solar radiation theory to build a model for solar radiation reception by solar wings.Laser experiment results show that the experimental data are in good agreement with the simulation results,thereby confirming the reliability of the built model.The solar wing TMS-CPC expands the acceptable angle range beyond that of the conventional S-CPC,providing sufficient error margin in satellite tracking systems.Significantly,within the acceptance half-angle range,the average uniformity index on the solar panel surface reaches 0.615,greatly enhancing its capability to capture solar radiation.During one orbital cycle,the satellite predominantly stays in the sunlit region,ensuring favorable conditions for photovoltaic components of the solar panels and guaranteeing the satellite's long-term stable operation.This reduces energy costs and enhances overall economic benefits for satellites.Numerical simulations of power generation from a single solar wing coupled with TMS-CPC,along with a comparative analysis against traditional solar wings,illustrate that the built model effectively enhances theoretical power generation.
geometric opticssolar energycompound parabolic concentratorirradiancesolar wingenergy flux density
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