Analysis of two heat storage integrations for an Organic Rankine Cycle Parabolic trough solar power plant

Among the concentrated solar power technologies, those based on Organic Rankine Cycles have a very low market presence. However they have favorable characteristics for applications with low temperature and small/medium size (<10 MW), such as off-grid applications or distributed power generation. In this paper is analyzed a 5MW parabolic trough plant integrated with an Organic Rankine cycle power block and thermal storage. On this purpose, two different thermal storage integrations are analyzed. They are based on two different heat storage layouts: direct system using Hitec XL both as Heat Transfer Fluid and as storage medium; indirect system using Therminol VP-1 as Heat Transfer Fluid and Hitec XL as storage medium. Full system performance at rated and off-design conditions is presented operating with different organic working fluids. Its potential application and main challenges for its development are discussed in terms of performance and costs. Among the analyzed working fluids, the best results were obtained for the cycle working with Toluene with an efficiency at the power block of 31.5% and an estimated power block cost of 825 €/kW. The indirect storage layout was the most interesting from the point of view of Levelized Electricity Cost (16.19 c€/kW) and productivity (28.2 GW h/y for a 5 MWel plant) for 10 h of storage However, it results in a storage tanks volume 26% greater than the obtained for the equivalent direct storage layout. The results show the competitiveness and the potential of the proposed integrated small size parabolic trough designs for isolated applications as mines or for some distributed generation uses where grid capacity is limited

Experimental study of the impact of ion orbit losses on the edge radial electric field at the ASDEX Upgrade tokamak

Spanish Ministry of Science, Innovation and Universities (grant FPU17/06273)EUROfusion Consortium 63305

Efecto de 16 semanas de ejercicio físico multicomponente para la prevención de la fragilidad y el riesgo de caídas en mayores de 65 años

Resumen: Introducción: Las personas de edad avanzada son vulnerables a la fragilidad y al riesgo de sufrir accidentes acentuados, sobre todo una vez superados los 65 años. Sin embargo, el ejercicio físico se ha mostrado como una herramienta eficaz para paliar la aparición temprana de la fragilidad. Diferentes programas de ejercicio físico multicomponente, en los cuales el entrenamiento de fuerza de forma especial, sumado a otros con objetivos centrados en la resistencia, agilidad y equilibrio, han mostrado efectos positivos sobre la disminución de la fragilidad como antesala de la dependencia y la discapacidad. Objetivos: Comprobar el efecto positivo de la practica de ejercicio físico sobre la disminución de la fragilidad, la mejora de la calidad de vida y de la capacidad funcional en adultos mayores. Métodos: 34 adultos en estado de fragilidad. con una edad media de 78,5 años se sometieron a una intervención de 16 semanas de ejercicio físico multicomponente. Resultados y discusión: El número de participantes con índice de fragilidad disminuyó (del 79,31% al 20,69%); el 72,41 % disminuyó su limitación funcional, y el porcentaje de personas con alto riesgo de caídas pasó del 58,62% al 37, 93 Conclusiones: La introducción de un programa de ejercicio físico multicomponente se plantea como una herramienta muy eficaz de disminución de la fragilidad y de aumento de la capacidad funcional en personas mayores.Abstract: Introduction: The elderly are vulnerable to frailty and the risk of serious accidents, especially after 65 years. However, physical exercise has been shown as an effective tool to mitigate the early onset of fragility. Different programs of multicomponent physical exercise, in which strength training in a special way, added to others with objectives focused on endurance, agility and balance, have shown positive effects on the reduction of fragility as a prelude to dependence and disability .Aim: To verify the positive effect of the practice of physical exercise on the reduction of fragility, the improvement of the quality of life and of the functional capacity in older adults. Methods: 34 adults in a state of fragility. With a mean age of 78,5 years they underwent a 16-week intervention of multicomponent physical exercise. Results & discussion: The number of participants with frailty index decreased (from 79.31% to 20.69%); 72.41% decreased their functional limitation, and the percentage of people at high risk of falls increased from 58.62% to 37, 93. Conclusions: The introduction of a multicomponent physical exercise program is proposed as a very effective tool for reducing frailty and increasing functional capacity in older people.Resumo: Introdução: Os idosos são vulneráveis à fragilidade e ao risco de acidentes graves, principalmente após os 65 anos. No entanto, o exercício físico tem se mostrado uma ferramenta eficaz para mitigar o início precoce da fragilidade. Diferentes programas de exercícios físicos multicomponentes, nos quais o treinamento de força de maneira especial, somado a outros com objetivos focados em resistência, agilidade e equilíbrio, têm demonstrado efeitos positivos na redução da fragilidade como um prelúdio para a dependência e a incapacidade. Objectivos: Verificar o efeito positivo da prática de exercícios físicos na redução da fragilidade, na melhoria da qualidade de vida e da capacidade funcional em idosos.. Métodos: 34 adultos em estado de fragilidade. Com idade média de 78,5 anos, foram submetidos a uma intervenção de 16 semanas de exercício físico multicomponente. Resultados e Discussão: O número de participantes com índice de fragilidade diminuiu (de 79,31% para 20,69%); 72,41% diminuíram sua limitação funcional e o percentual de pessoas com alto risco de quedas aumentou de 58,62% para 37, 93. Conclusões: A introdução de um programa de exercícios físicos multicomponentes é proposta como uma ferramenta muito eficaz para reduzir a fragilidade e aumentar a capacidade funcional em pessoas idosas

HD Diesel engine equipped with a bottoming Rankine cycle as a waste heat recovery system. Part 2: Evaluation of alternative solutions

A theoretical investigation has been performed on the feasibility of introducing a waste heat recovery (WHR) system in a two-stage turbocharged HDD engine. The WHR is attained by introducing a Rankine cycle, which uses an organic substance or directly water as a working fluid depending on energetic performance considerations. A previous research was carried out to evaluate the maximum potential of this WHR concept, a conventional layout was used for coupling the Rankine cycle to the thermal engine. The objective of the present research is to broad the scope of the previous analysis by considering new alternative solutions for the problems related to the coupling between the WHR Rankine cycle and the thermal engine. These solutions are based on adapting one of the turbochargers by removing its turbine and trying to recover the energy by the Rankine cycle. Finally, the turbine of the Rankine cycle supplies the recovered energy directly to the compressor of this turbocharger. Thus, in these layouts the coupling is simpler as it involves only two turbomachines, which are supposed to share a similar rotating speed. From the results of the global energy balance, these alternative layouts produce slight benefits in fuel consumption but in all cases these benefits are lower compared to those attained with conventional layouts. © 2011 Published by Elsevier Ltd. All rights reserved.This work was partially funded by "Programa de Apoyo a la Investigacion y Desarrollo de la Universidad Politecnica de Valencia".Serrano Cruz, JR.; Dolz Ruiz, V.; Novella Rosa, R.; García Martínez, A. (2012). HD Diesel engine equipped with a bottoming Rankine cycle as a waste heat recovery system. Part 2: Evaluation of alternative solutions. Applied Thermal Engineering. 36:279-287. doi:10.1016/j.applthermaleng.2011.10.024S2792873

A new model of the carbonator reactor in the Calcium Looping technology for post-combustion CO2 capture

The Ca-Looping (CaL) process is considered as a promising technology for CO2 post-combustion capture in power generation plants yielding a minor penalty on plant performance as compared with other capture technologies such as conventional amine-based capture systems. This manuscript presents a new carbonator reactor model based on lab-scale multicyclic CaO conversion results, which take into account realistic CaO regeneration conditions that necessarily involve calcination under high CO2 partial pressure and high temperature. Under these conditions, CaO conversion in the diffusion controlled stage is a relevant contribution to the carbonation degree during typical residence times. The main novelty of the model proposed in the present work is the consideration of the capture efficiency in the diffusion controlled phase of carbonation. It is demonstrated that increasing the residence time by a few minutes in the carbonator yields a significant improvement of the capture efficiency. Model predictions are shown to agree with experimental results retrieved from pilot-scale tests. The new model allows a more accurate evaluation and prediction of carbonator’s performance over a wider range of residence times. The results obtained may be relevant for the optimization of CaL operation parameters to be used in real power plants.Peer reviewe

Alternative ORC bottoming cycles FOR combined cycle power plants

In this work, low temperature Organic Rankine Cycles are studied as bottoming cycle in medium and large scale combined cycle power plants. The analysis aims to show the interest of using these alternative cycles with high efficiency heavy duty gas turbines, for example recuperative gas turbines with lower gas turbine exhaust temperatures than in conventional combined cycle gas turbines. The following organic fluids have been considered: R113, R245, isobutene, toluene, cyclohexane and isopentane. Competitive results have been obtained for toluene and cyclohexane ORC combined cycles, with reasonably high global efficiencies. The paper is structured in four main parts. A review of combined cycle and ORC cycle technologies is presented, followed by a thermodynamic analysis of combined cycles with commercial gas turbines and ORC low temperature bottoming cycles. Then, a parametric optimization of an ORC combined cycle plant is performed in order to achieve a better integration between these two technologies. Finally, some economic considerations related to the use of ORC in combined cycles are discussed.ORC Organic Rankine Cycle Combined cycle Heavy duty gas turbines

Analysis of two heat storage integrations for an Organic Rankine Cycle Parabolic trough solar power plant

Among the concentrated solar power technologies, those based on Organic Rankine Cycles have a very low market presence. However they have favorable characteristics for applications with low temperature and small/medium size (<10 MW), such as off-grid applications or distributed power generation. In this paper is analyzed a 5MW parabolic trough plant integrated with an Organic Rankine cycle power block and thermal storage. On this purpose, two different thermal storage integrations are analyzed. They are based on two different heat storage layouts: direct system using Hitec XL both as Heat Transfer Fluid and as storage medium; indirect system using Therminol VP-1 as Heat Transfer Fluid and Hitec XL as storage medium. Full system performance at rated and off-design conditions is presented operating with different organic working fluids. Its potential application and main challenges for its development are discussed in terms of performance and costs. Among the analyzed working fluids, the best results were obtained for the cycle working with Toluene with an efficiency at the power block of 31.5% and an estimated power block cost of 825 €/kW. The indirect storage layout was the most interesting from the point of view of Levelized Electricity Cost (16.19 c€/kW) and productivity (28.2 GW h/y for a 5 MWel plant) for 10 h of storage However, it results in a storage tanks volume 26% greater than the obtained for the equivalent direct storage layout. The results show the competitiveness and the potential of the proposed integrated small size parabolic trough designs for isolated applications as mines or for some distributed generation uses where grid capacity is limited