A theoretical study on the accuracy of the T-history method for enthalpy–temperature curve measurement: analysis of the influence of thermal gradients inside T-history samples

Mazo, Javier; Delgado, Mónica; Lázaro, Ana; Dolado, Pablo; Peñalosa, Conchita; Marı́n, José Marı́a; Zalba, Belén

doi:10.1088/0957-0233/26/12/125001

Cited by 16 publications

(9 citation statements)

References 17 publications

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“…High thermal gradients in the sample have been found experimentally and through detailed modelling [27], in direct contradiction with the use of the lumped parameter model. This conclusion is supported by the recent work of Mazo et al [34] which clearly demonstrates the effect of radial thermal gradients inside T-history samples cannot be neglected. Thus for all of these reasons it is evident that the application of the lumped parameter method should be avoided in favour of more rigorous and accurate representations.…”

Section: Methods and Calculationssupporting

confidence: 78%

Critical analysis of the T-history method: A fundamental approach

Badenhorst

Cabeza

2017

Thermochimica Acta

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Section: Methods and Calculationssupporting

confidence: 78%

Critical analysis of the T-history method: A fundamental approach

Badenhorst

Cabeza

2017

Thermochimica Acta

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“…The principle of the method [23,24] is to compare the temperature evolution inside a reservoir containing the PCM with a reference one (usually water). Supposing an homogeneous temperature and assuming that thermal transfers can be written as convective ones, an energy balance permit to retrieve the latent heat [25][26][27].…”

Section: T-history Methodsmentioning

confidence: 99%

Challenges of the Usual Graphical Methods Used to Characterize Phase Change Materials by Differential Scanning Calorimetry

et al. 2018

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Abstract:Modeling the thermal behavior of a plant or devices using Phase Change Materials (PCM) requires to know their thermophysical properties. The Differential Scanning Calorimetry (DSC) is a technic largely used to investigate them. However, under the pretext to experiment with small samples, some authors consider the DSC curves as directly representing the properties of the materials without realizing that this interpretation is very often incompatible with the thermodynamics laws: as an example, although a pure substance melts at a fixed temperature T F , it is proposed a melting through a temperature range higher than T F and depending on the experiments (heating rates, sample masses. . . ), for solutions the suggested characteristic temperatures are incompatible with the phase diagram, and also a hysteresis phenomenon is invented. . . . In this paper, we demonstrate by a model coupling thermodynamics and conduction heat transfers, that the DSC curves are exactly compatible with the thermodynamics of phase changes (melting at fixed temperature for pure substances, in conformity with phase diagrams for solutions. . . ). The cases of pure substances, saline solutions, substances with impurities or solid solutions are detailed. We indicate which information can, however, be given by the curves. We also propose a more sophisticated method by inverse calculations to determine the specific enthalpy whose all the thermodynamical properties can be deduced. Finally, we give some indications to understand and use the results indicating supercooling.

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“…The T-history has critically assessed based on their mathematical formulation and experimental configuration [29]. The effect of radial thermal gradients inside T-history samples on the enthalpy temperature curve measurement have been analysed [30], and has been and has been proposed a differential formulation of the T-History method in order to achieve thermodynamic consistency with phase transitions theory, including the experimental effect of the speed of the thermal process in calorimetric calculations [31].…”

Section: Introductionmentioning

confidence: 99%

Characterization of Thermophysical Properties of Phase Change Materials Using Unconventional Experimental Technologies

et al. 2020

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The growing interest in developing applications for the storage of thermal energy (TES) is highly linked to the knowledge of the properties of the materials that will be used for that purpose. Likewise, the validity of representing processes through numerical simulations will depend on the accuracy of the thermal properties of the materials. The most relevant properties in the characterization of phase change materials (PCM) are the phase change enthalpy, thermal conductivity, heat capacity and density. Differential scanning calorimetry (DSC) is the most widely used technique for determining thermophysical properties. However, several unconventional methods have been proposed in the literature, mainly due to overcome the limitations of DSC, namely, the small sample required which is unsuitable for studying inhomogeneous materials. This paper presents the characterization of two commercial paraffins commonly used in TES applications, using methods such as T-history and T-melting, which were selected due to their simplicity, high reproducibility, and low cost of implementation. In order to evaluate the reliability of the methods, values calculated with the proposed alternative methods are compared with the results obtained by DSC measurements and with the manufacturer’s technical datasheet. Results obtained show that these non-conventional techniques can be used for the accurate estimation of selected thermal properties. A detailed discussion of the advantage and disadvantage of each method is given.

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A theoretical study on the accuracy of the T-history method for enthalpy–temperature curve measurement: analysis of the influence of thermal gradients inside T-history samples

Cited by 16 publications

References 17 publications

Critical analysis of the T-history method: A fundamental approach

Critical analysis of the T-history method: A fundamental approach

Challenges of the Usual Graphical Methods Used to Characterize Phase Change Materials by Differential Scanning Calorimetry

Characterization of Thermophysical Properties of Phase Change Materials Using Unconventional Experimental Technologies

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