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Artículos en revistas Liberalization policies, the challenges of integrating distributed generation resources, and the recent flattening of electricity demand due to the economic crisis and technological change have led to lower returns for European electricity suppliers. Innovative and sustainable business models are needed to serve electricity customers while reflecting the operational needs of the system and maintaining supplier financial viability. This paper describes a novel model of Integrated Energy Services that encompasses distributed generation (DG) and demand response (DR) resources for industrial customers. We further reflect on some of the market opportunities and regulatory drivers for the development of similar schemes across Europe. info:eu-repo/semantics/publishedVersion

Abstract The aerodynamic design of small wind turbines for the urban setting attracts increasing interest within the scientific community, but the adoption of a proper control strategy may be just as important, especially in high turbulent winds, where such energy conversion devices should ideally operate. As a matter of fact, the mere rotor efficiency is meaningless unless the system has also the capability of rapidly changing its angular speed in case of a sudden variation of the wind velocity, to reach a new optimal operating condition. This work will attempt neither to develop dynamic simulation models nor to examine possible turbine control strategies, being the focus much broader, namely, the investigation of operational contexts where the peculiar inertial characteristics of wind turbines would compromise any form of robust control. Inertial and operational data of commercially available turbines (characterized by both horizontal and vertical-axis architectures), as well as the results disseminated in various literature sources, operational experiences and design best practices, are here collected under one cover and compared, thus deriving some basic and fundamental relations between rotor inertia and angular acceleration, highlighting how, in several cases, a control strategy based on the continuous tracking of the optimal operating condition is most unlikely. Such considerations raise the question of whether the problem of inertia renders futile many prevailing theories about small wind turbine operation and plans for implementing new control strategies, especially as far as vertical axis architectures are concerned. On the other hand, some constructive advice is also presented, in the form of a means to compare the effective performances of different turbines, in a given installation site, with respect to their nominal (i.e. steady state, or wind tunnel) behaviour. As a final result, a new bound for a reliable estimation of the amount of energy a wind turbine will generate in a specific site is suggested, based on the comparison between a representative time scale of the installation site and the response time of the candidate wind turbine.

The development of heat transfer fluids (HTF) and heat storage materials (HSM) is crucial to design concentrating solar plant (CSP). Binary alkaline nitrate mixtures are currently used as sensible thermal energy storage materials. However, multi-component nitrate/nitrite systems were proposed as possible better candidates. In particular, ternaries mixtures containing sodium, potassium, and calcium are extremely promising as thermal fluids, given their reduced toxicity and greater cost-effectiveness. Nevertheless, very few data are present in the scientific literature regarding the correspondent phase diagram, and only the properties of specific compositions are reported. For this reason, a regular solution model was developed and employed in this work, and validated by comparing the simulation results with experimentally obtained phase change values. In particular, given that the common calorimetric techniques are impracticable for detecting the transition temperatures of calcium containing nitrate mixtur...

<div class="section abstract"><div class="htmlview paragraph">The introduction of new light-duty vehicle emission limits to comply under real driving conditions (RDE) is pushing the diesel engine manufacturers to identify and improve the technologies and strategies for further emission reduction. The latest technology advancements on the after-treatment systems have permitted to achieve very low emission conformity factors over the RDE, and therefore, the biggest challenge of the diesel engine development is maintaining its competitiveness in the trade-off “CO₂-system cost” in comparison to other propulsion systems. In this regard, diesel engines can continue to play an important role, in the short-medium term, to enable cost-effective compliance of CO₂-fleet emission targets, either in conventional or hybrid propulsion systems configuration. This is especially true for large-size cars, SUVs and light commercial vehicles.</div><div class="htmlview paragraph">In this framework, a comprehensive approach covering the whole powertrain is of primary importance in order to simultaneously meet the performance, efficiency, noise and emission targets, and therefore, further development of the combustion system design and injection system represent important levers for additional improvements. For this purpose, a dedicated 0.5 dm³ single-cylinder engine has been developed and equipped with, a state-of-the-art Euro 6 combustion system, and an advanced common rail fuel injection system (FIS) offering higher flexibility in terms of injection strategy and higher quantity accuracy. Three injector nozzles with different hydraulic flow rates (HF) have been selected and employed for the overall combustion process optimization.</div><div class="htmlview paragraph">The optimization has been performed by means of an extensive DoE-based test campaign in which the engine and FIS operating parameters have been parametrized with the aim to carry out a proper combination in terms of HF and injection strategy. The results at partial load conditions evidence significant advantages in applying an advanced injection pattern, while the HF reduction can significantly improve the smoke emission and combustion noise without fuel consumption penalties. Therefore, a proper combination and optimization of the HF and injection strategy can provide low noise and engine-out smoke while maintaining the rated power performance targets.</div></div>

In Vietnam, the energy demand shows an ever-increasing trend. To limit the utilization of fossil fuels and the following consequences for the environment, renewable energy sources must be adopted. In this context, the paper assesses the utilization of offshore wind and sea wave, by considering a commercial wind turbine and a prototypical wave energy converter. Solar energy can be optionally also collected by this device. An algorithm is introduced to find the best composition of the three sources able to cover a desired share of energy demand. The approach is applied to Ca Mau, a province in the southern part of Vietnam. Finally, the results encourage the adoption of these energy sources that could be easily implemented up to a share of the local energy demand equal to 65%.

The real assets, procedures, systems,and subsystems of a city can be virtually represented throughan urban digital twin(DT),which integrates heterogeneous data to learn and evolve with the physical city,offering support to monitor the current status and predict possible future scenarios.A DT of a city can be organized into layers, which represent specific facets of the city and cooperate to address specifici ssues.In this work,we present an application scenario in which a geometric layer,representing the 3D morphology of the urbane nvironment, cooperates with an energy consumption layer,providing knowledge of the peculiarities of thebuilding urban area and in particular of the built fabric,to assess their impact in terms of energy efficiency.The analysis of the urban geometries provides quantitative measuresas useful input,for instance,to define heat leakage.

The aim of the paper is to study the influence of the power transformer on signal transmission in the case of a power line communication (PLC) system in a overhead Medium Voltage (MV) power network. A model of the PLC system was carried out by means of the Simulink® software. A distributed parameter MV overhead line, two power transformers, the signal coupling interface of a ST7540 FSK powerline transceiver were included in the model. The performances of the complete PLC communication system are evaluated for different line lengths by means of the attenuation computed as ratio between the received and transmitted voltage signals. © 2011 IEEE.

Abstract Rigid ceramic filters have emerged as the most promising technology for cleaning of hot gases due to their resistance to attack by aggressive gases and high temperatures. Their potential may be further extended by using them in combination with injection of a dry sorbent to remove acid gases and other chemical contaminants. A crucial factor in their successful utilisation is the ability of the cleaning pulse to remove the deposited cake effectively from the filter surface. In this study, laboratory experiments have been carried out using a single ceramic candle filter. The non-steady-state behaviour of the filter in the initial period of filtration was followed. ‘Patchy’ cleaning of the filter was observed and is consequently identified as the major cause of the inefficiency of filter cleaning indicated by the measured residual pressure drops. A simple correlation has been proposed to determine the cleaned fraction from pressure differences as a measure of the efficiency of cleaning. The conditioning curves have been successfully simulated using a recently developed probabilistic model and it has been shown that the model can also be applied to simulate the experimental results obtained in a pilot plant operating at high temperatures. The modelling results are consistent with the experimental observation that patchy cleaning with a thin residual dust layer in the cleaned areas can explain the conditioning behaviour.