https://hdl.handle.net/10259/8984 2026-04-27T19:58:33Z https://hdl.handle.net/10259/11457 High-Pressure Volumetric Properties of the Binary Mixtures (Di-isopropyl Ether + n-Heptane or Methylcyclohexane) Dakkach, Mohamed; Rubio Pérez, Gabriel; Alaoui, Fatima E. M.; Muñoz Rujas, Natalia; Aguilar Romero, Fernando; Montero García, Eduardo This work reports the experimental density data for the binary mixtures of n-heptane or methylcyclohexane + di-isopropyl ether, measured over the full composition range between 0.1 and 140 MPa, and for temperatures from 298.15 to 393.15 K, by means of a vibrating tube densitometer calibrated with an uncertainty of 0.0007 g·cm–3. Then, the experimental density data were fitted using a Tait-like equation to derive mixing thermodynamic coefficients, including the isobaric expansivity and isothermal compressibility. Finally, the excess volumes of the abovementioned binary mixtures were calculated, and their nonideal behavior was investigated. 2020-10-01T00:00:00Z https://hdl.handle.net/10259/11444 Isobaric Vapor–Liquid Equilibria at 50.0, 101.3, and 200.0 kPa. Density and Speed of Sound at 101.3 kPa and 298.15 K of Binary Mixtures HFE-7100 + 2-Propanol Muñoz Rujas, Natalia; Rubio Pérez, Gabriel; Montero García, Eduardo; Aguilar Romero, Fernando Isobaric vapor–liquid equilibria (VLE) at 50.0, 101.3, and 200.0 kPa, have been measured for the binary system methyl nonafluorobutyl ether (x1) HFE-7100 + (1 – x1) 2-propanol. Thermodynamic consistency was checked by applying the Wisniak point to point and area tests, as well as the Fredenslund point to the point test. Vapor–liquid equilibrium data have been correlated by means of Wilson, NRTL, and UNIQUAC equations. The three binary systems show positive azeotropes at every measured pressure. Densities and speeds of sound were determined experimentally at 101.3 kPa and at 298.15 K. Excess volumes, isentropic compressibilities, and deviations in isentropic compressibility were calculated from experimental data. The Redlich–Kister polynomial was used to correlate excess properties upon mixing, showing a good agreement between experimental and calculated values. 2020-05-01T00:00:00Z https://hdl.handle.net/10259/11443 Consistent DSC and TGA Methodology as Basis for the Measurement and Comparison of Thermo-Physical Properties of Phase Change Materials Müller, Lukas; Rubio Pérez, Gabriel; Bach, Andreas; Muñoz Rujas, Natalia; Aguilar Romero, Fernando; Worlitschek, Jörg Measuring thermo-physical properties of phase change materials (PCM) in a consistent and reliable manner is essential for system layout of thermal energy storages and correspondingly material selection. Only if basic properties are assessed in a comparable way a selection process leads to the top candidate for any given application and thus enhances market penetration of renewable energy sources coupled with thermal energy storage. In this study, we focus on differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) as basic assessment techniques and develop consistent measurement procedures to create a database with comparable results. We show consistency of the measured results through analysis of coefficient of variation (CV), being in the mean 1.69%, 0.05%, 0.06% and 4.00% for enthalpy, melting onset, melting peak and maximum operating temperature, respectively. Overall, 23 PCM have been measured with the presented methodology, which was mainly possible due to the reduced measurement and preparation time per PCM compared to standard techniques, while achieving similar accuracy and precision. 2020-10-01T00:00:00Z https://hdl.handle.net/10259/11440 Evolution of the Study of Phase Diagram of Binary and Ternary Mixtures Involving Fatty Acid Esters Rubio Pérez, Gabriel; Muñoz Rujas, Natalia; Aguilar Romero, Fernando; Ravotti, Rebecca; Müller, Lukas; Montero García, Eduardo Interest in phase change materials keeps on rising as thermal energy storage grows in popularity in the scientific community as a promising complement for renewable energies in the future. Extending the possibilities beyond pure compounds, the use of mixtures (especially eutectics) widens the range of suitable phase change materials (PCM) available in the market. However, a precise knowledge of the mixtures’ phase behavior is required, making phase diagrams the most appropriate tools to follow. The aim of this work is to collect and analyze published literature concerning the phase diagrams of fatty acid esters mixtures, which constitute promising candidates as PCM due to their attractive properties, such as high latent heat, chemical stability and the possibility of extracting them from vegetable and animal oils. The topic appears as a still open scientific field, where further studies need to be performed to complete, complement and perfect the currently available information. 2021-01-01T00:00:00Z