Analisi di fattibilità di accumulatore di energia domestico a volano in accordo ai piani energetici nazionali per lo sviluppo sostenibile

Nel primo punto del capitolo seguente si propone una panoramica sulla decarbonizzazione del settore energetico e si discutono i principali provvedimenti europei avviati a tal fine. Si analizza lo scenario energetico italiano e le sue prospettive future; anche l’Italia deve impegnarsi in termini di energie rinnovabili e riduzione dei gas serra. Nel settore energetico nazionale sono comprese la produzione, la trasformazione e l’utilizzo di energia elettrica. In questa fase in particolare, si studiano i dati relativi alla fase di produzione. Inoltre, si studia la dipendenza energetica dell’Italia dalle fonti fossili estere. Di seguito saranno analizzati i piani energetici auspicabili per il 2030 e per il 2050. Nel secondo punto si passa poi all’analisi dei consumi, attraverso lo studio dei consumi medi e l’approfondimento sui consumi dei principali elettrodomestici. Nella prima sezione del capito che segue vengono analizzati i principali sistemi di accumulo di energia domestica con particolare enfasi riguardo i limiti applicativi. Le batterie a litio seppur relativamente economiche hanno un forte impatto ambientale che sarebbe ammortizzato utilizzando un nuovo modello di volano (MechSTOR). Nella seconda parte del capitolo, si esamina invece la fattibilità del modello di accumulo a volano. I costi del volano verrebbero ammortizzati dal guadagno relativo all’immissione in rete di energia elettrica? L’analisi in Simulink ha permesso di lavorare con i segnali di potenza, utilizzando le curve di carico domestico e la curva di produzione fotovoltaica al fine di studiare la convenienza economica della batteria a volano.

Progettazione e analisi di impianti fotovoltaici in bassa tensione e autoconsumo collettivo

La tesi si propone di fornire un’analisi degli impianti fotovoltaici in bassa tensione sia dal punto di vista progettuale che economico e analizzare il recente schema di autoconsumo collettivo. La tesi prevede l’analisi di tre progetti differenti. Il primo riguarda la progettazione di un impianto residenziale di piccola taglia che si trova ad affrontare le problematiche causate dagli ombreggiamenti generati dai camini, comportando l’utilizzo di ottimizzatori. Viene discussa la pratica di connessione in iter semplificato e viene effettuata un’analisi economica riguardante la convenienza dell’installazione dell’impianto, della convenienza del sistema di accumulo e degli ottimizzatori in tre scenari di costo dell’energia differenti. Il secondo riguarda la progettazione di un impianto residenziale di piccola taglia con ridotto ombreggiamento. Viene discussa la pratica di connessione in iter ordinario e viene effettuata un’analisi economica riguardante la convenienza dell’installazione dell’impianto e della convenienza del sistema di accumulo suddividendo i consumi dell’utente nelle fasce di consumo e considerando una tariffa bioraria. L’ultimo progetto riguarda un impianto condominiale nello schema di autoconsumo collettivo. Vengono discussi i risultati della progettazione eseguita con il software SOLergo e in particolare viene mostrato il calcolo del carico vento secondo la normativa NTC 2018 e viene effettuata la verifica a ribaltamento per controllare la stabilità del sistema. Successivamente viene effettuata un’analisi dettagliata degli ombreggiamenti su PVsyst attraverso la realizzazione tridimensionale del condominio. Viene poi analizzato lo schema dell’autoconsumo collettivo per poi effettuare un’analisi economica complessiva con l’obiettivo di analizzare l’influenza degli incentivi presenti, in particolare per l’autoconsumo collettivo e valutare se l’installazione del sistema di accumulo risulti conveniente per i condomini.

Design and Performance Analysis of the Electrical Power System of a Petrochemical Facility

This thesis deals with the sizing and analysis of the electrical power system of a petrochemical plant. The activity was carried out in the framework of an electrical engineering internship. The sizing and electrical calculations, as well as the study of the dynamic behavior of network quantities, are accomplished by using the ETAP (Electrical Transient Analyzer Program) software. After determining the type and size of the loads, the calculation of power flows is carried out for all possible network layout and different power supply configurations. The network is normally operated in a double radial configuration. However, the sizing must be carried out taking into account the most critical configuration, i.e., the temporary one of single radial operation, and also considering the most unfavorable power supply conditions. The calculation of shortcircuit currents is then carried out and the appropriate circuit breakers are selected. Where necessary, capacitor banks are sized in order to keep power factor at the point of common coupling within the preset limits. The grounding system is sized by using the finite element method. For loads with the highest level of criticality, UPS are sized in order to ensure their operation even in the absence of the main power supply. The main faults that can occur in the plant are examined, determining the intervention times of the protections to ensure that, in case of failure on one component, the others can still properly operate. The report concludes with the dynamic and stability analysis of the power system during island operation, in order to ensure that the two gas turbines are able to support the load even during transient conditions.

Applicazione allo scenario italiano di un modello di costo dinamico per l'ottimizzazione del mix energetico e la gestione della rete elettrica

Nell’attuale contesto energetico di forte instabilità, prezzi e produttività subiscono continue variazioni a causa di fattori politici ed economici. Il sistema elettrico è chiamato a rispondere velocemente ai cambiamenti garantendo continuamente il soddisfacimento del fabbisogno di energia elettrica. Nel presente elaborato viene utilizzato un modello di costo dinamico, estratto dalla letteratura scientifica, con lo scopo di gestire efficientemente i flussi energetici e garantire una programmazione ottimale del mix produttivo. Viene analizzato lo scenario italiano mettendo in relazione produzione, trasmissione e domanda energetica. I dati utilizzati fanno riferimento, quanto più possibile, al contesto attuale. Coerentemente con la situazione reale i risultati ottenuti mettono in risalto le criticità e i punti di forza principali del sistema elettrico italiano delineando i possibili cambiamenti attuabili a medio termine.

Validation of the Edinburgh Postnatal Depression Scale for men, and comparison of item endorsement with their partners

Background: The Edinburgh Postnatal Depression Scale (EPDS) has been validated and used extensively in screening for depression in new mothers, both in English speaking and non-English speaking communities. While some studies have reported the use of the EPDS with Fathers, none have validated it for this group, and thus the appropriate cut-off score for screening for depression or anxiety caseness for this population is not known. Method: Couples were recruited antenatally and interviewed at six weeks postpartum. EPDS scores and distress caseness (depression or anxiety disorders) for 208 fathers and 230 mothers were determined using the Diagnostic Interview Schedule. Results: Analyses of the EPDS for fathers using distress caseness (depression or anxiety disorders) as the criterion shows that a cut-off of 5/6 has optimum receiver operating characteristics. Furthermore acceptable reliability (split-half and internal consistency) and validity (concurrent) coefficients were obtained. For mothers the optimum cut-off screening value to detect distress caseness was 7/8. Item analysis revealed that fathers endorsed seven of the ten items at lower rates to mothers, with the most significant being that referring to crying. Conclusions: The EPDS is a reliable and valid measure of mood in fathers. Screening for depression or anxiety disorders in fathers requires a two point lower cut-off than screening for depression or anxiety in mothers, and we recommend this cut-off to he 5/6. (C) 2001 Elsevier Science B.V. All rights reserved.

How to screen for problematic cannabis use in population surveys: an evaluation of the Cannabis Use Disorders Identification Test (CUDIT) in a Swiss sample of adolescents and young adults.

BACKGROUND/AIMS: Cannabis use is a growing challenge for public health, calling for adequate instruments to identify problematic consumption patterns. The Cannabis Use Disorders Identification Test (CUDIT) is a 10-item questionnaire used for screening cannabis abuse and dependency. The present study evaluated that screening instrument. METHODS: In a representative population sample of 5,025 Swiss adolescents and young adults, 593 current cannabis users replied to the CUDIT. Internal consistency was examined by means of Cronbach's alpha and confirmatory factor analysis. In addition, the CUDIT was compared to accepted concepts of problematic cannabis use (e.g. using cannabis and driving). ROC analyses were used to test the CUDIT's discriminative ability and to determine an appropriate cut-off. RESULTS: Two items ('injuries' and 'hours being stoned') had loadings below 0.5 on the unidimensional construct and correlated lower than 0.4 with the total CUDIT score. All concepts of problematic cannabis use were related to CUDIT scores. An ideal cut-off between six and eight points was found. CONCLUSIONS: Although the CUDIT seems to be a promising instrument to identify problematic cannabis use, there is a need to revise some of its items.

Alternative Energy Conversion Systems for a Micro Scale Wind Turbine

This Master's thesis deals with a Micro Scale Wind Wind Turbine application. The thesis consists of nine chapters. The first chapter is an introduction to the philosophy of a small scale wind turbine application. The second defines concepts, and lists the requirements. The third presents the whole application for an On-Grid , and for an Off-Grid arrangement, with main concentration on lighting, heating, and energy storage. The fourth deals with the Inverter's technology, which are used for the conversion of the produced power. The fifth chapter presents the available storage technology and it's possibilities. The sixth deals with the system, and the technological means used for the implementation. The seventh presents the PLC device, which was used as the controller for the management of the whole application. The eighth deals with the concept and the control application philosophy that the PLC involves. And the final chapter presents conclusions and ideas for further considerations.

Small wind energy

Master thesis represents the literature overview of small wind energy. I have given the description of principles of work wind turbines, the description of the types of wind turbines, their advantages and disadvantages, the characteristics of small wind turbines, have shown how to count the payback period, have given an overview of currently market wind turbines and the future forecast.

Economics of Hybrid Photovoltaic Power Plants

The global power supply stability is faced to several severe and fundamental threats, in particular steadily increasing power demand, diminishing and degrading fossil and nuclear energy resources, very harmful greenhouse gas emissions, significant energy injustice and a structurally misbalanced ecological footprint. Photovoltaic (PV) power systems are analysed in various aspects focusing on economic and technical considerations of supplemental and substitutional power supply to the constraint conventional power system. To infer the most relevant system approach for PV power plants several solar resources available for PV systems are compared. By combining the different solar resources and respective economics, two major PV systems are identified to be very competitive in almost all regions in the world. The experience curve concept is used as a key technique for the development of scenario assumptions on economic projections for the decade of the 2010s. Main drivers for cost reductions in PV systems are learning and production growth rate, thus several relevant aspects are discussed such as research and development investments, technical PV market potential, different PV technologies and the energetic sustainability of PV. Three major market segments for PV systems are identified: off-grid PV solutions, decentralised small scale on-grid PV systems (several kWp) and large scale PV power plants (tens of MWp). Mainly by application of ‘grid-parity’ and ‘fuel-parity’ concepts per country, local market and conventional power plant basis, the global economic market potential for all major PV system segments is derived. PV power plant hybridization potential of all relevant power technologies and the global power plant structure are analyzed regarding technical, economical and geographical feasibility. Key success criteria for hybrid PV power plants are discussed and comprehensively analysed for all adequate power plant technologies, i.e. oil, gas and coal fired power plants, wind power, solar thermal power (STEG) and hydro power plants. For the 2010s, detailed global demand curves are derived for hybrid PV-Fossil power plants on a per power plant, per country and per fuel type basis. The fundamental technical and economic potentials for hybrid PV-STEG, hybrid PV-Wind and hybrid PV-Hydro power plants are considered. The global resource availability for PV and wind power plants is excellent, thus knowing the competitive or complementary characteristic of hybrid PV-Wind power plants on a local basis is identified as being of utmost relevance. The complementarity of hybrid PV-Wind power plants is confirmed. As a result of that almost no reduction of the global economic PV market potential need to be expected and more complex power system designs on basis of hybrid PV-Wind power plants are feasible. The final target of implementing renewable power technologies into the global power system is a nearly 100% renewable power supply. Besides balancing facilities, storage options are needed, in particular for seasonal power storage. Renewable power methane (RPM) offers respective options. A comprehensive global and local analysis is performed for analysing a hybrid PV-Wind-RPM combined cycle gas turbine power system. Such a power system design might be competitive and could offer solutions for nearly all current energy system constraints including the heating and transportation sector and even the chemical industry. Summing up, hybrid PV power plants become very attractive and PV power systems will very likely evolve together with wind power to the major and final source of energy for mankind.

A testing and demonstration facility for PV systems and components

A test and demonstration facility for PV and PV hybrid systems and system components has been designed and installed at Dalarna University in Sweden. The facility allows studies of complete PV systems or single components in a range of 0.1-10 kW. The facility includes two grid-connected PV systems, a PV Hybrid off-grid system, three emulators and the necessary measurement and control equipment. Tests can be done manually or automatically through programmed test procedures controlled that will be implemented in Labview. The facility shall be used by researchers, professionals of the industry and engineering students.

Electricity Supply Solutions for an Educational Center in Tanzania

The aim of this study was to investigate electricity supply solutions for an educationalcenter that is being built in Chonyonyo Tanzania. Off-grid power generation solutions andfurther optimization possibilities were studied for the case.The study was done for Engineers Without Borders in Sweden. Who are working withMavuno Project on the educational center. The school is set to start operating in year 2015with 40 girl students in the beginning. The educational center will help to improve genderequality by offering high quality education in a safe environment for girls in rural area.It is important for the system to be economically and environmentally sustainable. Thearea has great potential for photovoltaic power generation. Thus PV was considered as theprimary power generation and a diesel generator as a reliable backup. The system sizeoptimization was done with HOMER. For the simulations HOMER required componentdata, weather data and load data. Common components were chose with standardproperties, the loads were based on load estimations from year 2011 and the weather datawas acquired from NASA database. The system size optimization result for this base casewas a system with 26 kW PW; 5.5 kW diesel generator, 15 kW converter and 112 T-105batteries. The initial cost of the system was 55 875 €, the total net present cost 92 121 €and the levelized cost of electricity 0.264 €/kWh.In addition three optimization possibilities were studied. First it was studied how thesystem should be designed and how it would affect the system size to have night loads(security lights) use DC and could the system then be extended in blocks. As a result it wasfound out that the system size could be decreased as the inverter losses would be avoided.Also the system extension in blocks was found to be possible. The second study was aboutinverter stacking where multiple inverters can work as one unit. This type of connectionallows only the required number of inverters to run while shutting down the excess ones.This would allow the converter-unit to run with higher efficiency and lower powerconsumption could be achieved. In future with higher loads the system could be easilyextendable by connecting more inverters either in parallel or series depending on what isneeded. Multiple inverters would also offer higher reliability than using one centralizedinverter. The third study examined how the choice of location for a centralized powergeneration affects the cable sizing for the system. As a result it was found that centralizedpower generation should be located close to high loads in order to avoid long runs of thickcables. Future loads should also be considered when choosing the location. For theeducational center the potential locations for centralized power generation were found outto be close to the school buildings and close to the dormitories.

Solar PV Powered Air Conditioner Analysis for an Office/Classroom in a Tropical Climate

This thesis focuses on using photovoltaic produced electricity to power air conditioners in a tropical climate. The study takes place in Surabaya, Indonesia at two different locations the classroom, located at the UBAYA campus and the home office, 10 km away. Indonesia has an average solar irradiation of about 4.8 kWh/m²/day (PWC Indonesia, 2013) which is for ideal conditions for these tests. At the home office, tests were conducted on different photovoltaic systems. A series of measuring devices recorded the performance of the 800 W PV system and the consumption of the 1.35 kW air conditioner (cooling capacity). To have an off grid system many of the components need to be oversized. The inverter has to be oversized to meet the startup load of the air conditioner, which can be 3 to 8 times the operating power (Rozenblat, 2013). High energy consumption of the air conditioner would require a large battery storage to provide one day of autonomy. The PV systems output must at least match the consumption of the air conditioner. A grid connect system provides a much better solution with the 800 W PV system providing 80 % of the 3.5 kWh load of the air conditioner, the other 20 % coming from the grid during periods of low irradiation. In this system the startup load is provided by the grid so the inverter does not need to be oversized. With the grid-connected system, the PV panel’s production does not need to match the consumption of the air conditioner, although a smaller PV array will mean a smaller percentage of the load will be covered by PV. Using the results from the home office tests and results from measurements made in the classroom. Two different PV systems (8 kW and 12 kW) were simulated to power both the current air conditioners (COP 2.78) and new air conditioners (COP 4.0). The payback period of the systems can vary greatly depending on if a feed in tariff is awarded or not. If the feed in tariff is awarded the best system is the 12 kW system, with a payback period of 4.3 years and a levelized cost of energy at -3,334 IDR/kWh. If the feed in tariff is not granted then the 8 kW system is the best choice with a lower payback period and lower levelized cost of energy than the 12 kW system under the same conditions.

Comparison of venous plasma glycemia and capillary glycemia for the screening of type 2 diabetes mellitus in the Japanese-Brazilian community of Mombuca (Guatapará-SP)

Abstract Background To identify the most appropriate cut-off points of fasting glycemia for the screening of diabetes mellitus type 2 (DM2) with the comparison of the properties of capillary glycemia (CG) and venous blood plasma glycemia (PG) in a population of Japanese origin from the community of Mombuca, Guatapará - SP, Brazil. Methods This was a population-based descriptive cross-sectional study conducted on a sample of 131 individuals of both genders aged 20 years or more (66.8% of the target population). CG was measured with a glucometer in a blood sample obtained from the fingertip and PG was determined by an enzymatic method (hexokinase) in venous blood plasma, after a 10-14 hour fast in both cases. Data were analyzed by the receiver operating characteristic (ROC) curve in order to identify the best cut-off point for fasting glycemia (CG and PG) for the diagnosis of DM, using the 2-hour plasma glycemia > 200 mg/dl as gold - standard. Results The ROC curve revealed that the best cut-off point for the screening of DM was 110 mg/dl for CG and 105 mg/dl for PG, values that would optimize the relation between individuals with positive and false-positive results. The area under the ROC curve was 0.814 for CG (p < 0.01) and 0.836 for PG (p < 0.01). Conclusions The cut-off points of 105 mg/dl(5.8 mmol/l) for PG and of 110 mg/dl(6.1 mmol/l) for CG appear to be the most appropriate for the screening of DM2 in the population under study, with emphasis on the fact that the value recommended for CG is 5 mg/dl higher than that for PG, in contrast to WHO recommendations.

Analisi e ottimizzazione termodinamica del sistema di generazione di potenza di un impianto solare a concentrazione ibrido

Impianto solare termodinamico a concentrazione per la produzione di energia elettrica.

Il settore Energy & Utilities: un modello di business per il recupero dell'efficienza nella gestione del Cliente

Il Lavoro si inserisce nel quadro complesso del settore Energy & Utilities e si propone l’obiettivo di analizzare l’attuale mercato dell’energia per individuarne i driver al cambiamento e presentare un innovativo modello di business per le aziende di vendita di energia, con lo scopo di recuperare efficienza nella gestione del Cliente finale, cercando di quantificarne i vantaggi potenziali. L’attività di studio e progettuale è stata svolta nell’ambito di un periodo di tirocinio formativo della durata di sei mesi, effettuato presso Engineering Ingegneria Informatica S.p.A., in particolare nella sede di viale Masini di Bologna, a seguito della candidatura autonoma dello studente e del suo immediato inserimento nei processi di business della divisione Utilities dell’azienda. Il Lavoro si suddivide in 9 capitoli: dopo una breve introduzione sul settore Energy&Utilities, nei primi quattro capitoli sono descritte le filiere produttive dei principali servizi, i principali attori del mercato e gli aspetti normativi e tariffari che caratterizzano l’intero settore, valutando in particolare la formazione del prezzo del gas e dell’energia elettrica. I capitoli cinque e sei descrivono invece le principali tendenze, le strategie competitive in atto nel mercato delle Utilities e l’importanza del Cliente, in un’ottica di CRM che segue i dettami del modello “Customer Centric”. Gli ultimi capitoli mostrano invece, dopo una breve presentazione dell’azienda in cui lo studente ha svolto l’attività, l’intero lavoro di analisi realizzato, input del modello di business a chiusura del Lavoro, volto a quantificare gli impatti del processo di liberalizzazione che ha radicalmente modificato il settore delle Utilities negli ultimi anni, valutando a proposito la profittabilità per un cliente medio in base ad un’opportuna pre-analisi di segmentazione. Il modello di business che occupa l’ultimo capitolo costituisce una soluzione originale e innovativa per incrementare tale profittabilità.