1,721,638 research outputs found
Reactive power control for an energy storage system: A real implementation in a Micro-Grid
No full textIn last years, the power system operators are tackling many challenges for the renewable energies integration on the grid. Further, the expected increase of electrical demand due to the uncoordinated contemporary charging of a huge number of Electric Vehicles (EVs) can create chaotic phenomena with a negative impact especially on the distribution network. Help can be offered by the deployment of Smart Grid technologies, such as Smart Metering Systems (SMSs), Information and Communications Technology (ICT) and Energy Storage Systems (ESSs). In particular, in Micro-Grids, Battery ESSs (BESSs) can play a fundamental role and can become fundamental for the integration of EV fast charging stations and distributed generations. In this case the storage can have peak shaving, load shifting and power quality functions. The ESSs can provide ancillary services also on the grid as the reactive control to adjust the power factor. In the present paper, a monitoring control program to manage the reactive power of a real ESS in a Micro-Grid has been implemented. The system is a prototype, designed, implemented and now available at ENEA (Italian National Agency for New Technologies, Energy and Sustainable Economic Development) labs. A wide experimental activity has been performed on the prototype system in order to test this functionality for the integration in a bigger Smart Grid available at the same ENEA labs including the Micro-grid. The integration has been possible, thanks to the free ICT protocols used by the researchers and which are described here. The results of the experimental tests show that the system can have good performance to adjust the power factor in respect to the main distribution grid and an EV charging station. © 2015 Elsevier Ltd. All rights reserved
AAA humanizing energy
Full text linkCome promuovere la transizione energetica a partire da quella sfera di innovazioni di senso tipicamente design-driven e capaci di agire sulla dimensione più profonda della cultura e dei comportamenti sostenibili? Questo libro traccia percorsi e possibili risposte che mirano a generare impatti socio-culturali nelle nostre città e nelle nostre comunità ma anche negli spazi più intimi delle nostre case. L’energia sostenibile è qui obiettivo imprescindibile e insieme “materia” che plasma il vissuto del quotidiano di individui e collettività. Umanizzare l’energia vuol dunque dire valorizzare la portata percettiva e relazionale di questa sull’ambiente abitato, spostando lo sguardo progettuale al di là della mera cifra dell’innovazione tecnica e tecnologica. Umanizzare l’energia implica trovare un nuovo lessico e una nuova sintassi di progetto per attivare dialoghi, per Avvicinare, Abilitare e Agire in modo nuovo verso la transizione energetica. Il testo è esito del progetto DE-sign, promosso dal Dipartimento Unità Efficienza Energetica dell’ENEA, finanziato dal Ministero dell’Ambiente e della Sicurezza Energetica nell’ambito del Programma Nazionale “Italia in Classe A” e sviluppato coralmente con il Dipartimento Design del Politecnico di Milano, il Dipartimento di Beni culturali e ambientali (Cattedra di Psicologia sociale) dell’Università degli Studi di Milano e il Dipartimento Culture del Progetto dell’Università IUAV di Venezia. La ricerca è finanziata dal Programma Nazionale Italia in classe A promosso dal Ministero dell’Ambiente e della Sicurezza Energetica e realizzato dall’ENEA, in attuazione delle disposizioni contenute nell’art. 13 D.Lgs 102/2014, come modificato dal D.Lgs 14 luglio 2020, n.73 in materia di Programma Nazionale di Informazione e Formazione sull’Efficienza Energetica
A new heat cost allocation method for social housing
No full textTo promote energy saving in the residential sector Directive 2012/27/EU has set the obligation for buildings supplied by central heating sources to install individual heat metering and accounting systems. However, in social housing, bills based exclusively on individual consumption should be unfair due to some unfavourable situations, such as first and top floors, presence of unheated common spaces, north oriented dwellings. Nevertheless, fair heat accounting rules should be introduced especially in social housing buildings, which are often thermally underperforming with inefficient heating plants and tenants are commonly low-income people and elderly. On the other hand, common regulations for heat accounting providing compensation to avoid inequalities among tenants have not been set and different approaches on this topic are present among EU Member States. In this paper the authors present a new heat accounting method for social housing based on the estimation of extra-consumptions due to building inefficiencies. According to this method, extra-consumptions are charged to all tenants in order to encourage energy efficient retrofit interventions. Finally, the new method has been experimented in a typical social housing building in Italy and compared to other methods applicable in EU, evidencing some advantages and weaknesses. © 2018 Elsevier B.V
NMR characterization of cytochrome b(562)
No full textThe backbone dynamics of ferricytochrome b(562), a four-helix bundle protein from Escherichia coli, have been studied by NMR spectroscopy. The consequences of the introduction of a c-type thioether linkage between the heme and protein and the reduction to the ferrous cytochrome have also been analyzed. (15)N relaxation rates R(1) and R(2) and (1)H-(15)N NOEs were measured at proton Larmor frequencies of 500 and 600 MHz for the oxidized and reduced protein as well as for the oxidized R98C variant. In the latter protein, an "artificial" thioether covalent bond has been introduced between the heme group and the protein frame [Arnesano, F., Banci, L., Bertini, I., Ciofi-Baffoni, S., de Lumley Woodyear, T., Johnson, C. M., and Barker, P. D. (2000) Biochemistry 39, 1499-1514]. The (15)N relaxation data were analyzed with the ModelFree protocol, and the mobility parameters on the picosecond to nanosecond time scale were compared for the three species. The three forms are rather rigid as a whole, with average generalized order parameters values of 0.87 +/- 0.08 (oxidized cytochrome b(562)), 0.84 +/- 0.07 (reduced cytochrome b(562)), and 0.85 +/- 0.07 (oxidized R98C cytochrome b(562)), indicating similar mobility for each system. Lower order parameters (S(2)) are found for residues belonging to loops 1 and 2. Higher mobility, as indicated by lower order parameters, is found for heme binding helices alpha 1 and alpha 4 in the R98C variant with respect to the wild-type protein. The analysis requires a relatively long rotational correlation time (tau(m) = 9.6 ns) whose value is accounted for on the basis of the anisotropy of the molecular shape and the high phosphate concentration needed to ensure the occurrence of monomer species. A parallel study of motions in the millisecond to microsecond time scale has also been performed on oxidized wild-type and R98C cytochrome b(562). In a CPMG experiment, decay rates were analyzed in the presence of spin-echo pulse trains of variable spacing. The dynamic behavior on this time scale is similar to that observed on the sub-nanosecond time scale, showing an increased mobility in the residues connected to the heme ligands in the R98C variant. It appears that the increased protein stability of the variant, established previously, is not correlated with an increase in rigidity
Comets
Full text linkThe paper reviews properties of comets, from historical sightings and interpretations, to contemporary ground- and space-based knowledge. The importance of comets in understanding the present Solar System and its dynamical, physical and chemical evolution, their relationship with other minor bodies, their possible role for the very early phases of our Earth, will be examined. Emphasis will be on the results of the recently completed European Rosetta mission to comet 67P/Churyumov-Gerasimenko, in particular those by OSIRIS, its imaging system. It is fair to say that Rosetta's results represent a most important step in the development of cometary science, whose full implications start just to surface and will be fully appreciated over several more years
Molecular Basis of Metal-Ion Selectivity and Ultrasensitivity of Metalloregulatory Proteins
No full textEfficient energy management in smart micro-grids: ZERO grid impact buildings
No full textIn a smart micro-grid (MG) each generator or load has to take part in the network management, joining in reactive power supply/voltage control, active power supply/frequency control, fault ride-through capability, and power quality control. This paper includes a new concept for building integration in MGs with zero grid-impact so improving the MG efficiency. These aims are shown to be achievable with an intelligent system, based on a dc/ac converter connected to the building point of coupling with the main grid. This system can provide active and reactive power services also including a dc link where storage, generation, and loads can be installed. The system employed for validation is a prototype available at ENEA Laboratories (Italian National Agency for New Technologies). A complete and versatile model in MATLAB/SIMULINK is also presented. The simulations results and the experimental test validation are included. The trial confirms the model goodness and the system usefulness in MG applications. © 2015 IEEE
Anthropometric features and body composition of young athletes practicing karate at a high and medium competitive level
Full text linkThe aim of the study was to examine the anthropometric features and body composition of athletes practising karate at a high and medium competitive level. Our study was carried out on a sample of 35 subjects practising karate and aged from 16.0 to 32.5 years. This sample was divided into two groups: group 1 (n=14 elite athletes) and group 2 (n=21 amateur athletes). Various anthropometric measurements were taken (weight, height both standing and sitting, diameters, circumferences and skinfold thickness) from which different anthropometric indices were calculated (body mass index, Scelic and Grant indices, arm muscle circumference and area), and the somatotype was then determined. The body composition of each subject was assessed using the skinfold technique and the Jackson-Pollock (J-P) and Sloan-Weir (S-W) equations. The two groups of athletes showed very similar measurements regarding anthropometric characteristics. Only the Scelix index presented a significantly different value in the two groups (49.6±1.3 for group 1 vs. 51.1±1.3 for group 2; p<0.01). Group 1 showed a mesomorphic-ectomorphic somatotype, while the amateur athletes presented a balanced mesomorphic type. Moreover, a lower percentage of fat mass was more frequent in the first group (J-P=8.1±2.4%; S-W=8.9±3.3%) than in the second one (J-P=9.8±1.6%; S-W=11.2±3.7%), although the differences between the two groups were not significant. We conclude that group 1 is characterized by a slightly prominent vertical development of the skeletal frame. This could be an anthropometric characteristic that is best suited to meet the specific functional requirements of this sport. Moreover, both groups of athletes are characterized by a low percentage of fat mass, particularly the elite group
- …
