半导体电子制冷原理

半导体电子制冷原理 Principle of semiconductor electronic refrigeration Application and development of semiconductor refrigeration technology Maqiaoshi This paper systematically expounds the development history and present situation of semiconductor refrigeration technology, introduces its main application in industry, and points out the development trend of semiconductor refrigeration technology Key word word文档格式规范word作业纸小票打印word模板word简历模板免费word简历 s semiconductor refrigeration; thermoelectric material; Perle tie effect; thermocouple; CLC number TP 211.51 Application, and, development, of, semiconductor, refrigerant, technique Ma Qiaoshi (Dept.of, Auto, Control, Shenyang, Arch.and, Civ.Eng.Inst., Shenyang, 110015, China) Abstract, This, paper, summarizes, the, history, and, present, situation, of, semiconductor, refrigerating, introduces, the, application,, in, industry.and, its, development, development, direction. Keywords semiconductor refrigerating; pyroelectric materials; Peltier effect; thermo-electric couplers Semiconductor refrigeration also called thermoelectric refrigeration, from a range of refrigeration technology and semiconductor technology developed in the 50s edge discipline, it uses a special semiconductor P-N junction, the formation of the thermocouple, the Perle post effect, through a new type of DC refrigeration cooling. Compared with the traditional refrigeration technology, it the advantages are: (1) has the advantages of simple structure, no noise, no wear, no pollution and high reliability; (2) cooling speed, flexible control; (3) the thermopile can be arbitrary distribution, size and shape variable. Because of the advantages, now at home and abroad are promoting this technology, 1, 3. This paper introduces and reviews the status quo of semiconductor refrigeration technology development in recent years, for engaged and interested in semiconductor refrigeration technology reference. From the historical point of view the development of semiconductor refrigeration, has experienced three stages. The first stage is the beginning of this century, sechel and Perle posts have found Thermocurrent phenomenon and temperature anomalies, and carried out the research of thermoelectric refrigeration and power generation. But at that time due to poor thermoelectric properties of the metal material used, the efficiency of energy conversion the thermoelectric effect is very low, not real application. The second stage is the beginning of the 50s, mainly through the extensive application of semiconductor materials, semiconductor materials with good thermoelectric properties, and the efficiency of the thermoelectric effect is greatly improved, so that the thermoelectric refrigeration and power generation in engineering practice. The third stage is after 80s, mainly to to improve the performance of semiconductor thermoelectric refrigeration, further development and application of thermoelectric refrigeration 4. 1 Application of semiconductor refrigeration technology The thermoelectric properties of semiconductor materials, can be made of a temperature range of -50 to 80 DEG C, the volume of work can be big or small, and can realize the temperature control point refrigerator. Although it is of low efficiency, high energy consumption, but less than the cooling capacity in less than 20 W and the temperature difference does not exceed 50 degrees. The efficiency of semiconductor refrigeration is higher than the efficiency of compression refrigeration. Therefore, in need of small size appearance and light weight, no wear, no noise, can accurately and smoothly a DJ DJ简历DJ简历DJ简历DJ简历DJ简历 ust the temperature condition and maintenance of refrigeration, air pollution and other areas to prevent refrigerant have been widely used. 1.1 applications in electronic technology In the last 20 years, cryoelectronics has gained rapid development, photomultiplier tube, infrared detector, sensitive devices, power devices, components and equipment cooling in optoelectronics, semiconductor refrigeration has a unique role. The semiconductor refrigeration technology, cooling of electronic circuit components, can effectively improve the stability of the parameters, or the signal-to-noise ratio is improved, so as to improve the sensitivity of amplification and measuring device and accuracy. The thermoelectric refrigerator can also use a different way to the cooling of electronic devices and equipment. It not only can the electronic components are mounted directly on the cold end of the refrigerator, direct cooling, and electronic equipment on a semiconductor refrigeration chamber, Indirect cooling is achieved by natural convection of air in a small chamber Semiconductor cooler for 1.1.1 photomultiplier tube In atomic physics, astronomy and other fields, the widespread use of photomultiplier tube, dark current, noise, but its sensitivity depends mainly on the cathode temperature. An antimony cesium negative photomultiplier tubes, when the cathode temperature at 0 DEG C when the dark current is 3 times lower, the temperature dropped to 30 degrees when the dark current reduced by 30 times, with two photoelectric thermoelectric refrigerator refrigeration photomultiplier, can meet the demand to reduce the dark current, 1, 5, 6. Semiconductor cooler for 1.1.2 infrared detector The infrared detector in the low temperature, remarkably reduce noise, sensitivity and detection rate is greatly improved and the response of infrared detector in -10 PBS, PbSe C several times larger than +20 DEG C, -78 C the detection rate can be increased by an order of magnitude. The infrared detector cooling requirements to tens of degrees below zero, the thermal load is very small, only tens of milliwatts, single stage thermoelectric cooler can be made from one to two to obtain the semiconductor galvanic effect 2, 7. 1.2 industrial applications From 70s, China began to explore the application of semiconductor refrigeration technology in the industry, and has basically completed the electronic refrigeration turning, electronic refrigeration milling, grinding, electronic electronic freeze casting, liquid film of frozen ice research. By fixing the workpiece instead of ice film fixture, electronic freezing technology to replace the traditional liquid ammonia refrigeration medium, fast loading and unloading and constant temperature control through the power converter, the past can not be processed materials, especially aerospace materials (rubber, thermoplastic, thin brittle material, etc.) to find a new method for processing. The most prominent is the research and application of cold freeze grinding, solution the surface grinding burn, stress relief and other issues, it is clean, odorless, improvement of environmental health, improve the quality of parts, has been in the field of mechanical processing has heavy A niche [4, 8] Applications of 1.2.1 electronic refrigeration [8] (1): freeze grinding grinding processing is only applicable to the ferromagnetic materials, and the residual magnetism and frozen, can solve the problem of grinding grinding of various materials, magnetic and does not change the original material, will not burn. A research on steel, stainless steel, high-speed steel, non metal materials etc. freeze in without cooling liquid under the condition of dry grinding experiments were satisfactory, 4. (2) precision machining sheet: tried on a lathe Aluminum Alloy a sheet of D * D * b=360 mm * 168 mm * 1.27 mm for a variety of processing methods, such as internal expansion and external hold for double cutter, vacuum suction and so on. But these methods of complex process, low efficiency, waste the freezing rate is high, turning, makes the sheet machining quality and efficiency are the ideal effect. For example, a factory using electronic freezing tool, the cutter head and the knife body temperature constant at -15 DEG C, so that the tool life is prolonged, the processing precision is improved. At the same time completely changed the cooling condition of the tool, save a lot of oil cooling. The practice proves that the electronic tool than refrigeration tool durability improve 42%. this method clean, economic power, small deformation, easy cutting, machining quality, tool life increased by 3 ~ 4 times, so the economic efficiency Significant [8] 1.2.2 electronic freeze casting [9] Semiconductor refrigeration is used in casting, it is the model of the metal plate and the temperature dropped to -25 DEG C, and then set on the adiabatic sandbox, containing water in the original sand, ramming scraping, for 4 ~ 8min, the power supply under the reverse draft, then the upper box box casting a a casting method. Electronic freeze casting machining allowance, good quality, precise size, shape and gas and other toxic gases released during the casting, casting sand falling and casting cleaning convenient, greatly simplifies the process of reuse of old sand. From Germany, Britain and the United States, France and other countries reported, they have successfully do some theoretical research and experimental work, solve the main parameters of freezing and frozen mold. Japanese scientists have successfully analyzed frozen cast moisture in the cohesion layer, bulk density, particle effects on frozen speed. Since our country began to study from the beginning of 80s, gradually to independent research from imitation, and achieved practical results, such as a factory in Shenyang using electronic freeze sculpt production by pressing ring welding machine, its features are as follows: (1) due to the casting accuracy, reduce machining allowance, casting weight by sand casting 4.35 kg drop for 3.35 kg, due to the use of non riser casting, riser weight from 2.8 kg to 0.75 kg. saves the molten iron and reduce the amount of processing. (2) because of the original sand without binder and additives, greatly reduce the material cost. (3) electronic refrigeration molding, each box consumes only 0.13 degrees, save energy 1.3 application in medical instruments Application of thermoelectric refrigeration in biology and medicine on the instrument earlier. Use it without noise, no vibration, small size and easy to use, has developed a series of new products, widely used in medical instruments and clinical care. 1.3.1 PCR instrument [2] PCR (polymerase chain reaction) method by enzymatic synthesis of specific DNA fragments. It consists of high temperature and low temperature annealing temperature, denaturation temperature of three thermal cycle extension ladder repeatedly composed so PCR instrument program is actually a temperature controller, also called gene amplification instrument. The conversion amplification effect and temperature ladder the time is closely related to, the shorter the time, the higher the specific amplification, the better the effect. Using ordinary refrigeration (heating) method, such as compressor, water cooling, air cooling, infrared heating, heating, to obtain better amplification effect is very difficult, and the use of the PCR instrument of semiconductor refrigeration technology can not only achieve the amplification effect very good, but also has the advantages of small size, no noise, temperature controlled in a wider range. 1.3.2 ventilator pump The pump is an important component of all especially in ventilator, air pressure to the hospital without using central air supply way, it is an essential part of it. To provide ventilation dry and clean gas. The gas cooling, then the water separator will separate condensate water, dry gas to achieve the pump adopts the semiconductor refrigeration technology. Compared with the traditional air cooling by ordinary air pump has the advantages of small size, simple structure, no noise, rapid condensation and condensation and high efficiency, has been widely used in the high gear pump in the ventilator. 2 developments in semiconductor refrigeration materials [2, 9] As early as 50s, when developing proper semiconductor technology, scientists have found that the semiconductor material has good thermoelectric properties. Then according to the characteristics of semiconductor material on the refrigeration effect, explored the experts, and according to the experimental results obtained the following conclusions: (1) in order to produce better cooling effect, the temperature difference of the material is higher than the electromotive force (it is a function of the selected material); (2) the resistivity of the material is low; otherwise, the heat generated by the resistance may exceed the performance of the refrigeration; (3) there is a large temperature difference between the hot and cold nodes, and the coefficient of thermal conductivity is low These three factors are integrated into the figure of merit Z, which determines the refrigeration coefficient of semiconductor refrigerator. The material Z value is high, the better the effect of semiconductor refrigeration. Therefore, scientists in all countries committed to improve the Z value of material, development of new materials for thermoelectric refrigeration, so that the thermal electric refrigeration effect is better, to in mid 60s, the value of Z has reached a very high level of P type semiconductor Z Zp=3.5 * 10-3K-1; N type semiconductor Z value ZN= (3 ~ 3.2) * 10-3K-1. insulation under the condition of the maximum temperature difference Tmax=70 K (hot end temperature Th=300K). At the same time, China Academy of semiconductor thermoelectric materials research institute., its performance has reached the international level. In 70s, the following three kinds of quasi three alloy has been a lot of research: (1) without doping; (2) doped P type and N type; (3) sulfide doped. Experiments show that the quasi three yuan Bi2Te3 - Sb2Te3 - Sb2Se3 alloy doped P type often show characteristics. According to Jin Xiangjian check, Located entirely within the scope of solid solubility. Due to the quasi three yuan alloy doped P type, so it must be transformed and adding proper amount of acceptor impurities to N type semiconductor. America R.B.Hort et al rich three alloy doped with SbI3, which has the best resistivity value, get the best type of N the figure of merit. It is proved that the content of Sb2Se3 is the best P materials in 70%. P rich Sb2Se3 alloy is three yuan, Te is one of the best additives. At present, thermoelectric materials ideal optimization coefficient Z= (3.4 ~ 3.6) * 10-3K-1, the temperature range of 223 ~ 423K (-50 to +150 DEG C). If you want to make the thermoelectric refrigeration to achieve economic and mechanical compression refrigeration, must make the optimization coefficient reach 13 * 10-3K-1. visible, thermoelectric cooling and mechanical refrigeration in the gap between the large, still need to greatly improve the figure of merit. 3 conclusion Although the development of domestic and international semiconductor refrigeration technology is very fast, more and more widely, but there are still many problems need to be improved: (1) by material constraints, can not produce a large enough amount of refrigeration, refrigeration technology, it can not completely replace the ordinary, only suitable for the requirements of production capacity of small areas. Efforts should be made to improve the thermoelectric the figure of merit of materials, semiconductor refrigeration device and the high efficiency in development; (2) require refrigeration thermoelectric current reactor, large current and low voltage, current source rectifier leads to large volume, high quality. To reduce the current and voltage increase direction; (3) computer control technology is adopted to control the temperature more accurate. Author: Marjorie rise 39 years old, male, engineer, Department of automatic control, Shenyang Construction Engineering College of Shenyang, 110015. Reference 1 Xu Desheng. Electronic refrigeration and semiconductor. Electronic technology, 1983, (3): 23~25 2 Xu Desheng. Semiconductor refrigeration and application technology. Shanghai: Shanghai Jiao Tong University press, 1992 3. Wu Zhenyao thermoelectric refrigeration technology. Refrigeration technology, 1986, (2): 6 ~ 7 4 ed. Li Wenbin. 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