Complete Characterization of Thermoelectric Materials by a Combined van der Pauw Approach and the Effect of Radiation Losses

2011 ◽  
Vol 1314 ◽  
Author(s):  
Johannes de Boor ◽  
Volker Schmidt
Keyword(s):  
Thermal Conductivity ◽  
Measurement Errors ◽  
Conductivity Measurement ◽  
Short Review ◽  
Complete Characterization ◽  
Radiative Heat Loss ◽  
Radiation Losses ◽  
Novel Method ◽  
Simple Estimation ◽  
Van Der Pauw

AbstractWe have recently presented a novel method for a complete thermoelectric characterization [J. de Boor, V. Schmidt. Adv. Mater. 22:4303, (2010)]. This method is based on the well-known electrical van der Pauw method and allows measurement of the electrical and thermal conductivity, the Seebeck coefficient and the thermoelectric figure of merit. After a short review of this method we will discuss the systematic measurement errors of the method. It turns out that radiative heat loss can affect the thermal conductivity measurement significantly. We will give a simple estimation for the relative error due to radiation losses and discuss error minimizing strategies.

scholarly journals Thermal Conductivity Measurement of Graphene Composite

2013 ◽  
Vol 1456 ◽  
Author(s):  
Jiuning Hu ◽  
Wonjun Park ◽  
Xiulin Ruan ◽  
Yong P. Chen
Keyword(s):  
Thermal Conductivity ◽  
Graphene Oxide ◽  
Room Temperature ◽  
Detrimental Effect ◽  
Conductivity Measurement ◽  
Filler Concentration ◽  
3Ω Method ◽  
Graphene Composite ◽  
Reduced Graphene ◽  
Novel Method

ABSTRACTGraphene composites (GCs) have attracted much attention recently. It is interesting to explore thermal properties of GCs in which graphene filler concentrations are tunable. Here, we use 3ω method to measure the thermal conductivity of GCs synthesized from reduced graphene oxide (RGO) dispersed in polystyrene. To avoid the detrimental effect of lithography processes to GCs, we have developed a novel method employing polyvinyl alcohol and poly(methyl methacrylate) (PMMA) as a holder film to transfer micrometer-sized metal heaters/sensors onto GC surface. Room temperature measurements of the thermal conductivity of GCs are performed. The thermal conductivity is enhanced by ∼ 35 % when adding 5 vol.% of RGO filler concentration. Our measurements will be helpful to probe and understand the thermal transport properties of graphene based composites.

Analysis of significant measures for thermal conductivity

2020 ◽  
pp. 35-42
Author(s):  
Yuri P. Zarichnyak ◽  
Vyacheslav P. Khodunkov
Keyword(s):  
Thermal Conductivity ◽  
Heat Flux ◽  
Surface Heat Flux ◽  
Heat Flux Density ◽  
Measurement Method ◽  
Conductivity Measurement ◽  
Surface Heat ◽  
Measuring Instrument ◽  
New Class ◽  
Achievable Accuracy

The analysis of a new class of measuring instrument for heat quantities based on the use of multi-valued measures of heat conductivity of solids. For example, measuring thermal conductivity of solids shown the fallacy of the proposed approach and the illegality of the use of the principle of ambiguity to intensive thermal quantities. As a proof of the error of the approach, the relations for the thermal conductivities of the component elements of a heat pump that implements a multi-valued measure of thermal conductivity are given, and the limiting cases are considered. In two ways, it is established that the thermal conductivity of the specified measure does not depend on the value of the supplied heat flow. It is shown that the declared accuracy of the thermal conductivity measurement method does not correspond to the actual achievable accuracy values and the standard for the unit of surface heat flux density GET 172-2016. The estimation of the currently achievable accuracy of measuring the thermal conductivity of solids is given. The directions of further research and possible solutions to the problem are given.

Construction of a thermal conductivity measurement system for small single crystals of organic conductors

2018 ◽  
Vol 135 (5) ◽  
pp. 2831-2836 ◽  
Author(s):  
Tetsuya Nomoto ◽  
Shusaku Imajo ◽  
Satoshi Yamashita ◽  
Hiroki Akutsu ◽  
Yasuhiro Nakazawa ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Single Crystals ◽  
Measurement System ◽  
Conductivity Measurement ◽  
Organic Conductors ◽  
Thermal Conductivity Measurement

Study of Method for Determination of Thermal Conductivity of Automotive Interior Materials

2014 ◽  
Vol 526 ◽  
pp. 46-51
Author(s):  
Li Xiong Zhang ◽  
Rong Gang Gao
Keyword(s):  
Thermal Conductivity ◽  
Conductivity Measurement ◽  
Transient Heat Conduction ◽  
Traditional Theory ◽  
Infinite Plane ◽  
Plane Source ◽  
Transient Plane Source ◽  
Wide Range ◽  
Automotive Interior

Based on the traditional theory of transient plane source for thermal conductivity measurement, this paper designed and developed a new pattern of heating and temperature sensing probe, presented the study of transient heat conduction of half-infinite plane while being heated, established a modified mathematical model of transient plane source method, and achieved the measurement of thermal conductivity of automotive interior material sample by the data processing method of mathematical iteration and liner regression using the modified transient plane source probe. According to the data of experiments, the instrument which this paper designed has a high precision of 5% and a wide range of 0.003-1W/(mK).This paper provides a practicable way for heat capacity determination of automotive interior materials.

scholarly journals Efficiency of the Needle Probe Test for Evaluation of Thermal Conductivity of Composite Materials: Two-Scale Analysis

2014 ◽  
Vol 36 (1) ◽  
pp. 55-62 ◽  
Author(s):  
Dariusz Łydżba ◽  
Adrian Różański ◽  
Magdalena Rajczakowska ◽  
Damian Stefaniuk
Keyword(s):  
Thermal Conductivity ◽  
Composite Materials ◽  
Numerical Simulations ◽  
Conductivity Measurement ◽  
Scale Analysis ◽  
Equivalent Conductivity ◽  
Inclusion Type ◽  
Two Phase ◽  
Needle Probe ◽  
Probe Test

Abstract The needle probe test, as a thermal conductivity measurement method, has become very popular in recent years. In the present study, the efficiency of this methodology, for the case of composite materials, is investigated based on the numerical simulations. The material under study is a two-phase composite with periodic microstructure of “matrix-inclusion” type. Two-scale analysis, incorporating micromechanics approach, is performed. First, the effective thermal conductivity of the composite considered is found by the solution of the appropriate boundary value problem stated for the single unit cell. Next, numerical simulations of the needle probe test are carried out. In this case, two different locations of the measuring sensor are considered. It is shown that the “equivalent” conductivity, derived from the probe test, is strongly affected by the location of the sensor. Moreover, comparing the results obtained for different scales, one can notice that the “equivalent” conductivity cannot be interpreted as the effective one for the composites considered. Hence, a crude approximation of the effective property is proposed based on the volume fractions of constituents and the equivalent conductivities derived from different sensor locations.

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