Hydrogen production from renewable energy resources: A case study

In the face of increasing demand for hydrogen, a feasibility study is conducted on its production by using Renewable Energy Resources (RERs), especially from wind and solar sources, with the latter preferring photovoltaic technology. The analysis performed is based on climate data for the Province of Brindisi, Apulia, Italy. The various types of electrolyzers will be analyzed, ultimately choosing the one that best suits the case study under consideration. The technical aspect of the land consumption for RER exploitation until 2050 is analyzed for the Italian case of study and for the Apulia Region. For both the 200 MW and 100 MW RER Power Plants, an economic analysis is carried out on the opportunities for using hydrogen. In the last part of the economic analysis, the trade-off between the high specific investment cost and the Capacity Factor of Wind technologies is also investigated. The results show the affordability of building high-scale Wind Farms, harnessing the existing scale economies. The lowest Hydrogen selling price is achieved by the 200 MW Wind Farms equal to 222 €/MWh against 232 €/MWh of the 200 MW Photovoltaic (PV) Farm. Finally, the feasibility analysis considers also the greenhouse gas emission reduction by including in the economic analysis the carbon dioxide (CO2) Average Auction Clearing Price leading for the 200 MW Wind Farms to a hydrogen selling price equal to 191.2 €/MWh against 201 €/MWh of the 200 MW Photovoltaic Farm

Scelta del ciclo di potenza e dimensionamento di uno scambiatore di calore per waste heat recovery da fluidi di pozzo

LAUREA MAGISTRALEIl presente lavoro studia il recupero di efficienza energetica attraverso la produzione di energia elettrica da fluidi a bassa temperatura. Viene quindi preso in esame il pozzo Cascina Cardana, sito presso la Centrale Olio Eni in Trecate (NO). Il recupero di efficienza viene realizzato attraverso la sostituzione dell’air cooler, adibito al raffreddamento dei fluidi di pozzo, con un ciclo di potenza volto alla produzione di energia elettrica. Verranno quindi analizzate le varie alternative tecnologiche presenti sul mercato per la conversione di energia termica ad energia elettrica e si individuerà la scelta che meglio si adatta alle caratteristiche tecniche dell’impianto. Il presente lavoro prende in esame anche la progettazione di uno scambiatore di calore adibito al trasferimento della potenza termica dai fluidi di pozzo al fluido termovettore del ciclo di potenza. Il design dello scambiatore sarà condotto attraverso modelli che descriveranno la fluidodinamica e lo scambio termico via via in maniera più completa; si partirà con l’ipotizzare i fluidi di pozzo come se fossero composti da sola acqua (Caso Monofase), tale ipotesi non è troppo restrittiva in quanto il water cut di questi fluidi è del 97.8%; quindi si procederà ad uno design dello scambiatore attraverso il metodo Kern e in seguito al più dettagliato metodo Bell-Delaware che prende in considerazione i vari leakages dentro lo scambiatore. In seguito, si rilascerà l’ipotesi di fluido monofase e si analizzerà come cambia il design considerando i fluidi di pozzo come una miscela di acqua e gas (Caso Bifase). Infine, si procederà con l’analisi economica per verificare la fattibilità e la sostenibilità finanziaria del progetto, oggetto dello studio.The purpose of this work is the recovery of energy efficiency by means of the production of electrical energy by using fluids at low temperature. The well taken into account for the development of my study is Cascina Cardana, at the Centrale Olio Eni located in Trecate (NO). The energy salvage is achieved through the replacement of the air cooler, designated for cooling the fluids’ well, with a power cycle, intended for the production of electrical energy. For this project, a series of technological options placed on the market is analysed in order to identify the best fitting to the machinery’s technical characteristics. Afterwards, the chosen one is used to convert thermal energy into electrical energy. The thesis also covers the planning of a heat exchanger, intended for the transfer of heat from the fluids’ well to the heat carrying fluid of the power cycle. The heat exchanger design is done by means of models, which describe the fluid dynamics and the thermal exchange in such a way to derive progressively a more complete characterisation. The first hypothesis made is that the fluids’ well are composed of water only (Monophasic Case). This is not an approximation too far from the reality since the water cut found in these fluids is 97.8%. A first heat exchanger design will be analysed by using the Kern method. Afterwards, a more detailed description is obtained by using the Bell-Delaware method, which takes into account the several leakages inside the heat exchanger. Afterwards, the study continues without the initial hypothesis of 100% water. In these conditions (Biphasic Case) it is analysed how the architecture changes considering the fluids’ well as a mixture composed of gas and water. Finally, it follows an economic analysis. This has been done in order to examine the feasibility and assess the project’s financial sustainability

Vibrational analysis to detect cavitation phenomena in a directional spool valve

The study of the cavitation phenomenon in directional spool valves has been widely addressed through different types of analysis, since the implosion of the bubbles compromises the operation of the system and it causes progressive damage up to the emergence of cracks which could lead to an early breakdown of the system. In this work, the cavitation phenomenon has been studied trough vibrational analysis of accelerometric signals acquired on a directional spool valve. The accelerometric signals have been processed by tools of statistical analysis able to identify three physical phenomena occurring in valve proximity: absence of cavitation, starting cavitation phenomenon and strong cavitation phenomenon. It has been demonstrated that some statistical indices are able to differentiate well the behaviour of the valve in various cavitation states

Progresses in Analytical Design of Distribution Grids and Energy Storage

In the last years, a change in the power generation paradigm has been promoted by the increasing use of renewable energy sources combined with the need to reduce CO2 emissions. Small and distributed power generators are preferred to the classical centralized and sizeable ones. Accordingly, this fact led to a new way to think and design distributions grids. One of the challenges is to handle bidirectional power flow at the distribution substations transformer from and to the national transportation grid. The aim of this paper is to review and analyze the different mathematical methods to design the architecture of a distribution grid and the state of the art of the technologies used to produce and eventually store or convert, in different energy carriers, electricity produced by renewable energy sources, coping with the aleatory of these sources.</jats:p

Progresses in Analytical Design of Distribution Grids and Energy Storage

In the last years, a change in the power generation paradigm has been promoted by the increasing use of renewable energy sources combined with the need to reduce CO2 emissions. Small and distributed power generators are preferred to the classical centralized and sizeable ones. Accordingly, this fact led to a new way to think and design distributions grids. One of the challenges is to handle bidirectional power flow at the distribution substations transformer from and to the national transportation grid. The aim of this paper is to review and analyze the different mathematical methods to design the architecture of a distribution grid and the state of the art of the technologies used to produce and eventually store or convert, in different energy carriers, electricity produced by renewable energy sources, coping with the aleatory of these sources

A. Nicolella, V. Niola, S. Pagano, S. Savino, M. Spirto

Articulated rocker-bogie suspension systems have gained a lot of attention since they were used for rovers destined for space exploration on Mars. This type of suspension allows the vertical load to be distributed equally between the wheels, reducing the risk of the most loaded wheels sinking in the case of soft ground. This peculiarity is verified if the rover moves on flat and horizontal surfaces; if the rover moves on uneven surfaces, the suspension still allows the wheels to be kept in contact with the ground, but the load distribution changes. This paper presents the study of the variation in the distribution of the load among the wheels and the rover stability for different ground geometries; the study involves a preventive kinematic analysis of position to define the configuration of the suspension as a function of the ground geometry

Study on the Dispersion of Lubricant Film from a Cylindrical Gearwheels with Helical Teeth by Vibrational Analysis

Gearwheels are a common mechanism for distributing torque from mechanical devices to other mechanical devices. The tribological state of gears reduces their performance and lifespan. This paper presents a signal-processing basis for evaluating the vibrational dynamics of a single pair of gears under various tribological situations. This method not only identifies the tribological state of the system, but also leads to different applications in several mechanical systems

An Overview on the Kinematic Analysis of the Rocker-Bogie Suspension for Six Wheeled Rovers Approaching an Obstacle

Articulated rocker-bogie suspension systems have gained a lot of attention since they were used for rovers destined for space exploration on Mars. This type of suspension allows the vertical load to be distributed equally between the wheels, reducing the risk of the most loaded wheels sinking in the case of soft ground. This peculiarity is verified if the rover moves on flat and horizontal surfaces; if the rover moves on uneven surfaces, the suspension still allows the wheels to be kept in contact with the ground, but the load distribution changes. This paper presents the study of the variation in the distribution of the load among the wheels and the rover stability for different ground geometries; the study involves a preventive kinematic analysis of position to define the configuration of the suspension as a function of the ground geometry