• Title/Summary/Keyword: Thermoelectric effects

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Effects of Thermoelectric Module Arrangement on the Performance of a Thermoelectric Air-Cooling System (열전모듈 냉방기에서 열전모듈의 개수 및 전원배열이 시스템의 성능에 미치는 영향)

  • Hwang, Jun;Kang, Byung-Ha
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.19 no.2
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    • pp.162-168
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    • 2007
  • This paper presents the effects of thermoelectric module arrangement on the cooling performance of an air conditioner using thermoelectric module. A prototype of air cooling system, employing several thermoelectric modules, has been designed and built. The evaporative cooling technique is adopted for hot side of the module. The number of thermoelectric module in the system has been varied in the range of $2{\sim}8$. The optimal operation conditions, such as input power to the thermoelectric module, fans and pump, have been determined for each arrangement of the system and the cooling performance has been compared under the optimal operation. It is found that both cooling capacity and COP are increased as the number of thermoelectric module increased. It is also found that cooling capacity can be improved by connecting the thermoelectric modules in series than in parallel, while the COP is little affected.

A Study for Thermoelectric Generator System And Caused Low Thermoelectric Power (열전발전량에 영향을 미치는 요인과 최적의 열전발전시스템에 관한연구)

  • Moon, Chae-Joo;Cheang, Eui-Heang;Lim, Jung-Min;Park, Sang-Jin;Kim, Tae-Gon;Kim, Young-Gu
    • 한국태양에너지학회:학술대회논문집
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    • 2008.04a
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    • pp.68-74
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    • 2008
  • This paper describes the causes and effects that have influence on thermoelectric generation. If heat transfer is unequal to thermoelectric modules, we could not get the maximum thermoelectric power. So, by experiment, we analysed the differences of power generation according to the state of the contact between thermoelectric module and heat source. And with the variation of heat transfer area, the generated power was analysed also. Using the experimental results we proposed a thermoelectric generation system.

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A Study on Enhancement of Thermoelectric Cooling System Performance by Piezoelectric Actuator (압전 액츄에이터를 이용한 열전냉각 시스템 성능 향상에 관한 연구)

  • Yang, Ho-Dong;Yoon, Hee-Sung;Oh, Yool-Kwon
    • Journal of the Korean Society of Safety
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    • v.24 no.6
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    • pp.13-19
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    • 2009
  • The thermoelectric cooling system consisted of the thermoelectric module, a heat sink and a cooling fan, respectively. Also, the piezoelectric actuator was applied to improve the performance of thermoelectric cooling system and investigate the heat transfer phenomenon. The temperature distribution of test section was measured to investigate cooling characteristics of thermoelectric cooling system. The flow phenomenon of test section was visualized using visualization device. When the piezoelectric actuator was applied to the heat transfer process of thermoelectric cooling system, acoustic streaming was occurred in test section. The acoustic streaming was occurred forced convection flow, and was regularly formed the temperature distribution in test section. The results clearly show that the acoustic streaming is one of the prime effects to enhance the convection heat transfer and can enhance the performance of thermoelectric cooling system.

Defect Engineering for High-Performance Thermoelectric Semiconductors (결함제어를 통한 열전 반도체 연구 동향)

  • Min, Yuho
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.35 no.5
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    • pp.419-430
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    • 2022
  • Defects in solids play a vital role on thermoelectric properties through the direct impacts of electronic band structure and electron/phonon transports, which can improve the electronic and thermal properties of a given thermoelectric semiconductor. Defects in semiconductors can be divided into four different types depending on their geometric dimensions, and thus understanding the effects on thermoelectric properties of each type is of a vital importance. This paper reviews the recent advances in the various thermoelectric semiconductors through defect engineering focusing on the charge carrier and phonon behaviors. First, we clarify and summarize each type of defects in thermoelectric semiconductors. Then, we review the recent achievements in thermoelectric properties by applying defect engineering when introducing defects into semiconductor lattices. This paper ends with a brief discussion on the challenges and future directions of defect engineering in the thermoelectric field.

Neutron-irradiated effect on the thermoelectric properties of Bi2Te3-based thermoelectric leg

  • Huanyu Zhao;Kai Liu;Zhiheng Xu;Yunpeng Liu;Xiaobin Tang
    • Nuclear Engineering and Technology
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    • v.55 no.8
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    • pp.3080-3087
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    • 2023
  • Thermoelectric (TE) materials working in radioisotope thermoelectric generators are irradiated by neutrons throughout its service; thus, investigating the neutron irradiation stability of TE devices is necessary. Herein, the influence of neutron irradiation with fluences of 4.56 × 1010 and 1 × 1013 n/cm2 by pulsed neutron reactor on the electrical and thermal transport properties of n-type Bi2Te2.7Se0.3 and p-type Bi0.5Sb1.5Te3 thermoelectric alloys prepared by cold-pressing and molding is investigated. After neutron irradiation, the properties of thermoelectric materials fluctuate, which is related to the material type and irradiation fluence. Different from p-type thermoelectric materials, neutron irradiation has a positive effect on n-type Bi2Te2.7Se0.3 materials. This result might be due to the increase of carrier mobility and the optimization of electrical conductivity. Afterward, the effects of p-type and n-type TE devices with different treatments on the output performance of TE devices are further discussed. The positive and negative effects caused by irradiation can cancel each other to a certain extent. For TE devices paired with p-type Bi0.5Sb1.5Te3 and n-type Bi2Te2.7Se0.3 thermoelectric legs, the generated power and conversion efficiency are stable after neutron irradiation.

Effects of Hydrogen Reduction in Microstructure, Mechanical and Thermoelectric Properties of Gas Atomized n-type Bi2Te2.7 Se0.3 Material

  • Rimal, Pradip;Yoon, Sang-Min;Kim, Eun-Bin;Lee, Chul-Hee;Hong, Soon-Jik
    • Journal of Powder Materials
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    • v.23 no.2
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    • pp.126-131
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    • 2016
  • The recent rise in applications of thermoelectric materials has attracted interest in studies toward the fabrication of thermoelectric materials using mass production techniques. In this study, we successfully fabricate n-type $Bi_2Te_{2.7}Se_{0.3}$ material by a combination of mass production powder metallurgy techniques, gas atomization, and spark plasma sintering. In addition, to examine the effects of hydrogen reduction in the microstructure, the thermoelectric and mechanical properties are measured and analyzed. Here, almost 60% of the oxygen content of the powder are eliminated after hydrogen reduction for 4 h at $360^{\circ}C$. Micrographs of the powder show that the reduced powder had a comparatively clean surface and larger grain sizes than unreduced powder. The density of the consolidated bulk using as-atomized powder and reduced atomized powder exceeds 99%. The thermoelectric power factor of the sample prepared by reduction of powder is 20% better than that of the sample prepared using unreduced powder.

A Study on the Hot Spot Cooling Using Thermoelectric Cooler (열전냉각 모듈을 이용한 국소 냉각에 관한 연구)

  • Kim, Ook-Joong;Lee, Kong-Hoon
    • Proceedings of the SAREK Conference
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    • 2007.11a
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    • pp.640-645
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    • 2007
  • An experimental apparatus to show the hot spot cooling of an IC chip using a thermoelectric cooler is developed. The spot heating in very small area is achieved by the applying CO$_2$ laser source and temperatures are measured using miniature thermocouples. The active effects of thermoelectric cooler on the hot spot cooling system such as rapid heat spreading in the chip and lowering the peak temperature around the hot spot region are investigated. The experimental results are simulated numerically using the TAS program, which the performance characteristics such as Seebeck coefficient, electrical resistance and thermal conductivity of the thermoelectric cooler are searched by trial and error. Good agreements are obtained between numerical and experimental results if the appropriate performance data of the thermoelectric cooler are given.

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Thickness and Annealing Effects on the Thermoelectric Properties of P-type Bi0.5Sb1.5Te3 Thin Films (P형 Bi0.5Sb1.5Te3 박막의 열전 특성에 미치는 두께 및 어닐링 효과)

  • Kim Il-Ho;Jang Kyug-Wook
    • Korean Journal of Materials Research
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    • v.14 no.1
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    • pp.41-45
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    • 2004
  • P-type $Bi_{0.5}$$Sb_{1.5}$ $Te_3$ thin films were deposited by the flash evaporation technique, and their thermoelectric properties and electronic transport parameters were investigated. The effective mean free path model was adopted to examine the thickness effect on the thermoelectric properties. Annealing effects on the carrier concentration and mobility were also studied, and their variations were analyzed in conjunction with the antisite defects. Seebeck coefficient and electrical resistivity versus inverse thickness showed a linear relationship, and the effective mean free path was found to be 3150$\AA$. No phase transformation and composition change were observed after annealing treatment, but carrier mobility increased due to grain growth. Carrier concentration decreased considerably due to reduction of the antisite defects, so that electrical conductivity decreased and Seebeck coefficient increased. When annealed at 473 K for 1 hr, Seebeck coefficient and electrical conductivity were $160\mu$V/K and 610 $W^{-1}$ $cm^{ -1}$, respectively. Therefore, the thermoelectric quality factor were also enhanced to be $16\mu$W/cm $K^2$.>.

Improvement of Thermoelectric Properties of Bismuth Telluride Thin Films using Rapid Thermal Processing (Bismuth Telluride 박막의 열전특성 개선을 위한 급속 열처리효과)

  • Kim, Dong-Ho;Lee, Gun-Hwan
    • Korean Journal of Materials Research
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    • v.16 no.5
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    • pp.292-296
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    • 2006
  • Effects of rapid thermal annealing of bismuth telluride thin films on their thermoelectric properties were investigated. Films with four different compositions were elaborated by co-sputtering of Bi and Te targets. Rapid thermal treatments in range of $300{\sim}400^{\circ}C$ were carried out during 10 minutes under the reducing atmosphere (Ar with 10% $H_2$). As the temperature of thermal treatment increased, carrier concentrations of films decreased while their mobilities increased. These changes were clearly observed for the films close to the stoichiometric composition. Rapid thermal treatment was found to be effective in improving the thermoelectric properties of $Bi_2Te_3$ films. Recrystallization of $Bi_2Te_3$ phase has caused the enhancement of thermoelectric properties, along with the decrease of the carrier concentration. Maximum values of Seebeck coefficient and power factor were obtained for the films treated at $400^{\circ}C$ (about $-128{\mu}V/K$ and $9{\times}10^{-4}\;W/K^2m$, respectively). With further higher temperature ($500^{\circ}C$), thermoelectric properties deteriorated due to the evaporation of Te element and subsequent disruption of film's structure.

An Experimental Study on the Effects of the Cooling Jacket Design Parameters on the Performance of Thermoelectric Cooling System (열전소자 냉각 자켓의 설계인자가 열전냉각 시스템의 성능에 미치는 효과에 대한 실험적 연구)

  • Lee, J.E.;Park, S.H.;Kim, K.;Kim, D.
    • Proceedings of the KSME Conference
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    • 2007.05b
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    • pp.2079-2084
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    • 2007
  • A small-scale thermoelectric cooling system was built in an effort to enhance the performance of the refrigeration system by utilizing the water-cooled jacket which was attached on the hot side of the thermoelectric module. Considered design parameters for the water-cooled jacket included the geometry of the flow passage inside the jacket and the flow rate of cooling water. The higher flow rate of cooling water in the jacket resulted in a better performance of the refrigeration system. The introduction of geometrical complexity of the cooling water flow passage to the cooling jacket also showed significant improvement on the performance of the thermoelectric refrigeration system such as the cooling capacity and the COP of the refrigeration system.

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