Thermal Methods

Johnson, Michel B.; White, Mary Anne

doi:10.1002/9781118683972.ch2

Cited by 4 publications

(5 citation statements)

References 92 publications

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“…For each DSC measurement, a sample of mass between 10 and 15 mg was hermetically sealed in a standard DSC aluminum pan and measured in a He gas atmosphere, at a gas flow rate of 25 mL min −1 . The latent heat of fusion was determined from measurements performed at heating rates of 10 K/min and the melting temperature was determined from measurements at rates of 2 K/min, as recommended for high accuracy [41]. Typical uncertainties for this DSC system are ± 10 % for ∆ fus H and ± 1.5 • C for T mpt and at least 3 samples from each PCM were measured, and their values of ∆ fus H and T mpt were within these uncertainties.…”

Section: Experimental Methodsmentioning

confidence: 99%

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Edible Oils as Practical Phase Change Materials for Thermal Energy Storage

Kahwaji

White

2019

Applied Sciences

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Edible oils could provide more accessible alternatives to other phase change materials (PCMs) for consumers who wish to build a thermal energy storage (TES) system with sustainable materials. Edible oils have good shelf life, can be acquired easily from local stores and can be less expensive than other PCMs. In this work, we explore whether margarine, vegetable shortening, and coconut oil are feasible PCMs, by investigations of their thermal properties and thermal stability. We found that margarine and vegetable shortening are not useful for TES due to their low latent heat of fusion, ΔfusH, and poor thermal stability. In contrast, coconut oil remained thermally stable after 200 melt-freeze cycles, and has a large ΔfusH of 105 ± 11 J g−1, a low degree of supercooling and a transition temperature, Tmpt = 24.5 ± 1.5 °C, that makes it very useful for TES in buildings. We also determined coconut oil’s heat capacity and thermal conductivity as functions of temperature and used the measured properties to evaluate the feasibility of coconut oil for thermal buffering and passive heating of a residential-scale greenhouse.

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Section: Experimental Methodsmentioning

confidence: 99%

“…The melting temperature of a material from a DSC experiment corresponds to the onset of the melting peak, T onset [41]. However, due to the large number of components in the edible oils which broaden melting, the onset of melting was not well defined.…”

Section: Experimental Methodsmentioning

confidence: 99%

Edible Oils as Practical Phase Change Materials for Thermal Energy Storage

Kahwaji

White

2019

Applied Sciences

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“…The instrument was calibrated using a fused quartz standard matched in length to the sample to within 5%. The standard uncertainty of the instrument in Δ / 0 was ±1%. , …”

Section: Experimental Sectionmentioning

confidence: 98%

“…The standard uncertainty of the instrument in Δ / 0 was ±1%. 17,63 Thermal Analysis. Differential scanning calorimetry (DSC) was used to delineate any phase transitions in ZrMgMo 3 O 12 with a 20.43 mg sample in an aluminum pan using a TA Instruments Q200 series differential scanning calorimeter equipped with a liquid N 2 cooling head.…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

Zero Thermal Expansion in ZrMgMo₃O₁₂: NMR Crystallography Reveals Origins of Thermoelastic Properties

et al. 2015

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ABSTRACT:The coefficient of thermal expansion of ZrMgMo 3 O 12 has been measured and was found to be extremely close to zero over a wide temperature range including room temperature (α = (1.6 ± 0.2) × 10 −7 K −1 from 25 to 450°C by X-ray diffraction (XRD)). ZrMgMo 3 O 12 belongs to the family of AMgM 3 O 12 materials, for which coefficients of thermal expansion have previously been reported to range from low-positive to low-negative. However, the low thermal expansion property had not previously been explained because atomic position information was not available for any members of this family of materials. We determined the structure of ZrMgMo 3 O 12 by nuclear magnetic resonance (NMR) crystallography, using 91 Zr, 25 Mg, 95 Mo, and 17 O magic angle spinning (MAS) and 17 O multiple quantum MAS (MQMAS) NMR in conjunction with XRD and density functional theory calculations. The resulting structure was of sufficient detail that the observed zero thermal expansion could be explained using quantitative measures of the properties of the coordination polyhedra. We also found that ZrMgMo 3 O 12 shows significant ionic conductivity, a property that is also related to its structure.

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“…Following recommendations in Ref. 43, all calibrations and sample protocols were the same: same pan type, purge gas, flow rate and heating rate were used. These include using TA Instruments standard hermetic sample pans, nitrogen gas at a flow rate of 50 ml min −1 and heating rates of 10 C min −1 .…”

Section: Electrochemical Impedance Spectroscopy (Eismentioning

confidence: 99%

Performance and Degradation of LiFePO₄/Graphite Cells: The Impact of Water Contamination and an Evaluation of Common Electrolyte Additives

Logan

Hebecker

Eldesoky

et al. 2020

J. Electrochem. Soc.

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LiFePO4 (LFP) is an appealing cathode material for Li-ion batteries. Its superior safety and lack of expensive transition metals make LFP attractive even with the commercialization of higher specific capacity materials. In this work the performance of LFP/graphite cells is tested at various temperatures and cycling protocols. The amount of water contamination is controlled to study the impact of water on capacity fade in LFP. Further, several additive systems that have been effective in NMC/graphite chemistries are tested in LFP/graphite cells. The presence of excess water impacts cell performance severely when no electrolyte additives are used, or when the electrodes are poorly passivated. When effective additive systems are used, the existence of up to 500 ppm excess water in the cell is does not strongly affect cycle life and storage performance. Fe dissolution is studied in LFP with micro X-ray fluorescence spectroscopy (μXRF), and most electrolyte additives virtually eliminate Fe dissolution, even at high temperature and with water contamination. Removing excess water contamination suppresses Fe dissolution in cells without electrolyte additives. Finally, the capacity retention of LFP/graphite cells at high temperature is compared with long lifetime NMC/graphite cells, demonstrating challenges for LFP/graphite cells.

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Thermal Methods

Cited by 4 publications

References 92 publications

Edible Oils as Practical Phase Change Materials for Thermal Energy Storage

Edible Oils as Practical Phase Change Materials for Thermal Energy Storage

Zero Thermal Expansion in ZrMgMo₃O₁₂: NMR Crystallography Reveals Origins of Thermoelastic Properties

Performance and Degradation of LiFePO₄/Graphite Cells: The Impact of Water Contamination and an Evaluation of Common Electrolyte Additives

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Thermal Methods

Cited by 4 publications

References 92 publications

Edible Oils as Practical Phase Change Materials for Thermal Energy Storage

Edible Oils as Practical Phase Change Materials for Thermal Energy Storage

Zero Thermal Expansion in ZrMgMo3O12: NMR Crystallography Reveals Origins of Thermoelastic Properties

Performance and Degradation of LiFePO4/Graphite Cells: The Impact of Water Contamination and an Evaluation of Common Electrolyte Additives

Contact Info

Product

Resources

About

Zero Thermal Expansion in ZrMgMo₃O₁₂: NMR Crystallography Reveals Origins of Thermoelastic Properties

Performance and Degradation of LiFePO₄/Graphite Cells: The Impact of Water Contamination and an Evaluation of Common Electrolyte Additives