Enhancing the thermal efficiency of a salinity gradient solar pond. Implementation of the study in the design, construction, salinity gradient establishment, operation and energy transfer at industrial scale

Tesi amb diferents seccions retallades per drets de l'editorThe energy model in the last decades has been dominated by the consumption of fossil fuels assuming a high environmental cost. Global warming and the destruction of the ozone layer are two examples of the deterioration that is being suffered due to the use of these energy sources. Increasingly, the use of renewable energy one of the alternatives in building a sustainable economic model. Among renewables, solar energy is presented as an inexhaustible and accessible source of energy. The solar pond is a technology that meets all requirements to be considered an energy storage device. It can store solar energy, charging during the months of high solar incidence (Spring-Summer), storing the energy through the time and making possible its use when it is requested. A salt gradient solar pond is a body of saline water with long term thermal storage capacity. The aim and scope of this PhD thesis is divided in two parts. First, the improvement of the efficiency of the solar pond technology through experimental evaluation the heat extraction and heat supply processes under different weather conditions. These experiments were carried out in a 50 m2 solar pond pilot plant located in Martorell (Catalonia). Heat extraction experiments were performed using both heat exchangers installed (lateral and bottom) individually or both at the same time. The results demonstrated that the efficiency of the pond increases when the heat is removed from the lateral heat exchanger compared to either using the bottom heat exchanger or using both heat exchangers simultaneously. On the other hand, the use of solar collectors as an external source of heat were conducted together with heat extraction process under two different seasonal temperature conditions: winter and summer. The results indicated that the use of solar collectors allowed a 50% increase in daily efficiency during the cold season tests. The second part was focused on the design, construction and operation of a 500 m2 solar pond in Solvay Minerales facilities (Granada). The solar pond was designed to supply the heat required to preheat the water (> 60 °C) and the reagents in the mineral flotation unit at the mineral processing facility. The overall efficiencies obtained after the first and second operation periods are 9.7 and 12.3%, respectively, with maximum values of 28 and 24% obtained during the first months of operation. Regarding the economic savings, reductions of 52 and 68% were obtained in the first and second periods compared with the traditional system without solar pond. Also, the environmental impact is clearly reduced considering the reduction of CO2 emissions. The experience of the Granada solar pond proves that the main advantage of a solar pond is the capacity to store energy in the months with the highest solar radiation to provide a flux of heat to an external system during the whole year even under strong weather conditions, as observed during the January 2015 snowfall.El modelo energético en las últimas décadas ha estado dominado por el consumo de combustibles fósiles, asumiendo un alto coste ambiental. El calentamiento global y la destrucción de la capa de ozono son dos ejemplos del deterioro que se está sufriendo debido al uso de estas fuentes de energía. Cada vez más, el uso de energías renovables es una de las alternativas en la construcción de un modelo económico sostenible. Entre las energías renovables, la energía solar se presenta como una fuente de energía inagotable y accesible. El estanque solar es una tecnología que cumple todos los requisitos para ser considerado un dispositivo de almacenamiento de energía. Puede almacenar energía solar, cargando durante los meses de alta incidencia solar (primavera-verano), almacenando la energía y haciendo posible su uso cuando es necesaria. Un estanque solar con gradiente salino es un cuerpo de agua salina con capacidad de almacenamiento térmico a largo plazo. El objetivo y alcance de esta tesis doctoral se divide en dos partes. Primero, la mejora de la eficiencia del estanque solar a través de la evaluación experimental de los procesos de extracción de calor y aportación de calor en diferentes condiciones climáticas. Estos experimentos se llevaron a cabo en un estanque solar a escala planta piloto de 50 m2 situada en Martorell (Cataluña). Los experimentos de extracción de calor se realizaron mediante el uso de intercambiadores de calor situados en el área lateral y en el área inferior del estanque. El proceso de extracción de calor se llevó a cabo de manera individual (área lateral o inferior) o simultáneamente (área global). Los resultados demostraron que la eficiencia del estanque aumenta cuando el calor es extraído usando el intercambiador de calor lateral en comparación con el uso del intercambiador de calor inferior o con los dos intercambiadores de calor simultáneamente. Por otro lado, el uso de placas solares como fuente externa de energía se llevó a cabo junto con el proceso de extracción de calor en dos condiciones climatológicas diferentes: invierno y verano. Los resultados obtenidos indicaron que el uso de placas solares permitió un aumento del 50% en la eficiencia diaria durante los experimentos llevados a cabo durante la estación fría. La segunda parte se centró en el diseño, construcción y operación de un estanque solar de 500 m2 en las instalaciones de Solvay Minerales (Granada). El estanque solar fue diseñado para suministrar el calor necesario para precalentar el agua (> 60 ° C) y los reactivos en la unidad de flotación de la instalación de procesamiento de minerales. Las eficiencias globales obtenidas después del primer y segundo período de operación son 9.7 y 12.3%, respectivamente, con valores máximos de 28 y 24% obtenidos durante los primeros meses de operación. En cuanto al ahorro económico, se obtuvieron reducciones de 52 y 68% en el primer y segundo período en comparación con el sistema tradicional sin estanque solar. Además, el impacto ambiental se reduce claramente considerando la reducción de las emisiones de CO2. La experiencia del estanque solar de Granada demuestra que la principal ventaja de estos sistemas es la capacidad de almacenar energía en los meses con mayor radiación solar, para poder proporcionar un flujo de calor a un sistema externo durante todo el año, incluso en condiciones climáticas adversas, como se pudo comprobar durante la nevada en enero de 2015.Postprint (published version

The effect of the combination of multiple woven fabric and nonwoven on acoustic absorption

[EN] Textile materials can be used as acoustic materials. In this study, the acoustic absorption coefficient of multilayer fabrics with 60 ends/cm and 15, 30, 45, and 60 picks/cm is measured when the fabric is added as a resistive layer on top of a polyester nonwoven, in order to study the influence of the fabric spatial structure in the acoustic absorption of the assembly. Five different fabric structures are used. Design of experiments and data analysis tools are used to describe the influence of two manufacturing factors on the sound absorption coefficient of the ensemble. These factors are the fabric weft count (picks/cm) and the thickness of the nonwoven (mm). The experimental conditions under which the maximum sound absorption coefficient is achieved are found. The influence of each factor and a mathematical model are obtained. Results of statistical and optimization analysis show that for the same fabric density, sound absorption coefficient increases as the number of layers decreases.Segura-Alcaraz, P.; Segura Alcaraz, JG.; Montava-Seguí, I.; Bonet-Aracil, M. (2021). The effect of the combination of multiple woven fabric and nonwoven on acoustic absorption. Journal of Industrial Textiles. 50(8):1262-1280. https://doi.org/10.1177/15280837198587711262128050

Mainstreaming remotely sensed ecosystem functioning in ecological niche models

Part of this work was funded by the EU H2020 Project 641762 ‘ECOPOTENTIAL: Improving Future Ecosystem Benefits through Earth Observations’, from which many valuable thoughts originated. A.R. was funded by the Xunta de Galicia (post‐doctoral fellowship ED481B2016/084‐0) and currently by ‘Juan de la Cierva’ fellowship program funded by the Spanish Ministry of Science and Innovation (IJC2019‐041033‐I). J.G. was funded by the Individual Scientific Employment Stimulus Program (2017) by the Portuguese Foundation for Science and Technology (FCT CEECIND/02331/2017/CP1423/CT0012). S.A‐C was funded by the PORBIOTA ‐ Portuguese e‐Infrastructure for Information and Research on Biodiversity (POCI‐01‐0145‐FEDER‐022127) project grant and is currently supported by the 'María Zambrano' program funded by the Spanish Ministry of Universities and the EU‐NextGenerationEU fund.Biodiversity is declining globally at unprecedented rates. Ecological niche models (ENMs) are one of the most widely used toolsets to appraise global change impacts on biodiversity. Here, we identify a variety of advantages of incorporating remotely sensed ecosystem functioning attributes (EFAs) into ENMs. The development of ENMs that explicitly incorporate ecosystem functioning will allow a more holistic and integrative perspective of the habitat dynamics. The synergies between the increasingly available open-access satellite images and cloud-based platforms for planetary-scale geospatial analysis offer an unprecedented opportunity to incorporate ecosystem processes and disturbances (such as fires, insect outbreaks or droughts) that have been so far largely neglected in ecological niche characterization and modelling. The most paradigmatic example of EFAs is the application of time series of spectral vegetation indices related to primary productivity and carbon cycle. EFAs related to surface energy balance and water cycles derived from remote sensing products such as land surface temperature or soil moisture enable a fine-scale characterization of the species' niche—eventually improving the predictive performance of ENMs. All these advantages confirm that a new generation of ENMs based on such EFAs would offer great perspectives to increase our ability to monitor habitat suitability trends and population dynamics. However, despite the technical advances and increasing effort of remote sensing community to develop integrative EFAs, ENMs have yet to make full profit of the most recent developments by integrating them in ENMs. A coordinated agenda for remote sensing experts and ecological modellers will be essential over the coming years to bridge the gap between remote sensing and ecology disciplines and to take full (and timely) advantage of the fast-growing body of Earth observation data and remote sensing technologies—with special emphasis on the development and testing of new variables related to key processes driving ecosystem functioning.EU H2020 641762Individual Scientific Employment Stimulus ProgramSpanish Ministry of Universitiese‐Infrastructure for Information and Research on BiodiversityFundação para a Ciência e a TecnologiaMinisterio de Ciencia e InnovaciónFundació Catalana de Trasplantament CEECIND/02331/2017/CP1423/CT0012, POCI‐01‐0145‐FEDER‐022127Xunta de Galicia ED481B2016/084‐

A data-driven methodological routine to identify key indicators for social-ecological system archetype mapping

We thank R Romero-Calcerrada and J M Requena-Mullor for helpful discussions, and three anonymous reviewers for their constructive suggestions to improve this paper. We also thank the Spanish Ministry of Economy and Business (Project CGL2014-61610-EXP) for the financial support, as well as the Spanish Ministry of Education for the FPU Predoctoral Fellowship of MPR (FPU14/06782) and MTTG (16/02214). MPR gratefully acknowledges funding from Universidad de Almeria for a research stay at the Laboratory of Regional Analysis and Remote Sensing (LART) of University of Buenos Aires to develop this study. This research was done within the LTSER Platforms of the Arid Iberian South East-Spain (LTER_EU_ES_027) and Sierra Nevada/Granada (ES- SNE)-Spain (LTER_EU_ES_010), and contributes to the Global Land Programme.The spatial mapping of social-ecological system (SES) archetypes constitutes a fundamental tool to operationalize the SES concept in empirical research. Approaches to detect, map, and characterize SES archetypes have evolved over the last decade towards more integrative and comparable perspectives guided by SES conceptual frameworks and reference lists of variables. However, hardly any studies have investigated how to empirically identify the most relevant set of indicators to map the diversity of SESs. In this study, we propose a data-driven methodological routine based on multivariate statistical analysis to identify the most relevant indicators for mapping and characterizing SES archetypes in a particular region. Taking Andalusia (Spain) as a case study, we applied this methodological routine to 86 indicators representing multiple variables and dimensions of the SES. Additionally, we assessed how the empirical relevance of these indicators contributes to previous expert and empirical knowledge on key variables for characterizing SESs. We identified 29 key indicators that allowed us to map 15 SES archetypes encompassing natural, mosaic, agricultural, and urban systems, which uncovered contrasting land sharing and land sparing patterns throughout the territory. We found synergies but also disagreements between empirical and expert knowledge on the relevance of variables: agreement on their widespread relevance (32.7% of the variables, e.g. crop and livestock production, net primary productivity, population density); relevance conditioned by the context or the scale (16.3%, e.g. land protection, educational level); lack of agreement (20.4%, e.g. economic level, land tenure); need of further assessments due to the lack of expert or empirical knowledge (30.6%). Overall, our data-driven approach can contribute to more objective selection of relevant indicators for SES mapping, which may help to produce comparable and generalizable empirical knowledge on key variables for characterizing SESs, as well as to derive more representative descriptions and causal factor configurations in SES archetype analysis.Spanish Government CGL2014-61610-EXP FPU14/06782 16/02214Universidad de AlmeriaLTSER Platforms of the Arid Iberian South East-Spain LTER_EU_ES_027Sierra Nevada/Granada (ES- SNE)-Spain LTER_EU_ES_01

Environmental and Human Controls of Ecosystem Functional Diversity in Temperate South America

The regional controls of biodiversity patterns have been traditionally evaluated using structural and compositional components at the species level, but evaluation of the functional component at the ecosystem level is still scarce. During the last decades, the role of ecosystem functioning in management and conservation has increased. Our aim was to use satellite-derived Ecosystem Functional Types (EFTs, patches of the land-surface with similar carbon gain dynamics) to characterize the regional patterns of ecosystem functional diversity and to evaluate the environmental and human controls that determine EFT richness across natural and human-modified systems in temperate South America. The EFT identification was based on three descriptors of carbon gain dynamics derived from seasonal curves of the MODIS Enhanced Vegetation Index (EVI): annual mean (surrogate of primary production), seasonal coefficient of variation (indicator of seasonality) and date of maximum EVI (descriptor of phenology). As observed for species richness in the southern hemisphere, water availability, not energy, emerged as the main climatic driver of EFT richness in natural areas of temperate South America. In anthropogenic areas, the role of both water and energy decreased and increasing human intervention increased richness at low levels of human influence, but decreased richness at high levels of human influence

Textiles in architectural acoustic conditioning: a review

[EN] Environmental noise is a problem of increasing interest in advanced societies. Different types of textiles have properties which are suitable for the construction of elements able to condition sound in rooms. The use of these elements can foster acoustic comfort in all kind of rooms, both public and private. This work is a review of the possibilities and trends of textile materials in the field of acoustic conditioning. The use of textile materials for acoustic conditioning is widely extended. On the other hand, many efforts have been done in the last decades to understand the sound absorption mechanisms and to design materials and devices able to customize the sound space. Many of these new developments have used materials like wood, metal, plastic. Textiles can be thought as fully designable materials and potential base of composites, providing their unique technical and aesthetical characteristics to any ensemble.Segura Alcaraz, MP.; Bonet-Aracil, M.; Juliá Sanchis, E.; Segura Alcaraz, JG.; Montava-Seguí, I. (2022). Textiles in architectural acoustic conditioning: a review. Journal of the Textile Institute. 113(1):166-172. https://doi.org/10.1080/00405000.2021.1976483166172113

Sound absorption of textile material using a microfibres resistive layer

[EN] Acoustic comfort is a basic human need. One of the adverse effects of noise is its interference with speech discrimination. Textile materials are suitable to be used as sound absorptive materials and thus help to improve acoustic comfort in rooms. Micro-fibre fabrics can be considered as better sound absorbers than regular fibre fabrics mainly due to the higher surface of its fibres and bigger contact area with the air thus, allowing greater dissipation of sound energy. In this work, the use of a microfibre woven fabric as an upstream layer is analysed considering acoustic issues. Authors demonstrate it improves the sound absorption of a polyester nonwoven, resulting in a material suitable for absorption at the sound frequencies of the human voice.Segura-Alcaraz, MDP.; Bonet-Aracil, M.; Segura Alcaraz, JG.; Montava Segui, I. (2017). Sound absorption of textile material using a microfibres resistive layer. IOP Conference Series Materials Science and Engineering. 254:1-6. doi:10.1088/1757-899X/254/7/072022S1625

Las necesidades energéticas de Asia Oriental: el impacto sobre la seguridad y las pautas de gobernanza regional

Las últimas tres décadas han presenciado un espectacular y difícilmente sostenible aumento de la demanda energética global. Esta tendencia adquiere una significación especial en Asia Oriental debido a la fuerte industrialización que impulsa el elevado crecimiento económico regional, al ya de por sí delicado equilibrio de la seguridad regional y al tradicional rechazo de los estados de la región a delegar poder y gestión en entidades supranacionales. Este artículo tiene como objetivo analizar el impacto de las necesidades energéticas de Asia Oriental sobre la seguridad y sobre los instrumentos de orden y gobernanza desarrollados hasta la fecha en la región. Para ello, se estructura en dos partes. La primera analiza el panorama energético de Asia Oriental y sus rasgos más significativos: 1) la alta dependencia de las importaciones de petróleo procedentes de otras regiones, especialmente de Oriente Medio; 2) la persistencia de una elevada dependencia de combustibles fósiles contaminantes; y 3) un alto nivel de inseguridad energética. La segunda parte evalúa el impacto de la energía sobre las relaciones regionales en diferentes aspectos de la seguridad y las pautas de gobernanza regional: 1) la securitización de la energía y del medio ambiente; 2) la reactivación de algunos conflictos marítimos; 3) la transformación de algunas amenazas y desafíos convencionales y no convencionales a la seguridad regional; 4) el ascenso de actores no estatales, principalmente empresas y ONG medioambientalistas, en las relaciones internacionales de Asia Oriental; 5) el mantenimiento del bilateralismo y el impulso de iniciativas multilaterales; así como 6) la emergencia de nuevos vínculos y equilibrios geopolíticos extraregionales