Engineering Thermodynamics

A special issue of Applied Sciences (ISSN 2076-3417).

Deadline for manuscript submissions: closed (30 September 2019) | Viewed by 13383

Special Issue Editors


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Guest Editor
E.T.S. of Industrial Engineers, Department of Applied Mechanics and Project Engineering, University of Castilla-La Mancha, 02071 Albacete, Spain
Interests: concentrated solar power; thermal energy storage; solid particles as heat transfer fluid; beam-down reflector
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Guest Editor
Carlos III University of Madrid, Spain
Interests: particle technology; thermal energy storage; solar energy

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Guest Editor
Castilla-La Mancha University, Spain
Interests: energy efficiency; energy and buildings; HVAC systems

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Guest Editor
Renewable Energy Research Institute, Industrial Engineering School, Castilla – La Mancha University, Campus Universitario s/n, 02071 Albacete, Spain
Interests: heat exchangers; computational fluid dynamics; fluidized beds; rheometer; non-Newtonian fluids
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Engineering thermodynamics covers a wide variety of engineering processes. Among them, engineering thermodynamics is primary involved in renewable energy development, energy efficiency in different systems (buildings, transport and industry) and, in general, in any process where there is an interchange of energy. It also helps us to reduce the greenhouse effect and to reduce the global warming of our planet.

This Special Issue aims to cover different works where engineering thermodynamics plays an important role in understanding, modeling or optimizing different engineering processes and to provide the reader with a fresh and wide overview of the topic. The papers published can be either theoretical, experimental or numerical works, covering different research topics of interest in the interchange of energy related to renewable energies, energy storage, thermal properties of new fluids and materials, thermal engines, power plants, energy and exergy optimization, etc.

Prof. Dr. José A. Almendros-Ibáñez
Prof. Dr. Dra. Celia Sobrino
Prof. Dr. Juan F. Belmonte
Prof. Dr. Juan I. Córcoles-Tendero
Guest Editors

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Keywords

  • renewable energy
  • heat transfer
  • energy storage
  • thermal properties
  • energy efficiency
  • exergy analysis
  • combustion
  • thermal power plants
  • thermal engines
  • buildings simulation

Published Papers (4 papers)

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Research

24 pages, 2063 KiB  
Article
Heat Transfer Performance of Fruit Juice in a Heat Exchanger Tube Using Numerical Simulations
by Juan Ignacio Córcoles, Ernesto Marín-Alarcón and Jose Antonio Almendros-Ibáñez
Appl. Sci. 2020, 10(2), 648; https://doi.org/10.3390/app10020648 - 16 Jan 2020
Cited by 9 | Viewed by 3696
Abstract
Enhancing heat transfer rates in heat exchangers is essential in many applications, such as in the food industry. Most fluids used in the food industry are non-Newtonian, whose viscosity is not uniform, and depends on the shear rate and temperature gradient. This is [...] Read more.
Enhancing heat transfer rates in heat exchangers is essential in many applications, such as in the food industry. Most fluids used in the food industry are non-Newtonian, whose viscosity is not uniform, and depends on the shear rate and temperature gradient. This is important in the selection of equipment and type of processing. The aim of this work was to numerically simulate, with a non-Newtonian fluid in laminar regime, the heat transfer process in a tube with a curved elbow. The numerical model was validated with published correlations using water as heat transfer fluid. A commercially available fruit juice was used as a non-Newtonian fluid. Its rheological properties were measured using a Modular Compact Rheometer, as well as the activation energy. The difference between outlet temperature and inlet temperature was higher for the laminar simulation (approximately 4 °C) than for the turbulent one (approximately 0.7 °C). The highest dynamic viscosity values were found at the centre of the pipe (between 0.05 and 0.09 Pa·s), with the lowest values at the wall (0.0076 Pa·s). This behaviour is explained by the pseudoplastic condition of the fruit juice. The activation energy did not yield high values, showing a moderate viscosity variation with the temperature change. Full article
(This article belongs to the Special Issue Engineering Thermodynamics)
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18 pages, 6590 KiB  
Article
Supercritical CO2 Mixtures for Advanced Brayton Power Cycles in Line-Focusing Solar Power Plants
by Robert Valencia-Chapi, Luis Coco-Enríquez and Javier Muñoz-Antón
Appl. Sci. 2020, 10(1), 55; https://doi.org/10.3390/app10010055 - 19 Dec 2019
Cited by 21 | Viewed by 2937
Abstract
This work quantifies the impact of using sCO2-mixtures (s-CO2/He, s-CO2/Kr, s-CO2/H2S, s-CO2/CH4, s-CO2/C2H6, s-CO2/C3H8, s-CO2/C [...] Read more.
This work quantifies the impact of using sCO2-mixtures (s-CO2/He, s-CO2/Kr, s-CO2/H2S, s-CO2/CH4, s-CO2/C2H6, s-CO2/C3H8, s-CO2/C4H8, s-CO2/C4H10, s-CO2/C5H10, s-CO2/C5H12 and s-CO2/C6H6) as the working fluid in the supercritical CO2 recompression Brayton cycle coupled with line-focusing solar power plants (with parabolic trough collectors (PTC) or linear Fresnel (LF)). Design parameters assessed are the solar plant performance at the design point, heat exchange dimensions, solar field aperture area, and cost variations in relation with admixtures mole fraction. The adopted methodology for the plant performance calculation is setting a constant heat recuperator total conductance (UAtotal). The main conclusion of this work is that the power cycle thermodynamic efficiency improves by about 3–4%, on a scale comparable to increasing the turbine inlet temperature when the cycle utilizes the mentioned sCO2-mixtures as the working fluid. On one hand, the substances He, Kr, CH4, and C2H6 reduce the critical temperature to approximately 273.15 K; in this scenario, the thermal efficiency is improved from 49% to 53% with pure s-CO2. This solution is very suitable for concentrated solar power plants coupled to s-CO2 Brayton power cycles (CSP-sCO2) with night sky cooling. On the other hand, when adopting an air-cooled heat exchanger (dry-cooling) as the ultimate heat sink, the critical temperatures studied at compressor inlet are from 318.15 K to 333.15 K, for this scenario other substances (C3H8, C4H8, C4H10, C5H10, C5H12 and C6H6) were analyzed. Thermodynamic results confirmed that the Brayton cycle efficiency also increased by about 3–4%. Since the ambient temperature variation plays an important role in solar power plants with dry-cooling systems, a CIT sensitivity analysis was also conducted, which constitutes the first approach to defining the optimum working fluid mixture for a given operating condition. Full article
(This article belongs to the Special Issue Engineering Thermodynamics)
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23 pages, 10605 KiB  
Article
Economic Optimization of the Energy Supply for a Logistics Center Considering Variable-Rate Energy Tariffs and Integration of Photovoltaics
by Alex Ximenes Naves, Victor Tulus, Elaine Garrido Vazquez, Laureano Jiménez Esteller, Assed Naked Haddad and Dieter Boer
Appl. Sci. 2019, 9(21), 4711; https://doi.org/10.3390/app9214711 - 05 Nov 2019
Cited by 6 | Viewed by 2468
Abstract
The energy supplied by photovoltaic (PV) panels connected to the grid creates more flexibility for energy management; however, oversizing the PV system may result in an energy surplus, an essential factor to be considered during energy efficiency optimization. The economic analysis of energy [...] Read more.
The energy supplied by photovoltaic (PV) panels connected to the grid creates more flexibility for energy management; however, oversizing the PV system may result in an energy surplus, an essential factor to be considered during energy efficiency optimization. The economic analysis of energy supply systems for buildings and industry should include a detailed feasibility analysis and a life cycle perspective. Simulations were performed to quantify the potential savings when the excess of PV energy (surplus) is supposed to be exported to the grid by considering the net metering and net billing approaches. Our objective was to evaluate the electrical demand of a logistics center with pre-design modeling and simulation, and determine the adequate system configurations by considering the life cycle costing (LCC). We established a baseline and three alternative economic scenarios for optimization. Combining the use of TRNSYS 180 Simulation Studio and its optimization library component, GenOp (Generic Optimization Program), we simulated different options of grid energy contracts considering the variable tariffs and the integration with PVs. Based on the LCC, a single-objective optimization (SOO) process was performed. This approach allowed us to envisage possible configurations, reducing up to a quarter of annual grid energy consumption that represents savings of around 21% for the LCC in a timeframe of 20 years, reaching up to 39% when the export of the PV surplus energy is considered. The payback period of investments is below six years for the optimal scenarios. Full article
(This article belongs to the Special Issue Engineering Thermodynamics)
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20 pages, 4636 KiB  
Article
Thermoeconomic Analysis of Different Exhaust Waste-Heat Recovery Systems for Natural Gas Engine Based on ORC
by Guillermo Valencia, Jorge Duarte and Cesar Isaza-Roldan
Appl. Sci. 2019, 9(19), 4017; https://doi.org/10.3390/app9194017 - 25 Sep 2019
Cited by 35 | Viewed by 3662
Abstract
Waste-heat recovery (WHR) systems based on the organic Rankine cycle (ORC) improve the thermal efficiency of natural gas engines because they generate additional electric power without consuming more gas fuel. However, to obtain a cost-effective design, thermoeconomic criteria must be considered to facilitate [...] Read more.
Waste-heat recovery (WHR) systems based on the organic Rankine cycle (ORC) improve the thermal efficiency of natural gas engines because they generate additional electric power without consuming more gas fuel. However, to obtain a cost-effective design, thermoeconomic criteria must be considered to facilitate installation, operation, and penetration into real industrial contexts. Therefore, a thermo-economic analyses of a simple ORC (SORC), ORC with recuperator (RORC) and a double-pressure ORC (DORC) integrated with a 2 MW Jenbacher JMS 612 GS-N. L is presented using toluene as the organic working fluid. In addition, the cost rate balances for each system are presented in detail, with the analysis of some thermoeconomics indicator such as the relative cost difference, the exergoeconomic factor, and the cost rates of exergy destruction and exergy loss. The results reported opportunities to improve the thermoeconomic performance in the condenser and turbine, because the exergoeconomic factor for the condenser and the turbine were in the RORC (0.41 and 0.90), and DORC (0.99 and 0.99) respectively, which implies for the RORC configuration that 59% and 10% of the increase of the total cost of the system is caused by the exergy destruction of these devices. Also, the pumps present the higher values of relative cost difference and exergoeconomic factor for B1 (rk = 8.5, fk = 80%), B2 (rk = 8, fk = 85%). Full article
(This article belongs to the Special Issue Engineering Thermodynamics)
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