The Measurement of Thermal Conductivity by the Comparative Method

Tye, R. P.

doi:10.1007/978-1-4615-3286-6_3

Cited by 8 publications

(9 citation statements)

References 3 publications

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“…In the current study, 37 mol% LiCl–63 mol% LiOH was tested for their thermal properties. It was observed that the average melting temperature was 270 °C, which is closer to the reported values by Tye et al However, the average heat of fusion of the samples was 297 J/g which was significantly different from the values reported in literature [ 25 ]. The observed difference could be due to the accuracy and reliability of the equipment in 1976, which might have affected their results.…”

Section: Resultssupporting

confidence: 65%

“…The result from FactSage (FactSage, 28 March 2022) indicated eutectic composition of 37 mol% LiCl and 63 mol% LiOH exhibited at a temperature of 262 °C. Thermophysical properties of 37 mol%–63 mol% were investigated in literature [ 25 ] experimentally. The report showed the melting temperature was 258 °C and the heat of fusion was 485 J/g.…”

Section: Resultsmentioning

confidence: 99%

“…For this project, four lithium salt mixtures at different compositions were made and tabulated in Table 2 with their respective lithium chloride (LiCl) and lithium hydroxide (LiOH) compositions as stated. We chose 37 mol% LiCl-63 mol% LiOH, the eutectic composition of the binary salt, from the literature [ 25 ] and a phase diagram obtained from the FactSage [ 27 ]. While the compositions of the other three samples were chosen randomly with a difference of 5 mol% from each other.…”

Section: Experimental and Methodologymentioning

confidence: 99%

“…Due to their suitable melting temperature, high heat of fusion, and good thermal stability, the mixture of lithium salts (LiCl–LiOH) is selected for the current study. The eutectic composition (37 mol% LiCl-63 mol% LiOH) was investigated in [ 25 ] only for their thermal properties. The melting temperature and heat of fusion were reported as 258 °C and 485 J/g, respectively.…”

Section: Introductionmentioning

confidence: 99%

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A Binary Salt Mixture LiCl–LiOH for Thermal Energy Storage

et al. 2023

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For thermal energy storage, the most promising method that has been considered is latent heat storage associated with molten salt mixtures as phase-change material (PCM). The binary salt mixture lithium chloride—lithium hydroxide (LiCl–LiOH) with a specific composition can store thermal energy. However, to the best of our knowledge, there is no information on their thermal stability in previous literature. The key objectives of this article were to investigate the thermophysical properties, thermal repeatability, and thermal decomposition behavior of the chosen binary salt mixture. FactSage software was used to determine the composition of the binary salt mixture. Thermophysical properties were investigated with a simultaneous thermal analyzer (STA). The thermal results show that the binary salt 32 mol% LiCl-68 mol% LiOH melts within the range of 269 °C to 292 °C and its heat of fusion is 379 J/g. Thermal repeatability was tested with a thermogravimetric analyzer (TGA) for 30 heating and cooling cycles, which resulted in little change to the melting temperature and heat of fusion. Thermal decomposition analysis indicated negligible weight loss until 500 °C and showed good thermal stability. Chemical and structural instability was verified by X-ray diffraction (XRD) by analysing the binary salt system before and after thermal treatment. A minor peak corresponding to lithium oxide was observed in the sample decomposed at 700 °C which resulted from the decomposition of LiOH at high temperature. The morphology and elemental distribution examinations of the binary salt mixture were carried out via scanning electron microscopy (SEM) coupled with energy dispersive spectroscopy (EDS). X-ray photoelectron spectroscopy was conducted for surface analysis, and their elemental composition verified the chemical stability of the binary salt mixture. Overall, the results confirmed that the binary salt mixture is a potential candidate to be used as thermal energy storage material in energy storage applications of up to 500 °C.

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Section: Resultssupporting

confidence: 65%

Section: Resultsmentioning

confidence: 99%

Section: Experimental and Methodologymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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A Binary Salt Mixture LiCl–LiOH for Thermal Energy Storage

et al. 2023

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“…The most widespread technique is the so-called reference principle [ 61 , 62 , 63 ], which uses reference blocks as heat flow meters (HFM). Technical details and uncertainty sources of this measurement principle have been described extensively, but only for thermal conductivity measurements on material samples by the standard test method ASTM-E1225 [ 64 ] and within scientific publications [ 65 , 66 , 67 , 68 ]. Analogous to thermal conductivity measurement, used reference blocks are made from materials with known thermal conductivity and placed thermally in series to the TEM under test.…”

Section: Methodsmentioning

confidence: 99%

International Round Robin Test of Thermoelectric Generator Modules

et al. 2022

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The status of metrology for the characterization of thermoelectric generator modules (TEM) is investigated in this work by an international round robin (RR) test including twelve laboratories from nine countries on three continents. Measurements have been performed with three samples of a Bi2Te3-based commercial TEM type, which has prevailed over three competing types during previous tests on the short- and long-term stability. A comparison of temperature-dependent results is provided up to 200 °C hot side temperature for the maximum power output Pmax, the incident heat flow Q˙In (at maximum efficiency conditions), and the maximum efficiency ηmax. Data evaluation from all RR participants reveals maximum standard deviations for these measurands of 27.2% (Pmax), 59.2% (Q˙In), and 25.9% (ηmax). A comparison between RR data sets and reference data from manufacturer specifications shows high deviations of up to 46%, too. These deviations reflect the absence of measurement guidelines and reference samples and confirm the need for improvements in the standardization of TEM metrology. Accordingly, the results of the RR are presented against the background of our own investigations on the uncertainty budgets for the determination of the abovementioned TEM properties using inhouse-developed characterization facilities, which comprise reference and absolute measurement techniques for the determination of heat flow.

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Thermal Conductivity of High-Temperature Multicomponent Materials with Phase Change

2007

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This work focuses on the investigation of the effective thermal conductivity (λ eff ) of heterogeneous materials consisting of a phase change material (PCM) and expanded graphite (EG). These composites may be employed in latent heat storage systems, where a PCM stores energy by being heated to a temperature higher than its melting point (T m ), and releases it during solidification. For the determination of λ eff , the steady-state comparative method was used and modified to measure composite samples at temperatures above T m . Results were compared with the thermal conductivity of the pure PCMs, and a significant increase could be observed. The dependence of λ eff on temperature, as well as the influence of the material microstructure on the enhancement of λ eff , were examined.

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The Measurement of Thermal Conductivity by the Comparative Method

Cited by 8 publications

References 3 publications

A Binary Salt Mixture LiCl–LiOH for Thermal Energy Storage

A Binary Salt Mixture LiCl–LiOH for Thermal Energy Storage

International Round Robin Test of Thermoelectric Generator Modules

Thermal Conductivity of High-Temperature Multicomponent Materials with Phase Change

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