This thesis describes two systems for generating energy from wave motion that exploit the existence or construction of new harbor defense works (wharves or breakwater) or coastal protection and, in addition to providing the principles of operation of such plants, it faces the problem of their realization in the port of Ancona. The high variability of the waves as regards time and space make it essential to study the characteristics of the wave motion at the point of installation and starting from them we can find the best technology to be used and the device that is best suited to such conditions. From the analysis of the wave data recorded by the buoy that measures waves in the period 2009-2013 were obtained the percentage distributions of the wave heights and was obtained the wave climate as well, crucial to characterize all the phenomena which combine in the design of a maritime facility. To these data were also added the ones including the period 1999-2008 resulting in a more complete picture of the wave climate. Through the use of the program MIKE 21 it was possible to evaluate the propagation of the wave motion from the open sea to the harbor-mouth and in particular the frequency of occurrence of the significant wave height at the breakwater (chosen as the site of installation) with the direction waves 10°N. The functioning of a device OWC, the REWEC3 (Boccotti, 2002) was analyzed. In the case of Ancona instead there are numerous traditional breakwaters consisting of natural and artificial boulders with the classic trapezoidal section, and in such cases it is advisable to adopt a different methodology which may integrate with what has already been built. For this reason another type of energy converter which exploits the phenomenon of overtopping has been devised: an integrated system which needs a suitably inclined ramp which pours the water into a catchment basin; raising the average water level in the basin a hydraulic gradient is created which drives a water turbine, which sets a generator in motion. The sizing of the ramp and the basin were carried out so as to produce the greatest amount of energy by using the wave conditions analyzed using the Matlab software. Moreover the use of a new-generation turbine of hydraulic wheel type (water wheel) was taken into consideration through laboratory tests to better characterize its working, in addition to the classic hydraulic turbines. Having calculated the value of Rr (ramp ridge level) by which we get the maximum producible energy we have chosen to consider a lower resolution and therefore increase Rr (1.05 m) in that the original datum does not take into account the storm surge of mean water level caused by sea-storms. The windward wharf of Ancona Harbor is slanted in such a way that the maximum-efficiency waves are the ones coming from Bora, which, in the case of a heavy sea-storm, produce a surge of about 40 cm. To calculate the hydraulic gradient a decrease of approximately 40% should be considered when such sea-storms occur. Under optimal conditions and considering the original value of Rr, the energy converter is able to produce 955 MWh per year if we assume a hundred-meter-long dam. From the curve of duration of the flow rate capacity within the basin, and taking into consideration unfavorable case (with the storm surge and, therefore, with a lower hydraulic head), the producible power amounts to about 300 MWh per year. The use of the water wheel, which works with low hydraulic head, could increase the production of energy in comparison with traditional turbines as shown by laboratory tests, but in this case full-scale testing is required and a protection/chamber must be provided for the wheel itself in such a way that it is not exposed to the waves attack. The second device studied allows an easier interpretation, and the more reduced efficiency in comparison with other devices is compensated by low manufacturing costs, by reliability (it modulates the flows by disengaging the plant from the discontinuity of the waves attacks) and by its ability to improve the quality of harbor waters (creating a recirculation).
L’energia dal mare può essere estratta attraverso tecnologie che utilizzano l’acqua di mare come forza motrice. Nella tesi vengono descritti due sistemi per produrre energia dal moto ondoso che sfruttano l’esistenza o la costruzione di nuove opere di difesa portuali o costiera e oltre a fornire i principi di funzionamento di tali impianti, affronta una possibile applicazione nel porto di Ancona. Sono stati analizzati i dati ondametrici della boa di Ancona per un periodo complessivo di 11 anni di misurazioni. I Dati ondosi al largo sono stati trasferiti fino a molo sopraflutto (scelto come sito di installazione) con il programma MIKE 21. Si è analizzato il funzionamento di un dispositivo OWC il REWEC3 che può essere installato con una modifica strutturale in una diga a cassoni. Tuttavia, nel caso di Ancona sono presenti scogliere a “gettata”. Per questo si è studiato un altro tipo di convertitore che sfrutta il fenomeno dell’overtopping: una rampa opportunamente inclinata che riversa l’acqua in un bacino di raccolta. Si è proceduto con il dimensionamento della rampa e del bacino in modo tale da produrre il maggior quantitativo di energia in base alle condizioni ondose analizzate con il software Matlab. Inoltre si è preso in considerazione l’uso di una turbina di nuova generazione (water wheel) attraverso prove di laboratorio. E’ stato calcolato il valore di Rr (livello di cresta della rampa)che massimizza l’energia producibile; si è scelto di considerare una risoluzione minore tenendo conto del fenomeno del sovralzo del livello medio mare (Rr=1.15 m). In condizioni ottimali e considerando il valore originario di Rr, il convertitore di energia riesce a produrre 955 MWh/anno se ipotizziamo una diga di lunghezza 100 m. Dalla curva di durata della portata tracimante all’interno del bacino, e prendendo in considerazione il caso sfavorevole (con sovralzo e, quindi, con minore carico idraulico), la potenza producibile è di circa 300 MWh/anno. Questo dispositivo risulta di più facile interpretazione e la minore efficienza rispetto ad altri dispositivi viene compensata da bassi costi di realizzazione, dall’affidabilità (modula le portate svincolando l’impianto dalla discontinuità degli attacchi ondosi) e dalla capacità di migliorare la qualità delle acque portuali (creando un ricircolo)
Energia dalle onde applicazioni nel porto di Ancona / Sartini, Maila. - (2016 Mar 04).
Energia dalle onde applicazioni nel porto di Ancona
Sartini, Maila
2016-03-04
Abstract
This thesis describes two systems for generating energy from wave motion that exploit the existence or construction of new harbor defense works (wharves or breakwater) or coastal protection and, in addition to providing the principles of operation of such plants, it faces the problem of their realization in the port of Ancona. The high variability of the waves as regards time and space make it essential to study the characteristics of the wave motion at the point of installation and starting from them we can find the best technology to be used and the device that is best suited to such conditions. From the analysis of the wave data recorded by the buoy that measures waves in the period 2009-2013 were obtained the percentage distributions of the wave heights and was obtained the wave climate as well, crucial to characterize all the phenomena which combine in the design of a maritime facility. To these data were also added the ones including the period 1999-2008 resulting in a more complete picture of the wave climate. Through the use of the program MIKE 21 it was possible to evaluate the propagation of the wave motion from the open sea to the harbor-mouth and in particular the frequency of occurrence of the significant wave height at the breakwater (chosen as the site of installation) with the direction waves 10°N. The functioning of a device OWC, the REWEC3 (Boccotti, 2002) was analyzed. In the case of Ancona instead there are numerous traditional breakwaters consisting of natural and artificial boulders with the classic trapezoidal section, and in such cases it is advisable to adopt a different methodology which may integrate with what has already been built. For this reason another type of energy converter which exploits the phenomenon of overtopping has been devised: an integrated system which needs a suitably inclined ramp which pours the water into a catchment basin; raising the average water level in the basin a hydraulic gradient is created which drives a water turbine, which sets a generator in motion. The sizing of the ramp and the basin were carried out so as to produce the greatest amount of energy by using the wave conditions analyzed using the Matlab software. Moreover the use of a new-generation turbine of hydraulic wheel type (water wheel) was taken into consideration through laboratory tests to better characterize its working, in addition to the classic hydraulic turbines. Having calculated the value of Rr (ramp ridge level) by which we get the maximum producible energy we have chosen to consider a lower resolution and therefore increase Rr (1.05 m) in that the original datum does not take into account the storm surge of mean water level caused by sea-storms. The windward wharf of Ancona Harbor is slanted in such a way that the maximum-efficiency waves are the ones coming from Bora, which, in the case of a heavy sea-storm, produce a surge of about 40 cm. To calculate the hydraulic gradient a decrease of approximately 40% should be considered when such sea-storms occur. Under optimal conditions and considering the original value of Rr, the energy converter is able to produce 955 MWh per year if we assume a hundred-meter-long dam. From the curve of duration of the flow rate capacity within the basin, and taking into consideration unfavorable case (with the storm surge and, therefore, with a lower hydraulic head), the producible power amounts to about 300 MWh per year. The use of the water wheel, which works with low hydraulic head, could increase the production of energy in comparison with traditional turbines as shown by laboratory tests, but in this case full-scale testing is required and a protection/chamber must be provided for the wheel itself in such a way that it is not exposed to the waves attack. The second device studied allows an easier interpretation, and the more reduced efficiency in comparison with other devices is compensated by low manufacturing costs, by reliability (it modulates the flows by disengaging the plant from the discontinuity of the waves attacks) and by its ability to improve the quality of harbor waters (creating a recirculation).File | Dimensione | Formato | |
---|---|---|---|
Tesi_Sartini.pdf
embargo fino al 31/12/2030
Descrizione: Tesi_Sartini.pdf
Tipologia:
Tesi di dottorato
Licenza d'uso:
Creative commons
Dimensione
6.52 MB
Formato
Adobe PDF
|
6.52 MB | Adobe PDF | Visualizza/Apri Richiedi una copia |
I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.