温差半导体空调制冷器制冷性能研究

设计了两种不同散热方式的半导体制冷器,实验表明制冷性能良好,为太阳能驱动半导体制冷装置的优化设计提供依据、奠定基础。半导体制冷模块热端采用汽车发动机散热系统标准部件、采取水冷却,能在有限的空间内将高热流密度热量散发出去,有利于提高制冷性能。半导体制冷模块在等功率状态下工作,制冷量为半导体器件最大制冷量的55%;若倾向于获得较大制冷系数,制冷量按最大制冷量的40%进行设计,制冷系数ε达1.65。     

半导体制冷器的进展

半导体制冷器具有微型化、轻量化、无振动、长寿命等许多重要优点。目前３００Ｋ室温下优值系数Ｚ最高的半导体制冷材料是Ｐ型Ａｇ０．５８ＣＵ０．２９Ｔｉ０．９４Ｔｅ四元合金,２００－３００Ｋ普冷范围内三元Ｂｉ２Ｔｅ３－Ｓｂ２Ｔｅ３－Ｓｂ２Ｓｅ３固溶体合仍然应用最广且性能优良,而２０－２００Ｋ低温下则是Ｂｉ－Ｓｂ合金热电性能最好,电臂材料是决定半导体制冷器性能的主要因素,但通过改进电臂结构,设计特殊的电臂联     

半导体制冷器原理与应用

本文主要介绍了半导体制冷器的基本原理及其应用,并对涉及到制冷器的有关公式进行了推导,文章最后得出了关于半导体制冷器的一些重要结论。     

基于半导体制冷器的"纯净电源"

提出了一种基于半导体制冷器的"纯净电源"方案,该电源具有电气安全性能优异,抗干扰能力强,输出纯净,寿命长,体积小等特点.指出了其能源转化效率低.负载能力低,需采用适当的高温防护措施等应用局限性,并给出了模型测试结果.     

汤姆孙效应对半导体制冷器性能的影响

本文应用非平衡态热力学理论建立了热电器件的热传导方程，导出半导体制冷器的制冷系数和制冷率，并详细地讨论了汤姆孙效应对制冷器性能的影响，得到了一些有意义的新结论，同时澄清了有关研究中普遍存在的一些问题。     

锥状电臂半导体制冷器工作参数的理论分析

通过求解导热微分方程 ,推导出锥状电臂半导体制冷器的理论工作参数。结果表明 ,采用锥状电臂不仅可以节约材料 ,而且在达到相同制冷温差时 ,可减小工作电流 ,降低直流功耗 ,缩短降温时间 ,而制冷效率不变。     

一种测试半导体制冷器的瞬态方法

ZT值、最大制冷温差和响应时间是表征半导体制冷器性能的重要参数.文中介绍了一种能同时测量这三个参数的瞬态方法,并讨论了热沉对测试结果的影响.利用一个由恒流脉冲发生器和数据采集卡组成的简单测试系统测得制冷器在小电流下的电阻电压和塞贝克电压,通过这两个电压推导出ZT值、最大制冷温差.这种瞬态方法是非接触式测量,准确度高,可用于薄膜热电器件测试;另外瞬态方法耗时短,可大大缩短半导体制冷器可靠性测试的周期.采用这种方法对4mm×4mm×2.4mm的热电制冷器进行实验,环境温度300K时,测得ZT值为0.39,最大温差58.5K,响应时间20s.     

基于半导体制冷器的小型黑体参考源设计

文章针对红外热像仪在实际应用中非均匀性多点校正问题,选择了体积小、制冷迅速的半导体制冷器作为黑体参考源,并采用模糊-PID控制算法对参考源进行控制,设计出一种精度高、便于安装并且能够进行多温度点控制的小型黑体参考源.经过测试和分析,对黑体的稳定性、发射率和均匀性做出了客观的评价,表明了该设计具有较强的实用性.     

半导体制冷器“无限级联”温差电对工作参数的理论分析

在普通温差电对的ｐ型和ｎ型电臂之间淀积一层厚度适当的银膜实现短接,可在单级温差电对中形成类似多级半导体制冷器的无限级微温差电对串联,从而提高电对的制冷量和制冷温差．实验证明,这种“无限级联”温差电对的最大制冷温差可提高到普通电对的１．５～３倍．本文通过合理的简化,求解导热微分方程,给出“无限级联”温差电对的理论工作参数,并且给出焦耳热在电对冷端和热端的分配情况,从而在理论上对这种电对结构的优越性作出解释．     

半导体致冷器与探测器杜瓦瓶钎焊的实验研究

本文论述了四级微型半导体致冷器与红外探测器金属杜瓦瓶的钎焊方法。实验证明:预先在致冷器底面和杜瓦瓶底座挂上钎料,采用钎剂和保护气体加热钎焊,可降低加热温度,提高钎焊质量;采用快速冷却可大大减小由于长时间热滞所导致致冷器性能的下降,从而为半导体致冷的红外探测器提供了最佳的组装方法和实验参考。     

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。     

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。     

Self-Assembly for Integration of Microscale Thermoelectric Coolers

Optimum thermoelectric cooling (TEC) solutions often require the integration of component sizes inaccessible by common manufacturing techniques such as thin-film processing and robotic assembly. This work considers an application case in which small elements (100 μm to 300 μm thick) are optimal. A capillary self-assembly process is presented as a potential route to manufacturing TECs in these size ranges. A millimeter-scale demonstration of the assembly concept is presented and Monte Carlo simulation is used to study the scaling of the self-assembly approach to assemblies with more components. While assembly rate and system yield can be a challenge, several approaches are presented for increasing both rate and yield.     

Three-Stage Thin-Film Superlattice Thermoelectric Multistage Microcoolers with a Δ<Emphasis Type="Italic">T</Emphasis><Subscript>max</Subscript> of 102 K

Thin-film Bi₂Te₃- and Sb₂Te₃-based superlattice (SL) thermoelectric (TE) devices are an enabling technology for high-power and low-temperature applications, which include low-noise amplifier cooling, electronics hot-spot cooling, radio frequency (RF) amplifier thermal management, and direct sensor cooling. Bulk TE devices, which can pump heat loads on the order of 10 W/cm², are not suitable in these applications due to their large size and low heat pumping capacity. Recently, we have demonstrated an external maximum temperature difference, ΔT _max, as high as 58 K in an SL thin-film p–n couple. This state-of-the-art couple exhibited a cold-side minimum temperature, T _cmin, of −30.9°C. We regularly attain ΔT _max values in excess of 53 K, in spite of the many significant electrical and thermal parasitics that are unique to thin-film devices. These measurements do not use any complex thermal management at the heat sink to remove the heat flux from the TE device’s hot side. We describe here multistage SL cooling technologies currently being developed at RTI that can provide useful microcooling cold-side temperatures of 200 K. This effort includes a three-stage module employing independently powered stages which produced a ΔT _max of 101.6 K with a T _cmin of −75°C, as well as a novel two-wire three-stage SL cascade which demonstrated a T _cmin of −46°C and a ΔT _max of nearly 74 K. These RTI modules are only 2.5 mm thick, significantly thinner than a similar commercial three-stage module (5.3 mm thick) that produces a ΔT _max of 96 K. In addition, TE coolers fabricated from these thin-film SL materials perform significantly better than the extrapolated performance of similar thickness bulk alloy materials.     

含内热源密闭空间两级半导体制冷器瞬态特性分析

针对工作在含内热源密闭空间的空冷和热管式两级热电制冷装置,分别建立了瞬态性能计算模型,得到了制冷空间温度、模块两端温差,以及制冷系数随时间的变化规律;对比两种散热方式对装置特性的影响;分析了工作电流和热电偶热冷两级面积比,对温度、耗时和制冷系数的影响。结果表明:当元件功率为6W时,空冷和热管式制冷器温度分别比无热源时升高了8.28和7.86℃,热管式的制冷温度比空冷式低1.85℃,制冷系数比空冷式高12.12%。     

波纹管J-T制冷器的可靠性改进研究

作为红外探测器组件的重要组成部分,波纹管J-T制冷器得到了广泛应用.在振动环境下长期使用时,作为自主调节元件的波纹管会出现流量异常、无法实现自调等故障.为了提高制冷器在长期振动环境中的可靠性,更改了制冷器结构,并创新性地使用了加装膜片弹簧与聚四氟乙烯导环的两点支撑结构.该结构对制冷器的弹性运动部件具有可靠的径向支撑,明...     

The Impact of Nanostructuring on the Thermal Conductivity of Thermoelectric CoSb3

The high concentration of grain boundaries provided by nanostructuring is expected to lower the thermal conductivity of thermoelectric materials, which favors an increase in their thermoelectric figure‐of‐merit, ZT. A novel chemical alloying method has been used for the synthesis of nanoengineered‐skutterudite CoSb₃. The CoSb₃ powders were annealed for different durations to obtain a set of samples with different particle sizes. The samples were then compacted into pellets by uniaxial pressing under various conditions and used for the thermoelectric characterization. The transport properties were investigated by measuring the Seebeck coefficient and the electrical and thermal conductivities in the temperature range 300 K to 650 K. A substantial reduction in the thermal conductivity of CoSb₃ was observed with decreasing grain size in the nanometer region. For an average grain size of 140 nm, the thermal conductivity was reduced by almost an order of magnitude compared to that of a single crystalline or highly annealed polycrystalline material. The highest ZT value obtained was 0.17 at 611 K for a sample with an average grain size of 220 nm. The observed decrease in the thermal conductivity with decreasing grain size is quantified using a model that combines the macroscopic effective medium approaches with the concept of the Kapitza resistance. The compacted samples exhibit Kapitza resistances typical of semiconductors and comparable to those of Si–Ge alloys.     

Thermoelectric Properties of Zn-Substituted Magnetite

Thermoelectric properties of Zn-substituted magnetite were investigated experimentally. Since Zn is incorporated in the A-site of magnetite for 0 ≤ x ≤ 0.2 in Zn _x Fe_3−x O_4−δ , electrical resistivity remained constant in this region and the thermoelectric power factor (PF) increased with Zn content. At x = 0.2, it attained 1.66 μW/K² cm at 700°C. Above x = 0.2, where Zn began to enter the B-site, the PF decreased with x.