1,721,788 research outputs found
CFD-based reduced model for the simulation of thermocline thermal energy storage systems
No full textThermocline thermal storages are widely used in energy systems. Computational Fluid Dynamic (CFD) can be used for an accurate simulation of the physical phenomenon but its implementation in system-level annual simulations is hardly possible because of the huge computational time required. The present paper proposes a novel approach for the utilization of CFD simulation results in system-level annual simulations and optimizations. An analytical function able to represent the dimensionless vertical temperature profile inside the tank is parameterized statistically using the results of multiple simulations of a CFD model, which have been previously validated with experimental data. The reduced model obtained is then compared to other CFD simulations under highly variable conditions, showing a satisfactory degree of agreement (the mean absolute error and the error standard deviation are calculated to be 1.52 K and 1.93 K respectively). Furthermore, it is demonstrated that this approach can be conveniently adopted for the modeling of a wide range of systems with a single tank thermal energy storage, from Concentrated Solar Power to District Heating. © 2014 Elsevier Ltd
CSP plants with thermocline thermal energy storage and integrated steam generator – Techno-economic modeling and design optimization
No full textii) identify two optimized CSP plant designs to achieve best energetic and economic performances. To achieve these aims we developed a numerical model of the main system components and validated it against experimental data. This model was then integrated in a full simulation and heuristic design optimization of the plant. The results revealed that the system proposed can generate electricity in middle-Italy (Rome) at a cost of 230.25 $/MWh with a 15% reduction compared to the double tank option. Furthermore, if cogeneration is used to recover the waste heat, this system is an interesting option for users such as small districts, university campuses and hospitals. In the latter case, the optimized system pays off in 6 years and covers 80% of the heating and cooling requirements. © 2017 Elsevier LtdAlthough CSP has reached technological maturity, high capital investment and specific electricity cost remain the major development barriers. To reduce them, highly efficient, integrated, and cheaper CSP components are urgently needed. In this paper, we investigate a novel CSP plant configuration with a single-tank Thermal Energy Storage (TES) fully integrated with the steam generator. The objective of this research is twofold: i) provide a reliable model of single-tank thermal storages with integrated steam generato
Techno-economic optimization of Concentrated Solar Power plants with thermocline thermal energy storage and integrated steam generator
No full textThe utilization of molten salts as the Heat Transfer Fluid (HTF) in Concentrated Solar Power (CSP) allows to increase the maximum operational temperature of parabolic trough power plants, with a substantial gain in the power cycle efficiency. ENEA has recently tested a way to further ameliorate this concept by introducing a single- Tank configuration of the storage system with an integrated steam generator, which can dramatically reduce the total investment cost and simplify the power plant layout. In this paper we propose to couple this system to a waste-heat recovery unit for the cogeneration of power, heating and cooling, which has the potential to extend the range of applications of CSP plants to small-size systems and to regions with a moderate solar resource. In this paper, a techno-economic analysis is implemented to investigate the feasibility of this innovative technological pathway, to determine the optimal design of a representative 1 MWe plant located in Rome and to analyze its performances. Results reveal that the heat market brings a 28 % reduction of the Levelized Electricity Cost, allowing to reach the competitive value of 230.25
Developing local cultural networks: the case of Dante 2021 in Ravenna
Full text linkIn the last decades and especially after the latest financial crisis, scholars are suggesting collaborative processes to address the reduction of public funds, as first discussed by New Public Management literature and later emphasised by Public Governance theories. As cultural activities belong to the wider set of public services, this paper enters the debate on delivering public services. It is aimed at analysing which factors contribute to an effective development of local cultural networks, also considering advantages, criticalities and potential for their future strengthening. Starting from a theoretical analysis, the paper carries out a case study of a local cultural network. The research focuses on the case of Ravenna, a town in northern Italy, and it is based on document analysis and semi-structured interviews. Results indicate that factors as geographic proximity, social relationships, a common cultural background and common values are crucial for the development of local cultural networks, consistently with isomorphism theory
A register of architectural research: a model for the evaluation of its impact on training and professional practice
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Defining authorship in the era of big data collection and its consequences on the academic career
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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
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