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Abstract
Developing high-efficiency cooling with safe, low-global warming potential refrigerants is a grand challenge for tackling climate change. Caloric effect-based cooling technologies, such as magneto- or electrocaloric refrigeration, are promising but often require large applied fields for a relatively low coefficient of performance and adiabatic temperature change. We propose using the ionocaloric effect and the accompanying thermodynamic cycle as a caloric-based, all-condensed-phase cooling technology. Theoretical and experimental results show higher adiabatic temperature change and entropy change per unit mass and volume compared with other caloric effects under low applied field strengths. We demonstrated the viability of a practical system using an ionocaloric Stirling refrigeration cycle. Our experimental results show a coefficient of performance of 30% relative to Carnot and a temperature lift as high as 25°C using a voltage strength of ~0.22 volts.
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Affiliation(s)
- Drew Lilley
- Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.,Department of Mechanical Engineering, University of California, Berkeley, CA 94720, USA
| | - Ravi Prasher
- Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.,Department of Mechanical Engineering, University of California, Berkeley, CA 94720, USA
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Lobo Ferreira AIMC, Vilas-Boas SM, Silva RMA, Martins MAR, Abranches DO, Soares-Santos PCR, Almeida Paz FA, Ferreira O, Pinho SP, Santos LMNBF, Coutinho JAP. Extensive characterization of choline chloride and its solid-liquid equilibrium with water. Phys Chem Chem Phys 2022; 24:14886-14897. [PMID: 35674089 DOI: 10.1039/d2cp00377e] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The importance of choline chloride (ChCl) is recognized due to its widespread use in the formulation of deep eutectic solvents. The controlled addition of water in deep eutectic solvents has been proposed to overcome some of the major drawbacks of these solvents, namely their high hygroscopicities and viscosities. Recently, aqueous solutions of ChCl at specific mole ratios have been presented as a novel, low viscous deep eutectic solvent. Nevertheless, these proposals are suggested without any information about the solid-liquid phase diagram of this system or the deviations from the thermodynamic ideality of its precursors. This work contributes significantly to this matter as the phase behavior of pure ChCl and (ChCl + H2O) binary mixtures was investigated by calorimetric and analytical techniques. The thermal behavior and stability of ChCl were studied by polarized light optical microscopy and differential scanning calorimetry, confirming the existence of a solid-solid transition at 352.2 ± 0.6 K. Additionally, heat capacity measurements of pure ChCl (covering both ChCl solid phases) and aqueous solutions of ChCl (xChCl < 0.4) were performed using a heat-flow differential scanning microcalorimeter or a high-precision heat capacity drop calorimeter, allowing the estimation of a heat capacity change of (ChCl) ≈ 39.3 ± 10 J K-1 mol-1, between the hypothetical liquid and the observed crystalline phase at 298.15 K. The solid-liquid phase diagram of the ChCl + water mixture was investigated in the whole concentration range by differential scanning calorimetry and the analytical shake-flask method. The phase diagram obtained for the mixture shows an eutectic temperature of 204 K, at a mole fraction of choline chloride close to xChCl = 0.2, and a shift of the solid-solid transition of ChCl-water mixtures of 10 K below the value observed for pure choline chloride, suggesting the appearance of a new crystalline structure of ChCl in the presence of water, as confirmed by X-ray diffraction. The liquid phase presents significant negative deviations to ideality for water while COSMO-RS predicts a near ideal behaviour for ChCl.
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Affiliation(s)
- Ana I M C Lobo Ferreira
- CIQUP, Institute of Molecular Sciences (IMS) - Departamento de Química e Bioquímica, Faculdade de Ciências da Universidade do Porto, Rua Campo Alegre, 4169-007 Porto, Portugal.
| | - Sérgio M Vilas-Boas
- Centro de Investigação de Montanha (CIMO), Instituto Politécnico de Bragança, Campus de Santa Apolónia, 5300-253 Bragança, Portugal. .,CICECO - Aveiro Institute of Materials, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal
| | - Rodrigo M A Silva
- CIQUP, Institute of Molecular Sciences (IMS) - Departamento de Química e Bioquímica, Faculdade de Ciências da Universidade do Porto, Rua Campo Alegre, 4169-007 Porto, Portugal.
| | - Mónia A R Martins
- CICECO - Aveiro Institute of Materials, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal
| | - Dinis O Abranches
- CICECO - Aveiro Institute of Materials, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal
| | - Paula C R Soares-Santos
- CICECO - Aveiro Institute of Materials, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal
| | - Filipe A Almeida Paz
- CICECO - Aveiro Institute of Materials, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal
| | - Olga Ferreira
- Centro de Investigação de Montanha (CIMO), Instituto Politécnico de Bragança, Campus de Santa Apolónia, 5300-253 Bragança, Portugal.
| | - Simão P Pinho
- Centro de Investigação de Montanha (CIMO), Instituto Politécnico de Bragança, Campus de Santa Apolónia, 5300-253 Bragança, Portugal.
| | - Luís M N B F Santos
- CIQUP, Institute of Molecular Sciences (IMS) - Departamento de Química e Bioquímica, Faculdade de Ciências da Universidade do Porto, Rua Campo Alegre, 4169-007 Porto, Portugal.
| | - João A P Coutinho
- CICECO - Aveiro Institute of Materials, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal
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Investigation of an Organogel by Micro-Differential Scanning Calorimetry: Quantitative Relationship between the Shapes of the Thermograms and the Phase Diagram. Gels 2021; 7:gels7030093. [PMID: 34287343 PMCID: PMC8293151 DOI: 10.3390/gels7030093] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Revised: 07/09/2021] [Accepted: 07/11/2021] [Indexed: 12/04/2022] Open
Abstract
The phase diagrams of organogels are necessary for applications and fundamental aspects, for instance to understand their thermodynamics. Differential scanning calorimetry is one of the techniques implemented to map these diagrams. The thermograms of organogels upon heating show broad endotherms, increasing gradually to a maximum, at a temperature Tmax, and decreasing back to the baseline, sometimes 10 °C above. This broadening can lead to uncertainty in determining the molar enthalpies and the melting temperatures Tm of the gels. Herein, we have measured the thermograms of the 12-hydroxystearic acid/nitrobenzene gels for weight fractions ranging from 0.0015 to 0.04. Compared with transition temperatures measured by other techniques, the inflection points of the thermograms provide a measurement of Tm with less bias than Tmax. The phase diagram explains why the molar melting enthalpies derived from the thermograms for samples of low concentration are lower than expected. The shapes of the heat flows below the peak correlate quantitatively with the diagrams: after suitable correction and normalization, the integral curves superimpose with the phase diagram in their ascending branch and reach a plateau when the gel is fully melted. The shape of the thermograms upon cooling is also qualitatively explained within the frame of the diagrams.
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Phase equilibrium temperature and dissociation enthalpy in the tri-n-butylalkylphosphonium bromide semiclathrate hydrate systems. Chem Eng Sci 2021. [DOI: 10.1016/j.ces.2021.116514] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Chang KY, Chu CK, Chu LS, Chen YA, Lin ST, Chen YP, Chen LJ. Effect of Small Cage Guests on Dissociation Properties of Tetrahydrofuran Hydrates. J Phys Chem B 2020; 124:7217-7228. [PMID: 32786717 DOI: 10.1021/acs.jpcb.0c03938] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
It is well understood that tetrahydrofuran (THF) molecules are able to stabilize the large cages (51264) of structure II to form the THF hydrate with empty small cages even at atmospheric pressure. This leaves the small cages to store gas molecules at relatively lower pressures and higher temperatures. The dissociation enthalpy and temperature strongly depend on the size of gas molecules enclathrated in the small cages of structure II THF hydrate. A high-pressure microdifferential scanning calorimeter was applied to measure the dissociation enthalpies and temperatures of THF hydrates pressurized by helium and methane under a constant pressure ranging from 0.10 to 35.00 MPa and a wide THF concentration ranging from 0.25 to 8.11 mol %. The dissociation temperature of binary He + THF and methane + THF hydrates increases along with an increase in the THF concentration in the liquid phase at a fixed pressure (e.g., 30 MPa), reaching a maximum value of 280.8 and 312.8 K, respectively, at stoichiometric concentration (5.56 mol % THF), and then remains nearly constant for even higher THF concentrations (>5.56 mol %). The effect of gas occupancy in the small cages on the dissociation enthalpy of He + THF and methane + THF mixed hydrates was further examined by using molecular dynamics (MD) simulations. The dissociation enthalpy of the He-THF mixed hydrates is independent of pressure with an average of 5.68 kJ/mol H2O over the pressure ranging from 0.10 to 30.0 MPa, consistent with the MD results of the He-THF mixed hydrates with low single occupancy (<23%) of helium molecules in the small cages. Consequently, the heat of adsorption of helium molecules in the small cages of the He-THF mixed hydrates is rather too weak to be identified. On the other hand, the dissociation enthalpy of the methane-THF hydrates increases from 9.11 to 10.01 kJ/mol H2O along with an increase in methane pressure over the pressure ranging from 5.0 to 30.0 MPa, consistent with the MD results of the methane-THF mixed hydrates with full occupancy of methane molecules in the small cages. These findings provide important information for the design of a potential medium of gas storage and transportation.
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Affiliation(s)
- Kuang-Yu Chang
- Department of Chemical Engineering, National Taiwan University, Taipei 10617, Taiwan, China
| | - Che-Kang Chu
- Department of Chemical Engineering, National Taiwan University, Taipei 10617, Taiwan, China
| | - Lee-Shin Chu
- Department of Chemical Engineering, National Taiwan University, Taipei 10617, Taiwan, China
| | - Yen-An Chen
- Department of Chemical Engineering, National Taiwan University, Taipei 10617, Taiwan, China
| | - Shiang-Tai Lin
- Department of Chemical Engineering, National Taiwan University, Taipei 10617, Taiwan, China
| | - Yan-Ping Chen
- Department of Chemical Engineering, National Taiwan University, Taipei 10617, Taiwan, China
| | - Li-Jen Chen
- Department of Chemical Engineering, National Taiwan University, Taipei 10617, Taiwan, China
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Watanabe Y, Hirasawa I. Numerical Evaluation of Melting Point and Fusion Heat for Potassium Acetate Dihydrate as a Latent Heat Storage Material. KAGAKU KOGAKU RONBUN 2020. [DOI: 10.1252/kakoronbunshu.46.41] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | - Izumi Hirasawa
- Department of Applied Chemistry, Faculty of Science and Engineering, Waseda University
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Christ E, Collin D, Lamps JP, Mésini PJ. Variable temperature NMR of organogelators: the intensities of a single sample describe the full phase diagram. Phys Chem Chem Phys 2018; 20:9644-9650. [PMID: 29582031 DOI: 10.1039/c8cp00009c] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Organogelators constitute a numerous class of compounds, able to form gels in organic solvents. Their phase diagrams are useful to understand their mechanisms of formation and their stability, but their mapping is often a tedious task. We show that liquid NMR can simplify and quicken the acquisition of phase diagrams. In liquid NMR spectra of organogels, the visible signals of the gelator represent only its soluble fraction. The intensities increase with temperature, until the gel melts. Suitable normalization of these intensities yields the solubility as a function of temperature, which is sufficient to map the phase diagram. We verified it experimentally with three organogelators, chosen because independent authors have previously mapped out their phase diagram by other techniques including DSC and rheology. We show that the curves obtained by NMR superimpose with these diagrams. A variable temperature NMR experiment with a single sample can yield the phase diagram with sensitivity of the order of 0.01 wt%.
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Affiliation(s)
- Elliot Christ
- Institut Charles Sadron, Université de Strasbourg, 23 rue du Loess, BP 84047, 67034 Strasbourg Cedex, France.
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Challenges of the Usual Graphical Methods Used to Characterize Phase Change Materials by Differential Scanning Calorimetry. APPLIED SCIENCES-BASEL 2018. [DOI: 10.3390/app8010066] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Plantier F, Marlin L, Missima D, Torré JP. Development of a new type of high pressure calorimetric cell, mechanically agitated and equipped with a dynamic pressure control system: application to the characterization of gas hydrates. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2013; 84:125107. [PMID: 24387468 DOI: 10.1063/1.4848955] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
A novel prototype of calorimetric cell has been developed allowing experiments under pressure with an in situ agitation system and a dynamic control of the pressure inside the cell. The use of such a system opens a wide range of potential practical applications for determining properties of complex fluids in both pressurized and agitated conditions. The technical details of this prototype and its calibration procedure are described, and an application devoted to the determination of phase equilibrium and phase change enthalpy of gas hydrates is presented. Our results, obtained with a good precision and reproducibility, were found in fairly good agreement with those found in literature, illustrate the various interests to use this novel apparatus.
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Affiliation(s)
- F Plantier
- Univ Pau & Pays Adour, CNRS, TOTAL - UMR 5150 - LFC-R - Laboratoire des Fluides Complexes et leurs Réservoirs, BP 1155 - PAU, F-64013, France
| | - L Marlin
- Univ Pau & Pays Adour, IPRA FR2952 - Fédération de Recherche- Atelier de Physique Générale, BP 1155 - PAU, F-64013, France
| | - D Missima
- Univ Pau & Pays Adour, CNRS, TOTAL - UMR 5150 - LFC-R - Laboratoire des Fluides Complexes et leurs Réservoirs, BP 1155 - PAU, F-64013, France
| | - J-P Torré
- Univ Pau & Pays Adour, CNRS, TOTAL - UMR 5150 - LFC-R - Laboratoire des Fluides Complexes et leurs Réservoirs, BP 1155 - PAU, F-64013, France
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Kholmurodov K, Dushanov E, Yasuoka K, Khalil H, Galal A, Ahmed S, Sweilam N, Moharram H. Molecular dynamics study of ethanol solvated by water on the Pt (111) surface. Chem Phys 2012. [DOI: 10.1016/j.chemphys.2012.04.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Jamil A, Caubet S, Grassl B, Kousksou T, El Omari K, Zeraouli Y, Le Guer Y. Thermal properties of non-crystallizable oil-in-water highly concentrated emulsions. Colloids Surf A Physicochem Eng Asp 2011. [DOI: 10.1016/j.colsurfa.2010.12.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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WANG YC, CHEN C, JU SP. Adsorption Mechanism and Dynamic Behavior of Water and Ethanol Molecules inside Au Nanotubes. CHINESE JOURNAL OF CATALYSIS 2008. [DOI: 10.1016/s1872-2067(09)60008-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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