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Waste Biomass Fast Pyrolysis in a Drop-Tube Reactor Using Concentrated Solar Power: CIRCULAR FUELS - EU PROJECT
Full text linkSolar-assisted pyrolysis is a sustainable process for the conversion of biomass into bio-oil using renewable solar-thermal energy with potentially zero carbon footprint. The EU’s target of reducing net greenhouse gas emissions to at least 55% by 2030 leads the way to effective measures in limiting carbon emissions for a climate-neutral future. This study focuses on the initial design and development of a drop-tube fast pyrolysis reactor that performs the conversion of waste biomasses into bio-oil at 600°C, by using concentrated solar power. This work is part of the European Union-funded project, Circular Fuels, which focuses on the production of sustainable aviation fuels (SAFs). The numerical CFD simulations were performed using the ANSYS FLUENT 2020 commercial CFD solver for the sizing and design optimization of the experimental solar reactor prototype
Expanding the Western U.S. Grid With CSP: An Update on the Findings of the CalCSP Study
Full text linkAs states within the United States respond to future grid development goals, there is a growing demand for reliable and resilient nighttime generation that can be addressed by low-cost, long-duration energy storage solutions. This paper summarizes the findings of a study for the state of California that evaluated how molten-salt tower concentrating solar power (CSP) plants with thermal energy storage (TES) can be utilized to address the goals within the state established by Senate Bill 100. The study found that CSP exhibits deployment potential both in California and in the rest of the Western Interconnection and is utilized primarily to serve nighttime load. The plants are designed to collect and store energy during the day and then are dispatched to produce power at night. The paper presents a technoeconomic analysis that compares the cost of CSP to photovoltaics (PV) plus battery energy storage systems (BESS), provides an overview of capacity expansion modeling performed by NREL, and a screening analysis that identifies CSP siting potential in the U.S
Large-Scale Production of Heliostats: Determination and Reduction of Fabrication Cost
Full text linkHeliostats are the main cost factor of solar tower plants. To optimize them in terms of cost, it is mandatory to estimate the fabrication cost. A method to do so is presented and applied to a sample heliostat. The sample heliostat that is optimized for low production cost is of 2 m² size. The design already provides a low part-count, an efficient material usage and low-cost purchased parts but is also of high accuracy. A part list of the heliostat is created and every part is analyzed. For production cost optimization, the optimal manufacturing process both from a technical and an economical view has to be determined. Furthermore, the material cost has to be estimated based on the weight and material of the heliostat components. Also cost for control and energy supply has to be considered. Optimizing their cost depends significantly on unit quantities. Higher volumes generally translate to lower development costs, yet component and manufacturing expenses become predominant. The circuit board design proves to be a central point here. Selecting easily accessible, interchangeable components suited for function and longevity, optimizes component and manufacturing costs
Central Receiver-Based CSP Plants: Trends and Categorization
Full text linkCentral receiver-based concentrated solar power (CSP) systems play a crucial role in solar energy technology, particularly for their ability to operate at higher temperatures than conventional linear concentrators, and for better integration of thermal energy storage in a more direct manner. This paper methodically examines the development and classification of central receiver-based CSP technologies, including power towers, solar furnaces, and beam-down configurations. It aims to emphasize the operational advantages and challenges of these technologies through a literature review. Through an in-depth examination of strategic pathways, including hybridization and co-location, this study reveals critical trends in market deployment frameworks, underpinning the future of CSP integration in the transition to renewable energy solutions
A Simplified Numerical Model to Study the Thermal Behavior of a Cascade LHTES System
Full text linkTo promote the integration of Solar Heat for Industrial processes (SHIP), through the development of innovative cascade Latent Heat Thermal Energy Storage (LHTES) systems, a simplified zero-dimensional model for “shell&tube” LHTES systems that is fast, flexible and sufficiently accurate was set up. This model, programmed in Fortran 90, was developed not only to predict the thermal behavior of a cascade LHTES but also to be usable within a software to evaluate its integration in any plant, including a Concentrated Solar Thermal (CST). The model was validated through a comparison both with a more sophisticated numerical simulation and the experimental results. Finally, the simplified model was applied to a case study to analyse the thermal behavior of a system of three LHTES connected in serie
Measurement of the Density of Biphenyl / Diphenyl Oxide Mixtures at Isobaric Conditions
Full text linkThe density of the eutectic mixture of biphenyl and diphenyl oxide was measured at 12 to 40 bar and up to 400 °C for the first time. An unused quality as delivered and a used quality from a parabolic trough plant were tested. Significant compressibility was observed for both qualities giving rise to density increases of 3% for the unused fluid at 40 bar and 4.8% for the used fluid compared to the technical data sheet of Dowtherm A
Multi-Flow Falling Particle Receiver Modeling
Full text linkGeneration 3 Concentrating Solar Power systems use solid particles for heat transfer and thermal energy storage. Particle-based systems use a falling particle receiver with an open cavity where particles flow together as a curtain that is directly exposed to solar radiation absorbed by the particles as they descend. The efficiency of the receiver depends on curtain opacity (influenced by the particle mass flow rate), the average particle temperature, and environmental factors. We present a free-falling particle receiver design that incorporates ten individually controlled valves for precise particle supply management. Each valve is equipped with a slide gate and an actuator, ensuring a consistent mass flow rate. In a uniform mass flow rate curtain, the hottest particles accumulate in the center due to non-uniform flux distribution, leading to higher radiative and advective losses. Accordingly, lower flux levels at the periphery result in lower temperature particles. Our modular valve design enhances receiver efficiency by improving curtain opacity in key areas. The outer valves have the lowest mass flow rate, while the center valves have the highest, allowing more uniform heating. The 10-section model outperforms the 1D model by reaching a maximum efficiency of 85%, compared to 84%
First-Principles Study of Radiation-Induced Defects in Silicon Solar Cells Using Density-Functional Theory Simulation
Full text linkDisplacement damage from high-energy electron and proton irradiation is a critical degradation mechanism in space solar cells, particularly within the Van Allen radiation belts. These energetic particles induce atomic displacements in semiconductor materials, generating lattice defects such as vacancies, di-vacancies, and impurity-related complexes (e.g., BiOi, BiCs and BiHi) that significantly impact the electronic structure of silicon, reducing solar cell efficiency and power output. A fundamental understanding of these defects is critical for designing radiation-resistant photovoltaics. To address this challenge, we employ first-principles Density Functional Theory(DFT) using the SIESTA code with localized orbital basis sets to model the electronic structure of silicon systems with induced defects and impurities. Our study focuses on boron-related defect complexes, including interstitial boron (Bi) and its interactions with oxygen (O) and hydrogen (H), with validation against experimental data and comparative calculations using QUANTUM-ESPRESSO to assess computational robustness. Our simulation identifies key defect energy levels, including BiOi at Ec – 0.23 eV and BiCs at Ev + 0.31 eV, which exhibit strong agreement with experimental data, reinforcing the reliability of our approach. We further analyze the passivating role of interstitial hydrogen (Hi) and its influence on defect neutralization. These findings provide critical insights for defect engineering strategies, enabling optimized doping and thermal processing to mitigate radiation-induced degradation. This research advances the development of next-generation, radiation-tolerant photovoltaics for prolonged space missions by identifying dominant defect configurations and their electronic structure
It Makes No Sense at All. It All Makes a Lot of Sense.: Anniversaries. Part Two. A Space of Memory for Uwe Johnson\u27s Anniversaries. A Project by Anna-Sophie Mahler and Ensemble, Premiere at Schauspiel Leipzig on 2 March 2024
No full textDas im Frühjahr 2024 uraufgeführte Leipziger Theaterprojekt Jahrestage. Zweiter Teil unterschied sich erheblich von der eher narrativen und sehr unterhaltsamen Adaption des Ersten Teils im Jahr davor. Ein überraschender und herausfordernder Zugang anhand von starken Bildern führte zum Kern von Johnsons Roman: zum Erinnern, zum Gedenken, und zu jenen persönlichen und kollektiven eigenen Familiengeschichten, die zu erzählen Johnsons Roman uns auch einlädt.The Leipzig theatre project Jahrestage (Anniversaries). Part Two, which premiered in spring 2024, was fundamentally different to the more narrative and very entertaining adaptation of Part One. A surprising and challenging approach based on forceful imagery went straight to the heart of Johnson’s novel: to remembering and remembrance, and to those personal and collective stories from our the history of our own families that Johnson’s novel also invites us to relate
Employing “Webby” FAIR Digital Objects to Support Large-Scale Ecosystem Monitoring and Mitigation of Biodiversity Loss in the Anthropocene
Full text linkWe developed the WildLIVE platform to enable curation, analysis and mobilization of data from high-throughput biodiversity monitoring for European and global cross-domain data space pro-grams. The platform implements “webby” FAIR Digital Objects leveraging on RO-Crate and FAIR Signposting to foster self-contained operation of machines on contained digital resources (machine actionability)