Brayton technology for Concentrated Solar Power plants: Comparative analysis of central tower plants and parabolic dish farms

[EN]Concentrated solar power plants intend to be key in the pool of renewable energy production technologies in the next future because of their versatility and high efficiency. In this work a comparative study between two promising technologies is developed. A central tower receiver surrounded by a heliostat field and a farm of parabolic dishes, both coupled to a hybrid Brayton cycle, are considered. Two power scales are surveyed (between 5 and 20 MW) at three different locations with quite different latitudes (between Sahara desert and medium European latitudes) and meteorological conditions. A modelling scheme developed by our group that allows to obtain the expected thermodynamic and thermo-economic plant records is applied. Key indicators like efficiency, net generated energy, levelized cost of electricity, and specific plant investment are calculated and analysed. Variability of natural gas prices and also land cost uncertainty are reflected on levelized cost of electricity range. Among the plants compared, minimum values are found within the interval [135–163] USD/MWh for central towers at the highest power considered and southern latitudes. In addition, the area needed for the installation of the plants and the influence of CO taxes is also analysed. Displayed cashflows show larger investment costs for central tower than for dish farms. Finally, those systems are put into the context of other concentrated solar power, other renewable, like wind or photovoltaic, and other conventional power plants.PC_TCUE18-20P_010. Universidad de Salamanca and Banco de Santande

Modeling a solar pressurized volumetric receiver integrated in a parabolic dish: Off-design heat transfers, temperatures, and efficiencies

Concentrated solar power plants are commonly recognized as one of the most attractive options within carbon-free power generation technologies because of their high efficiency and feasible hybridization and/or storage implementation. In this work, a complete heat transfer analysis for an air volumetric receiver coupled to a parabolic dish focused on distributed generation (in the range of kWe) is carried out. It includes most relevant heat losses. Dish collector optical efficiency is computed by means of a ray-tracing software while the thermal performance of the solar receiver is modeled under steady-state conditions using a comprehensive set of equations with a clear physical origin and meaning. Detailed information on the temperatures and heat transfers along the different inner and outer receiver zones are computed with a built from scratch in-house code programmed in Mathematica. The model considers the main losses from convection, conduction and radiation and through the surrounding insulator. The resulting thermal efficiency mainly depends on the incoming solar irradiance at the glass window, the receiver geometry and the type of materials considered, as well as on the ambient temperature. Explicit numerical results are given at two locations under different meteorological conditions. Optical efficiencies reach values of about 84%. For irradiance values around 800–900 W/m2, at the receiver outlet, air can reach temperatures of about 1200 K and receiver thermal efficiency is over 80%. It is expected that this model (precise but not too expensive from the computational viewpoint) could help to identify the main efficiency bottlenecks, paving the way for optimization when designing this type of concentrated solar plants through further coupling with a power block, as Brayton or other cycles

Gamification and neurological motor rehabilitation in children and adolescents: a systematic review

Introduction: Gamification consists of the use of games in non-playful contexts. It is widely employed in the motor rehabilitation of neurological diseases, but mainly in adult patients. The objective of this review was to describe the use of gamification in the rehabilitation of children and adolescents with neuromotor impairment. Methods: We performed a systematic review of clinical trials published to date on the MEDLINE (PubMed), Scielo, SCOPUS, Dialnet, CINAHL, and PEDro databases, following the PRISMA protocol. The methodological quality of the studies identified was assessed using the PEDro scale. Results: From a total of 469 studies, 11 clinical trials met the inclusion criteria. We analysed the gamification systems used as part of the rehabilitation treatment of different neuromotor conditions in children and adolescents. Cerebral palsy was the most frequently studied condition (6 studies), followed by developmental coordination disorder (3), neurological gait disorders (1), and neurological impairment of balance and coordination (1). Conclusion: The use of gamification in rehabilitation is helpful in the conventional treatment of neuromotor disorders in children and adolescents, with increased motivation and therapeutic adherence being the benefits with the greatest consensus among authors. While strength, balance, functional status, and coordination also appear to improve, future research should aim to determine an optimal dosage. Resumen: Introducción: La ludificación consiste en emplear el juego en contextos no lúdicos. Su uso en la rehabilitación motora de patologías neurológicas está muy extendido, pero sobre todo en pacientes adultos. El objetivo de esta revisión fue describir el uso de la ludificación en los tratamientos de rehabilitación en niños y adolescentes con afectación neuromotora. Métodos: Se realizó una revisión sistemática de ensayos clínicos en diferentes bases de datos: Medline (a través de Pubmed), Scielo, SCOPUS, Dialnet, Cinahl y PEDro de la literatura científica publicada hasta la fecha siguiendo el protocolo PRISMA. La calidad metodológica de los estudios identificados se evaluó a través de la escala PEDro. Resultados: De un total de 469 estudios localizados se seleccionaron 11 ensayos clínicos que cumplieron los criterios de inclusión. Se analizaron los sistemas de ludificación utilizados como parte del tratamiento rehabilitador en distintas afecciones neuromotoras en niños y adolescentes. La Parálisis Cerebral fue la afección con mayor número de estudios (n = 6) seguida del Trastorno del Desarrollo de la Coordinación (n = 3). También se estudió la alteración de la marcha por causa neurológica (n = 1) y la alteración del equilibrio y coordinación por causa neurológica (n = 1). Conclusión: El uso de la ludificación en rehabilitación aporta beneficios al tratamiento convencional de las alteraciones neuromotoras en niños y adolescentes siendo el incremento de la motivación y adherencia terapéutica los que mayor consenso han alcanzado entre autores. Fuerza, equilibrio, funcionalidad y coordinación son otras variables analizadas que, si bien sugieren mejoras, necesitarían futuras investigaciones para determinar una óptima dosificación