Heat flow measurement as a key to standardization of thermoelectric generator module metrology: A comparison of reference and absolute techniques

Ziółkowski, Pawel; Blaschkewitz, Przemyslaw; Müller, Eckhard

doi:10.1016/j.measurement.2020.108273

Cited by 23 publications

(28 citation statements)

References 27 publications

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“…This section gives a brief survey on the custom-made TEM characterization facilities at AIST [24,47] (Figure 2a) and DLR (Figure 2b) [48] with respect to the applied techniques, construction of measuring sections, specific differences in the instrumentation, and evaluation procedures which are relevant for the uncertainty of particular measurands. Both facilities use oxygen-free copper heat exchangers and HFM with high thermal conductivity to improve the temperature homogeneity on the coupling faces at the hot and cold side of the TEM.…”

Section: Reference Methods For Heat Flow Determination (Aist and Dlr)mentioning

confidence: 99%

“…The error in the heat flow measurement is mainly due to the 2.5% uncertainty in the thermal conductivity of Cu block, which is calibrated using Standard Reference Materials of the National Institute of Standards and Technology (NIST SRM) pure electrolytic iron and partially due to the uncertainty in the temperature measured by Pt resistance thermometers. [ 39 ] The uncertainty of the reference method at DLR was determined from repetitive measurements [ 48 ] on a certified thermal reference material from the National Physical Laboratory (Inconel 600, NPL 2I09), [ 49 ] which yielded the derivation of the full uncertainty budget. The uncertainty of the heat flow measurement was determined in accordance to the “ Guide to the expression of uncertainty in measurement ” (GUM).…”

Section: Te Module Characterization Facilities At Aist and Dlrmentioning

confidence: 99%

“…This section gives a brief survey on the custom‐made TEM characterization facilities at AIST [ 24,47 ] ( Figure 2 a) and DLR (Figure 2b) [ 48 ] with respect to the applied techniques, construction of measuring sections, specific differences in the instrumentation, and evaluation procedures which are relevant for the uncertainty of particular measurands.…”

Section: Te Module Characterization Facilities At Aist and Dlrmentioning

confidence: 99%

“…Investigations on the accuracy of the GHP‐based heat flow determination were conducted using a certified thermal reference material (NPL 2109, Inconel600). [ 48 ] The comparison to reference values in the temperature range between 423 and 823 K revealed a deviation of the heat flow determination by the GHP of u ( Q ) < ±2.41% ( k = 2). This deviation is lower than the specified uncertainty of the thermal reference material which equals u ( κ ) = ±4.8% ( k = 2).…”

Section: Te Module Characterization Facilities At Aist and Dlrmentioning

confidence: 99%

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Interlaboratory Testing for High‐Temperature Power Generation Characteristics of a Ni‐Based Alloy Thermoelectric Module

et al. 2020

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Standardization of metrology for thermoelectric generator modules (TEMs) is a necessary step toward industrialization of thermoelectric applications. Unspecified uncertainty budgets of the widely used custom‐built characterization facilities seem insufficient to validate technological developments, industrial benchmarks, or allow sound conclusions in scientific studies. Particularly, works on high‐temperature TEM have to be supported by suitable characterization techniques. This shall accelerate progress toward product releases for thermoelectric energy conversion. Herein, a Ni‐based alloy TEM is reported, which is developed at the National Institute of Advanced Industrial Science and Technology (AIST) as a prospective standard reference TEM. Comparative measurements at AIST and the German Aerospace Center (DLR) demonstrate the high repeatability and precision of custom‐built TEM characterization facilities at AIST and DLR. Tests at elevated temperatures up to 773 K hot side temperature and 450 K temperature difference reveal excellent accordance of electric measurands with a standard deviation <0.3% for the open‐circuit voltage and <0.85% for electric resistance and maximum power output. Deviations of the heat flow measurement of up to 7.22% arise from individual uncertainties of the used characterization methods and point to the importance of standardization for TEM metrology.

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Section: Reference Methods For Heat Flow Determination (Aist and Dlr)mentioning

confidence: 99%

Section: Te Module Characterization Facilities At Aist and Dlrmentioning

confidence: 99%

Section: Te Module Characterization Facilities At Aist and Dlrmentioning

confidence: 99%

Section: Te Module Characterization Facilities At Aist and Dlrmentioning

confidence: 99%

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Interlaboratory Testing for High‐Temperature Power Generation Characteristics of a Ni‐Based Alloy Thermoelectric Module

et al. 2020

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“…The precise characterization of HS components is essential in research or for industrial applications. According to Ziolkowski et al [98], through a round-robin campaign, it was noticed that the TEG properties are obtained with a 20% deviation. Therefore, Ziolkowski et al propose a generic procedure for TEG characterization.…”

Section: Discussionmentioning

confidence: 99%

Comprehensive Review of Methods and Instruments for Photovoltaic–Thermoelectric Generator Hybrid System Characterization

Cotfas

2020

Energies

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Finding new sustainable energy sources or improving the efficiencies of the existing ones represents a very important research and development direction. The hybridization approach is one solution for increasing the efficiency of the existing energy sources. In the case of photovoltaic technology, the hybridization of the photovoltaic panels (PV) with thermoelectric generators (TEGs) has become a more interesting solution for the research community in the last decade. Thus, a comprehensive review of the characterization methods and instruments used in PV-TEG hybrid system study represents the objective of this work. PV and TEG equivalent circuits are presented. The instruments and software applications used for the measurements and simulations are presented and analyzed. The analysis of the literature reveals that there are many papers that offer partial or no information about the instruments used or about the measurement quality (accuracies, uncertainties, etc.). In hybrid system modeling, the preferred software applications are MATLAB (MathWorks, Natick, MA, USA) and COMSOL Multiphysics (Comsol, Burlington, MA, USA), while for experimental studies based on computers, LabVIEW (NI, Austin, TX, USA) is preferred. This review work could be interesting for researchers and engineers who are interested in finding solutions for characterizing or monitoring hybrid system components, but it is not limited to these.

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Efficiency Measurement and Modeling of a High‐Performance Mg₂(Si,Sn)‐Based Thermoelectric Generator

et al. 2022

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Mg2(Si,Sn) is an attractive material class due to its excellent thermoelectric (TE) properties, its eco‐friendly constituents, its low mass density, and its low price. A lot of research has been done on optimizing its TE properties; however, works on its use in thermoelectric generators (TEG) are scarce. Herein, the first conversion efficiency measurement of a functional, fully Mg2(Si,Sn)‐based TEG, approaching a maximum value of 4% for an applied ΔT = 375 °C, is shown. A maximum power density of 0.9 W cm−2 (related to the cross‐sectional area of the TE legs) at ΔT=375 °C is also reported, which is among the highest performance of silicide‐based modules reported in literature. Efficiency measurements can be tricky due to the uncertainty of heat flow measurement and parasitic heat losses; therefore, assessing the measurement reliability by confronting it to theoretical calculations is necessary. TEG device simulation in a constant property model is used to compare measured data to expected values and a good match is found (<1% deviation for current at maximum power, <4% difference for maximum power output, deviation within measurement uncertainty range for heat flows and efficiency). The significant discrepancy between measurement and calculations of the inner electrical resistance reveals room for improvement. Cracks form due to thermally induced mechanical stress, which dramatically increase the inner electrical resistance. It is shown that by avoiding those cracks, the maximum power output and conversion efficiency of the TEG could be improved by 30%.

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Heat flow measurement as a key to standardization of thermoelectric generator module metrology: A comparison of reference and absolute techniques

Cited by 23 publications

References 27 publications

Interlaboratory Testing for High‐Temperature Power Generation Characteristics of a Ni‐Based Alloy Thermoelectric Module

Interlaboratory Testing for High‐Temperature Power Generation Characteristics of a Ni‐Based Alloy Thermoelectric Module

Comprehensive Review of Methods and Instruments for Photovoltaic–Thermoelectric Generator Hybrid System Characterization

Efficiency Measurement and Modeling of a High‐Performance Mg₂(Si,Sn)‐Based Thermoelectric Generator

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Heat flow measurement as a key to standardization of thermoelectric generator module metrology: A comparison of reference and absolute techniques

Cited by 23 publications

References 27 publications

Interlaboratory Testing for High‐Temperature Power Generation Characteristics of a Ni‐Based Alloy Thermoelectric Module

Interlaboratory Testing for High‐Temperature Power Generation Characteristics of a Ni‐Based Alloy Thermoelectric Module

Comprehensive Review of Methods and Instruments for Photovoltaic–Thermoelectric Generator Hybrid System Characterization

Efficiency Measurement and Modeling of a High‐Performance Mg2(Si,Sn)‐Based Thermoelectric Generator

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Product

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Efficiency Measurement and Modeling of a High‐Performance Mg₂(Si,Sn)‐Based Thermoelectric Generator