The thesis deals with the optimisation of U-Oscillating Water Columns (U-OWC) integrated into vertical breakwaters. The case study considered in the present work was a wave power plant installed in the Mediterranean Sea. Specifically, the optimal geometrical configuration of a U-OWC was computed for the port of Roccella Jonica, Italy. In this context, the statistical linearisation technique was used in combination with optimisation algorithms to identify the optimal U-OWC configuration with reduced computational cost. Next, the power plant's performance was assessed and optimised using a non-linear time-domain wave-to-wire model. This numerical model allowed the testing of different PTO control strategies aiming to maximise the power conversion of the Roccella Jonica power plant. Capture width ratio results for single and multi-stage Wells turbines were compared with the biradial turbine. The possibility of connecting one turbine to several air chambers was also investigated to reduce the overall PTO costs. A bypass relief valve system was introduced to control the PTO rotational speed during the most energetic sea states without turning off the power plant for safety reasons. The presented results demonstrated that the U-OWC efficiency depends on the device's geometry, the adopted power take-off (PTO) system and the selected control strategy. Finally, an innovative class of power take-off systems -- the dielectric elastomer generators (DEGs) -- was also studied. The performance of a U-OWC with DEGs was estimated through an experimental campaign conducted on a small scale prototype installed at the NOEL laboratory of Reggio Calabria without electrical activation. In addition, a hardware-in-the-loop (HIL) simulation was conducted to replicate real operating conditions with reduced experimental burden and fewer risks than wave tank or field tests.

La tesi tratta dell'ottimizzazione di convertitori di tipo U-Oscillating Water Column (U-OWC) integrati in dighe a parete verticale. Il caso studio considerato in questo lavoro è un impianto di energia dal moto ondoso nel Mar Mediterraneo. In particolare, la configurazione geometrica ottimale di un U-OWC è stata ottenuta per il porto di Roccella Jonica, Italia. In questo contesto, la tecnica della linearizzazione statistica è stata utilizzata in combinazione con algoritmi di ottimizzazione per identificare la configurazione ottimale dell'U-OWC con un costo computazionale ridotto. Successivamente, le performance dell'impianto sono state valutate e ottimizzate utlizzando un modello non lineare wave-to-wire nel dominio del tempo. Questo modello numerico ha permesso di testare differenti strategie di controllo del PTO con l'obiettivo di massimizzare la conversione di energia dell'impianto di Roccella Jonica. I risultati del capture width ratio per turbine di Wells monoplana e multi-stage sono stati confrontati con la turbina biradiale. É stata anche valutata la possibilità di connettere una singola turbina a diverse camere d'aria per ridurre il costo complessivo dei PTO. Un sistema di valvole di sfogo è stato introdotto per controllare la velocità rotazionale del PTO durante gli stati di mare più energetici senza la necessità di spegnere l'impianto per ragioni di sicurezza. I risultati presentati hanno dimostrato che l'efficienza dell'U-OWC dipende dalla geometria del dispositivo, dal sistema di power take-off (PTO) utilizzato e dalla strategia di controllo selezionata. Infine, è stata anche studiata una classe di sistemi power take-off innovativi, i generatori ad elastomero dielettrico (DEG). Le performance di un U-OWC con DEG sono state valutate attraverso una campagna sperimentale condotta su un prototipo in piccola scala installato nel laboratorio NOEL di Reggio Calabria senza attivazione elettrica. Inoltre, una simulazione hardware-in-the-loop (HIL) è stata effettuata per replicare le condizioni operative reali con un carico sperimentale ridotto e meno rischi rispetto a test in vasche di laboratorio o in mare.

Performance optimization of U-OWC wave energy converters / Scialo', Andrea. - (2021 Oct 19).

Performance optimization of U-OWC wave energy converters

SCIALO', Andrea
2021-10-19

Abstract

The thesis deals with the optimisation of U-Oscillating Water Columns (U-OWC) integrated into vertical breakwaters. The case study considered in the present work was a wave power plant installed in the Mediterranean Sea. Specifically, the optimal geometrical configuration of a U-OWC was computed for the port of Roccella Jonica, Italy. In this context, the statistical linearisation technique was used in combination with optimisation algorithms to identify the optimal U-OWC configuration with reduced computational cost. Next, the power plant's performance was assessed and optimised using a non-linear time-domain wave-to-wire model. This numerical model allowed the testing of different PTO control strategies aiming to maximise the power conversion of the Roccella Jonica power plant. Capture width ratio results for single and multi-stage Wells turbines were compared with the biradial turbine. The possibility of connecting one turbine to several air chambers was also investigated to reduce the overall PTO costs. A bypass relief valve system was introduced to control the PTO rotational speed during the most energetic sea states without turning off the power plant for safety reasons. The presented results demonstrated that the U-OWC efficiency depends on the device's geometry, the adopted power take-off (PTO) system and the selected control strategy. Finally, an innovative class of power take-off systems -- the dielectric elastomer generators (DEGs) -- was also studied. The performance of a U-OWC with DEGs was estimated through an experimental campaign conducted on a small scale prototype installed at the NOEL laboratory of Reggio Calabria without electrical activation. In addition, a hardware-in-the-loop (HIL) simulation was conducted to replicate real operating conditions with reduced experimental burden and fewer risks than wave tank or field tests.
19-ott-2021
Settore ICAR/02 - COSTRUZIONI IDRAULICHE E MARITTIME E IDROLOGIA
ARENA, Felice
MALARA, GIOVANNI
ARENA, Felice
Doctoral Thesis
File in questo prodotto:
File Dimensione Formato  
Scialò Andrea.pdf

accesso aperto

Tipologia: Tesi di dottorato
Licenza: DRM non definito
Dimensione 11.97 MB
Formato Adobe PDF
11.97 MB Adobe PDF Visualizza/Apri

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.12318/111865
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus ND
  • ???jsp.display-item.citation.isi??? ND
social impact