半导体冰箱热管及变工况控制的研究

详细阐述了分离式热管散热方式和变工况控制半导体制冷片运行参数在半导体冰箱中的应用,并对分离式重力热管散热、半导体冰箱变工况控制与冰箱的制作进行了探讨。实验表明:该冰箱的制冷效率有了较大的提高,实现了整机的高效节能效果。     

半导体制冷强化传热研究

对半导体制冷片进行了稳态传热分析,对半导体制冷风冷式散热片的底座厚度、翅片长度、翅片厚度、翅片数目、翅片顶端厚度等结构进行ANSYS模拟分析优化,并通过实验对比得出风冷式、水冷式散热的半导体制冷效率与传统压缩机制冷效率的区别;同时,通过改变风冷式散热半导体制冷的风扇功率、散热片结构等分析优化了半导体制冷的散热模式。     

热电制冷式温湿度调节机的散热技术研究

基于热电制冷的温湿度调节机的制冷和除湿性能主要受其热端散热性能的制约。为了探究热电制冷式温湿度调节机热端散热性能的影响因素,该研究在实际项目的基础上设计了三组实验,分别用于探究风机安装方式,风速大小以及散热翅片间距对其散热性能的影响。结果表明,在所研究的六种风机安装方式中,单风扇单侧吹风的安装方式在实际工程中可以达到相对最佳的散热效果,且其最适宜的风速为5 m/s,最佳散热翅片间距为4 mm,于实际工程来说具有重要的参考意义。     

天基望远镜探测器组件热电制冷系统设计与试验

天基空间望远镜探测器必须采用主动制冷方式以满足其噪声抑制需求.为此,采用热电制冷为核心技术,开展了探测器热电制冷器封装设计、热电制冷器热排散系统设计、热电制冷控制系统设计,并从抑制寄生漏热、降低热电制冷器热排散路径热阻两方面进行了优化,以减小热电制冷器输入功率及辐射散热面积.根据帕尔帖效应、焦耳效应、傅里叶效应,获得了净制冷量、热端散热热阻、热端边界温度等环境特性参数与热电制冷器输入电流、电压、功率等工作特性参数间的关系,并分析了制冷热负荷、热端散热热阻与热电制冷器输入功率间的敏感度.研制了望远镜鉴定产品,并开展了真空热平衡试验.试验结果表明系统设计合理有效,能够将探测器制冷至-75℃温度水平,稳定度可达到±0.2℃.基于环境条件及热电制冷器工作参数等试验数据,对比并修正了热分析模型.研究结果可为类似空间望远镜热电制冷系统的研制提供参考和借鉴.     

基于单片机和半导体制冷片的热敏电阻实验

介绍了半导体制冷片的基本结构,基于单片机和半导体制冷片设计了热敏电阻温度特性研究实验,设计完成了温度特性研究系统的硬件电路和软件构造,探讨了单片机和半导体制冷片在物理实验中的应用.此实验平台具有很好的扩张性,可用于设计组成各种温度控制类的实验内容.所完成的温度特性研究实验系统具有集成度高、体积小、使用方便等特点.     

红外CCD探测器半导体制冷组件的研制

红外CCD成像器件在高温环境下工作,暗电流噪声大大增加,严重影响探测灵敏度。对此,使用半导体制冷和真空封装技术设计了探测器制冷组件,使CCD探测器稳定工作在合适温度,以相对较小的体积和功耗显著地提高红外器件的探测灵敏度。本文对探测器制冷组件整体结构、半导体制冷器选型、冷端耦合结构和热端散热结构进行了研究,最终在高温65℃环境下工作时,CCD探测器制冷温度达到-27℃,组件重量0.8kg。     

具有半导体制冷的新型膜蒸馏组件性能实验研究

设计了一种新型的半导体制冷空气隙膜蒸馏系统,将具有半导体制冷的冷腔与膜蒸馏系统的热腔有机地结合起来。实验研究了半导体输入电流、冷却水流量及热液温度对通量的影响。实验表明:冷却水流量900 L/h,输入电流8 A时的冷壁温度平均为5℃,制冷面各测点的温差最大只有0.5℃,制冷面温度均匀;实验工况8~12 A,冷却水流量300L/h时,膜通量随半导体输入电流的增大而增大。本文的研究为小型半导体制冷空气隙膜蒸馏系统的理论与应用研究奠定了基础。     

过冷技术在蒸气压缩制冷系统中应用的研究现状

分析了在压缩蒸汽制冷循环中增加液体制冷剂的过冷度后,对循环制冷性能的影响;综述了机械式过冷、依靠自身冷量过冷、冰蓄冷式过冷和基于热电原理的过冷四种过冷方式的研究现状。通过对比发现,这些过冷方式一方面以牺牲一部分制冷量来获得过冷,另一方面则是增加了能量的消耗,对整个系统而言并不一定能达到节能的目的。然而对于基于热电原理的过冷技术而言,热电元件结构简单、运行稳定,在很小的温差下,具有很高的制冷效率;但是其热端散热不佳,是制约其制冷效率低的主要原因,文中提出采用热管为其散热,保证热电元件在高效率下运行,可以达到节能的目的。     

基于C8051F120的TEC温度控制系统

文章以C8051F120为核心,采用高精度的PT100温度传感器作为测温元件,在PID温度控制算法的基础上利用第三代制冷技术——半导体制冷设计了一种小型自动控温系统。可以将温度控制在3℃以下,控温精度可达±0.5℃。     

地下水辅助空气源复合热泵系统的制冷特性研究

提出了一种以地下水辅助空气源热泵的新型双热源复合热泵装置,并设计出实验样机。针对夏季工况研究了地下水侧流量的变化对复合热泵系统性能参数的影响。实验结果表明,在最大负荷制冷工况时,采用少量的地下水作为辅助热源,可使系统制冷量提高约20%,系统能效比EER提高近65%。     

热电发电机驱动热电制冷机联合系统最优性能

用非平衡热力学与有限时间热力学相结合的方法,考虑装置内部的Seebeck效应、Peltier效应、焦耳热效应、傅立叶效应及装置与热源间传热损失,建立了牛顿传热规律下热电发电机驱动热电制冷机联合系统的有限时间热力学模型,得到装置制冷率和制冷系数的解析式.在装置热电单元总数和换热器总换热面积一定的条件下,优化热电单元和换热面积的分配,获得装置的最大制冷率和制冷系数,并着重分析了热电发电机高温热源温度和热电制冷机制冷空间温度对装置最优性能的影响.结果表明,优化可以有效地提高装置制冷率和制冷系数,增大装置极限制冷温差,拓宽装置工作范围.     

Calculation and optimization of thermoelectric cooling modes of thermally loaded elements

The results of calculating the characteristics of the heat-transfer process in thermoelectric cooling and temperature control are presented. The influence of the inhomogeneity of the heat flux and thermal contacts on the temperature increase of the heat-loaded element has been defined. The analysis of the cooling efficiency depending on the operating characteristics and the current strength of the power supply of thermoelectric modules, parameters of the heat-loaded element and the individual components of the system, and the conditions of the heat exchange with the external environment has been performed. It has been shown that, under certain conditions, the use of the thermoelectric modules cannot lead to a cooling of the element, but rather to heating. The possibility of optimizing the cooling to reduce the temperature of the heat-loaded element and power consumption of the thermoelectric module has been considered.     

Evaluating the efficiency of thermo-electric conversion of heat from gas combustion in a small-scale system with counterflow heat exchange

The efficiency of thermoelectric conversion of heat from gas combustion was evaluated in a small-scale system consisting of two channels with opposing gas flows and thermocouples located in the separating wall. Combustion occurred in the chamber fed with fresh mixture heated by combustion products through heat-conducting walls of the channel. In the channel walls, there were thermoelectric converters. It has been shown that in this system, the maximum conversion efficiency of heat from gas combustion may be close to the maximum efficiency of thermoelectric conversion calculated by the maximum acceptable working temperature of the hot side of the converter. This conclusion is valid in the case when the adiabatic combustion temperature of the gas mixture is below the maximum allowable operating temperature of the hot side of the thermoelectric converter. The considered system is promising for the burning of low-calorific gas mixtures and does not require additional energy for cooling the cold side of the thermoelectric converter.     

改进冷端换热器的大功率脉冲管制冷机

依据热力学非对称理论对脉冲管制冷机冷端的热力学过程进行分析 ,对脉冲管制冷机制冷功率的提高提出了改进方案 ,搭建了单级低频大功率脉冲管制冷机的实验台 ,在实验中首次采用新型的填料烧结型换热器作为脉冲管的冷头 ,对这种换热器的效率在不同实验条件下进行了计算 ,并通过实验验证了这种新型换热器在脉冲管制冷机中应用的可行性。实验表明 :改进冷端换热器是提高脉冲管制冷机制冷效率的关键问题。在使用烧结换热器的单级脉冲管制冷机实验台上 ,采用输出功率 3k W的压缩机在 80 K时得到了 35W的制冷量 ,在效率上属国内领先水平。     

热电制冷机性能分析与实验验证

1引言用有限时间热力学1‘－‘］分析热电制冷单元的最优性能已取得了一些成果［3－‘l。实际的热电制冷机往往由很多个制冷单元组成,是多热电堆制冷机。本文分析由任意个热电单元组成的制冷机性能,导出考虑传热不可逆性、焦耳效应、内部导热效应时的制冷率、制冷系数与...     

Thermoelectricity without absorbing energy from the heat sources

We analyze the power output of a quantum dot machine coupled to two electronic reservoirs via thermoelectric contacts, and to two thermal reservoirs – one hot and one cold. This machine is a nanoscale analogue of a conventional thermocouple heat-engine, in which the active region being heated is unavoidably also exchanging heat with its cold environment. Heat exchange between the dot and the thermal reservoirs is treated as a capacitive coupling to electronic fluctuations in localized levels, modeled as two additional quantum dots. The resulting multiple-dot setup is described using a master equation approach. We observe an “exotic” power generation, which remains finite even when the heat absorbed from the thermal reservoirs is zero (in other words the heat coming from the hot reservoir all escapes into the cold environment). This effect can be understood in terms of a non-local effect in which the heat flow from heat source to the cold environment generates power via a mechanism which we refer to as Coulomb heat drag. It relies on the fact that there is no relaxation in the quantum dot system, so electrons within it have a non-thermal energy distribution. More poetically, one can say that we find a spatial separation of the first-law of thermodynamics (heat to work conversion) from the second-law of thermodynamics (generation of entropy). We present circumstances in which this non-thermal system can generate more power than any conventional macroscopic thermocouple (with local thermalization), even when the latter works with Carnot efficiency.     

Reprint of : Thermoelectricity without absorbing energy from the heat sources

We analyze the power output of a quantum dot machine coupled to two electronic reservoirs via thermoelectric contacts, and to two thermal reservoirs – one hot and one cold. This machine is a nanoscale analogue of a conventional thermocouple heat-engine, in which the active region being heated is unavoidably also exchanging heat with its cold environment. Heat exchange between the dot and the thermal reservoirs is treated as a capacitive coupling to electronic fluctuations in localized levels, modeled as two additional quantum dots. The resulting multiple-dot setup is described using a master equation approach. We observe an “exotic” power generation, which remains finite even when the heat absorbed from the thermal reservoirs is zero (in other words the heat coming from the hot reservoir all escapes into the cold environment). This effect can be understood in terms of a non-local effect in which the heat flow from heat source to the cold environment generates power via a mechanism which we refer to as Coulomb heat drag. It relies on the fact that there is no relaxation in the quantum dot system, so electrons within it have a non-thermal energy distribution. More poetically, one can say that we find a spatial separation of the first-law of thermodynamics (heat to work conversion) from the second-law of thermodynamics (generation of entropy). We present circumstances in which this non-thermal system can generate more power than any conventional macroscopic thermocouple (with local thermalization), even when the latter works with Carnot efficiency.     

半导体冷藏箱热端风冷散热器CFD辅助设计和实验研究

在保证半导体冷藏箱热端散热的情况下,将热端水冷改为风冷以简化制冷系统。运用CFD软件进行辅助设计,并对换热过程进行场协同分析,得到肋间距为2mm,肋厚为0.6mm,顶部送风方式下散热器性能达到最优化。将设计的散热器用于试验,试验结果与模拟设计结果最大相差10.7%。试验结果证明了运用CFD辅助设计的风冷式半导体热端散热器的可靠性。研究结果有助于半导体热端风冷散热器的热设计和提高其散热性能。     

Heat flow and efficiency in a microscopic engine

We study the energetics of a thermal motor driven by temperature differences, which consists of a Brownian particle moving in a sawtooth potential with an external load where the viscous medium is periodically in contact with hot and cold heat reservoir along space coordinate. The motor can work as a heat engine or a refrigerator under different conditions. The heat flow via both potential and kinetic energy is considered. The former is reversible when the engine works quasistatically and the latter is always irreversible. The efficiency of the heat engine can never approach Carnot efficiency.     

Thermoelectric excess heat effect in electrolytic cells

A new thermo-electrochemical effect similar to Peltier heat is introduced in this paper and suggested as a main cause of the excess heat observed in electrolytic cells. If the cell electrodes are made from different materials, we show that the system will function like a thermoelectric heat pump. With finite work input, this thermodynamic engine will pump in an infinite amount of low-grade environmental heat for vanishing temperature differences between the hot and cold source in the reversible, low current density, limit. A partial irreproducibility of excess heat observations is expected due to differences in the location of the calorimeter wall in each experiment. The heat pump nature and the thermoelectric properties of electrolytic cells are basic new notions introduced here. They may solve the excess heat paradox in electrolytic cold fusion, thus removing the well-known discrepancy between the small output of nuclear reaction products and the large excess heat, redefining this way both the notion of excess heat and the focus of our cold fusion research.