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International Journal of Thermodynamics
Journal Prestige (SJR): 0.233

Citation Impact (citeScore): 1
Number of Followers: 11

This is an Open Access Journal

Open Access journal
ISSN (Print) 1301-9724 - ISSN (Online) 2146-1511
Published by International Centre for Applied Thermodynamics

[1 journal]

3E Analysis of a Hybrid Biomass / Solar System for Power Generation and
Desalination
- Authors: Elisangela Leal; E. A. Teixeira
  Abstract: The study addresses global energy challenges by proposing a hybrid biomass and solar energy system for power generation and water desalination. A model is applied to two cities in Northeast Brazil (Natal-RN and Fortaleza-CE), targeting urban centers with waste and sunny coastal regions. Key variables include residue composition, heating value, and quantity, essential for energy efficiency assessment. Energy, exergy, and economic (3E) analyses using Scilab software compare four configurations: the base Rankine cycle, Rankine with an external superheater (ESH), Rankine with concentrated solar power (CSP), and Rankine with CSP integrated with desalination. Results show that higher pressures and temperatures enhance efficiency, reducing solar field area by 16% when pressure and temperature increase from 4.5 MPa/400°C to 6.5 MPa/500°C. Fortaleza-CE, with higher solar irradiation, requires smaller solar fields than Natal-RN. Integrating desalination into CSP cycles increases Levelized Cost of Energy (LCOE) by up to 7.6% and solar field area due to higher energy demands but provides potable water, with water recovery rates around 10% of seawater input. The findings underscore the importance of optimizing operating conditions and leveraging local solar resources to maximize socio-economic benefits.
  PubDate: Sat, 01 Mar 2025 00:00:00 +030
General Thermodynamically Unification of the First and Second Laws of
Thermodynamics
- Authors: Saeed Shahsavari; S. M. A Boutorabi
  Abstract: The unification of the first and second laws of thermodynamics into a single equation has long been a key goal in thermodynamic research. However, significant mathematical and physical challenges have hindered its achievement. In this paper, we go a step further and seek a general as well as completely thermodynamically unification of these laws. The generality, energy fundamental-based and statistical perspective of the Boltzmann entropy equation can provide a valuable solution to unify the first and second laws of classical thermodynamics. Here, “entropy generation function” is considered as a function that takes a measure of lost available work of any thermodynamic energy conversion system, and also “integrator function” is considered as a function that is applied for the mathematical unification. Also, the quasi-statistical approach of entropy is considered as an approach that studies macroscopic energy components instead of studying the energy of individual particles. So, in this paper, by applying the entropy generation function g, as a novel integrator function, we consider the second law as an equality. In the following, using a new quasi-statistical approach to the entropy with the same base as Boltzmann entropy equation, function g is derived. Finally, we extract two innovative general thermodynamically equations resulting from unification of the first and second laws of classical thermodynamics as well as a novel general thermodynamically unified second law equation is established. Contrary to what is common in classical thermodynamics, the established unified equations are sufficient for the thermodynamically analysis of physical processes, and there is no need to add any additional condition relation or non-thermodynamic quantity. In fact, we are looking for a general thermodynamically unification of the first and second laws, which is one of the highlights of this paper. Finally, a general mathematical-physical validation is presented and in the general case, it is shown that there are no contradictions in the established unified equations.
  PubDate: Sat, 01 Mar 2025 00:00:00 +030
Exact Thermodynamic Solution of Gas Behavior in Propellant Tanks and
Storage Capsules During Pressurization
- Authors: Mahdi Mohseni
  Abstract: The gas properties, particularly the pressure within the propellant tanks of a liquid-fueled rocket, play an essential role in the performance of the propulsion system. This study examines the thermodynamic behavior of the gas inside the propellant tanks and gas storage capsules of a class of pressurized systems. To this end, the governing thermodynamic equations were extracted, and exact thermodynamic solutions for the changes in the gas properties were obtained. The changes in the gas properties have been studied during the whole operation of the propulsion system, i.e. in the pre-pressurization period and before and after the gas cut-off time. A comparison of the analytical modelling results with the experimental data indicates a good agreement between the two, with the total mass of gas required for tank pressurization being approximately 4% higher than the experimental data. Additionally, the approximate changes in the throat area of the pressure-reducing valve were obtained. The simple thermodynamic model developed in this study allows for the rapid design and observation of the pressurization system's performance.
  PubDate: Sat, 01 Mar 2025 00:00:00 +030
Excess Molar Viscosities and Excess Molar Gibbs Energies of The Mixtures
of Tire Pyrolytic Oil + Diesel Fuel at 293.15 K and 303.15 K
- Authors: Ufuk Sancar Vural
  Abstract: Diesel-like fuel mixtures are obtained by blending the pyrolytic oil obtained from the pyrolysis of tires and diesel fuel. The excess thermodynamic properties of blended fuel mixtures give a preliminary idea about the transport, storage and combustion properties of the fuel mixture. In this study, pyrolytic oil and diesel fuel were mixed in different proportions at temperatures of 293.15 K and 303.15 K and their excess molar properties were determined. A positive deviation was observed in the excess molar volume and excess molar Gibbs energy values of the two-component mixture, and a negative deviation was observed in the excess molar viscosity values. Volumetric expansion and flow rate of the mixture were found to be higher at 303.15 K. It has been observed that at low pyrolytic oil concentrations, dispersive and physical forces are dominant between molecules, while at high pyrolytic oil concentrations, π-π interactions are more dominant for the molecules.
  PubDate: Sat, 01 Mar 2025 00:00:00 +030

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