无量纲优值对热电制冷系统性能影响分析

建立了无量纲稳态系统热力学模型。并用该模型分析了优值系数对系统性能的影响,优值系数是热电制冷器性能的内在制约,散热和温度条件则是热电制冷性能的外在制约,无量纲优值体现了二者对系统的影响。热电制冷系统的特殊优势再度受到人们关注,但在热电材料优值系数受到限制的现实条件下,热电制冷系统在能效上是难以与压缩式制冷空调系统比较的。     

影响热电制冷性能的关键因素及其分析

在忽略汤姆逊效应的情形下,推导出热电制冷臂的传热微分方程,利用数值模拟的方法,分析了在不同工作电流下各种热电效应的影响,及工作电流和冷、热端换热系数3种因素对热电制冷性能的综合影响。分析了3种因素对热电制冷性能的影响程度与顺序,发现电流是最关键的影响因素,且需要较低制冷温度时可提高冷端换热系数,需要较大制冷量或制冷系数时可适当提高热端换热系数,但冷、热端换热系数对制冷性能的影响存在一个最优值。提出了热电制冷器件的设计和应用的优化工况及方案,在提高制冷性能的同时节约了成本。     

热电制冷器制冷工作电流特性分析

随着高性能制冷CCD成像系统已经成为航天成像式探测的一个重要发展方向,热电制冷作为一种有效的电子设备冷却方法广泛用于重要部件的主动热控.为了实现热电制冷器工作电流的合理选择,在分析热电制冷机理的基础上,首先介绍了热电模块的3种工作模式(制冷、加热和热电发电),同时研究了热电偶内温度分布的一般形式,最后,在第一类边界条件...     

制备工艺对新型热电材料制冷性能的影响

通过取点法得到了由Ingot法、BM法、S-MS法和Te-MS法制备的四种新型p型热电材料(Bi0.5Sb1.5)Te3的变物性参数拟合公式,分析了温度对不同方法制备的热电材料的影响,得到了热电材料无量纲优值与绝对温度的关系曲线.从热力学方面研究了制备工艺对基于新型热电材料的热电制冷器最大制冷系数的影响.结果表明:由Te-MS法制备的新型p型热电材料(Bi0.5Sb1.5)Te3具有最大的优值系数,基于该材料的热电制冷器最大制冷系数可达2.49,较其他三种方法制备的热电材料分别提升了 34.59％,37.57％和25.76％.     

电子元器件热电冷却技术研究进展

在深刻分析热电制冷机理的基础上,结合国内外学者对热电制冷技术用于电子元器件热管理的理论分析,从芯片整体表面散热和局部热点消除两方面,详细介绍了集成电路芯片热电冷却实验的国内外研究进展;对芯片热电冷却技术的数值模拟与热电制冷器(TEC)的选型优化进行了详细报道;指出国内缺乏芯片热电冷却的应用研究,在芯片散热的整体研究水平上与国外仍有差距.芯片热电冷却及其表面的热管理将是今后提高电子元器件散热性能的一个重要研究方向.     

脉冲方波驱动强化热电制冷的瞬态特性

采用有限差分法对脉冲电压驱动下的瞬态热电效应及其动态特性过程进行了理论分析,探索了非稳态工况下帕尔帖效应、焦耳热效应与傅里叶导热效应之间的耦合关系及其关键制约因素对制冷性能的影响规律,进而探讨了脉冲驱动强化热电制冷性能的作用机理。分析结果得到,在合理电压域值内采用主动控制方法,对热电模块周期性施加数倍于稳态工况理想电压的脉冲突变电压,有益于充分利用帕尔贴制冷效应而推迟出现以焦耳热和傅里叶热耗散形式为主的内部热积聚对热电模块冷端引起的负效应,并能瞬态实现冷端面的制冷强化作用和最大程度实现输入电能的有效转换。该结论不仅为进一步提出脉冲驱动模式的优化控制策略提供了理论依据,也为瞬态热电制冷效应的应用开辟了一条新思路。     

基于热电制冷的大功率LED散热性能分析

提出了一种新型的基于热电制冷的大功率LED热管理方法。这种大功率LED阵列模块采用板上封装技术制造。为了解决散热问题,采用了热电制冷器将LED芯片产生的热量转移到周围的环境中。利用热电偶测量了大功率LED阵列模块在不同工作条件下的温度分布,LED的光学性能则通过光强分布测试仪来测试。结果表明,这种采用热电制冷的大功率LED阵列封装模块能够显著降低器件的工作温度,与不采用热电制冷器相比,基板温度能够降低36％以上,光学性能测量表明LED阵列模块的发光效率达到30．18lm／W。     

芯片冷却中热电制冷器性能的实验研究

设计了电子芯片冷却实验装置,对热电制冷器在电子芯片冷却中的冷却效果和制冷性能进行了研究。实验结果表明,不仅热电制冷片热端冷却水流量是影响冷却效果的重要因素,而且热电电流和芯片功率与热电冷却性能也有着密切的关系。实验结果对热电冷却器的最佳冷却性能的确定具有一定的参考意义。     

热电制冷HgCdTe中波红外探测器的研制

利用碲镉汞(HgCdTe)体晶材料,采用HgCdTe材料拼接技术、磨抛技术等成熟的探测器芯片制备工艺以及三级热电制冷技术,设计并研制出了热电制冷型13元HgCdTe中波红外光导探测器.在-50℃时,峰值电压响应率可达2.7×104 V/W,峰值探测率达到2.3×1010 cm·Hz1/2·W-1,响应波段在3.0~4.6μm之间,峰值响应波长为4.2μm.     

热电制冷技术的研究进展北大核心

热电制冷（TEC）已成为制冷领域的一个重要发展方向,但是由于其转换效率过低且材料成本较高,目前难以得到广泛应用。对热电制冷技术进行了简要介绍,并综述了热电制冷技术的研究进展,包括热电材料、结构优化和散热方式。讨论并分析了有机热电材料和无机热电材料的热电性能、不同结构设计所导致的性能系数、不同散热方式对制冷效率的影响。最后,对热电制冷技术的优化进行了简单总结,只有不断提高热电材料的优值系数,并选择合适的结构设计和散热方式,才能使热电制冷技术在各个领域拥有更大的发展空间。     

Advanced Thermoelectric Materials for Flexible Cooling Application

Flexible cooling devices, which aim to fulfill the essential requirement of complex working environments and enable local heat dissipation, have become the cutting-edge area of refrigeration technology. Thermoelectric (TE) material represents a promising candidate for various flexible cooling applications, including wearable personal thermoregulation devices. With the increasing interest in the Peltier effect of conductive polymers and inorganic films on flexible substrates, flexible cooling devices have undergone rapid development. Herein, the fundamental mechanisms, basic parameters, and temperature measurement techniques for evaluating the cooling performance are summarized. Moreover, recent progress on TE materials, such as flexible inorganic and organic materials for Peltier cooling studies, is reviewed. More importantly, insights are provided into the key strategies for high-performance Peltier devices. The final part details the existing challenges and perspectives on flexible TE cooling to inspire additional research interests toward the advancement of refrigeration technology.     

Thermoelectric quantum-dot superlattices with high ZT

Following the experimentally observed Seebeck coefficient enhancement in PbTe quantum wells in Pb_1−xEu_xTe/PbTe multiple-quantum-well structures which indicated the potential usefulness of low dimensionality, we have investigated the thermoelectric properties of PbSe_xTe_1−x/PbTe quantum-dot superlattices for possible improved thermoelectric materials. We have again found enhancements in Seebeck coefficient and thermoelectric figure of merit (ZT) relative to bulk values, which occur through the various physics and materials science phenomena associated with the quantum-dot structures. To date, we have obtained estimated ZT values approximately double the best bulk PbTe values, with estimated ZT as high as about 0.9 at 300 K.     

Electrostatic Control of the Thermoelectric Figure of Merit in Ion-Gated Nanotransistors

Semiconductor nanostructures have raised much hope for the implementation of high-performance thermoelectric generators. Indeed, they are expected to make available reduced thermal conductivity without a heavy trade-off on electrical conductivity, a key requirement to optimize the thermoelectric figure of merit. Here, a novel nanodevice architecture is presented in which ionic liquids are employed as thermally-insulating gate dielectrics. These devices allow the field-effect control of electrical transport in suspended semiconducting nanowires in which thermal conductivity can be simultaneously measured using an all-electrical setup. The resulting experimental data on electrical and thermal transport properties taken on individual nanodevices can be combined to extract ZT, guide device optimization and dynamical tuning of the thermoelectric properties.     

Toward High Thermoelectric Performance of Thiophene and Ethylenedioxythiophene (EDOT) Molecular Wires

The design of thermoelectric materials for the efficient conversion of waste heat into electricity requires simultaneous tuning of their electrical and thermal conductance. A comparative theoretical study of electron and phonon transport in thiophene and ethylenedioxythiophene (EDOT) based molecular wires is performed. It is shown that modifying thiophene by substituting ethylenedioxy enhances the thermoelectric figure of merit ZT for molecules of the same length. Furthermore, it is demonstrated that the electrical conductance of EDOT‐based wires decays more slowly with length than that of thiophene‐based wires and that their thermal conductance is lower. The room‐temperature ZT of undoped EDOT is found to be rather low. However, doping of EDOT by the electron acceptor tolunenesulfunate increases the Seebeck coefficient and electrical conductance, while decreasing the thermal conductance, leading to a thermoelectric figure of merit as high as ZT = 2.4.     

The Criteria for Beneficial Disorder in Thermoelectric Solid Solutions

Forming solid solutions has long been considered an effective approach for good thermoelectrics because the lattice thermal conductivities are lower than those of the constituent compounds due to phonon scattering from disordered atoms. However, this effect could also be compensated by a reduction in carrier mobility due to electron scattering from the same disorder. Using a detailed study of n‐type (PbTe)_1–x (PbSe)_x solid solution (0 ≤ x ≤ 1) as a function of composition, temperature, and doping level, quantitative modeling of transport properties reveals the important parameters characterizing these effects. Based on this analysis, a general criterion for the improvement of zT due to atomic disorder in solid solutions is derived and can be applied to several thermoelectric solid solutions, allowing a convenient prediction of whether better thermoelectric performance could be achieved in a given solid solution. Alloying is shown to be most effective at low temperatures and in materials that are unfavorable for thermoelectrics in their unalloyed forms: high lattice thermal conductivity (stiff materials with low Grüneisen parameters) and high deformation potential.     

基于微/纳尺度冷却扩展热电元件的制冷极限(英文)

提出一种借助于在热电冷却器热端引入微尺度冷却,以提高其制冷性能参数的新方法,并建立了相应的理论模型来刻画该过程,并在此基础上对各类有助于提高制冷性能的潜在途径进行了参数化研究。结果表明,热电臂中存在一个最佳冷却长度,可在其冷热端实现最大的温度差。讨论了将该方法在低温环境及其他几类特殊场合的应用,并分析了加工该结构的相关问题。与通过改进材料来提高制冷性能的方法相比,该方法可在材料性能已趋极限时,提供一种新的物理途径用以强化热电冷却元件制冷性能。     

Comprehensive System-Level Optimization of Thermoelectric Devices for Electronic Cooling Applications

Advanced cooling solutions are needed to address the growing challenges posed by future generations of microprocessors. This paper outlines an optimization methodology for electronic system based thermoelectric (TE) cooling. This study stresses that an optimum TE cooling system should keep the electronic device below a critical junction temperature while utilizing the smallest possible heat sink. The methodology considers the electric current and TE geometry that will minimize the junction temperature. A comparison is made between the junction temperature minimization scheme and the more conventional coefficient of performance (COP) maximization scheme. It is found that it is possible to design a TE solution that will both maximize the COP and minimize the junction temperature. Experimental measurements that validate the modeling are also presented.