http://hdl.handle.net/10366/138605 2026-06-09T07:26:16Z 2026-06-09T07:26:16Z Santos Sánchez, María Jesús Medina Domínguez, Alejandro Mateos Roco, José Miguel Queiruga Dios, María Araceli http://hdl.handle.net/10366/171392 2026-05-15T00:02:14Z 2020-01-01T00:00:00Z

[EN]Sophomore students from the Chemical Engineering Degree at the University of Salamanca, are involved in a Mathematics course during the first semester and in an Engineering Thermodynamics course during the second one. When they participate in the latter they are already familiar with mathematical software to solve numerical methods problems, including non-linear equations, interpolation or differential equations. On one hand, we present in this paper some of the materials elaborated in both courses with the Wolfram Mathematica package, and on the other, the didactic organization of the Engineering Thermodynamics course. The objective of the experience is to increase the interrelationship between different subjects, to promote transversal skills, and to make the subject closer to real working procedures the students will find in their future careers. The satisfactory results of the experience are exposed in this work.

2020-01-01T00:00:00Z Santos Sánchez, María Jesús Miguel, Mario Queiruga Dios, María Araceli Hernández Encinas, María Ascensión http://hdl.handle.net/10366/171390 2026-05-15T00:02:12Z 2019-04-28T00:00:00Z

[EN]This article presents a Breakout played with students of the Master in Teaching of Compulsory Secondary Education and Higher Secondary School, at the University of Salamanca, as part of their training as future teachers. Both the difficulties and the advantages that this type of educational activities bring out are analyzed. Moreover, some possibilities of its possible utilization in the classroom, at different educational levels, are also discussed and presented.

2019-04-28T00:00:00Z Queiruga-Dios, Araceli Santos Sánchez, María Jesús Bullón Pérez, Juan José Hernández Encinas, Ascensión Gocheva-Ilieva, Snezhana Dias Rasteiro, Deolinda Demlova, Marie Gayoso-Martínez, Víctor Martín-Vaquero, Jesús Caridade, Cristina http://hdl.handle.net/10366/171387 2026-05-15T00:02:09Z 2018-04-20T00:00:00Z

[EN]The team that has developed this project is part of a consortium of several European institutions that have joined with a common goal: to help the current engineering teachinglearning system, so that to make possible a competencies-based assessment. Moreover advocacy and networking will be part of the consortium activities during the whole project. RULES_MATH acronym corresponds to ‘New rules for assessing mathematical competencies’, and that is exactly what we propose: to work with the mathematical competencies, specifically try to incorporate them into the assessment process. We focus on science and engineering degrees, since in all these studies several Mathematics courses are part of their curriculum, mainly in the first couple of years. In this paper we present one of our first activities that we want to achieve under the project: the selection of several tools and rules that will make possible an assessment and evaluation according to our high education common European space. These ideas are part of the objectives of promoting and institutionalizing good teaching practices and the enhancement of teaching materials. Other goals are to improve the dissemination of academic activities to the business world, administrations and society in general.

2018-04-20T00:00:00Z Santos Sánchez, María Jesús Merchán Corral, Rosa Pilar Medina Domínguez, Alejandro Calvo Hernández, Antonio http://hdl.handle.net/10366/171386 2026-05-15T00:01:24Z 2015-01-01T00:00:00Z

[ES]Desde el punto de vista termodinámico, se realiza el estudio dinámico de una planta termosolar híbrida de tipo Brayton: un tipo de plantas de generación de energía eléctrica con las que se pretende reducir el consumo de combustible y la emisión de contaminantes, así como conseguir una potencia neta constante. Lo más característico de estas plantas híbridas es que emplean dos fuentes principales de energía para su funcionamiento: la energía termosolar, proveniente de un campo de heliostatos que recoge y concentra la radiación solar recibida dirigiéndola hacia una torre central; y la energía que se origina en la oxidación de combustibles fósiles dentro de la cámara de combustión. Con `dinámico’ se indica que se realiza un análisis de los parámetros de salida de la planta con la hora solar y con la estación del año. En primer lugar se expone brevemente en qué consiste una planta termosolar de receptor central (o planta CRS), además de especificar los objetivos del trabajo. Posteriormente se presenta el modelo termodinámico que se ha desarrollado, así como su validación. Finalmente se presentan y analizan los resultados de la simulación y las conclusiones obtenidas.

2015-01-01T00:00:00Z Santos Sánchez, María Jesús Merchán Corral, Rosa Pilar García Ferrero, Judit Pérez Gallego, David González Ayala, Julián Medina Domínguez, Alejandro Calvo Hernández, Antonio http://hdl.handle.net/10366/171089 2026-04-28T00:02:10Z 2025-07-02T00:00:00Z

[EN]We live in a critical moment for humanity in which energy consumption is growing as the population grows, while fossil fuel resources are diminishing. It is time to bet on the search for renewable energy sources. Here arises, as researchers, the challenge of making these sources e cient and adapting them to the real demand. If we were able to harness all the solar energy that our planet receives, it would be enough to supply our current demand. And here we come into play as engineers, physicists and of course! Mathematicians. On the one hand, regarding the production of renewable electrical energy, one of the main lines of research that we develop at the Energy Optimization, Thermodynamics and Statistical Physics Group of the University of Salamanca is the simulation of Concentrated Solar thermal Power (CSP) such as central tower plants, analyzing possible aspects to improve the e ciency of the subsystems involved. And, on the other hand, to try to adapt the production to the demand, to study di erent aspects of thermal storage. All these processes are simulated by means of di erent programs such as Mathematica, Python, Matlab, etc. And, of course, mathematical tools such as analytical and numerical integrals, nonlinear equation solving, di erential equation, interpolations, multiobjective optimization, etc., are used for this purpose. Let's see how mathematics becomes a magic wand that transforms this desire to harness the energy coming from the sun into a reality.

2025-07-02T00:00:00Z Pérez-Gallego, David González Ayala, Julián Medina Domínguez, Alejandro Anvari, Simin Calderón-Vásquez, I. Cardemil, J.M. Calvo Hernández, Antonio http://hdl.handle.net/10366/169838 2026-02-18T01:01:32Z 2026-01-01T00:00:00Z

[EN]Adiabatic compressed air energy storage is a promising, in-development technology for storing renewable energy, for instance, from wind parks or photovoltaic installations. This work presents a multi-objective thermoeconomic optimization analysis. It is based on a dynamic model of the plant’s thermodynamic performance, in which the dynamics of the thermal energy storage (packed-bed type) and the charge and discharge processes of the air reservoir are solved in detail. A plant configuration, as determined from previous work in our group, with a priori good round-trip efficiencies (around 0.76–0.78), is considered the starting point. It encompasses two-stage compression and expansion trains, along with two radial packedbeds (utilizing either sensible or phase-change materials) to capitalize on the cooling between compression steps. In the developed optimization procedure, the levelized cost of storage (LCoS) and the total capital expenditure (CAPEX) are taken as key performance indicators. The decision variables include, among others, mass flows, thermal energy storage dimensions, maximum and minimum cavern pressures, and the symmetry of the pressure ratios between compressors and turbines. The optimization procedure uses an NSGA-II genetic algorithm. One of the main novelties of the work is that accurate dynamic simulations have been used to obtain Pareto fronts. They are analyzed from different perspectives: the size, geometry, and materials of the packedbeds; the type of compressor (axial or centrifugal); energetic factors such as input and output energy and power; the maximum pressures in the cavern; and the mass flows in the charge and discharge processes. Values of LCoS are calculated with precision using realistic input data, resulting in approximately 80 e/MWh for a plant capable of storing 600 MWh (reference power of 200 MW for charge periods of 3 h) and electricity prices during charge of 50 e/MWh. The specific parameters and configurations that lead to those LCoS levels are made explicit. Furthermore, the influence of cavern costs, charging electricity prices, and idle time is analyzed in detail.

2026-01-01T00:00:00Z García Ferrero, Judit Merchán Corral, Rosa Pilar Moctezuma-Hernandez, J.A. Pérez-Gallego, David Anvari, Simin González Ayala, Julián Calvo Hernández, Antonio Mateos Roco, José Miguel Santos Sánchez, María Jesús Medina Domínguez, Alejandro http://hdl.handle.net/10366/168406 2026-01-21T11:24:59Z 2025-12-01T00:00:00Z

[EN]Parabolic dish collectors (PDCs) focus solar radiation onto a small area, minimizing the heat-loss area of the solar receiver and improving the heating of the working fluid. This fluid usually drives a Stirling-like or micro-gas turbine (Brayton-like) power generator. PDCs, initially intended for small-capacity applications, are well-suited for electricity and heat generation in remote rural areas, working alone and/or as parabolic dish arrays. PDCs have received considerable attention among solar thermal collectors due to their high concentration ratios and the high temperatures they achieve. However, nowadays, they are the least developed and least commissioned among concentrated solar power configurations, lacking a well-established technology. This review aims to compile the evolution of research on PDCs over recent years from a global perspective and is mainly focused on the subsystems constituting a PDC plant, their integration, and overall system optimisation, thereby addressing a gap in the current literature. Methodological tools used in the field are comprehensively revised, and recent related projects are summarized. Some innovative and promising applications are also highlighted.

2025-12-01T00:00:00Z Pérez-Gallego, David González Ayala, Julián Medina Domínguez, Alejandro Calderón-Vásquez, I. Calvo Hernández, Antonio http://hdl.handle.net/10366/167887 2026-01-21T11:25:59Z 2026-01-01T00:00:00Z

[EN]This work analyzes several adiabatic compressed air energy systems (ACAES) configurations with a thermodynamic time-dependent model. ACAES systems allow for large-scale energy storage, with fast response times and high output power. However, despite being a promising technology, few works have been done in systematically modeling the unsteady dynamic operation and integrating all components in ACAES plants. The developed model in this work can simulate the thermodynamic behavior of the plant components individually and their integration into an ACAES plant as a whole. The influence of an additional organic Rankine cycle on the round-trip efficiency of the plant is also studied. A comparison of the performance of several plant arrangements is obtained under a unified framework, filling an observed gap in the reported literature. Particular results include the centrifugal compression train working along the peak-line efficiency, the analysis and comparison of pressure drops in packed-bed subsystems used as thermal energy storage: axial or radial, and the optimization of the inlet pressure in the Rankine evaporator. As a conclusion, pressure drops in the radial packed-beds are found to be about 20% lower than in axial packed-beds, and global round-trip efficiencies can be improved by about 2%–3% (reaching values of 0.78) by selecting a suitable symmetrical configuration or by coupling a Rankine cycle. This increase in efficiency is due to the notable reduction in destroyed exergy when an optimized organic Rankine is used for heat recovery instead of discharging heat by an intercooler device.

2026-01-01T00:00:00Z González Ayala, Julián Pérez-Gallego, David Medina Domínguez, Alejandro Mateos Roco, José Miguel Calvo Hernández, Antonio Velasco Maíllo, Santiago Angulo-Brown, Fernando http://hdl.handle.net/10366/166836 2026-01-21T11:27:13Z 2025-08-01T00:00:00Z

[EN]In celebration of 50 years of the endoreversible Carnot-like heat engine, this work aims to link the thermodynamic success of the irreversible Carnot-like heat engine with the stability dynamics of the engine. This region of success is defined by two extreme configurations in the interaction between heat reservoirs and the working fluid. The first corresponds to a fully reversible limit, and the second one is the fully dissipative limit; in between both limits, the heat exchange between reservoirs and working fluid produces irreversibilities and entropy generation. The distance between these two extremal configurations is minimized, independently of the chosen metric, in the state where the efficiency is half the Carnot efficiency. This boundary encloses the region where irreversibilities dominate or the reversible behavior dominates (region of success). A general stability dynamics is proposed based on the endoreversible nature of the model and the operation parameter in charge of defining the operation regime. For this purpose, the maximum ecological and maximum Omega regimes are considered. The results show that for single perturbations, the dynamics rapidly directs the system towards the success region, and under random perturbations producing stochastic trajectories, the system remains always in this region. The results are contrasted with the case in which no restitution dynamics exist. It is shown that stability allows the system to depart from the original steady state to other states that enhance the system’s performance, which could favor the evolution and specialization of systems in nature and in artificial devices.

2025-08-01T00:00:00Z Anvari, Simin Medina Domínguez, Alejandro Merchán Corral, Rosa Pilar Calvo Hernández, Antonio http://hdl.handle.net/10366/166442 2025-07-15T00:01:24Z 2025-11-01T00:00:00Z

[EN]This review provides a comprehensive analysis of the critical challenges and recent advancements related to photovoltaic (PV), biomass gasification (BG), and energy storage (ES) technologies, beginning with technology- specific developments and progressing to their integration in hybrid configurations for power generation and multigeneration systems. Major challenges identified include PV intermittency and limited forecasting accuracy, short ES lifespan and scalability constraints, and persistent BG issues such as tar formation, feedstock variability, and high operational costs. Further difficulties arise during hybridization, including poor control synchroniza- tion, high capital costs, and the lack of robust, context-specific sustainability assessments. To address these barriers, this review synthesizes insights into three strategic pillars: (1) technological integration, including modular system design and advanced storage solutions, (2) advanced control strategies featuring AI-enabled energy management and demand-side optimization, and (3) comprehensive sustainability assessment frame- works grounded in life cycle analysis and socio-economic metrics. Original contributions include the develop- ment of three structured conceptual frameworks: one for guiding system-level hybridization, another for step-by- step implementation in multigeneration settings, and a third for enhancing sustainability, policy integration, and innovation pathways. The review concludes with a roadmap connecting theory to practice through smart grids, circular economy principles, and region-specific deployment strategies to support resilient, cost-effective, and environmentally sustainable energy systems.

2025-11-01T00:00:00Z García Ferrero, Judit Santos Sánchez, María Jesús Medina Domínguez, Alejandro Calvo Hernández, Antonio http://hdl.handle.net/10366/165961 2026-01-21T11:28:16Z 2025-01-01T00:00:00Z

[EN]Concentrated Solar Power (CSP) systems are among the most promising renewable energy technologies in the energy transition scenario. Parabolic dish collectors (PDCs) mainly gather solar power and concentrate it onto a receiver located at the focus of a reflecting paraboloid. They reach the highest concentration factor among CSP configurations. Thus, temperatures even above 1000°C can be achieved. Traditionally, these systems were devoted to producing electricity through a thermodynamic cycle running with a fluid heated up at the receiver working either alone or integrated within micro-cogeneration energy systems or smart grids. However, provided the high temperature these systems can achieve, a wide range of innovative applications related to thermal energy production are emerging. Combined heat and power, water desalination, synthetic fuel, hydrogen production, or thermal energy storage purposes constitute some examples of those new challenging uses. Besides aiming to decentralize electric energy production, parabolic dish collectors can compete or be hybridized with photovoltaic systems to fulfill distributed energy production demand. This work addresses theoretical and practical issues concerning the above novel and challenging applications, filling a gap in the current literature on the prospects for solar parabolic dish collectors.

2025-01-01T00:00:00Z Moctezuma-Hernandez, J.A. Merchán Corral, Rosa Pilar Roco, J. M. M. http://hdl.handle.net/10366/165888 2025-05-30T00:01:21Z 2025-01-01T00:00:00Z

[EN]A study of the integration of a supercritical CO2 hybrid Brayton–Organic Rankine Cycle (ORC) with a Concentrated Solar Power (CSP) system using a particle receiver is presented. It focuses on evaluating the energy and exergy performance of the system to improve its efficiency and reduce fuel consumption. The particle receiver uses a mixture of silicon carbide and air as the working fluid, allowing operation at higher temperatures suitable for coupling with the supercritical CO2 Brayton cycle. Detailed thermodynamic models were developed using Mathematica and Engineering Equation Solver (EES) to simulate the behavior of the system under various conditions. The results show that coupling the particle receiver with the hybrid Brayton cycle significantly reduces fuel consumption by 63.2%. The exergy analysis shows that the highest exergy destruction occurs in the heat exchangers of the entire system, indicating potential areas for further efficiency improvements. The study also highlights the critical role in system performance of the ORC working fluid used in the bottoming cycle. Among the fluids tested, R600a was found to be the most effective, providing the highest efficiency under the considered conditions. The results highlight the potential of integrating particle receivers into CSP systems to improve both the energy efficiency and sustainability of power generation, and thus, it represents a promising approach for achieving more effective and sustainable power generation.

2025-01-01T00:00:00Z Hassani, Samir Arrif, Toufik Guermoui, Mawloud Yassaa, Noureddine Belaid, Abdelfetah Merchán Corral, Rosa Pilar Bezza, Badraddine A.Taylor, Robert Mekhilef, Saad http://hdl.handle.net/10366/165887 2025-05-30T00:01:23Z 2025-01-01T00:00:00Z

[EN]The integration of solar and gas turbine technologies through hybridization emerges as a promising approach to enhance the sustainability of power generation systems. However, the design process for such hybrid systems is challenging, particularly in terms of optimization and decision-making strategies. In this research, a case study of redesigning of an existing gas power plant by integrating a heliostat field and a central air receiver for preheating purposes has been presented. To accurately adjust the critical parameters of the hybrid solar gas power plant, a tri-objectives optimization approach was employed using two advanced optimization methods: Non-dominated Sorting Genetic Algorithm III and Multi-Objective Grasshopper Optimization Algorithm. Furthermore, the hybrid Fuzzy Analytic Hierarchy Process and The Technique for Order of Preference by Similarity to Ideal Solution decision-making method has been employed to help select the optimal design points from various scenarios and priorities. The chosen design for the hybrid solar-gas power plant showcases an efficient heliostat field footprint, a competitive LCOE of , achieves an annual reduction in natural gas consumption by , and mitigates CO2 emissions by (,).Thus, this study presents a persuasive example of a low-carbon technological solution, offering a promising strategy for the ongoing energy transition in the Middle East and North Africa (MENA) region.

2025-01-01T00:00:00Z Pérez-Gallego, David González Ayala, Julián Medina Domínguez, Alejandro Calvo Hernández, Antonio http://hdl.handle.net/10366/163948 2026-01-21T11:29:17Z 2025-01-01T00:00:00Z

[EN]The need for large-scale energy storage in the context of renewable electricity production worldwide is evident. Among the various energy storage methods, thermal energy storage stands out. It is independent of geographical location, allows high storage capacities, does not require scarce materials, and is cheaper than its direct competitors. Currently, several technologies are being intensively developed. In some of them, packed-bed systems play a central role: a heat transfer fluid heats up or releases heat from a porous solid that acts as a thermal energy reservoir. This work compiles their application to concepts such as concentrated solar power, pumped thermal energy storage, and compressed or liquid air energy storage. Different physical models with diverse rfinement degrees and the corresponding computational schemes are comprehensively presented. Comparison with previous experimental works includes gas or liquid heat transfer fluids, sensible or latent heat transfers, and a wide range of temperature levels. It is shown that the continuous 1D solid phase model solved with an implicit Euler method provides satisfactory results with a reasonable computing time for various systems. The ifluence of time step and spatial mesh is surveyed, as well as that of pressure drops. Efficiencies and stored energies are calculated for some particular cases, and sensitivity analysis is presented, including parameters such as fluid velocity in discharge and storage time. Concerning the latter, discharge efficiencies for long-time storage (between 10 and 15 h) are fairly good, between 0.39 and 0.20.

2025-01-01T00:00:00Z Montes López, Estrella Santos Sánchez, María Jesús Jiménez Sánchez, Elena http://hdl.handle.net/10366/163947 2026-01-21T11:29:53Z 2022-01-01T00:00:00Z

[EN]Online education due to COVID-19 confinement impacted the use of the Information and Communication Technology (ICT) in Spain, where it was poorly implemented. The aim of this paper was to inspect the methodological changes in Physics and Chemistry teaching during the confinement as well as in the ICT use and the lockdown impact afterwards. For this purpose, an online survey was administered by email to the Physics and Chemistry teachers of three provinces of Spain. Based on the analysis, the most widely used methodology was the traditional one. Still, during the lockdown, its use decreased, and others, such as the flipped classroom, increased significantly. Other adaptations included increasing the use of virtual simulations and self-learning by the student. It can be outlined the incorporation of new tools such as WebQuests, the smartphone, or online education platforms, whose use has continued. The ICT was used for new functionalities such as evaluation or answering student questions. According to the respondents, the lockdown had entailed that they strengthen implementation of ICT. In conclusion, there have been changes that have remained in the Physics and Chemistry didactic and in the ICT use due to the lockdown situation.

2022-01-01T00:00:00Z Petrollese, Mario Marchionni, Matteo Merchán Corral, Rosa Pilar Migliari, Luca Cau, Giorgio http://hdl.handle.net/10366/163839 2026-01-21T11:30:31Z 2025-01-01T00:00:00Z

[EN]In this paper, four main configurations of a Rankine-based Pumped Thermal Energy Storage (PTES) system are proposed and compared in terms of achievable electrical and exergy roundtrip efficiency and energy density. The analysis considers a conventional setup employing commercial heat pumps and Organic Rankine Cycle (ORC) systems integrated with a Thermal Energy Storage (TES) unit as reference. The initial findings indicate that offthe- shelf systems result in roundtrip efficiencies lower than 40%, even under optimal high-temperature conditions at the heat pump evaporator inlet. This is primarily due to significant exogenous exergy destructions inherent in the commercial equipment. The study then explores upgraded alternatives to the reference PTES configuration, focusing on optimizing the heat pump layout and selecting non-conventional working fluids. This optimization process includes evaluating various working fluids, where n-hexane is identified as the optimal choice for achieving the highest electrical and exergy roundtrip efficiencies, particularly at evaporator inlet temperatures above 60◦C. For lower temperature ranges, acetone emerges as a more suitable fluid due to its favorable thermodynamic properties. Further enhancements are made by optimizing the ORC layout, specifically through the introduction of an additional thermal storage tank and improved heat exchangers. These modifications are aimed at minimizing heat transfer losses and thereby boosting the overall system performance. With these changes, the PTES system's roundtrip efficiency reaches approximately 70%. The most advanced configuration integrates the heat pump and ORC systems into a single assembly, utilizing the working fluid not only for energy transfer but also as a storage medium. This integration reduces the number of required components and further increases efficiency. As a result, roundtrip efficiencies of about 80% are achieved, representing a significant advancement over current commercial systems.

2025-01-01T00:00:00Z