Measurements and theoretical modelling of the effective thermal conductivity of zeolites

Griesinger, Andreas; Spindler, Klaus; Hahne, Ε.

doi:10.1016/s0017-9310(99)00096-4

Cited by 80 publications

(43 citation statements)

References 5 publications

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“…Accordingly, the mean pore diameter increases linearly. Figure 7 shows the effective thermal conductivities of the adsorbed MOF-5 crystals and bed at different pressures (0.01-50 MPa) and 298.15 K. The effective thermal conductivity of the MOF-5 crystals at the H2 atmosphere increases in an "S" shape, as confirmed by the experimental data on zeolite K under the H2 atmosphere [9]. The effective thermal conductivity of the MOF-5 crystals with consideration of the adsorbed phase is slightly higher than that without such consideration.…”

Section: Simulation Methodsmentioning

confidence: 54%

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Effective Thermal Conductivity of MOF-5 Powder under a Hydrogen Atmosphere

Wang

Wen

et al. 2015

Computation

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Abstract:Effective thermal conductivity is an important thermophysical property in the design of metal-organic framework-5 (MOF-5)-based hydrogen storage tanks. A modified thermal conductivity model is built by coupling a theoretical model with the grand canonical Monte Carlo simulation (GCMC) to predict the effect of the H2 adsorption process on the effective thermal conductivity of a MOF-5 powder bed at pressures ranging from 0.01 MPa to 50 MPa and temperatures ranging from 273.15 K to 368.15 K. Results show that the mean pore diameter of the MOF-5 crystal decreases with an increase in pressure and increases with an increase in temperature. The thermal conductivity of the adsorbed H2 increases with an increased amount of H2 adsorption. The effective thermal conductivity of the MOF-5 crystal is significantly enhanced by the H2 adsorption at high pressure and low temperature. The effective thermal conductivity of the MOF-5 powder bed increases with an increase in pressure and remains nearly unchanged with an increase in temperature. The thermal conductivity of the MOF-5 powder bed increases linearly with the decreased porosity and increased thermal conductivity of the skeleton of the MOF-5 crystal. The variation in the effective thermal conductivities of the MOF-5 crystals and bed mainly results from the thermal conductivities of the gaseous and adsorption phases.

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Section: Simulation Methodsmentioning

confidence: 54%

“…Effective thermal conductivity is related to adsorbate uptake, temperature, and pressure [9]. The amount of adsorption can be predicted with the grand canonical Monte Carlo (GCMC) simulation, which only requires macroscopic variables, such as temperature and pressure.…”

Section: Introductionmentioning

confidence: 99%

Effective Thermal Conductivity of MOF-5 Powder under a Hydrogen Atmosphere

Wang

Wen

et al. 2015

Computation

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“…Two models have been selected from literature in order to calculate the effective thermal conductivity; the A. Griesinger model (AG) [50] and the most extended Zehner-Bauer-Schlünder model (ZBS) [51]. The ZBS model has been adopted very often in literature for metal hydrides, whereas the AG model has only been used for zeolites.…”

Section: Effective Thermal Conductivitymentioning

confidence: 99%

Modelling and analysis of a metal hydride cooling system

Herrero¹

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The work which is presented by J. Payá Herrero, titled "Modelling and analysis of a metal hydride cooling system" has been carried out at the Institute for Energy Engineering under my supervision and assessment.As the modelling and experimental objectives have been reached, I authorise the submission of this PhD work for its evaluation by the corresponding examination board. This PhD thesis consists in the modelling and validation of a metal hydride cooling system. The experimental prototype is located in the institute IKE.In the first place, the hydrogen absorbing materials have been characterized in terms of the static P-C-T properties and of the intrinsic reaction kinetics. In the second place, after this first characterization phase, a completely dynamic model has been developed based on the heat and mass transfer processes which take place in the reactors. The results have been validated with an exhaustive experimental campaign of dynamic cooling tests and the adjustment of the model is very good.Finally, the cooling performance of the system has been improved by means of the model which has enabled the optimization of the operating conditions and of the sorption materials. El presente estudio consiste en el modelado y validación de un sistema de producción de frío basado en la absorción/desorción de hidrógeno en metales.La instalación experimental que se ha modelado se halla en el instituto IKE.En primer lugar, los materiales utilizados se han caracterizado tanto desde el punto de vista de las curvas P-C-T de equilibrio como de la cinética de absorción/desorción de cada aleación. En segundo lugar, se ha desarrollado un modelo completamente dinámico basado en las reacciones de transferencia de calor y masa que ocurren en los reactores. Los resultados se han validado con una amplia gama de medidas de IKE en régimen transitorio, obteniendo un ajuste muy bueno para diferentes ensayos.Finalmente, mediante la utilización del modelo, se han optimizado las condiciones de operación y las propiedades de los materiales, alcanzando así mejores prestaciones en refrigeración.

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“…

Several studies have reported the thermal conductivity of powdered zeolites [12][13][14][15]. Effects of temperature, filling gas, moisture, and pressure were investigated [12][13][14][15].

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confidence: 99%

“…Effects of temperature, filling gas, moisture, and pressure were investigated [12][13][14][15]. In addition, Greenstein et al [16] and Hudiono et al [17] measured thermal conductivity of PSZ MFI zeolite films with thickness ranging from 10 to 20 µm and temperature varying from 150 to 450 K. The MFI films were synthesized by secondary growth through a seeded hydrothermal process on alumina substrates.…”

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confidence: 99%

Temperature Dependent Thermal Conductivity of Pure Silica MEL and MFI Zeolite Thin Films

Fang

Huang

Pilon

et al. 2012

ASME 2012 Third International Conference on Micro/Nanoscale Heat and Mass Transfer

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Several studies have reported the thermal conductivity of powdered zeolites [12][13][14][15]. Effects of temperature, filling gas, moisture, and pressure were investigated [12][13][14][15]. In addition, Greenstein et al. [16] and Hudiono et al. [17] measured thermal conductivity of PSZ MFI zeolite films with thickness ranging from 10 to 20 µm and temperature varying from 150 to 450 K. The MFI films were synthesized by secondary growth through a seeded hydrothermal process on alumina substrates. The measured thermal conductivity of (h0l)-oriented PSZ MFI films varied from 1.0 to 1.4 W/m·K in the temperature range considered [17]. That of calcined and uncalcined c-oriented PSZ MFI films deposited on silicon substrates was found to range from 0.75 to 1.1 W/m·K and 1.0 to 1.6 W/m·K, respectively [16]. More recently, Coquil et al. [18] measured room temperature thermal conductivity of PSZ MFI and MEL zeolite thin films. The MFI thin films were b-oriented, fully crystalline, and had a porosity of 33%. The MEL thin films featured porosity, relative crystallinity, and particle size ranging from 40% to 59%, 23% to 47%, and 55 to 80 nm, respectively. The authors found the thermal conductivity to be around 1.02±0.10 W/m·K for all films despite their different porosity, relative crystallinity, and nanoparticle size. Methods and Experiments 2.1 Sample film preparationSynthesis of PSZ MFI and MEL thin films investigated in the present study were previously described in detail [1,6,18]. MFI thin films were synthesized by in situ crystallization and were b-oriented. The MEL films were prepared by spin coating a zeolite nanoparticle suspension onto silicon substrates. The MEL suspension was synthesized by a two-stage process [1]. The first stage consisted of a 2 days heating and stirring of a tetraethylorthosilicate (TEOS) based solution at 80 • C resulting in a MEL nanoparticle suspension. The second stage corresponded to the growth of the MEL nanoparticles from the same solution in a convection oven at 114 • C. Finally, MEL thin films were obtained by spin-coating the solution onto silicon substrates. Both relative crystallinity and nanoparticle size of the PSZ MEL increased as the second stage synthesis time increased. Here, the relative crystallinity is defined as the ratio of the micropore volume to the micropore volume of a fully crystalline PSZ MEL microcrystal [1]. Four different sets of MEL films corresponding to four different second stage synthesis times (15, 18, 21 and 24 hours) were studied. Note that all the MEL and MFI thin films were made hydrophobic by vapor-phase silylation with trimethylchlorosilane as described in Ref. [1].

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Measurements and theoretical modelling of the effective thermal conductivity of zeolites

Cited by 80 publications

References 5 publications

Effective Thermal Conductivity of MOF-5 Powder under a Hydrogen Atmosphere

Effective Thermal Conductivity of MOF-5 Powder under a Hydrogen Atmosphere

Modelling and analysis of a metal hydride cooling system

Temperature Dependent Thermal Conductivity of Pure Silica MEL and MFI Zeolite Thin Films

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