1,720,967 research outputs found
Modelling and analysis of V-shaped bifacial PV systems for agrivoltaic applications: A Python-based approach for energy optimization
Full text linkAgrivoltaic systems integrate photovoltaic (PV) energy production with agricultural activities, addressing the critical challenges of land use optimization and sustainable energy generation in the context of climate changes and food security. These systems are pivotal in offering a promising solution in mitigating the environmental and social impacts of utility-scale PV installations, such as habitat disruption and competition with agricultural land. This study evaluates a patented V-shaped bifacial photovoltaic system with a single-axis solar tracking, designed to optimize energy capture but also to minimize shading effects on crops like vineyards. A custom Python-based algorithm using PVlib was developed to simulate the performance of the system, accounting for mutual shading, multiple solar radiation reflections, and dynamic tilt adjustments. Simulations conducted for Palermo, Italy, revealed that the system collects 5.2 % less solar irradiation than traditional side-by-side configurations but achieves an annual energy output of 2089.3 kWh per pair of panels, along with 24 % reduction in land use. These results highlight the system capability to optimize spatial efficiency while maintaining high energy production. The novelty of this work lies in its tailored simulation approach, addressing the unique geometry and operational dynamics of the V-shaped configuration, and its potential adaptability to diverse agrivoltaics scenarios. Unlike existing tools and methodologies in the literature, this work introduces a customized Python-based model specifically designed to analyse the performance of this innovative structure, which is of recent conception and lacks precedent in both academic studies and commercial software solutions. By advancing the methodological framework for integrating renewable energy with agriculture, this study contribute to the broader goals of sustainable development and climate resilience
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
A novel model to assess the energy demand of outdoor swimming pools
Full text linkIn the Mediterranean region, outdoor swimming pools, despite having lower energy consumption compared to indoor pools, are nonetheless highly energy-intensive structures, offering significant opportunities for energy efficiency improvements. Although there are numerous studies in the literature, few of these works have been dedicated to estimating the energy consumption of outdoor pools while considering typical local meteorological conditions and their occupancy rates. This paper presents a novel energy balance model for outdoor pools that incorporates the latest correlations for calculating evaporation due to forced convection and sky temperature, a new phenomenological model for assessing the enhancement of evaporation as a function of occupancy rate, and an approach that takes into account atmospheric stability conditions in defining wind-related heat losses. The model successfully predicts the annual energy consumption data for outdoor Olympic swimming pools in Greece with a mean absolute percentage error of less than 12 %. Simulations of an outdoor swimming pool operating with water at 26.5 C and in which the cover is not used present indicate a specific thermal energy consumption of about 2300 kWh/m2. A decrease in water temperature by 1 C and the use of a cover result in approximately 11 % and 30 % reduction in consumption, respectively
Enhancing Renewable Energy Efficiency: A Study on Road Thermal Collector Prototype
No full textIn today's global energy scenario, the demand for renewable and efficient energy solutions is more pressing than ever before. Solar energy, with its availability and renewable nature, occupies a prominent position in this transitional phase. However, the intermittent nature of solar irradiance, primarily due to diurnal and seasonal variations, presents a significant challenge for its widespread adoption as a stable and reliable energy source. In this context, the advancement of innovative thermal energy storage (TES) systems represents a crucial development. These systems enable the capture of solar energy during peak insolation periods for subsequent use during off-peak times, thereby enhancing the efficiency and reliability of solar energy systems.
This paper introduces a novel mathematical model that characterizes the thermal exchange in a prototypical road thermal collector system (RTC), which has been built at the University of Palermo. The core of this research is the implementation of this model into a finite difference method (FDM) framework, developed in Python. This model accurately simulates the temperature dynamics across the RTC system, incorporating a comprehensive spectrum of energy contributions.
To validate the efficacy and accuracy of our mathematical model, the results derived from the Python-based FDM simulations have been compared with experimental data, encompassing temperature measurements, solar irradiance, and wind conditions collected over several days. This comparison not only confirm the reliability of our model but also highlights its potential in simulating the thermal dynamics of solar energy storage systems with enhanced precision and adaptability. Through these validation steps, our research demonstrates the robustness and applicability of the developed model in real-world scenarios, reinforcing its significance in the advancement of thermal energy storage technologies.
The significance of this study lies not only in its contribution to the field of thermal energy storage but also in its potential impact on the global energy paradigm. This model provides a tool for the design and optimization of TES systems, offering a promising solution to the critical challenge of integrating solar energy into the global energy mix in a consistent and reliable mode. Through this work, we aim to contribute to the broader effort of mitigating climate change and advancing towards a more sustainable and renewable energy-dominated future
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Modeling of a bidirectional substation in a district heating network: Validation, dynamic analysis, and application to a solar prosumer
Full text linkThermal grids will play a key role in the development of local energy communities and the achievement of 100% renewable societies. Such systems allow excess heat produced by distributed producers through renewable energy sources (also referred to as “thermal prosumers”) to be shared among other consumers characterized by high heat demand or who still depend on fossil fuels. However, to achieve more reliable results when performing energy analyses, it is of utmost importance to develop models of prosumers’ substations, where technical details (e.g., type of connections, heat exchangers, valves, etc.) and controllers are accounted for. Starting from the layout of a bidirectional substation for a thermal energy network proposed in the literature, this paper proposes a dynamic model that replicates the experimental setup in the TRNSYS environment. Validation results show a good matching between simulation and experiments in terms of dynamic behavior and energy balance. To show the capabilities of the proposed model, a prosumer with heat available from 205 m2 solar thermal collectors is considered as a case study. The analysis is performed by assuming two locations characterized by different irradiation values, i.e., Palermo (Italy) and Berlin (Germany). The results show that exchanging the excess heat produced on-site with a heating network allows the solar collectors to reach peak heat production, which is 130 kW and 110 kW for Palermo and Berlin, respectively. The surplus heat sold to the network is equal to 66% and 29% of the total energy exchange within the substation for Palermo and Berlin, respectively. Conversely, the self-consumption of the produced heat accounts for 21.2% and 30.6%, respectively. The model prospectively represents a valuable tool to develop feasibility studies in Thermal Energy Communities and assess the potential of innovative energy- and cost-effective operation strategies
- …
