International Journal of Thermophysics最新文献

筛选
英文 中文
Phase Relations in the Ag2S-Ag8SiS6-Ag8SnS6 System and Thermodynamic Properties of Polymorphic Transitions of Argyrodite Phases
IF 2.5 4区 工程技术
International Journal of Thermophysics Pub Date : 2025-01-23 DOI: 10.1007/s10765-025-03501-z
Samaddin R. Aslanli, Isfendiyar J. Alverdiyev, Samira Z. Imamaliyeva, Yasin I. Jafarov, Yusif A. Yusibov, Mahammad B.Babanly
{"title":"Phase Relations in the Ag2S-Ag8SiS6-Ag8SnS6 System and Thermodynamic Properties of Polymorphic Transitions of Argyrodite Phases","authors":"Samaddin R. Aslanli,&nbsp;Isfendiyar J. Alverdiyev,&nbsp;Samira Z. Imamaliyeva,&nbsp;Yasin I. Jafarov,&nbsp;Yusif A. Yusibov,&nbsp;Mahammad B.Babanly","doi":"10.1007/s10765-025-03501-z","DOIUrl":"10.1007/s10765-025-03501-z","url":null,"abstract":"<div><p>The Ag<sub>2</sub>S-Ag<sub>8</sub>SiS<sub>6</sub>-Ag<sub>8</sub>SnS<sub>6</sub> system was studied using DTA/DSC, diffraction of X-ray, as well as SEM methods. The T-x phase diagram of the Ag<sub>8</sub>SiS<sub>6</sub>-Ag<sub>8</sub>SnS<sub>6</sub> boundary system, several vertical and isothermal sections of the phase diagram, as well as a projection of the liquidus surface, were plotted, and the thermodynamic functions of polymorphic transitions of the Ag<sub>8</sub>SiS<sub>6</sub> compound and Ag<sub>8</sub>Si<sub>1-x</sub>Sn<sub>x</sub>S<sub>6</sub> solid solutions were calculated. It was obtained that the Ag<sub>8</sub>SiS<sub>6</sub>-Ag<sub>8</sub>SnS<sub>6</sub> boundary system is quasi-binary and is characterized by the formation of a continuous solid solutions during low-temperature orthorhombic and high-temperature cubic modifications of the initial compounds. It is shown that investigated system is a quasi-ternary plane of the Ag–Si–Sn–S concentration tetrahedron. The liquidus surface consists of two fields corresponding to the primary crystallization of high-temperature Ag<sub>8</sub>Si<sub>1-x</sub>Sn<sub>x</sub>S<sub>6</sub> solid solutions based on HT-Ag<sub>2</sub>S. Below the solidus, phase transformations associated with the polymorphism of the initial compounds and phases based on them were observed. Based on DSC data, the temperatures, enthalpies, and entropies of phase transitions of the argyrodite phases from low-temperature orthorhombic modification to high-temperature cubic modification were calculated. It was determined that the heats and entropies of tranformations of above phases have anomalously high values ​​compared to ordinary polymorphic transitions. In addition, it was established that the entropies of phase transformations of solid solutions are practically equal to the sum of the corresponding functions of the original compounds. This indirectly indicates the quasi-ideality of solutions between both modifications of these compounds.</p></div>","PeriodicalId":598,"journal":{"name":"International Journal of Thermophysics","volume":"46 2","pages":""},"PeriodicalIF":2.5,"publicationDate":"2025-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143108815","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Effective Thermal Conductivity of Nanofluids Containing Silicon Dioxide, Titanium Dioxide, Copper Oxide, Polystyrene, or Polymethylmethacrylate Nanoparticles Dispersed in Water, Ethylene Glycol, or Glycerol
IF 2.5 4区 工程技术
International Journal of Thermophysics Pub Date : 2025-01-23 DOI: 10.1007/s10765-024-03488-z
Francisco E. Berger Bioucas, Thomas M. Koller, Andreas P. Fröba
{"title":"Effective Thermal Conductivity of Nanofluids Containing Silicon Dioxide, Titanium Dioxide, Copper Oxide, Polystyrene, or Polymethylmethacrylate Nanoparticles Dispersed in Water, Ethylene Glycol, or Glycerol","authors":"Francisco E. Berger Bioucas,&nbsp;Thomas M. Koller,&nbsp;Andreas P. Fröba","doi":"10.1007/s10765-024-03488-z","DOIUrl":"10.1007/s10765-024-03488-z","url":null,"abstract":"<div><p>The present study represents a continuation of our investigations on the effective thermal conductivity <i>λ</i><sub>eff</sub> of nanofluids by systematically varying the types of base fluids and particles. For the spherical nanoparticles with mean diameters between (20 and 175) nm, the metal oxides silicon dioxide (SiO<sub>2</sub>), titanium dioxide (TiO<sub>2</sub>), and copper oxide (CuO) as well as the polymers polystyrene (PS) and polymethylmethacrylate (PMMA) were selected to cover a broad range for the particle thermal conductivity <i>λ</i><sub>p</sub> from about (0.1 to 30) W⋅m<sup>–1</sup>⋅K<sup>–1</sup>. The corresponding polar base fluids water, ethylene glycol, and glycerol allow to not only vary their thermal conductivity <i>λ</i><sub>bf</sub> by a factor of more than two, but also their dynamic viscosity by about three orders of magnitude. For the measurement of <i>λ</i><sub>eff</sub> of the twelve different particle–fluid combinations, i.e., TiO<sub>2</sub> or CuO with all three liquids as well as SiO<sub>2</sub>, PS, or PMMA with water or ethylene glycol, a steady-state guarded parallel-plate instrument (GPPI) associated with an expanded (<i>k</i> = 2) relative uncertainty between 0.022 and 0.032 was used at atmospheric pressure over a temperature range from (283 to 358) K at varying particle volume fractions up to 0.31. The results for the thermal-conductivity ratio <i>λ</i><sub>eff</sub>·<i>λ</i><sub>bf</sub><sup>–1</sup> are independent of temperature and show a moderate and relatively linear change as a function of the particle volume fraction. For similar ratios <i>λ</i><sub>p</sub>·<i>λ</i><sub>bf</sub><sup>–1</sup>, the experimental data for <i>λ</i><sub>eff</sub>·<i>λ</i><sub>bf</sub><sup>–1</sup> are also very similar, which are above, close to, or below 1 if <i>λ</i><sub>p</sub> is larger than, comparable to, or smaller than <i>λ</i><sub>bf</sub>, respectively. For all nanofluids investigated, the Hamilton–Crosser model can describe the present measurement results and reliable experimental data reported in the literature for <i>λ</i><sub>eff</sub>·<i>λ</i><sub>bf</sub><sup>–1</sup> typically within ± 5 %. Overall, the measurement results from this work contribute to an extension of the database for <i>λ</i><sub>eff</sub> of nanofluids with respect to the investigated wide ranges of systems, temperature, and particle volume fraction.</p></div>","PeriodicalId":598,"journal":{"name":"International Journal of Thermophysics","volume":"46 2","pages":""},"PeriodicalIF":2.5,"publicationDate":"2025-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10765-024-03488-z.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143108814","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
The Extended Pulse Method for the Measurement of the Thermal Diffusivity of Solids 测量固体热扩散系数的扩展脉冲法
IF 2.5 4区 工程技术
International Journal of Thermophysics Pub Date : 2025-01-20 DOI: 10.1007/s10765-025-03504-w
William A. Wakeham, Peter S. Gaal, Zachary D. Withrow, Daniela S. Gaal
{"title":"The Extended Pulse Method for the Measurement of the Thermal Diffusivity of Solids","authors":"William A. Wakeham,&nbsp;Peter S. Gaal,&nbsp;Zachary D. Withrow,&nbsp;Daniela S. Gaal","doi":"10.1007/s10765-025-03504-w","DOIUrl":"10.1007/s10765-025-03504-w","url":null,"abstract":"<div><p>The paper presents a complete theory for a new method for the determination of the thermal diffusivity of a bulk solid in the form of a cylinder using a pulse of energy of finite duration delivered on one face and the subsequent temperature rise detected on a parallel face. It is an important feature of the method that the departure from equilibrium in the solid sample is small so that the temperature rise is no more than a few degrees Kelvin. The energy pulse may be of any temporal distribution and the detection of the temperature rise can be conducted at any point on the opposing face of the sample. The theory explicitly accounts for heat losses at all the surfaces of the sample and enables absolute measurement of the thermal diffusivity of the sample. A prototype instrument is described to realize this theory in which the heating pulse is generated by an array of light emitting diodes in a circular configuration which is then guided by a light pipe so that a uniform distribution is ensured across the flat face of the solid sample being tested. The instrument is designed for operation over the temperature range from ambient to 1300 K but, in the current proof of principle, measurements are conducted at room temperature on a sample of Pyroceram™ 9606.<sup>1</sup> In this case, the detection is performed with a micro-thermocouple at the center of the sample. Several different rectangular heating pulse durations are employed to show that the theory provides an appropriate description of the experiment. The potential for future applications of the technique is demonstrated.</p></div>","PeriodicalId":598,"journal":{"name":"International Journal of Thermophysics","volume":"46 2","pages":""},"PeriodicalIF":2.5,"publicationDate":"2025-01-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10765-025-03504-w.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142995274","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Parametrical Identity Mapping: An Evaluation Procedure for THW Signals and Other Time-Series Methods 参数恒等映射:THW信号和其他时间序列方法的评估程序
IF 2.5 4区 工程技术
International Journal of Thermophysics Pub Date : 2025-01-15 DOI: 10.1007/s10765-024-03499-w
U. Hammerschmidt
{"title":"Parametrical Identity Mapping: An Evaluation Procedure for THW Signals and Other Time-Series Methods","authors":"U. Hammerschmidt","doi":"10.1007/s10765-024-03499-w","DOIUrl":"10.1007/s10765-024-03499-w","url":null,"abstract":"<div><p>The mathematical tool “Parametrical Identity Mapping (PIM)” is presented in detail. Its tasks are to effectively assists (1) in choosing the best form of a measurement model, e.g., for the transient hot-wire method and (2) in completely adjusting the selected model by two global correction factors. These factors control the amplitude and time-response of the adjusted model in a way that this form of the model optimally predicts the experimental data points. The goodness of the adjusted model can easily be determined by a simple statistic, the level of similarity, <span>(R^{2} le 1)</span>. <span>(R^{2})</span> is known as the coefficient of determination. Here, it describes the proportion of the variation in the observed values that is predictable from the estimated values. PIM is able to create an adjusted model of a level of similarity that comes very close to unity, <span>(R^{2} approx 1)</span>.</p></div>","PeriodicalId":598,"journal":{"name":"International Journal of Thermophysics","volume":"46 2","pages":""},"PeriodicalIF":2.5,"publicationDate":"2025-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142976532","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Investigating Anisotropic Three-Phonon Interactions in Graphene’s Thermal Conductivity Using Monte Carlo Method 用蒙特卡罗方法研究石墨烯导热性中的各向异性三声子相互作用
IF 2.5 4区 工程技术
International Journal of Thermophysics Pub Date : 2025-01-15 DOI: 10.1007/s10765-024-03498-x
Shixian Liu, Fei Yin, Vladimir I. Khvesyuk
{"title":"Investigating Anisotropic Three-Phonon Interactions in Graphene’s Thermal Conductivity Using Monte Carlo Method","authors":"Shixian Liu,&nbsp;Fei Yin,&nbsp;Vladimir I. Khvesyuk","doi":"10.1007/s10765-024-03498-x","DOIUrl":"10.1007/s10765-024-03498-x","url":null,"abstract":"<div><p>This study introduces a novel method for calculating the thermal conductivity of graphene using a Monte Carlo approach to evaluate anisotropic three-phonon interactions. The phonon dispersion relation is derived using a force constant model that incorporates up to fifth-order nearest neighbor interactions, while the phonon density of states (DOS) is computed via a generalized Gilat–Raubenheimer method. A quantitative relationship for the scaling exponent of the specific heat capacity at low temperatures is established, emphasizing the unique two-dimensional characteristics of graphene. To address anisotropic effects, the Monte Carlo approach efficiently identifies three-phonon combinations that adhere to the conservation laws of energy and momentum. The findings highlight the pivotal role of anisotropic phonon interactions in graphene’s thermal conductivity. The thermal conductivity values obtained through the iterative method exhibit strong agreement with previous three-phonon calculations, thereby validating the model. Nevertheless, discrepancies with experimental data suggest that incorporating higher-order phonon processes, such as four-phonon scattering, may further improve predictive accuracy.</p></div>","PeriodicalId":598,"journal":{"name":"International Journal of Thermophysics","volume":"46 2","pages":""},"PeriodicalIF":2.5,"publicationDate":"2025-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142976481","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
A Helmholtz Energy Equation of State for 3,3,3-Trifluoroprop-1-ene (R-1243zf) 3,3,3-三氟丙烷-1-烯(R-1243zf)的Helmholtz能量状态方程
IF 2.5 4区 工程技术
International Journal of Thermophysics Pub Date : 2025-01-15 DOI: 10.1007/s10765-024-03481-6
Ryo Akasaka, Eric W. Lemmon
{"title":"A Helmholtz Energy Equation of State for 3,3,3-Trifluoroprop-1-ene (R-1243zf)","authors":"Ryo Akasaka,&nbsp;Eric W. Lemmon","doi":"10.1007/s10765-024-03481-6","DOIUrl":"10.1007/s10765-024-03481-6","url":null,"abstract":"<div><p>A new fundamental equation of state expressed as a function of the Helmholtz energy is presented for 3,3,3-trifluoroprop-1-ene (R-1243zf). The equation is valid from the triple-point temperature (122.35 K) to 430 K at pressures up to 35 MPa. The expected uncertainties (<span>(k = 2)</span>) in calculated properties from the equation of state are 0.1 % for vapor pressures, 0.1 % for liquid densities, 1 % for vapor densities, 0.3 % for saturated liquid densities, 1 % for saturated vapor densities, 0.06 % for vapor-phase sound speeds, and 2 % for liquid-phase isobaric heat capacities. Differences between experimental and calculated vapor pressures are within 2 kPa in most cases. Uncertainties for caloric properties are particularly improved from the former equations of state. Various plots of constant-property lines demonstrate that not only does the equation exhibit correct behavior over all temperatures and pressures within the range of validity, but also that it shows reasonable extrapolation behavior at extremely low and high temperatures, and at high pressures.</p></div>","PeriodicalId":598,"journal":{"name":"International Journal of Thermophysics","volume":"46 2","pages":""},"PeriodicalIF":2.5,"publicationDate":"2025-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142976531","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Joule Effect in Electrically Aligned CNFs: Toward Fast Heating of Liquids 电排列CNFs中的焦耳效应:对液体的快速加热
IF 2.5 4区 工程技术
International Journal of Thermophysics Pub Date : 2025-01-15 DOI: 10.1007/s10765-024-03486-1
A. P. Franco-Bacca, I. Y. Forero-Sandoval, N. W. Pech-May, J. J. Alvarado-Gil, F. Cervantes-Alvarez
{"title":"Joule Effect in Electrically Aligned CNFs: Toward Fast Heating of Liquids","authors":"A. P. Franco-Bacca,&nbsp;I. Y. Forero-Sandoval,&nbsp;N. W. Pech-May,&nbsp;J. J. Alvarado-Gil,&nbsp;F. Cervantes-Alvarez","doi":"10.1007/s10765-024-03486-1","DOIUrl":"10.1007/s10765-024-03486-1","url":null,"abstract":"<div><p>Efficient use of heating systems is necessary from an environmental and economic perspective. This work analyses the Joule effect and the thermal transport properties of carbon nanofibers dispersed in ethylene–glycol aligned by applying a constant AC electric field. We tested several weight fraction concentrations from 0.1 % to 1 % wt of carbon nanofibers. The evolution of temperature and electric current as a function of time was analyzed. The amount of heat generated was quantified using Joule's law equation, and we estimated the thermal conductivity as a function of the concentration before and after the voltage application. The dependence of the temperature increase on the concentration of carbon nanofibers and electric voltage was investigated. Our work explores the viability of using carbon nanofiber dispersed in ethylene glycol in developing intelligent fluids useful for heat generation and release, with applications in heat management systems, such as those used for deicing.</p></div>","PeriodicalId":598,"journal":{"name":"International Journal of Thermophysics","volume":"46 2","pages":""},"PeriodicalIF":2.5,"publicationDate":"2025-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10765-024-03486-1.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142976482","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Density, Viscosity, and Refractive Index Variations in Diesel Fuel + Higher Alcohols Blends at Various Temperatures 密度,粘度和折射率变化在柴油燃料+高醇混合物在不同的温度
IF 2.5 4区 工程技术
International Journal of Thermophysics Pub Date : 2025-01-09 DOI: 10.1007/s10765-024-03475-4
Sibel Osman, Mert Gülüm, Amalia Stefaniu
{"title":"Density, Viscosity, and Refractive Index Variations in Diesel Fuel + Higher Alcohols Blends at Various Temperatures","authors":"Sibel Osman,&nbsp;Mert Gülüm,&nbsp;Amalia Stefaniu","doi":"10.1007/s10765-024-03475-4","DOIUrl":"10.1007/s10765-024-03475-4","url":null,"abstract":"<div><p>Understanding the physical properties of diesel fuel blends is essential for evaluating spray characteristics, engine performance, and exhaust emissions of internal combustion engines. Moreover, higher alcohols (n-butanol, n-pentanol, and n-octanol) have recently garnered attention as promising oxygenated additives for enhancing the fuel characteristics of diesel fuel in various combustion applications. For these reasons, in this study, density (ρ), kinematic viscosity (ν), and refractive index (n<sub>D</sub>) values of pseudo-binary blends (diesel fuel + n-butanol, diesel fuel + n-pentanol, and diesel fuel + n-octanol) are measured at different temperatures (288.15 K–323.15 K with 5 K interval) and over the entire range of composition (mole fractions). Experimental results for n-butanol, n-pentanol, and n-octanol obtained in this study are consistent with literature values, showing average absolute percentage deviation less than 0.11 %, 3.94 %, and 0.14 % for density, viscosity, and refractive index, respectively. The studied blends meet density and kinematic viscosity limits imposed by the diesel fuel standard (EN 590). Derived from the experimental data, excess molar volumes, viscosity deviations, and refractive index deviations are calculated. These deviation from ideality are fitted using the Redlich–Kister polynomial equation. Refractive index data of pseudo-binary blends are predicted using different models (Lorentz–Lorenz, Gladstone–Dale, Newton, Eykman, Heller, and Edwards). These models have low average absolute percentage deviation (less than 0.67%) for all studied pseudo-binary blends and temperature ranges (293.15 K–308.15 K), which shows they give excellent fitting results between measured data and calculated values.</p></div>","PeriodicalId":598,"journal":{"name":"International Journal of Thermophysics","volume":"46 2","pages":""},"PeriodicalIF":2.5,"publicationDate":"2025-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142939274","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Exploring Low-GWP Alternatives for Heat Pumps: A Drop-in Comparative Study of R1234yf/R600a and R134a 探索低gwp热泵替代方案:R1234yf/R600a和R134a的直接对比研究
IF 2.5 4区 工程技术
International Journal of Thermophysics Pub Date : 2025-01-09 DOI: 10.1007/s10765-024-03495-0
Giulia Lombardo, Davide Menegazzo, Laura Vallese, Michele De Carli, Fabio Poletto, Sergio Bobbo
{"title":"Exploring Low-GWP Alternatives for Heat Pumps: A Drop-in Comparative Study of R1234yf/R600a and R134a","authors":"Giulia Lombardo,&nbsp;Davide Menegazzo,&nbsp;Laura Vallese,&nbsp;Michele De Carli,&nbsp;Fabio Poletto,&nbsp;Sergio Bobbo","doi":"10.1007/s10765-024-03495-0","DOIUrl":"10.1007/s10765-024-03495-0","url":null,"abstract":"<div><p>The progressive phase-out of high-GWP refrigerants as mandated by the Kigali Amendment to the Montreal Protocol and the EU F-gas Regulation necessitates the exploration of sustainable alternatives within the HVAC&amp;R industry. A recent proposal by the Council and the European Parliament aims to significantly reduce Hydrofluorocarbons (HFCs) consumption by 2050, including specific bans on high-GWP fluorinated gases in heat pumps and small air conditioning units. Heat pumps, pivotal in mitigating climate change, are expected to see a significant rise in residential applications. However, R134a, widely employed in these systems, has a high GWP of 1530, highlighting the need for more eco-friendly substitutes. Hydrofluoroolefins (HFOs) and natural fluids, particularly hydrocarbons (HCs), have emerged as promising fourth-generation refrigerants due to their negligible ozone depletion potential (ODP) and very low global warming potential (GWP). Despite the potential of these new refrigerants, an optimal replacement for R134a in heat pumps has yet to be found. In this regard, this study investigates the potential of the low-GWP HFO/HC mixture R1234yf/R600a (0.85/0.15) as a drop-in replacement for R134a in water-to-water heat pumps. The research conducts a comparative analysis between R134a and the nearly-azeotropic mixture, assessing their performance under identical heating conditions across 20 different combinations of heat sink and heat source temperatures, ranging from 35 °C to 70 °C and from 10 °C to 20 °C respectively. The R1234yf/R600a mixture exhibited a lower pressure ratio and higher mass flow rates compared to R134a. Additionally, the mixture showed favorable performance in terms of power consumption and compressor outlet temperatures, with slightly lower COP compared to the baseline fluid. These findings suggest that with proper optimization, the R1234yf/R600a mixture could be a viable and sustainable alternative to R134a in residential heat pump applications.</p></div>","PeriodicalId":598,"journal":{"name":"International Journal of Thermophysics","volume":"46 2","pages":""},"PeriodicalIF":2.5,"publicationDate":"2025-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142939202","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Quest for a Single van der Waals Loop: A Four-Parameter Cubic Equation of State Tailored to a Reference Formulation for Propane 寻求单一范德瓦尔斯环:一个适合丙烷参考公式的四参数三次状态方程
IF 2.5 4区 工程技术
International Journal of Thermophysics Pub Date : 2025-01-09 DOI: 10.1007/s10765-024-03483-4
Jan Hrubý, Aleš Blahut
{"title":"Quest for a Single van der Waals Loop: A Four-Parameter Cubic Equation of State Tailored to a Reference Formulation for Propane","authors":"Jan Hrubý,&nbsp;Aleš Blahut","doi":"10.1007/s10765-024-03483-4","DOIUrl":"10.1007/s10765-024-03483-4","url":null,"abstract":"<div><p>Modern multiparameter equations of state (MP EOSs) enable accurate computation of thermodynamic properties of fluids in broad ranges of temperature and pressure. Between the saturated vapor and saturated liquid densities, a pressure vs. density isotherm computed with an MP EOS exhibits several oscillations with large amplitudes. This is not a problem for most engineering computations, because this portion of isotherm is replaced with a horizontal line, representing an equilibrium mixture of the vapor and liquid phases. However, for computing properties in metastable states, modeling phase interfaces with gradient theory, and certain models of fluid mixtures, an isotherm with a single maximum and a single minimum (single van der Waals loop) is needed. As a step toward an accurate, single-loop EOS, we propose a generalized four-parameter cubic (G4C) EOS. The four parameters are temperature functions which are fitted, at subcritical temperatures, to the second virial coefficient, saturation pressure, liquid density and compressibility, and, in the supercritical region, to the second virial coefficient and derivatives of pressure. Fitted data were generated from thermodynamic property formulation for propane (Lemmon et al. J Chem Eng Data 54:3141, 2009). The G4C EOS provides a representation of thermodynamic properties of propane in the gaseous, liquid, and supercritical regions, which is sufficiently accurate for the intended applications. The equation can be extrapolated to high temperatures. Between 85.5 K and 296 K, the density and compressibility of the saturated liquid are represented with an average absolute relative deviation (AARD) of, respectively, 0.04 and 0.25 percent, the density and compressibility of saturated vapor show AARD of 0.31 and 0.39 percent, and the saturation pressure deviates by 0.23 percent. Features to be improved in future are temperature dependencies of the third- and higher-order virial coefficients at low temperatures, the curvature of isotherms in the liquid region, liquid density at very high pressures, and the critical region. Developed G4C EOS was successfully used in a new mixture model (Hrubý Int J Thermophys 44:130, 2023) to model volumetric behavior and vapor–liquid equilibrium in asymmetric mixtures with propane as a low-volatile component.</p></div>","PeriodicalId":598,"journal":{"name":"International Journal of Thermophysics","volume":"46 2","pages":""},"PeriodicalIF":2.5,"publicationDate":"2025-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142939273","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
0
×
引用
GB/T 7714-2015
复制
MLA
复制
APA
复制
导出至
BibTeX EndNote RefMan NoteFirst NoteExpress
×
提示
您的信息不完整,为了账户安全,请先补充。
现在去补充
×
提示
您因"违规操作"
具体请查看互助需知
我知道了
×
提示
确定
请完成安全验证×
相关产品
×
本文献相关产品
联系我们:info@booksci.cn Book学术提供免费学术资源搜索服务,方便国内外学者检索中英文文献。致力于提供最便捷和优质的服务体验。 Copyright © 2023 布克学术 All rights reserved.
京ICP备2023020795号-1
ghs 京公网安备 11010802042870号
Book学术文献互助
Book学术文献互助群
群 号:481959085
Book学术官方微信