Thermochemical investigation of the water uptake behavior of MgSO4 hydrates in host materials with different pore size

Posern, Konrad; Linnow, Kirsten; Niermann, Michael; Kaps, Ch.; Steiger, Michael

doi:10.1016/j.tca.2015.04.031

Cited by 54 publications

(27 citation statements)

References 27 publications

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“…One of the salts that have been extensively evaluated in the scientific literature is MgSO 4 •7H 2 O, whose theoretical energy storage density is 2.8 GJ/m 3 [11] and can be used under both ambient pressure and sub-atmospheric pressure [12], thus being suitable for the application in open cycles or closed cycles. The salt can be efficiently regenerated also at temperatures < 150 • C, compatible with the integration in low-grade heat recovery systems or solar systems in buildings [13].…”

Section: Introductionmentioning

confidence: 99%

Morphological and Structural Evaluation of Hydration/Dehydration Stages of MgSO4 Filled Composite Silicone Foam for Thermal Energy Storage Applications

et al. 2020

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Salt hydrates, such as MgSO4∙7H2O, are considered attractive materials for thermal energy storage, thanks to their high theoretical storage density. However, pure salt hydrates present some challenges in real application due to agglomeration, corrosion and swelling problems during hydration/dehydration cycles. In order to overcome these limitations, a composite material based on silicone vapor-permeable foam filled with the salt hydrate is here presented. For its characterization, a real-time in situ environmental scanning electron microscopy (ESEM) investigation was carried out in controlled temperature and humidity conditions. The specific set-up was proposed as an innovative method in order to evaluate the morphological evolution of the composite material during the hydrating and dehydrating stages of the salt. The results evidenced an effective micro-thermal stability of the material. Furthermore, dehydration thermogravimetric/differential scanning calorimetric (TG/DSC) analysis confirmed the improved reactivity of the realized composite foam compared to pure MgSO4∙7H2O.

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Section: Introductionmentioning

confidence: 99%

Morphological and Structural Evaluation of Hydration/Dehydration Stages of MgSO4 Filled Composite Silicone Foam for Thermal Energy Storage Applications

et al. 2020

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“…Since the salt crystal of small size is dispersed within the porous structure, the problem of agglomeration is limited and both heat and mass transfer in the granular medium remain efficient, leading to an improvement of the material lifetime. The use of active porous matrix such as silica gel, zeolite, MOFs, etc... allows to benefit from the heat produced by the chemical reaction on the hygroscopic salt and by the adsorption on the porous material [14][15][16][17][18][19][20][21][22][23][24][25]. Nevertheless, the development of such a system remains a technological challenge, the main obstacle being the incomplete understanding of the involved physicochemical phenomena.…”

Section: Introductionmentioning

confidence: 99%

New kinetic model of the dehydration reaction of magnesium sulfate hexahydrate: Application for heat storage

et al. 2020

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Magnesium sulfate-water vapor is an interesting working pair of thermochemical materials for compact inter-seasonal heat storage at low temperature. Total dehydration of magnesium sulfate heptahydrate shows a theoretical storage energy density of 2.8 GJ•m −3. However, kinetic data are poorly studied up to now making use of this material difficult for a practical storage application. In the present work, a kinetic study of the dehydration of MgSO4•6H2O powder at low temperature (35 to 60°C) and at low water vapor pressure (2 to 21 hPa) is carried out using thermogravimetric analysis in isobaric-isothermal conditions. A mathematical model is developed for this bivariant system and validated representing the mechanism of dehydration: water molecules diffusion in the solid solution followed by transfer of these molecules from the surface to the atmosphere. The transfer of water molecules at the surface during dehydration is identified as rate-determining step. The fractional conversion and reaction rate of the dehydration reaction are calculated and compared to the experimental data.

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“…The kinetic hindrance prevents the material to display its full theoretical TES capability. The impregnation of the salt into host matrices and physical adsorbents is a measure to disperse the salt and solve the kinetic hindrance to the hydration reaction [13][14][15]. Meanwhile, the overall performance of the physical adsorbents also can be improved by the salt.…”

Section: Introductionmentioning

confidence: 99%

Performance characterizations and thermodynamic analysis of magnesium sulfate-impregnated zeolite 13X and activated alumina composite sorbents for thermal energy storage

Wang

et al. 2019

Energy

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The composite sorbents of MgSO4-impregnated zeolite 13X and activated alumina are developed for thermal energy storage (TES) with different temperature ranges. The sorption and desorption characteristics of raw and MgSO4-impregnated activated alumina are studied, and the performances of the selected sorbents are tested in a closed-system TES device. The results are compared with those of raw and MgSO4-impregnated zeolite 13X. It is shown that the impregnated MgSO4 improves the overall TES performances of zeolite 13X and activated alumina. Compared to the raw host matrices, the impregnated MgSO4 remarkably accelerates the temperature-rising rate of zeolite 13X to about three times and improves the temperature lift of activated alumina by 32.5%. The experimental energy storage densities of MgSO4-impregnated zeolite 13X and activated alumina are 123.4 kWh m −3 and 82.6 kWh m −3 , respectively. The sorption temperature region of activated alumina is more aligned with the preferred hydration temperature of MgSO4 in comparison with zeolite 13X. The hydration characteristics of MgSO4 can resolve the solution leakage issue of open systems.Thermodynamic analysis is conducted to evaluate the performances of the TES device with different sorbents.It is found that entransy can be used to assess thermally and electrically driven TES systems reasonably.

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Thermochemical investigation of the water uptake behavior of MgSO4 hydrates in host materials with different pore size

Cited by 54 publications

References 27 publications

Morphological and Structural Evaluation of Hydration/Dehydration Stages of MgSO4 Filled Composite Silicone Foam for Thermal Energy Storage Applications

Morphological and Structural Evaluation of Hydration/Dehydration Stages of MgSO4 Filled Composite Silicone Foam for Thermal Energy Storage Applications

New kinetic model of the dehydration reaction of magnesium sulfate hexahydrate: Application for heat storage

Performance characterizations and thermodynamic analysis of magnesium sulfate-impregnated zeolite 13X and activated alumina composite sorbents for thermal energy storage

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