【作者】 杨帆；

【导师】 罗小兵；

【作者基本信息】 华中科技大学 ， 新能源科学与工程， 2023， 硕士

【摘要】 近场辐射因其远超于黑体辐射功率而受到广泛研究。由于其巨大的传热功率,近场辐射被提出可用于热电能量转换器件,例如热光伏器件。为进一步克服热光伏器件对热源温度的依赖而导致的转换效率问题,热光子器件成为了一项可行的替代方案。结合近场辐射,热光子器件亦有望在较低的工作温度范围下实现热电双向转换,从而为能量转换提供了新思路。另一方面,参考近场辐射原理,传统热光伏系统有望通过改变辐射介质的方法提升输出功率。基于以上背景,本文探究了热光伏和热光子中的近场辐射传热问题,研究内容如下:提出了近场热光伏系统的模型,使用贴近实际情况的泊松-漂移-扩散模型考虑了电池内部化学势对系统输出功率和效率的影响,并与常用的化学势常数假设和细致平衡模型对比,评估了不同模型对系统性能的误差。另外,考虑了不同工作距离和温度对系统性能的影响并给出了近场热光伏系统的实际应用建议。分析了在较低工作温度下利用近场热光子系统进行低品位热能发电和电致发光制冷的可能性,并构建了由Cd Te和In P构成的近场热光子系统,该系统在无需更换材料和系统结构的情况下可实现发电到制冷的转换,并具有较高的发电或制冷功率。最后,进一步提出了利用覆盖金属Pt膜以提高系统功率的方法。考虑了近场系统存在的缺陷,分析了近场辐射功率高功率的特点,提出了两种可在长距离下实现高功率输出的热光伏系统模型,并分别对比采用硅和理想双曲材料作为介质的系统性能差异,揭示了不同方法和不同介质下系统性能差异的原因,最后给出了长距热光伏系统的使用建议。更多还原

【Abstract】 The near-field radiation is extensively studied due to the heat transfer far beyond the blackbody theory.Consierding its huge power density,such a radiation is proposed for heatelectricity conversion system like thermophotovoltaics.In order to overcome problem caused by the dependence of temperature on thermophotovoltaics,thermophotonics becomes a feasible alternative way.Via near-field radiation,thermophotonics are also expected to achieve heat-electricity bidirectional conversion at lower temperature.On the other hand,referring to the mechanism of near-field radiation,thermophotovoltaics is expected to increase the output power by substituting the radiation medium.This reserch is organized as follows.A model of near-field thermophotovoltaics is proposed.The Poisson-Drift-Diffusion model for actual situation is employed to consider the effect of the chemical potential inside the cell on the output power and efficiency.The error between constant chemical potential and the detailed balance is evaluated.In addition,the effects of different distances and temperatures on the performance are considered,and the conclusions of the near-field thermophotovoltaics are given.The possibility of low-grade thermal power generation and electroluminescence refrigeration via near-field thermophotonics is analyzed,and a near-field thermophotonic system composed of Cd Te and In P is constructed.The system can fulfil the conversion from power generation to refrigeration without changing the materials or structure,while maintaining high power.Finally,a method to improve output power by covering Pt film is proposed.Considering the mechanism and defects of the near-field system,two models of thermophotovoltaics with high power output while operating at long distance are proposed.The performance of systems with silicon and ideally hyperbolic materials are compared,and the discrepancy for different models are analyzed.Finally,the application suggestions of long-distance thermophotovoltaics are given.更多还原