风冷热电空调器的研制

建立了风冷热电空调器数值模拟模型 ,对空调器进行了模拟计算 .在对风冷热电空调器研制的基础上 ,进行了最佳隔热层厚度、不同结构形式、变工况、变风量和复现性实验 ,验证了仿真程序的可靠性 ,并应用模拟程序对热电材料的优值系数和空调器冷、热端的传热系数进行了分析     

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...     

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.     

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。     

量热式集成传感器的热电模拟及实验研究

本文把最热式传感器中的热传输看成行波,利用热电模拟及传输线分析方法,计算了热传输函数并得到了实验的验证,在此基础上进一步计算了传感器的增益稳定裕度、相对不平衡度和闭环增益等性能,为传感器的设计提供了重要的依据.该方法具有准确、直观、求解方便等优点.最后本文给出了上述理论计算为基础设计的集成温度传感器的实验结果.     

Bi2Te3热电材料研究现状

Bi2Te3热电材料是半导体材料,室温下具有良好的热电特性,能够实现热能和电能的相互转化,应用前景十分广阔。Bi2Te3热电材料的转换效率低是影响其应用的瓶颈之一,目前世界范围内的研究热点主要集中在如何提高热电材料的能量转换效率上。综述了热电材料的种类、国内外关于Bi2Te3热电薄膜的制备方法和性能研究,对多种典型制备方法进行分析对比,探讨了影响Bi2Te3热电薄膜质量的因素及机制。结合Bi2Te3热电薄膜在温差发电和热电制冷方面的应用,如果微型热电制冷器实现与大功率LED芯片集成封装,那么芯片级低温散热问题有望解决。     

CCD芯片热电制冷系统的非稳态性能分析

随着电子设备不断向小型化、集成化发展,热电制冷技术作为一种有效的主动冷却方法被广泛用于重要部件的温度控制。为了获得最佳的制冷效果,文中针对散热受限条件下的CCD芯片热电制冷系统非稳态过程,建立了一个数值分析模型。分析结果表明:在散热受限时,热电制冷系统的传热过程长时间处于非稳态过程;在不超过最大制冷电流的条件下,增大制冷电流可以提高制冷效果,但是大的制冷电流可能出现温度回升的现象;虽然热端散热能力的提高可以改善制冷效果,但是存在一个极限值,这与热电制冷器(TEC)的优值系数有关;当系统载荷发生变化时,合理改变制冷电流和热端散热能力可以提高系统的温度稳定性,其中制冷电流对系统温度稳定性的影响更大。     

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。     

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％.     

Investigation of the Thermoelectric Properties of LiAlSi and LiAlGe

The compounds LiAlSi and LiAlGe were synthesized and their thermoelectric properties and temperature stability were investigated. The samples were synthesized by arc melting of the constituent elements. For the determination of the structure type and the lattice parameter, x-ray powder diffraction was used. Both compounds were of the C1 _b structure type. The stability of the compounds was investigated by differential thermal analysis and thermal gravimetry. The Seebeck coefficient and the electrical resistivity were determined in the temperature range from 2 K to 650 K. All compounds showed p-type behavior. The thermal conductivity was measured from 2 K to 400 K. The evaluation of the thermal conductivity yielded values as low as 2.4 W m⁻¹ K⁻¹ at 400 K for LiAlGe. The low values are ascribed to high mass fluctuation scattering and a possible rattling effect of the Li atoms.     

Development of Skutterudite Thermoelectric Materials and Modules

Multifilling with La, Ba, Ga, and Ti in p-type skutterudite and Yb, Ca, Al, Ga, and In in n-type skutterudite remarkably reduces their thermal conductivity, resulting in enhancement of their dimensionless figure of merit ZT to ZT?=?0.75 for p-type (La,Ba,Ga,Ti)₁(Fe,Co)₄Sb₁₂ and ZT?=?1.0 for n-type (Yb,Ca,Al,Ga,In)_0.7(Co,Fe)₄Sb₁₂. A thermoelectric module technology suitable for these skutterudites including diffusion barrier and electrode materials has been established. The diffusion barrier materials allow the electrode to coexist stably with the p/n skutterudites in the module??s working temperature range of room temperature to 600°C. Under conditions of hot/cold-side temperatures of 600°C/50°C, a skutterudite module with size of 50?mm?×?50?mm?×?7.6?mm exhibited generation performance of 32?W power output and 8% thermoelectric conversion efficiency.     

温差电致冷元件损伤层探索

通过探索温差电致冷元件的损伤层，提出“平均电导率”等概念。     

Development of Thermoelectric Self-Powered Heating Equipment

In this work, a self-powered residential heating system was developed using thermoelectric generation technology. A full-size prototype was designed, constructed, and tested, in which Bi₂Te₃-based thermoelectric modules were incorporated into a gas-fired heating boiler. Up to 161 W of electricity is generated by the thermoelectric modules. This is sufficient to power all the electrical components of the residential heating equipment including pump, fan, blower, valves, and control panel. In this way, the heating system can operate entirely on fuel combustion and does not need externally generated electricity. The performance of the thermoelectric devices has been investigated in the integrated heating system under various operating conditions. The energy system’s advantages include simplicity, low noise, clean operation, and low maintenance. The thermoelectric self-powered heating system could provide the consumer with heating system reliability and a reduction in electric power consumption.     

Simulations for the Development of Thermoelectric Measurements

In thermoelectricity, continuum theoretical equations are usually used for the calculation of the characteristics and performance of thermoelectric elements, modules or devices as a function of external parameters (material, geometry, temperatures, current, flow, load, etc.). An increasing number of commercial software packages aimed at applications, such as COMSOL and ANSYS, contain vkernels using direct thermoelectric coupling. Application of these numerical tools also allows analysis of physical measurement conditions and can lead to specifically adapted methods for developing special test equipment required for the determination of TE material and module properties. System-theoretical and simulation-based considerations of favorable geometries are taken into account to create draft sketches in the development of such measurement systems. Particular consideration is given to the development of transient measurement methods, which have great advantages compared with the conventional static methods in terms of the measurement duration required. In this paper the benefits of using numerical tools in designing measurement facilities are shown using two examples. The first is the determination of geometric correction factors in four-point probe measurement of electrical conductivity, whereas the second example is focused on the so-called combined thermoelectric measurement (CTEM) system, where all thermoelectric material properties (Seebeck coefficient, electrical and thermal conductivity, and Harman measurement of zT) are measured in a combined way. Here, we want to highlight especially the measurement of thermal conductivity in a transient mode. Factors influencing the measurement results such as coupling to the environment due to radiation, heat losses via the mounting of the probe head, as well as contact resistance between the sample and sample holder are illustrated, analyzed, and discussed. By employing the results of the simulations, we have developed an improved sample head that allows for measurements over a larger temperature interval with enhanced accuracy.     

Investigation of Maximum Power Point Tracking for Thermoelectric Generators

In this paper, a thermoelectric generator (TEG) model is developed as a tool for investigating optimized maximum power point tracking (MPPT) algorithms for TEG systems within automotive exhaust heat energy recovery applications. The model comprises three main subsystems that make up the TEG system: the heat exchanger, thermoelectric material, and power conditioning unit (PCU). In this study, two MPPT algorithms known as the perturb and observe (P&O) algorithm and extremum seeking control (ESC) are investigated. A synchronous buck–boost converter is implemented as the preferred DC–DC converter topology, and together with the MPPT algorithm completes the PCU architecture. The process of developing the subsystems is discussed, and the advantage of using the MPPT controller is demonstrated. The simulation results demonstrate that the ESC algorithm implemented in combination with a synchronous buck–boost converter achieves favorable power outputs for TEG systems. The appropriateness is by virtue of greater responsiveness to changes in the system’s thermal conditions and hence the electrical potential difference generated in comparison with the P&O algorithm. The MATLAB/Simulink environment is used for simulation of the TEG system and comparison of the investigated control strategies.     

半导体温差发电实验仪器的研制

为了测试温差发电模块性能,根据半导体温差发电原理设计制作了一种半导体温差发电仪器,该仪器主要由发电模块、温控系统和显示电路组成。它以STC89C52RC单片机为控制核心,可以在一定范围内设定温差进行发电,并且无需手动测量即可实时显示相应温差下的发电模块输出电压值/电流值,不但定性而且定量的测试了温差发电模块的输出特性,绘制了相关曲线,分析了影响其输出特性的因素。结果表明:该仪器操作简单、灵敏度高、速度快。     

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。