Towards a comprehensive model for characterising and assessing thermoelectric modules by impedance spectroscopy
Towards a comprehensive model for characterising and assessing thermoelectric modules by impedance spectroscopy
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DOI：
10.1016/j.apenergy.2018.05.041
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发表时间：
2018-09-15
期刊：
影响因子：
11.2
通讯作者：
Stephenson, Keith
中科院分区：
文献类型：
--
作者：
Mesalam, Ramy;Williams, Hugo R.;Stephenson, Keith
热电设备具有潜在的能量转换应用，从太空探索到大众市场产品。对它们的特性进行标准化、准确且可重复的高通量测量是一项关键的支持技术。阻抗谱已显示出作为一种通过简单测量对热电模块进行参数表征的工具的前景。然而，之前发布的试图表征热电模块基本特性的模型被发现依赖于严重简化的假设，其有效性受到质疑。本文在数学上开发了一种新的综合阻抗模型。新模型集成了所有相关的传输现象：热对流、辐射和连接界面处的扩散收缩。此外，首次引入非绝热内表面边界条件。人们发现这些现象显着改变了奈奎斯特频谱的低频和高频响应，表明了精确表征的必要性。为了验证该模型，对商用热电模块的阻抗谱进行了实验测量和参数拟合。使用蒙特卡罗残差重采样方法研究技术精度。所有关键热电特性随温度变化的完整表征均通过模块制造商提供的材料特性数据进行验证。此外，通过首先在真空中表征模块，证明了表征自由对流和强制对流的传热系数的能力。因此，本研究开发的模型是一个关键的推动因素，有可能使阻抗谱能够表征和监测跨多个领域的实际热电模块的制造和操作缺陷，并推广新的传感器技术。
Thermoelectric devices have potential energy conversion applications ranging from space exploration through to mass-market products. Standardised, accurate and repeatable high-throughput measurement of their properties is a key enabling technology. Impedance spectroscopy has shown promise as a tool to parametrically characterise thermoelectric modules with one simple measurement. However, previously published models which attempt to characterise fundamental properties of a thermoelectric module have been found to rely on heavily simplified assumptions, leaving its validity in question. In this paper a new comprehensive impedance model is mathematically developed. The new model integrates all relevant transport phenomena: thermal convection, radiation, and spreading-constriction at junction interfaces. Additionally, non-adiabatic internal surface boundary conditions are introduced for the first time. These phenomena were found to significantly alter the low and high frequency response of Nyquist spectra, showing their necessity for accurate characterisation. To validate the model, impedance spectra of a commercial thermoelectric module was experimentally measured and parametrically fitted. Technique precision is investigated using a Monte-Carlo residual resampling approach. A complete characterisation of all key thermoelectric properties as a function of temperature is validated with material property data provided by the module manufacturer. Additionally, by firstly characterising the module in vacuum, the ability to characterise a heat transfer coefficient for free and forced convection is demonstrated. The model developed in this study is therefore a critical enabler to potentially allow impedance spectroscopy to characterise and monitor manufacturing and operational defects in practical thermoelectric modules across multiple sectors, as well as promote new sensor technologies.