Ricardo Chacartegui | Universidad de Sevilla (original) (raw)

Papers by Ricardo Chacartegui

Energy Conversion and Management, 2021

Abstract The present work proposes integrating a high-temperature thermochemical energy storage c... more Abstract The present work proposes integrating a high-temperature thermochemical energy storage cycle to boost the solar contribution in solar combined cycles. The main feature of the plant is the possibility of storing solar energy at a very high temperature and releasing it on demand to drive the combined cycle in the absence of solar radiation. Based on the reversible calcination-carbonation of CaCO3/CaO, the Calcium-looping process is proposed since it allows power production above 900 °C by using cheap, non-toxic and widely available raw materials (i.e. limestone or dolomite). Based on an air-open and a CO2-closed combined cycle, two potential configurations are modelled and analysed, including designing a 360° solar field with a 200-meter tower. The novel solar combined cycle analyzed in the present work enhances the annual solar share above 50%, whilst the current state-of-the-art technology is below 15%. From actual solar irradiation data and clustering analysis, results show overall plant efficiencies over 45% (considering off-design performance) with a very high dispatchability, which justifies the interest in further developing this novel cycle.

With educational aims a program in MATLAB has been developed that simulates a zone combustion mod... more With educational aims a program in MATLAB has been developed that simulates a zone combustion model of compression ignition engine and submodels for the inlet and exhaust processes, for the blow by, the exhaust emissions and the mechanical losses. For the validation of the model the results with the real ones of several engines have been observed. The greater differences appear for high rpm where the dynamics effects, not considered by this model, are more important Keyword: compression ignition engine, MDID. 1.Introduccion La formación docente de los alumnos de ingeniería en las asignaturas vinculadas a los motores alternativos debe incluir como una parte significativa los aspectos prácticos o experimentales. El elevado coste de los laboratorios dedicado a los motores alternativos y la excesiva dedicación para la realización de los ensayos fomenta la utilización de software para complementar la formación practica. Este trabajo presenta un modelo integral para MDID implementado en M...

Libro de Actas del XVI Congreso Iberico y XII Congreso Iberoamericano de Energia Solar, 20 – 22 d... more Libro de Actas del XVI Congreso Iberico y XII Congreso Iberoamericano de Energia Solar, 20 – 22 de junio de 2018 Madrid, Espana

Energy and Buildings, 2016

Abstract Building sector is responsible for 40% of European energy consumption, of which heating ... more Abstract Building sector is responsible for 40% of European energy consumption, of which heating and cooling account for around 70%. Moreover, 75% of buildings for 2050 are already built in Europe. On the road to a sustainable energy transition, this article develops a multi-criteria assessment methodology for the environmental, economic and social evaluation of different residential energy retrofit solutions, based on effectiveness indices. This methodology allows improving the decision management in residential energy retrofitting by identifying the most effective solutions according to the requirements and needs of each intervening agent (citizens, public administrations and private promoters). The methodology is based on the integrated analysis of environmental, economic and social variables. It is applied to a Mediterranean case study from Southern Spain built in 1955. As part of methodology, survey data from the different stakeholders were collected, identifying the keys that condition the viability of the measures. The results show that measures with few inconveniences to tenants, investment costs below 2000 ⿬/dwelling and payback periods below 15 years are the most viable by end-users⿿ implementation in the Mediterranean area, but between them, only efficient heat pumps allow achieving more than 45% of CO 2 emissions reduction (with a payback period of 6 years).

Journal of Power Sources, 2009

This paper presents a new design for high temperature fuel cell and bottoming thermal engine hybr... more This paper presents a new design for high temperature fuel cell and bottoming thermal engine hybrid systems. Now, instead of the commonly used gas turbine engine, an externally fired-Stirling-piston engine is used, showing outstanding performance when compared to previous designs. Firstly, a comparison between three thermal cycles potentially usable for recovering waste heat from the cell is presented, concluding the interest of the Stirling engine against other solutions used in the past. Secondly, the interest shown in the previous section is confirmed when the complete hybrid system is analyzed. Advantages are not only related to pure thermal and electrochemical parameters like specific power or overall efficiency. Additionally, further benefits can be obtained from the atmospheric operation of the fuel cell and the possibility to disconnect the bottoming engine from the cell to operate the latter on stand alone mode. This analysis includes on design and off design operation.

AIP Conference Proceedings

A novel integrated model is used to evaluate the technical feasibility of a large scale Concentra... more A novel integrated model is used to evaluate the technical feasibility of a large scale Concentrating Solar Power (CSP) plant with thermochemical energy storage based on the Calcium-Looping (CaCO 3 /CaO) process. Instead of using a solar particle receiver to carry out the calcination of limestone, as the usual solution considered in previous literature, this work proposes an indirect calcination system based on using a pressurized Heat Transfer Fluid (HTF) heated up inside a tubed volumetric cavity receiver, to heat indirectly the particles for calcination to take place in an Entrained Flow (EF) reactor. After the reactor, the HTF follows a typical closed combined cycle path for power production before entering again in the receiver. On the other hand, the CaO particles and CO 2 are stored for power production under demand. Results show that full calcination of 10 kg/s can be achieved in a 51 m length and 2.5 m diameter downer reactor from an HTF releasing 17.2 MWth at temperatures higher than 1100ºC. This opens a promising research line for the development of systems based on materials calcination from renewable energies. 178 1) Several CSP-CaL process schemes have been proposed in the last years (2). Most of the equipment involved, such as solid-gas reactors, conveying systems and heat exchangers are well-known at large industrial scale as calcination

RESUMEN. El presente trabajo se ocupa del modelado lluidodinámico de un compresor de seis cilindr... more RESUMEN. El presente trabajo se ocupa del modelado lluidodinámico de un compresor de seis cilindros dispuestos en W por medio de un modelo matemático O dimensional de avance temporal. basado en la metodología "Filling and Emptying". Para ello. se estudia su configuración geométrica ()ara poder así establecer una discretización espacial del mismo. se le aplican las ecuaciones básicas a dicho modelo teniendo en cuenta las particularidades del fluido de trabajo y se ensayan experimentalmente las válvulas para representar el flujo a través de ellas. Todo lo anterior se integra en un algoritmo de resolución para poder enjuiciar la bondad del modelo comparándolo con unos resultados experimentales sobre una máquina real. Una vez validado. se varían algunos parámetros para optimizar las variables fundamentales potencia consumida y gasto suministrado.

In this work a numerical analysis of meridional flow in axial turbomachinery has been performed a... more In this work a numerical analysis of meridional flow in axial turbomachinery has been performed applying the actuator disk theory. A numerical tool for non compressible flows was implemented based on the actuator disk theory, improving the results from the simple radial equilibrium analysis. Later on the model was also extended to the analysis for compressible flows under the actuator disk theory.

Chemical engineering transactions, 2018

Thermochemical reactions have a great potential for energy storage and transport. Their applicati... more Thermochemical reactions have a great potential for energy storage and transport. Their application to solar energy is of utmost interest because the possibility of reaching high energy densities and seasonal storage capacity. In this work, thermochemical energy storage of Concentrated Solar Power (CSP) based on an ammonia looping (AL) system is analysed. The AL process for energy storage is based on the reversible reaction of ammonia to produce hydrogen and nitrogen. Concentrating solar energy is used to carry out the decomposition endothermic reaction at temperatures around 650 oC, which fits in the range of currently commercial CSP plants with tower technology. The stored energy is released through the reverse exothermic reaction. Our work is focused on energy integration in the system modelled by pinch analysis to optimize the process performance and competitiveness. As result a novel configuration is derived which is able to recover high-temperature heat for electricity product...

Journal of Building Engineering, 2021

Journal of Cleaner Production, 2020

This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Renewable and Sustainable Energy Reviews, 2019

Energy storage based on thermochemical systems is gaining momentum as potential alternative to mo... more Energy storage based on thermochemical systems is gaining momentum as potential alternative to molten salts in Concentrating Solar Power (CSP) plants. Several systems have been proposed in the last years, mainly based on hydroxides, organic compounds, carbonates, metal redox, hydrides, ammonia or sulfur. This work is a detailed review about the promising integration of a CaCO3/CaO based system, the so-called Calcium-Looping (CaL) process, in CSP plants with tower technology. The CaL process relies on low cost, widely available and non-toxic natural materials (such as limestone or dolomite), which are necessary conditions for the commercial expansion of any energy storage technology at large scale. A comprehensive analysis of the advantages of this process and challenges to be faced for it to reach a commercial scale is carried out. The review includes a deep overview of reaction mechanisms and process integration schemes proposed in the recent literature. In addition, the technological maturity and potential of the process is assessed. The direction towards which future works should be headed is discussed. CO2 (g) CALCINER CaCO3 (s) CaO (s) + CO2 (g) ΔHr 0 = +178 kJ/mol CaO (s) HEAT EXCHANGER NETWORK CO2 COMP CO2 storage CaCO3/CaO storage CaO storage CARBONATOR CaO (s) + CO2 (g) CaCO3 (s) ΔHr 0 =-178 kJ/mol HEAT EXCHANGER NETWORK CO2 TUR Q CSP CO2 (g) CaO (s) POWER CYCLE

E3S Web of Conferences, 2017

European regulations set the condition of Zero Energy Buildings for new buildings since 2020, wit... more European regulations set the condition of Zero Energy Buildings for new buildings since 2020, with an intermediate milestone in 2018 for public buildings, in order to control greenhouse gases emissions control and climate change mitigation. Given that main fraction of energy consumption in buildings operation is due to HVAC systems, advances in its design and operation conditions are required. One key element for energy demand control is passive design of buildings. On this purpose, different recent studies and publications analyse natural ventilation systems potential to provide indoor air quality and comfort conditions minimizing electric power consumption. In these passive systems are of special relevance their capacities as passive cooling systems as well as air renovation systems, especially in high-density occupied spaces. With adequate designs, in warm/mild climates natural ventilation systems can be used along the whole year, maintaining indoor air quality and comfort conditions with small support of other heating/cooling systems. In this paper is analysed the state of the art of natural ventilation systems applied to high density occupied spaces with special focus on school buildings. The paper shows the potential and applicability of these systems for energy savings and discusses main criteria for their adequate integration in school building designs.

Renewable and Sustainable Energy Reviews, 2018

Thermal energy storage and management in builtable dings play a major role in the transition towa... more Thermal energy storage and management in builtable dings play a major role in the transition towards a lowcarbon economy. Buildings are the largest energy-consuming sector in the world, where heating and cooling are around 60-70%. This paper provides a comprehensive review of advanced low-carbon energy measures based on thermal energy storage technologies for heating and cooling applications in buildings. With the aim of structuring and identifying the most promising solutions towards low-carbon energy buildings, a global classification of technologies for thermal storage and management is carried out. The most advanced commercial solutions, emerging technologies, and recent research activities reported in the literature and international projects are analysed. The main achievements are reported together with the status of research and the most promising solutions in the short-and long-term. It is a comprehensive review of the most outstanding applications, operation modes, implementation techniques and their potential benefits. Solutions based on sensible and latent heat storage show a higher development status and the best performance, through the use of aerothermal energy in free-cooling ventilation systems, solar energy through small-scale thermal energy storage units, and largescale underground thermal energy storage systems. For an optimal integration in buildings, they should be combined with heating and cooling generation technologies through smart demand-side management strategies. Regarding thermochemical storage applications for buildings, despite the high energy density of thermochemical storage materials and their reduced heat losses, at the current research stage, the final volume of prototypes is highly penalized by the required auxiliary components. Moreover, recent studies report low-to-moderate efficiency values and poor heat transfer rates after a relatively large number of storage cycles. Therefore, although promising developments are expected in this field, at the present time the greater advances with thermochemical storage processes have been obtained on cooling applications based on solar sorption cycles and large-scale systems.

Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy, 2008

ABSTRACT Conventional recuperative micro gas turbines have a 30 per cent low heating value (LHV)m... more ABSTRACT Conventional recuperative micro gas turbines have a 30 per cent low heating value (LHV)maximum efficiency at full load. Therefore, if they are to be used in a potential distributed energy scenario, solutions must be developed that increase efficiency. An innovative gas turbine-based technology is the fuel cell - gas turbine hybrid system. This work is aimed at studying how the basic performance of a conventional Brayton cycle changes when heat addition is done at a fuel cell. Two layouts are considered: a direct system where the compressor feeds the fuel cell directly and an indirect system where only heat is transferred between subsystems. Direct and indirect systems have been studied at full and part load, concluding that the efficiency versus pressure ratio curves of hybrid systems change substantially with respect to a traditional gas turbine; part-load efficiency hardly decreases. Maximum efficiency of hybrid systems doubles the efficiency of state of the art micro gas turbine and remains high at part load. Furthermore, the benefit of a certain increase in temperature is higher for hybrid systems than for conventional engines. Finally, a simple economic analysis shows that the total installation and operation/ maintenance costs of hybrid systems make them competitive against conventional gas turbines.

Journal of Sustainable Development of Energy, Water and Environment Systems, 2019

New and improved energy storage technologies are required to overcome non-dispatchability, which ... more New and improved energy storage technologies are required to overcome non-dispatchability, which is the main challenge for the successful integration of large shares of renewable energy within energy supply systems. Energy storage is proposed to tackle daily variations on the demand side, i.e., storing low-price energy during off-peak

Energy Conversion and Management, 2022

Ademas de en las actas del congreso se publico en: Anales de ingenieria mecanica, 12 (1), 618-624.

Fuel, 2021

Small solid biomass combustion systems are among the main contributors to the global particulate ... more Small solid biomass combustion systems are among the main contributors to the global particulate emissions share, and cheap, efficient abatement systems are not yet available for them. The placement of inert porous material to confine the combustion region is being recently explored as a possible mitigation system for this kind of pollution. However, given the complexity of biomass thermochemical decomposition processes, it is challenging to justify the performance of these systems on the basis of a physicochemical understanding. A foundational experiment-based study is carried out in this work to understand how combustion confinement affects the particulate emissions production mechanisms. A combustion unit was designed and built to systematically test ceramic foams with different porosities: keeping constant airflow and fuel feed rates. A comprehensive characterisation study was carried out on the solid biomass fuel, the temperature profile, the particulate emissions, and the rema...