Prototipo di schermo adattativo basato su Android e Bluetooth Low Energy

La tesi nasce da un'attivit�� di ricerca approfondita su alcune tecnologie innovative e all'avanguardia nell'ambito del mobile computing e dell'Internet of Things. Tra queste il focus principale �� orientato allo studio del Bluetooth Low Energy, nuova specifica di Bluetooth caratterizzata principalmente da un consumo di energia assai ridotto. In particolare, si �� approfondito il suo funzionamento nel caso dei beacon, piccoli dispositivi che permettono una localizzazione mediante l'invio di un segnale BLE. Inoltre �� stata analizzata la possibilit�� di interazione con Android, poich�� oggigiorno non si pu�� evitare di pensare a come queste tecnologie possano interfacciarsi con il mondo degli smartphone e dei tablet. Come conseguenza di tale attivit�� di ricerca �� stato analizzato un caso di studio che permettesse di applicare le tecnologie studiate e la loro interazione. Si �� pensato quindi a un piccolo sistema distribuito per schermi adattativi (capaci di modificare i contenuti visualizzati in relazione ad eventi esterni) affinch�� ogni schermo mostrasse dinamicamente l'orario delle lezioni di ciascuno studente all'avvicinarsi di quest'ultimo, e solo per il tempo di permanenza nei pressi dello schermo. Si �� quindi progettato e sviluppato un prototipo, e infine durante il testing si sono potute verificare le attuali potenzialit�� di queste tecnologie e trarre conclusioni sulla possibilit�� della loro futura diffusione e di impiego in contesti differenti.

Analisi e realizzazione di un convertitore multilivello ad alta efficienza per applicazioni fotovoltaiche

Nei primi vent���anni, la ricerca in ambito fotovoltaico si �� focalizzata sull���evoluzione di quelle tecnologie associate alla semplice cella ed al sistema intero, per offrire miglioramenti con particolare riguardo al fronte dell���efficienza. Negli ultimi decenni, lo studio sull���energia rinnovabile ha ampliato i propri confini, sino a quella branca denominata elettronica di potenza, che ne permette la conversione e lo sfruttamento da parte dell���utente. L���elaborato si propone quindi di apportare un contributo verso tale direzione, teorico piuttosto che pratico, esaminando dapprima il mondo che effettivamente circonda l���impianto fotovoltaico grid-connected e successivamente ponderando e pianificando le scelte che conseguono dall���analisi letteraria. Particolare attenzione sar�� rivolta al concetto di multilivello relativo agli inverter e agli aspetti che ne comportano il largo utilizzo nell���elettronica di potenza. Si stima che i primi brevetti risalgano a circa trent���anni orsono e uno di questi, tracciabile, riguarderebbe la configurazione a cascata di full-bridge, alimentati separatamente in DC, per ottenere a valle una scala di tensioni AC. Per mezzo di manipolazioni, nascer�� in seguito il diode-clamped, attuale predecessore del Neutral Point Clamped T-Type Inverter. Si introdurranno pertanto le principali caratteristiche che contraddistinguono il convertitore, peculiare riguardo per la configurazione single leg nonch�� trifase. Ardua sar�� la scelta sulla tecnica di controllo dell���inverter, sia per quanto concerne la fase simulativa che quella realizzativa, in quanto il dispositivo �� indubbiamente considerato innovativo nel proprio campo di appartenenza. Convalidando la letteratura per mezzo di opportune simulazioni, si potr�� procedere alla progettazione e quindi all���assemblaggio della scheda che effettivamente include l���inverter. Il lavoro implicher�� numerose prove, effettuate in svariate condizioni di funzionamento, al fine di sostenere le conclusioni teoriche.

Analisi della rete di teleriscaldamento di Corticella in presenza di utenze attive

Oggetto di questa tesi �� lo studio di una rete di teleriscaldamento (TLR) preesistente, la rete di Corticella (Bo) ipotizzando la presenza di sottostazioni di scambio termico attive. Inizialmente sono state presentate le sottostazioni di scambio termico sia tradizionali che attive. Nelle tradizionali ci si �� soffermato sul tipo di regolazione che pu�� avvenire. Per quanto riguarda le sottostazioni di scambio termico attive son stati esaminati i 4 layout che permettono uno scambio termico bidirezionale di energia termica. E��� stato presentato il software IHENA (intelligent Heat Energy Network Analysis) creato dal dipartimento di ingegneria industriale, che ha permesso di effettuare le simulazioni sulla rete analizzata. Viene mostrato l���algoritmo di Todini-Pilati generalizzato dall���utilizzo delle equazioni di Darcy-Weisbach su cui si basa il motore di calcolo. Inoltre vengono presentati i vari input che �� necessario inserire per ottenere il calcolo della rete. Dopo nozioni di base relative al teleriscaldamento attivo e la presentazione del software utilizzato si �� passati alla vera e propria analisi della rete di teleriscaldamento. Sono state effettuate varie simulazioni per vedere l���andamento della rete di Corticella sia considerandola passiva (come nella realt��) che ipotizzandola attiva tramite l���inserimento di sottostazioni di scambio termico ative. Le analisi condotte riguardano i seguenti punti. a) E��� stata presentata la rete di Corticella cosi come �� andando a studiare quindi il caso base. b) Sono state svolte delle analisi per vedere come si comportava la rete nel caso in cui venivano variati dei parametri operativi come i carichi termici richiesti dalle utenze. c) Sono stati valutati i percorsi pi�� critici. d) Si �� condotta un analisi sulla regolazione al variare delle temperature esterne. Dopo l'analisi del caso base sono state introdotte delle sottostazioni di scambio termico attive, prima solo una, e poi varie lungo determinati percorsi. Le valutazioni effettuate mettevano in primo piano gli andamenti della temperatura nei percorsi, la potenza termica generata dalla sorgente, la temperatura di ritorno in centrale e se si verificano delle problematiche sugli scambiatori di calore. In queste simulazioni sono stati valutati tutti e quattro gli schemi utilizzabili. Infine �� stata effettuata un analisi comparativa tra le varie soluzioni studiate per poter mettere a confronto i casi. In particolare anche qui si sono voluti confrontare i valori di potenza spesa per il pompaggio, temperatura di ritorno in centrale e potenza termica offerta dalla sorgente.

Misure di rumore in corrente in un circuito per la generazione di un campo magnetico stabile

Questo lavoro di Tesi, svolto nell���ambito dell���esperimento BEC3 presso il LENS, costituisce il primo approccio al problema della stabilizzazione del campo magnetico di bias in una trappola per atomi ultra-freddi. Stabilizzare il campo magnetico generato da una coppia di bobine si traduce nello stabilizzare la corrente che le attraversa e il primo passo verso la soluzione di questo problema consiste nello stimare lo spettro di potenza del rumore in corrente del circuito. A questo scopo �� stata misurata la PSD (Power Spectral Density) del segnale ai capi di diversi sensori per alcuni valori di corrente erogata da due diversi alimentatori. La PSD �� stata misurata sia in maniera diretta, che indiretta, attraverso la trasformata di Fourier della Funzione di Autocorrelazione del segnale, misurata nelle stesse condizioni descritte. I dati raccolti costituiscono la base da cui partire per la progettazione e la realizzazione del circuito di stabilizzazione.

Quantum dot / optical protein bio-nano hybrid system biosensing

The integration of novel nanomaterials with highly-functional biological molecules has advanced multiple fields including electronics, sensing, imaging, and energy harvesting. This work focuses on the creation of a new type of bio-nano hybrid substrate for military biosensing applications. Specifically it is shown that the nano-scale interactions of the optical protein bacteriorhodopsin and colloidal semiconductor quantum dots can be utilized as a generic sensing substrate. This work spans from the basic creation of the protein to its application in a novel biosensing system. The functionality of this sensor design originates from the unique interactions between the quantum dot and bacteriorhodopsin molecule when in nanoscale proximity. A direct energy transfer relationship has been established between coreshell quantum dots and the optical protein bacteriorhodopsin that substantially enhances the protein���s native photovoltaic capabilities. This energy transfer phenomena is largely distance dependent, in the sub-10nm realm, and is characterized experimentally at multiple separation distances. Experimental results on the energy transfer efficiency in this hybrid system correlate closely to theoretical predictions. Deposition of the hybrid system with nano-scale control has allowed for the utilization of this energy transfer phenomena as a modulation point for a functional biosensor prototype. This work reveals that quantum dots have the ability to activate the bacteriorhodopsin photocycle through both photonic and non-photonic energy transfer mechanisms. By altering the energy transferred to the bacteriorhodopsin molecule from the quantum dot, the electrical output of the protein can be modulated. A biosensing prototype was created in which the energy transfer relationship is altered upon target binding, demonstrating the applicability of a quantum dot/bacteriorhodopsin hybrid system for sensor applications. The electrical nature of this sensing substrate will allow for its efficient integration into a nanoelectronics array form, potentially leading to a small-low power sensing platform for remote toxin detection applications.

Design and Realization of an Energy Harvester Using Pulsating Arterial Pressure

Most medical implants run on batteries, which require costly and tedious replacement or recharging. It is believed that micro-generators utilizing intracorporeal energy could solve these problems. However, such generators do not, at this time, meet the energy requirements of medical implants.This paper highlights some essential aspects of designing and implementing a power source that scavenges energy from arterial expansion and contraction to operate an implanted medical device. After evaluating various potentially viable transduction mechanisms, the fabricated prototype employs an electromagnetic transduction mechanism. The artery is inserted into a laboratory-fabricated flexible coil which is permitted to freely deform in a magnetic field. This work also investigates the effects of the arterial wall's material properties on energy harvesting potential. For that purpose, two types of arteries (Penrose X-ray tube, which behave elastically, and an artery of a G��ttinger minipig, which behaves viscoelastically) were tested. No noticeable difference could be observed between these two cases. For the pig artery, average harvestable power was 42 nW. Moreover, peak power was 2.38 ��W. Both values are higher than those of the current state of the art (6 nW/16 nW). A theoretical modelling of the prototype was developed and compared to the experimental results.

Analytical study and evaluation results of power optimizers for distributed power conditioning in PV arrays

The use of modular or ���micro��� maximum power point tracking (MPPT) converters at module level in series association, commercially known as ���power optimizers���, allows the individual adaptation of each panel to the load, solving part of the problems related to partial shadows and different tilt and/or orientation angles of the photovoltaic (PV) modules. This is particularly relevant in building integrated PV systems. This paper presents useful behavioural analytical studies of cascade MPPT converters and evaluation test results of a prototype developed under a Spanish national research project. On the one hand, this work focuses on the development of new useful expressions which can be used to identify the behaviour of individual MPPT converters applied to each module and connected in series, in a typical grid-connected PV system. On the other hand, a novel characterization method of MPPT converters is developed, and experimental results of the prototype are obtained: when individual partial shading is applied, and they are connected in a typical grid connected PV array

Single-Stage Grid-Connected Forward Microinverter with Boundary Mode Control

This paper presents a microinverter to be integrated into a solar module. The proposed solution combines a forward converter and a constant off-time boundary mode control, providing MPPT capability and unity power factor in a single-stage converter. The transformer structure of the power stage remains as in the classical DC-DC forward converter. Transformer primary windings are utilized for power transfer or demagnetization depending on the grid semi-cycle. Furthermore, bidirectional switches are used on the secondary side allowing direct connection of the inverter to the grid. Design considerations for the proposed solution are provided, regarding the inductance value, transformer turns ratio and frequency variation during a line semi-cycle. The decoupling of the twice the line frequency power pulsation is also discussed, as well as the maximum power point tracking (MPPT) capability. Simulation and experimental results for a 100W prototype are enclosed

Modelado de materiales piezoel��ctricos para aplicaciones de autoalimentaci��n en entornos viales

Este proyecto continua con el estudio iniciado en los proyectos: Alimentaci��n ���Energy Harvesting��� basada en fuentes piezoel��ctricas, Alimentaci��n aut��noma: aplicaci��n a fuente piezoel��ctrica y Banco de pruebas para sistemas autoalimentados en aplicaciones viales, que se realizaron anteriormente. Este estudio se basa en la b��squeda de soluciones de alimentaci��n Energy Harvesting centrados en fuentes piezoel��ctricas. El objetivo de este estudio es conocer las posibilidades que pueden ofrecer los materiales piezoel��ctricos para alimentaci��n aut��noma cuando son excitados por veh��culos en diferentes circunstancias y entornos viales. Para la realizaci��n de este estudio se han utilizado se��ales provenientes del banco de ensayos, as�� como se��ales obtenidas de una instalaci��n construida en un vial del Campus. Para poder realizar el estudio de los diversos materiales piezoel��ctricos utilizados en este proyecto, se necesitan conocer las caracter��sticas de los modelos el��ctricos. Para obtener estas caracter��sticas se ha dise��ado un programa basado en LabView, este programa adem��s puede modificar la se��al para que simule las diversas circunstancias a las que pueden estar sometidos los diferentes materiales piezoel��ctricos. En este estudio se ha tenido en cuenta la distancia de seguridad entre veh��culos para diferentes velocidades y la posibilidad de poder amplificar la excitaci��n que pueden recibir los diversos materiales. Utilizando el programa PSpice OrCAD�� se realizan los diferentes modelos con el objetivo de observar el comportamiento de los materiales bajo diversas circunstancias. Tambi��n se han utilizado varias topolog��as rectificadoras diferentes para poder comprobar en que situaci��n se puede obtener la m��xima tensi��n acumulada posible. Adem��s tambi��n se ha evaluado la m��xima potencia que puede entregar cada material en cada situaci��n. Por ultimo se han realizado varias pruebas pr��cticas con el banco de ensayos para comprobar la acumulaci��n energ��tica real que se puede obtener de los materiales instalados en ��l. Tambi��n se ha realizado el estudio de una aplicaci��n pr��ctica que sea capaz de alimentar peque��os circuitos o sensores de poco consumo. Abstract This Project goes on with the study started in the projects Feeding ���Energy Harvesting��� based on piezoelectric sources, independent feeding: application to piezoelectric source and testing bench to self fed systems in roads applications that were previously done. This study is based on the search of feeding solutions Energy Harvesting focus on piezoelectric sources. The aim of this study is know the different piezoelectric materials possibilities that can offer to independent feeding when different circumstances and road surroundings are excited by vehicles in. To develop this study several signals of the testing bench have been used and also signals get from an installation constructed on a Campus road. As far as the study of the different piezoelectric materials used in this project is concerned we should know the electrical models features. In order to obtain these characteristics a program based on LabView was designed, this program can modify the signal so that it simulates the diverse circumstances to which they can be put under the different piezoelectric materials. In this study I have bearded in mind the safe distance between vehicles for different speeds and the possibility of being able to amplify the excitation that can receive the diverse materials. Using the program PSpice OrCAD�� the different models with the objective are made to observe the behaviour of the materials under diverse circumstances. Also several different rectifying topologies have been used to be able to verify the maximum overvoltage accumulated. In addition I have assessed the maximum power that can give each material in each situation. Last but not least different practical proofs with the testing bench have been done to check the actual energy accumulation that can be obtained from the materials installed on it. Also the study of a practical application has been made that is able to feed small circuits or low consumption sensor.

Caracterizaci��n y modelado de grandes centrales fotovoltaicas

La presente tesis doctoral propone un conjunto de ensayos de corta duraci��n destinados a cubrir la ausencia de est��ndares internacionales espec��ficamente adaptados a la tecnolog��a y al panorama fotovoltaico actual que indiquen como realizar los procedimientos de control de calidad para comprobar que las grandes centrales fotovoltaicas ejecutadas responden a las expectativas establecidas durante la fase de proyecto. Dichos ensayos buscan, desde el punto de vista estrictamente t��cnico, obtener en un corto periodo de tiempo (t��picamente una semana) resultados altamente repetitivos y representativos del comportamiento de la instalaci��n bajo an��lisis, a la vez que minimizar al m��ximo la incertidumbre global, aspectos fundamentales para los procedimientos de control general de la calidad de una central. Los ensayos propuestos comprueban tanto el comportamiento general de la central, en t��rminos de su capacidad de producci��n energ��tica, como el de sus principales componentes, generadores fotovoltaicos e inversores, en t��rminos de potencia m��xima y eficiencia, respectivamente. Tambi��n se aconseja una revisi��n de la calidad y seguridad de la instalaci��n y de los materiales empleados en la ejecuci��n de la central para evitar un envejecimiento prematuro de los mismos. Todos los ensayos recogidos en el texto se apoyan en la experiencia recopilada por el ���Grupo de Sistemas Fotovoltaicos del Instituto de Energ��a Solar de la Universidad Polit��cnica de Madrid���, que ha estado involucrado en procedimientos de control de calidad de unas 50 centrales fotovoltaicas, con una potencia acumulada cercana a 250 MW, la mayor��a de ellas instaladas en Espa��a. ABSTRACT This PhD thesis proposes a set of short-duration tests to establish quality control procedures to ensure that large photovoltaic plants fulfil the initial expectations. The motivation for this work is the lack of international standards specifically adapted to the present photovoltaic technology and its state of the art. From a strict technical point of view, these tests seek to obtain highly repetitive and representative results about the behaviour of the installation under study in a short period of time (typically one single week); and to minimize the global uncertainty. These are the two keys aspects required in quality control procedures. The proposed tests evaluate the general behaviour of the photovoltaic plants, in terms of energy production, as well as the particular behaviour of their main devices, photovoltaic arrays and inverters, in terms of maximum power and efficiency, respectively. A review of the installation quality and safety, and the employed materials in its execution to avoid premature aging is also recommended. The tests here presented are based on the experience accumulated by the ���Grupo de Sistemas Fotovoltaicos del Instituto de Energia Solar de la Universidad Politecnica de Madrid���. This group has been involved in quality control procedures of about 50 photovoltaic plants, with an accumulated power close to 250 MW, most of them installed in Spain.

Pre-Feasibility Study of Hybrid Wind Power-H-2 System Connected to Electrical Grid

The growth of wind power as an electric energy source is profitable from an environmental point of view and improves the energetic independence of countries with little fossil fuel resources. However, the wind resource randomness poses a great challenge in the management of electric grids. This study raises the possibility of using hydrogen as a mean to damp the variability of the wind resource. Thus, it is proposed the use of all the energy produced by a typical wind farm for hydrogen generation, that will in turn be used after for suitable generation of electric energy according to the operation rules in a liberalized electric market.

Modeling Piezoelectric Harvesting Materials in Road Traffic Applications.

En esta comunicaci��n se presenta el m��todo para obtener modelos equivalentes el��ctricos de materiales piezoel��ctricos utilizados en entornos con tr��fico vial para aplicaciones "Energy Harvesting". Los resultados experimentales se procesan para determinar la estructura topol��gica ��ptima y la tecnolog��a de los elementos semiconductores utilizados en la etapa de entrada del sistema de alimentaci��n "harvesting". Asimismo se presenta el modelo de la fuente de alimentaci��n no regulada bajo demanda variable de corriente. Abstract: The method to obtain electrical equivalent models of piezoelectric materials used in energy harvesting road traffic environment is presented in this paper. The experimental results are processed in order to determine the optimal topological structure and technology of the semiconductor elements used in the input stage of the power harvesting system. The non regulated power supply model under variable current demand is also presented.

Transport and mixing enhancement in fluid-thermal microsystems

En esta tesis se investiga de forma experimental el transporte pasivo de magnitudes f��sicas en micro-sistemas con car��cter de inmediata aplicaci��n industrial, usando m��todos innovadores para mejorar la eficiencia de los mismos optimizando par��metros cr��ticos del dise��o o encontrar nuevos destinos de posible aplicaci��n. Parte de los resultados obtenidos en estos experimentos han sido publicados en revistas con un ��ndice de impacto tal que pertenecen al primer cuarto del JCR. Primero de todo se ha analizado el efecto que produce en un intercambiador de calor basado en micro-canales el hecho de dejar un espacio entre canales y tapa superior para la interconexi��n de los mismos. Esto genera efectos tridimensionales que mejoran la exracci��n de calor del intercambiador y reducen la ca��da de presi��n que aparece por el transcurso del fluido a trav��s de los micro-canales, lo que tiene un gran impacto en la potencia que ha de suministrar la bomba de refrigerante. Se ha analizado tambi��n la mejora producida en t��rminos de calor disipado de un micro-procesador refrigerado con un ampliamente usado plato de aletas al implementar en ��ste una c��mara de vapor que almacena un fluido bif��sico. Se ha desarrollado de forma paralela un modelo num��rico para optimizar las nuevas dimensiones del plato de aletas modificado compatibles con una serie de requerimientos de dise��o en el que tanto las dimensiones como el peso juegan un papel esencial. Por otro lado, se han estudiado los fenomenos fluido-din��micos que aparecen aguas abajo de un cuerpo romo en el seno de un fluido fluyendo por un canal con una alta relaci��n de bloqueo. Los resultados de este estudio confirman, de forma experimental, la existencia de un r��gimen intermedio, caracterizado por el desarrollo de una burbuja de recirculaci��n oscilante entre los reg��menes, bien diferenciados, de burbuja de recirculaci��n estacionaria y calle de torbellinos de Karman, como funci��n del n��mero de Reynolds del flujo incidente. Para la obtenci��n, an��lisis y post-proceso de los datos, se ha contado con la ayuda de un sistema de Velocimetr��a por Im��genes de Part��culas (PIV). Finalmente y como adici��n a este ��ltimo punto, se ha estudiado las vibraciones de un cuerpo romo producidas por el desprendimiento de torbellinos en un canal de alta relaci��n de bloqueo con la base obtenida del estudio anterior. El prisma se mueve con un movimiento arm��nico simple para un intervalo de n��meros de Reynolds y este movimiento se transforma en vibraci��n alrededor de su eje a partir de un ciero n��mero de Reynolds. En relaci��n al fluido, el r��gimen de desprendimiento de torbellinos se alcanza a menores n��meros de Reynolds que en el caso de tener el cuerpo romo fijo. Uniendo estos dos registros de movimientos y variando la relaci��n de masas entre prisma y fluido se obtiene un mapa con diferentes estados globales del sistema. Esto no solo tiene aplicaci��n como m��todo para promover el mezclado sino tambi��n como m��todo para obtener energ��a a partir del movimiento del cuerpo en el seno del fluido. Abstract In this thesis, experimental research focused on passive scalar transport is performed in micro-systems with marked sense of industrial application, using innovative methods in order to obtain better performances optimizing critical design parameters or finding new utilities. Part of the results obtained in these experiments have been published into high impact factor journals belonged to the first quarter of the Journal Citation Reports (JCR). First of all the effect of tip clearance in a micro-channel based heat sink is analyzed. Leaving a gap between channels and top cover, letting the channels communicate each other causes three-dimensional effects which improve the heat transfer between fluid and heat sink and also reducing the pressure drop caused by the fluid passing through the micro-channels which has a great impact on the total cooling pumping power needed. It is also analyzed the enhancement produced in terms of dissipated heat in a micro-processor cooling system by improving the predominantly used fin plate with a vapour chamber based heat spreader which contains a two-phase fluid inside. It has also been developed at the same time a numerical model to optimize the new fin plate dimensions compatible with a series of design requirements in which both size and wight plays a very restrictive role. On the other hand, fluid-dynamics phenomena that appears downstream of a bluff body in the bosom of a fluid flow with high blockage ratio has been studied. This research experimentally confirms the existence of an intermediate regime characterized by an oscillating closed recirculation bubble intermediate regime between the steady closed recirculation bubble regime and the vortex shedding regime (Karman street like regime) as a function of the incoming flow Reynolds number. A particle image velocimetry technique (PIV) has been used in order to obtain, analyze and post-process the fluid-dynamic data. Finally and as an addition to the last point, a study on the vortexinduced vibrations (VIV) of a bluff body inside a high blockage ratio channel has been carried out taking advantage of the results obtained with the fixed square prism. The prism moves with simple harmonic motion for a Reynolds number interval and this movement becomes vibrational around its axial axis after overcoming at definite Reynolds number. Regarding the fluid, vortex shedding regime is reached at Reynolds numbers lower than the previous critical ones. Merging both movement spectra and varying the square prism to fluid mass ratio, a map with different global states is reached. This is not only applicable as a mixing enhancement technique but as an energy harvesting method.

Extracting energy from Vortex-Induced Vibrations: A parametric study

Here, Vortex-Induced Vibrations (VIVs) of a circular cylinder are analyzed as a potential source for energy harvesting. To this end, VIV is described by a one-degree-of-freedom model where fluid forces are introduced from experimental data from forced vibration tests. The influence of some influencing parameters, like the mass ratio m��� or the mechanical damping �� in the energy conversion factor is investigated. The analysis reveals that: (i) the maximum efficiency ��M is principally influenced by the mass-damping parameter m����� and there is an optimum value of m����� where ��M presents a maximum; (ii) the range of reduced velocities with significant efficiency is mainly governed by m���, and (iii) it seems that encouraging high efficiency values can be achieved for high Reynolds numbers.

Assessing the potential of hybrid fossil���solar thermal plants for energy policy making: Brayton cycles

This paper proposes a first study in-depth of solar-fossil hybridization from a general perspective. It develops a set of useful parameters for analyzing and comparing hybrid plants, it studies the case of hybridizing Brayton cycles with current solar technologies and shows a tentative extrapolation of the results to integrated combined cycle systems (ISCSS). In particular, three points have been analyzed: the technical requirements for solar technologies to be hybridized with Brayton cycles, the temperatures and pressures at which hybridization would produce maximum power per unit of fossil fuel, and their mapping to current solar technologies and Brayton cycles. Major conclusions are that a hybrid plant works in optimum conditions which are not equal to those of the solar or power blocks considered independently, and that hybridizing at the Brayton cycle of a combined cycle could be energetically advantageous.