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La idea de este proyecto es analizar y optimizar la red que distribuye aire comprimido en una planta de producción de la empresa Ausmar, para verificar el buen funcionamiento del sistema de verificación de las balsas salvavidas. El principal objetivo es rediseñar el recorrido de la instalación de las tuberías para reducir fugas, minimizar pérdidas de carga y mejorar la eficiencia del sistema. Primero, se analizaron las condiciones actuales de la instalación, para poder identificar los puntos críticos y hacer una investigación de los datos de funcionamiento, consumo y configuración. A partir de esto, se propuso una configuración nueva basada en criterios técnicos, como el cálculo de pérdidas de carga, la selección de diámetros óptimos y un estudio profundo del material para seleccionar uno mejor. Seguidamente se realizó un diseño en 3D mediante SolidWorks de una posible propuesta para poder ver las modificaciones planteadas y asegurar que el montaje de esta sea viable, teniendo en cuenta las limitaciones del espacio existente de la planta. Finalmente, se han analizado los resultados obtenidos de los cálculos, y se ha podido confirmar una mejora en el rendimiento del sistema mediante la reducción de pérdidas de carga y una mayor estabilidad en la distribución del aire. Con este proyecto se puede concluir que una mejora técnica bien planteada en una instalación existente puede aportar beneficios reales tanto operativos como económicos sin hacer una gran inversión.

In recent times, renewable energy sources have gained significant popularity because of the dwindling reserves of fossil fuels and the significant environmental damage resulting from their use. Among the various renewable energy sources, hydrogen stands out as one of the most crucial technologies for the future. Hydrogen can be produced through several different methods, and electrolysis is among the most frequently used methods. This method employs electrical energy to decompose water into its constituent hydrogen and oxygen molecules. When this electrical energy is derived from renewable sources such as solar or wind, then green hydrogen is produced. Systems that use electrolysis to produce hydrogen are known as electrolyzers. One of the primary challenges in the electrolysis process is ensuring the purity of hydrogen; proper control of the levels and pressures of the gas tanks can improve this purity. Automatic control strategies are very important for regulating the levels and pressures of the oxygen and hydrogen tanks. Researchers have proposed various classical techniques for controller design to mitigate this issue. This study seeks to offer a comprehensive and up-to-date review of existing research on control methods for alkaline electrolyzers, which has attracted considerable attention in recent times. The findings of this review offer valuable insight for future studies aimed at developing new control strategies to enhance hydrogen purity. Peer Reviewed

Energy efficiency has long been considered a key component of an industrial company's competitive repertoire. However, despite the potential benefits of adopting so-called energy efficiency measures, their uptake in such companies remains low. In response, this study proposes a framework aimed at supporting key decision-makers in undertaking a thorough assessment of energy efficiency measures. This involves, on the one hand, providing a complete characterization of a general industrial energy efficiency measure and, on the other, identifying the multiple impacts stemming from its adoption based on a novel performance measurement system that encompasses sustainability features and is defined at the shop floor level. Once theoretically validated through literature, the framework is empirically tested with a heterogeneous sample of Italian companies. The preliminary results demonstrate the framework's ability to thoroughly assess energy efficiency measures, highlighting characteristics and impacts that are sometimes considered more critical than energy saving by industrial decision-makers and therefore able to guide the outcome of the adoption decision.

ABSTRACTClimate change projections predict warming and increased weather variability, mainly in polar regions, altering freeze–thaw patterns. However, the effects of rising temperatures and more frequent freeze–thaw events on the water and CO2 management of Antarctic plants remain unclear. To address this, we conducted a laboratory experiment to investigate how growth temperature (5°C and 15°C) and successive freeze–thaw cycles influence the hydraulic and photosynthetic performance of Deschampsia antarctica (D. antarctica) and Colobanthus quitensis (C. quitensis). Our results showed that warmer conditions improved hydraulic and photosynthetic performance in both species, driven by anatomical adjustments in leaf xylem vessels. Additionally, plants exposed to successive freeze–thaw cycles exhibited a coordinated decline in whole‐plant hydraulic conductivity and leaf gas exchange, regardless of growth temperature. The magnitude of changes (%) in photosynthetic traits after freeze–thaw cycles varied between species, with D. antarctica showing similar responses at both growth temperatures, while C. quitensis experienced more pronounced changes at the lower temperature. Overall, these findings suggest that while Antarctic plants benefit from warmer temperatures, repeated freeze–thaw events could disrupt their hydraulic balance and limit photosynthesis, particularly under natural environmental conditions.

The transition to cleaner energy sources is fundamental for mitigating the effects of climate change. One promising example is lignocellulosic biomass, a renewable and sustainable energy source that serves as a precursor to various compounds, including γ-valerolactone (GVL). GVL can be utilized as a biofuel or biopolymer. This project evaluates the potential use of SrFe12O19/Ni-P and graphite/Ni-P as catalysts for the photo-thermocatalytic and cost-effective production of GVL from levulinic acid, using a laser light as a source of energy. The goal is to scale up this process for future industrial applications. The catalysts were functionalized via a Ni-P electroless deposition process. The impact of temperature, reaction time, and electroless deposition coating time on catalyst efficiency was analysed. For the effective catalysts, different coverages thicknesses were tested. Optimal experimental conditions for reactor experiments with a laser dispositive were previously established by conducting autoclave tests in a conventional oven. Autoclave tests results evidenced that the SrFe12O19/Ni-P material did not exhibit catalytic properties for the production of γ-valerolactone. In contrast, graphite/Ni-P catalysts achieved nearly 100% conversion, with an optimum minimum reaction temperature of 120 ºC. To evaluate the potential of the graphite/Ni-P catalyst as a photo-thermal catalysts for γ-valerolactone production, experiments were conducted using the laser apparatus under the aforementioned conditions. The results showed that the graphite/Ni-P catalyst with a 10-minute deposition time exhibited higher conversion rates at lower reaction times and demonstrated greater durability and stability throughout the reusability cycles. Consequently, the graphite/Ni-P catalyst with a 10-minute deposition time was identifies as a suitable catalyst for GVL production. Treballs Finals de Grau de Química, Facultat de Química, Universitat de Barcelona, Any: 2024, Tutors: Albert Serrà Ramos, Elvira Gómez Valentín

The increasing proportion of renewable energy introduces both long-term and short-term uncertainty to power systems, which restricts the implementation of energy management systems (EMSs) with high dependency on accurate prediction techniques. A hierarchical online EMS (HEMS) is proposed in this paper to economically operate the Hybrid hydrogen–electricity Storage System (HSS) in a residential microgrid (RMG). The HEMS dispatches an electrolyzer-fuel cell-based hydrogen energy storage (ES) unit for seasonal energy shifting and an on-site battery stack for daily energy allocation against the uncertainty from the renewable energy source (RES) and demand side. The online decision-making of the proposed HEMS is realized through two parallel fuzzy logic (FL)-based controllers which are decoupled by different operating frequencies. An original local energy estimation model (LEEM) is specifically designed for the decision process of FL controllers to comprehensively evaluate the system status and quantify the electricity price expectation for the HEMS. The proposed HEMS is independent of RES prediction or load forecasting, and gives the optimal operation for HSS in separated resolutions: the hydrogen ES unit is dispatched hourly and the battery is operated every minute. The performance of the proposed method is verified by numerical experiments fed by real-world datasets. The superiority of the HEMS in expense-saving manner is validated through comparison with PSO-based day-ahead optimization methods, fuzzy logic EMS, and rule-based online EMS.

ABSTRACTIn this study, we present a new light absorption enhancement method forp‐i‐nthin film silicon solar cells using pyramidal surface structures, larger than the wavelength of visible light. Calculations show a maximum possible current enhancement of 45% compared with cells on a flat substrate. We deposited amorphous silicon (a‐Si) thin film solar cells directly onto periodically pyramidal‐structured polycarbonate (PC) substrates, which show a significant increase (30%) in short‐circuit current over reference cells deposited on flat glass substrates. The current of the cells on our pyramidal structures on PC is only slightly lower than that of cells on Asahi U‐type TCO glass (Asahi Glass Co., Tokyo, Japan), but suffer from a somewhat lower open circuit voltage and fill factor. Because the used substrates have a locally flat surface area due to the fabrication process, we believe that the current enhancement in the cells on structured PC can be increased using larger or more closely spaced pyramids, which can have a smaller flat surface area. Copyright © 2012 John Wiley & Sons, Ltd.

The element concentration in lettuces grouped in 5 categories (baby variety, cultivated in agricultural soils with low or high percentages of spent coffee grounds-SCG, without SCG and with NPK) were measured. Lettuces cultivated in agricultural soils amended with SCG had significantly higher levels of several essential (V, Fe, Co, V, and probably Mn and Zn) and toxic elements (Al and probably As), without reaching their toxicological limits. Additionally, blocking of N uptake and therefore plant biomass, and probably Cd absorption from agricultural soil was observed. Organic farming with SCG ameliorates element concentrations in lettuces vs. NPK fertilization. The linear correlations among element uptake and the amendment of SCG could be related with their chelation by some SCG components, such as melanoidins and with the decrease in the soil pH. In conclusion, the addition of SCG produces lettuces with higher element content.

Aquest Treball de Fi de Grau consisteix en el disseny d’un pla d’acció per descarbonitzar i millorar l’eficiència energètica d’una fàbrica de gelatina. A través de l’estudi d’un cas real, es proposen actuacions concretes que no només contribueixen positivament a la mi- tigació del canvi climàtic i al desenvolupament sostenible, sinó que representen un estalvi energètic significatiu i una inversió viable per a l’entitat assessorada. L’estudi comença amb la determinació dels fluxos energètics i màssics del procés industri- al en qüestió i s’estableix una base on realitzar un inventari d’emissions inicials. Després s’identifiquen ineficiències i oportunitats de millora, donant lloc a la introducció d’alter- natives energètiques. L’actuació principal proposada consisteix en la substitució del subministrament actual de calor per cogeneració per una bomba de calor, aprofitant el balanç de les demandes tèrmiques de fred i de calor del procés. Aquesta mesura genera un estalvi energètic i una reducció de les emissions molt considerable. A més, es detallen altres actuacions que busquen assolir una electrificació total de la demanda energètica substituint les calderes de gas natural. Aquest pla de descarbonització estableix una metodologia clara, que permet a l’entitat assolir la situació de zero emissions netes l’any 2050. Alineant-se amb els objectius i nor- matives de sostenibilitat internacionals.