Enthalpy Of Vaporization Research Articles

Efficient CO2 capture by non-aqueous imide/ethylene glycol solvent

Man-made CO2 emissions give rise to an important influence on climate and human survival, which has attracted widespread attention. Traditional absorbents such as aqueous amines used for CO2 capture often suffer from high regeneration energy and corrosiveness. In this regard, non-aqueous amine solutions have high energy-saving potential because organics have lower vaporization enthalpy and heat capacity than water. Herein, we explored the potential absorbent composed of ethylene glycol and imide-based bases to capture CO2. The CO2 uptake in imide-based ethylene glycol absorbent was studied, experimental results showed that succinimide/glycol-20 wt% have the highest CO2 solubility, and still maintains a high absorption capacity after 8 regeneration cycles. And the absorption mechanism has been confirmed the possible intermolecular hydrogen bonding and van der Waals forces between carbon dioxide and succinimide molecules through molecular simulation. The regeneration energy consumption is only 2.243 GJ/t CO2 through process simulation calculation, which is lower than the conventional absorbent, further indicating that the fabricated absorbent have exhibits the large potential to absorb CO2 from flue gas.

Enhancing Solar Steam Generation of Hydrogels via Silver Nanoparticle-Doped Cellulose Nanofibers.

Solar steam generation (SSG) is regarded as an efficient approach for harnessing solar energy to purify polluted or saline water. Herein, we demonstrate a hydrogel composed of cellulose nanofibers (CNFs), polyethylenimine (PEI), and reduced graphene oxide (rGO) that functions as an independent solar steam generator, which shows enhanced solar water evaporation efficiency by incorporating silver nanoparticles (AgNPs). It presented that the presence of AgNPs increases the photothermal conversion efficiency and thermal conductivity of the evaporator and reduces the enthalpy of evaporation. As a result, an outstanding water evaporation rate of 3.62 kg m-2 h-1 and a photothermal conversion efficiency of 96.25% are successfully obtained under one sun illumination. Also, the resulting hydrogel exhibits exceptional mechanical properties, as well as outstanding desalination and salt-resistant abilities during prolonged seawater desalination. In oil/water mixtures, the evaporation of the hydrogel decreases to 2.94 kg m-2 h-1, owing to the oil layer barrier. This work paves a reference approach to produce easily addressed cellulose nanofiber (CNF)-based hydrogel evaporators with significantly enhanced evaporation rates.

Hollow carbon fiber wrapped by regular rGO wave-like folds for efficient solar driven interfacial water steam generation

Efficient seawater desalination is an effective way to solve the shortages of fresh water and energy but with limitations of the low fresh water production rate and high cost. Here, a hollow carbon fiber (HCF) wrapped by regular reduced graphene oxide (rGO) wave-like folds (rGO@HCF) is prepared on account of the differences in thermal shrinkage performance between graphene oxide (GO) and willow catkins fiber. Under one sun irradiation (1 kW m−2), the dry and wet surface temperature of the resulting evaporator reached up to 119.1 °C and 61.7 °C, respectively, and the water steam production rate reached 3.42 kg m−2 h−1. Also, for the outdoor experiment, the rGO@HCF exhibits good evaporator performance which reach up 27.8 kg m−2 day−1. Additionally, rGO@HCF also shows good seawater desalination performance and excellent durability for longtime work. DSC results indicate that the evaporation enthalpy of bulk water and adsorbed water decreased from 2503.92 to 1020.54 J g−1. The excellent evaporating performance is mainly attributed to the regular wave-like microstructure surface of the HCF, which can enhance the light absorption, reduced the vaporization enthalpy of the adsorption water. The findings not only introduce a novel approach for agricultural utilization, but also establish a crucial theoretical foundation for the design of regular wave-like microstructures.

Sustainable upcycling of waste polyethylene terephthalate into hierarchically porous carbon nanosheet for interfacial solar steam and hydroelectricity generation

Solar-driven interfacial evaporation coupled with hydroelectricity technology is regarded as a hopeful tactic to co-generate freshwater and electricity. However, constructing low-cost evaporators/generators remain a grand challenge. Herein, we report a salt-assisted carbonization method to convert waste polyethylene terephthalate to be hierarchically porous carbon nanosheet (HPCN) and build a flexible HPCN-based evaporator for freshwater and hydroelectricity co-generation. HPCN exhibits a wrinkled structure with the thickness of ca. 3.4 nm. The HPCN-based evaporator displays good hydrophilicity, high sunlight absorption (98%), high solar-to-thermal conversion, reduced water evaporation enthalpy, and low thermal conductivity. It exhibits high evaporation rate (2.65 kg m−2 h−1) and conversion efficiency (98.0%) through 1 kW m−2 irradiation, exceeding many advanced solar evaporators. Importantly, the HPCN evaporator-based hydroelectricity generator realizes high voltage (255 mV) and current (310 nA) with good stability. The combination of large specific surface area with wealthy oxygen-containing groups of HPCN plays important roles in hydroelectricity generation. In outdoor experiment, the freshwater production amount from per meter square achieves 6.32 kg. This work provides a green approach to upcycle waste plastics to be functional carbon materials and offers a new platform to construct advanced evaporators for solar evaporation and hydroelectricity generation.

Biofuel Concentration in Low-Speed Pre-Ignition in Gasoline Engines

Low-Speed Pre-Ignition (LSPI) is a destructive combustion event associated primarily with new, ultra-efficient, downsized gasoline engines, which provide efficiency benefits in general operation. Biofuels, specifically bio-gasoline, are an alternative fuel that attempts to reduce the harmful emissions output by modern Internal Combustion Engines (ICEs). This study attempts to understand the effect of biofuel use on LSPI, through the use of a numerical simulation tool developed in Ricardo Wave. Development of the tool includes the integration of RFlame, an extension capable of modeling autoignition within a 1D domain. Use of the tool highlights the impact of five ethanol blends, E10, E20, E30, E50 and E85, with clear impacts on both the severity and frequency of LSPI events correlated with chemical properties, such as the enthalpy of vaporization (HoV) and octane number. E30 is highlighted as the critical blend for LSPI severity, with both increased severity and intensity seen with a 30% concentration, and a greater sensitivity to effects such as the start of ignition (SOI). Higher-concentration biofuels, such as E50 and E85 bio-gasoline, show much more favorable behaviors, such as a vast reduction in end-gas knock events, but are limited in their use due to their deployment being both cost-prohibitive and potentially damaging in current hardware. Future work on this topic will surround the further development of the simulation tool to integrate 3D solving elements, understand the role of fluid interactions in LSPI, and study optimal fuel characteristics for future use in ICEs.

Multi-strategy coupling of custom hydrogel evaporators for sustained, high-efficiency clean water production and anti-pollution

The emergence of hydrogel evaporators has greatly improved the evaporation rate and has attracted widespread attention. However, single-strategy design yields limited evaporation rates and anti-fouling properties, restricting their utility. Here, we report a superhydrophilic interconnected porous hydrogel (SIPH) evaporator that incorporates multiple strategirs. This design enhances water transport, light absorption, and heat localization, reducing heat loss from the evaporating surfaces. By modulating polymer network-water interactions with −NH2 groups, we achieved a high proportion of activated water, lowering the evaporation enthalpy to about one-third that of pure water. Based on this diversified design, SIPH achieves a high evaporation rate of 4.80 kg m−2 h−1 under one sun. Moreover, SIPH demonstrates excellent stability in various water qualities and long-lasting anti-pollution properties, offering significant practical application potential.

A temperature-responsive, repairable and renewable self-floating hydrogel steam generator

The design and synthesis of materials dedicated to solar evaporation have attracted substantial attention. Hydrogels, known for their elevated evaporation rates, are perceived as potential candidates in the subsequent evolution of solar evaporation technology. This research introduces an efficient, harmless, and sustainable design of a porous hydrogel interface evaporator, possessing self-repair and regenerative capabilities. For a hydrogel matrix composed of carrageenan and konjac gum, an element of activated carbon serving as a light absorber is integrated. Notably, the evaporator’s capability for regeneration and repair is facilitated by the unique thermally reversible three-dimensional architecture of carrageenan. The konjac gum provides the interpenetrating network with carrageenan, which significantly enhances the hydrogel’s mechanical durability. Additionally, its hydroxyl-rich components precisely modulate the state and content of the water molecules, contributing to reduce the enthalpy of water evaporation. Lastly, the inclusion of activated carbon effectively mitigates the retention of low-boiling-point contaminants and endows the hydrogel with a light absorption of 97 %. These outstanding benefits result in an evaporation rate as high as 2.6 kg m−2 h−1 for the formulated hydrogel. Given the ready availability of raw materials, this biomass evaporator introduces new prospects for eco-friendly solar evaporators.

Large-area, low-cost, highly durable solar evaporators for sustainable solarizing seawater

Conventional solarizing seawater technology faces significant challenges including a large footprint, time-consuming processes, and inefficient energy utilization. Solar-driven interfacial water evaporation (SIWE) technology, offers a promising approach for sustainable solarizing seawater, facilitating the production of solid salt with reduced time and land requirements. Nevertheless, the urgent challenge lies in the development of low-cost, large-area solar evaporators that are highly salt-resistant and adaptable, enabling efficient and sustainable solar desalination for solid salt production. As such, a large-area, affordable, and highly durable melamine foam/reduced graphene oxide/sodium alginate (MGS) solar evaporator is proposed for continuous solarizing seawater using a simple method of “immersion-crosslinking-reduction”. Among them, hydrophilic melamine foam serves as the supportive framework, immersed with graphene as light absorption material, and hydrophilic sodium alginate polymeric network for fixing graphene sheets and regulating water evaporation enthalpy. As such, MGS solar evaporator can be prepared in a large-area of 0.5 m × 0.5 m at the cost prices as low as $2.91 m−2. The optimized MGS solar evaporator achieves a high water evaporation rate of 2.30 kg m−2h−1 with the photothermal conversion efficiency of 89.2 % under one sun irradiation. In outdoor environments, MGS allows for timely convective/diffusive salt discharge through its macropores, thus allowing for prolonged seawater solarization without obvious solid salt accumulation. Notably, the original seawater can be highly concentrated until all the water evaporates and solid salt precipitates. This developed MGS solar evaporator offers a novel perspective on efficient seawater solarization, conserving both time and land.

New QSPR molecular descriptors based on low-cost quantum chemistry computations using DFT/COSMO approach

This work presents a simple computational methodology to determine new theoretical molecular descriptor scales convenient for use in QSPR correlations and the analysis of solvation-related properties. On the basis of low-cost quantum chemical computations using DFT/COSMO approach, in particular that implemented in the ADF/COSMO-RS module of the Amsterdam Modeling Studio program package, optimized geometry and local screening charge density of a considered molecule are obtained and related to the proposed descriptors through an a priori simple reasoning. Values of four molecular descriptors, namely volume VCOSMO∗, hydrogen bond/Lewis acidity αCOSMO and basicity βCOSMO, and charge asymmetry of the nonpolar region of the molecule δCOSMO have been calculated and are presented for sets of 128 non-ionic organic molecules and 47 ions composing ionic liquids. Relation of the proposed scales to some others that are widely known or presented recently in the literature has been examined. Although the present methodology is completely independent of any experimental data, the theoretical descriptor scales proposed here have been found to correlate linearly quite well with the respective empirical scales (mostly R2 > 0.8, and for some R2 > 0.9). For non-ionic organics, just the direct proportionality provided adequate fits of the well-established prominent scales such as those of Abraham, Klamt, Kamlet-Taft, Catalan, Gutmann, and Laurence and showed only a few statistically justifiable outliers. For ions composing ILs, the linear fits of seven acidity or basicity scales presented previously with those proposed in this work were of similar quality. Examining the observed outliers, several descriptor values reported in the literature were identified as being in error. Good performance of the new descriptor scales has been demonstrated by employing them for LSER fitting of various solvation-related thermodynamic and kinetic properties such as standard vaporization enthalpy, standard hydration enthalpy, air–water partition coefficient, air-IL partition coefficient, and solvent effects on the activation Gibbs energy or rate constant of SN1 and SNAr reactions. The quality of these correlations appears to be comparable to that of the correlations currently available for these properties, regardless of the role, solute or solvent, the involved molecules played.

Thermosensitive Hydrogel PNIPAAm‐Alg‐PEDOT for Sustainable and Efficient Water Purification Powered by Solar Energy

AbstractUnrestricted access to clean drinking water is essential for the well‐being of the global population, yet this necessary resource is not universally guaranteed, particularly amidst the escalating climate crisis that accentuates disparities across regions. Harnessing solar energy in conjunction with advanced synthetic solar absorbent hydrogels (SAHs) is increasingly recognized as a promising solution and a significant challenge in addressing the purification of brackish water sustainably. This work outlines the development of a SAH using the thermosensitive polymer poly(N‐isopropylacrylamide) (PNIPAAm) in combination with alginate (Alg), enriched with poly(3,4‐ethylenedioxythiophene) (PEDOT) nanoparticles (NPs). Through solar evaporation tests using different conducting polymer (CP) concentrations, a discernible relationship between the ratio of free water to intermediate water (FW/IW) within the hydrogel structure and its performance is observed. The hydrogel's remarkable evaporation rate for synthetic seawater (2.82 kg m−2 h−1) aligns with the lowest FW/IW, which is directly related to a reduction in water vaporization enthalpy. Characterization of intermediate water enables easy adjustment of the optimal conductive polymer content within the hydrogel. This technology, based on thermosensitive materials, not only introduces innovative methodologies for designing and customizing functional composite materials but also aligns with global objectives by addressing challenges in sustainable drinking water supply without additional energy inputs.

QSPR/QSAR study of antiviral drugs modeled as multigraphs by using TI’s and MLR method to treat COVID-19 disease

The ongoing COVID-19 pandemic continues to pose significant challenges worldwide, despite widespread vaccination. Researchers are actively exploring antiviral treatments to assess their efficacy against emerging virus variants. The aim of the study is to employ M-polynomial, neighborhood M-polynomial approach and QSPR/QSAR analysis to evaluate specific antiviral drugs including Lopinavir, Ritonavir, Arbidol, Thalidomide, Chloroquine, Hydroxychloroquine, Theaflavin and Remdesivir. Utilizing degree-based and neighborhood degree sum-based topological indices on molecular multigraphs reveals insights into the physicochemical properties of these drugs, such as polar surface area, polarizability, surface tension, boiling point, enthalpy of vaporization, flash point, molar refraction and molar volume are crucial in predicting their efficacy against viruses. These properties influence the solubility, permeability, and bio availability of the drugs, which in turn affect their ability to interact with viral targets and inhibit viral replication. In QSPR analysis, molecular multigraphs yield notable correlation coefficients exceeding those from simple graphs: molar refraction (MR) (0.9860), polarizability (P) (0.9861), surface tension (ST) (0.6086), molar volume (MV) (0.9353) using degree-based indices, and flash point (FP) (0.9781), surface tension (ST) (0.7841) using neighborhood degree sum-based indices. QSAR models, constructed through multiple linear regressions (MLR) with a backward elimination approach at a significance level of 0.05, exhibit promising predictive capabilities highlighting the significance of the biological activity IC50\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$IC_{50}$$\\end{document} (Half maximal inhibitory concentration). Notably, the alignment of predicted and observed values for Remdesivir’s with obs pIC50=6.01\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${pIC_{50} = 6.01}$$\\end{document},pred pIC50=6.01\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${pIC_{50} = 6.01}$$\\end{document} (pIC50\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$pIC_{50}$$\\end{document} represents the negative logarithm of IC50\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$IC_{50}$$\\end{document}) underscores the accuracy of multigraph-based QSAR analysis. The primary objective is to showcase the valuable contribution of multigraphs to QSPR and QSAR analyses, offering crucial insights into molecular structures and antiviral properties. The integration of physicochemical applications enhances our understanding of factors influencing antiviral drug efficacy, essential for combating emerging viral strains effectively.

Thermochemical Research on Furfurylamine and 5-Methylfurfurylamine: Experimental and Computational Insights.

The need to transition from fossil fuels to renewables arises from factors such as depletion, price fluctuations, and environmental considerations. Lignocellulosic biomass, being abundant, and quickly renewable, and not interfering with food supplies, offers a standout alternative for chemical production. This paper explores the energetic characteristics of two derivatives of furfural-a versatile chemical obtained from biomass with great potential for commercial sustainable chemical and fuel production. The standard (p° = 0.1 MPa) molar enthalpies of formation of the liquids furfurylamine and 5-methylfurfurylamine were derived from the standard molar energies of combustion, determined in oxygen and at T = 298.15 K, by static bomb combustion calorimetry. Their standard molar enthalpies of vaporization were also determined at the same temperature using high-temperature Calvet microcalorimetry. By combining these data, the gas-phase enthalpies of formation at T = 298.15 K were calculated as -(43.5 ± 1.4) kJ·mol-1 for furfurylamine, and -(81.2 ± 1.7) kJ·mol-1 for 5-methylfurfurylamine. Furthermore, a theoretical analysis using G3 level calculations was performed, comparing the calculated enthalpies of formation with the experimental values to validate both results. This method has been successfully applied to similar molecules. The discussion looks into substituent effects in terms of stability and compares them with similar compounds.

Thermophysical Properties of FUNaK (NaF-KF-UF4) Eutectics.

General interest in the deployment of molten salt reactors (MSRs) is growing, while the available data on uranium-containing fuel salt candidates remains scarce. Thermophysical data are one of the key parameters for reactor design and understanding reactor operability. Hence, filling in the gap of the missing data is crucial to allow for the advancement of MSRs. This study provides novel data for two eutectic compositions within the NaF-KF-UF4 ternary system which serve as potential fuel candidates for MSRs. Experimental measurements include their melting point, density, fusion enthalpy, and vapor pressure. Additionally, their boiling point was extrapolated from the vapor pressure data, which were, at the same time, used to determine the enthalpy of vaporization. The obtained thermodynamic values were compared with available data from the literature but also with results from thermochemical equilibrium calculations using the JRCMSD database, finding a good correlation, which thus contributed to database validation. Preliminary thoughts on fluoride salt reactor operability based on the obtained results are discussed in this study.

MnO2/Poly-L-lysine Co-decorated Carbon Fiber Cloth with Decreased Evaporation Enthalpy and Enhanced Photoabsorption/Antibacterial Performance for Solar-Enabled Anti-fouling Seawater Desalination

MnO2/Poly-L-lysine Co-decorated Carbon Fiber Cloth with Decreased Evaporation Enthalpy and Enhanced Photoabsorption/Antibacterial Performance for Solar-Enabled Anti-fouling Seawater Desalination

Thermodynamic properties of 3-(1,5-diphenylpyrrol-2-yl)- propanoic acid

Using precision equipment, the enthalpies of vaporization, fusion and formation in the condensed state of 3-(1,5-diphenylpyrrol-2-yl)-propanoic acid were experimentally determined. The enthalpy of sublimation at 298 K and the enthalpy of formation in the gaseous state were calculated. A comparative analysis of the experimentally determined values with theoretically calculated values using additive calculation methods is given.

A new setup for measurements of absolute saturation vapor pressures using a dynamical method: Experimental concept and validation.

We describe a new experimental system for direct measurements of the absolute saturation vapor pressures of liquid or solid samples. The setup allows the isolation of the sample under steady conditions in an ultra-high vacuum chamber, where the measurement of the sample's vapor pressure as a function of its temperature can be performed in a range around room temperature and in a pressure range defined only by the applied absolute pressure sensor. We characterize the setup and illustrate its capability to measure saturation vapor pressures as well as enthalpies of evaporation around room temperature with explicit measurements on four liquid compounds (diethyl phthalate, 1-decanol, 1-heptanol, and 1-hexanol) for which accurate vapor pressures have previously been reported.

Highly Potent Transparent Passive Cooling Coating via Microphase-Separated Hydrogel Combining Radiative and Evaporative Cooling.

Transparent passive cooling materials can cool targets environmentally without interfering with light transmission or visual information reception. They play a prominent role in solar cells and flexible display cooling. However, achieving potent transparent cooling remains challenging, because light transmission is accompanied by thermal energy. Here we propose to realize effective passive cooling in transparent materials via a microscale phase separation hydrogel film. The poly(N-isopropylacrylamide-co-acrylamide) hydrogel presents light transmittance of >96% and infrared emissivity as high as 95%. The microphase-separated structure affords a higher enthalpy of evaporation. The film is highly adhesive. In field applications, it reduces temperatures by 9.14 °C compared to those with uncovered photovoltaic panels and 7.68 °C compared to those for bare flexible light-emitting diode screens. Simulations indicate that energy savings of 32.76-51.65 MJ m-2 year-1 can be achieved in typical tropical monsoon climates and temperate continental climates. We expect this work to contribute to energy-efficient materials and a carbon-neutral society.

Vapor Pressure and Enthalpy of Vaporization of Guanidinium Methanesulfonate as a Phase Change Material for Thermal Energy Storage.

This paper reports the vapor pressure and enthalpy of vaporization for a promising phase change material (PCM) guanidinium methanesulfonate ([Gdm][OMs]), which is a typical guanidinium organomonosulfonate that displays a lamellar crystalline architecture. [Gdm][OMs] was purified by recrystallization. The elemental analysis and infrared spectrum of [Gdm][OMs] confirmed the purity and composition. Differential scanning calorimetry (DSC) also confirmed its high purity and showed a sharp and symmetrical endothermic melting peak with a melting point (Tm) of 207.6 °C and a specific latent heat of fusion of 183.0 J g-1. Thermogravimetric analysis (TGA) reveals its thermal stability over a wide temperature range, and yet three thermal events at higher temperatures of 351 °C, 447 °C, and 649 °C were associated with vaporization or decomposition. The vapor pressure was measured using the isothermogravimetric method from 220 °C to 300 °C. The Antoine equation was used to describe the temperature dependence of its vapor pressure, and the substance-dependent Antoine constants were obtained by non-linear regression. The enthalpy of vaporization (ΔvapH) was derived from the linear regression of the slopes associated with the linear temperature dependence of the rate of weight loss per unit area of vaporization. Hence, the temperature dependence of vapor pressures ln Pvap (Pa) = 10.99 - 344.58/(T (K) - 493.64) over the temperature range from 493.15 K to 573.15 K and the enthalpy of vaporization ΔvapH = 157.10 ± 20.10 kJ mol-1 at the arithmetic mean temperature of 240 °C were obtained from isothermogravimetric measurements using the Antoine equation and the Clausius-Clapeyron equation, respectively. The flammability test indicates that [Gdm][OMs] is non-flammable. Hence, [Gdm][OMs] enjoys very low volatility, high enthalpy of vaporization, and non-flammability in addition to its known advantages. This work thus offers data support, methodologies, and insights for the application of [Gdm][OMs] and other organic salts as PCMs in thermal energy storage and beyond.

BF3 Complexing Phosphate/Phosphonate Ionic Liquids: Synthesis, Characterization and Thermophysical Properties.

A new group of BF3 complexing phosphate/phosphonate ionic liquids (ILs) [Emim][X(BF3)2] (X=dimethyl phosphate, diethyl phosphate, methyl phosphonate, and ethyl phosphonate) were synthesized and characterized. Key thermophysical properties of the new complex ionic liquids, including density, viscosity, conductivity, surface tension, solid-liquid phase transition, and thermal stability were determined and compared with those of [Emim][X]. Some other important thermophysical properties such as isobaric thermal expansion coefficient, molecular volume, standard molar entropy, and lattice potential energy were obtained from measured density data, and the free volume was estimated by a linear equation presented in this article, while critical temperature, normal boiling temperature, and enthalpy of vaporization were estimated from measured surface tension and density data. Furthermore, Fragility study shows that [Emim][X(BF3)2] should be considered as fragile liquids, while [Emim][X] could be considered as extremely fragile liquids. The ionicity of [Emim][X(BF3)2] was predicted by Walden rule, and the result shows that these ILs fit well with Walden law. The key features of these complex ILs are their extremely low glass transition (-95.33~-98.46 °C) without melting, considerably low viscosities (33.876~58.117 mPa ⋅ s), and high values of free volume fraction (comparable to [Omim][BF4], [Emim][NTf2], and [Emim][TCB]).

Experimental analysis of the storage of thermal power by a thermosyphon amalgamated nanophase change material in thermal management systems

Current research examines thermal power storage by thermosyphon amalgamated nanophase change material in thermal management systems. The experiments were analysed with heat inputs ranging from 40 to 90 W using deionized water, ethyl acetate, hydrofluoroether-7100, and n-propylamine as thermal fluids. The copper‑titanium nanocomposite particles at different concentrations (0.5, 0.3, 0.1, 0.08, and 0.05 wt%) are disseminated in a phase change material (methyl cinnamate). Due to its high thermal conductivity, a 0.5 wt% concentrated nanophase change material was used in this study. The heat transfer effectiveness, charging, and retrieving attributes of the nanophase change material are investigated using thermal fluids. The results indicate that hydrofluoroether-7100 has a lower thermal resistance, maximum heat transfer coefficient, and highest heat dissipation rate of about 0.26 K/W, 203.8 W/(m2‧K), and 98.9 %, respectively, at the maximum heat input. The low enthalpy of vaporization and surface tension are the causes of the acquired results. The maximum thermal power storage by the nanophase change material is 7.2 W during charging due to the influence of vaporized hydrofluoroether-7100 at 90 W, which is attributed to the increased vapor mass flow and shorter time required to reach the steady-state temperature of the melted nanophase change material. The overall exergy efficiency is greater in the case of deionized water and is 4.8 % owing to the greater temperature difference and heat loss. Moreover, the minimum possible power savings of approximately 6.2 % are obtained using the developed setup.