Climate change has challenged the water sector to optimize the energy use and limit greenhouse gas emissions of their operations. In water industry and in particular in supply systems there is still a potential for hydropower production at several scales, from small hydro to micro and several areas from adduction to waste water treatment. Energy can be recovered from the network at locations of excessively high flow or pressure. Suitable locations may be found at break pressure tanks, storage reservoirs or pressure reducing valves, while other new promising positions can be identified using a search algorithm for optimization of pressure. The first part of the thesis is related to the water adduction networks. After a comparison among the used turbines and the evaluation of the exploitable hydraulic potential based on GIS and GSE data, all the information for the technical and economic assessment of a mini and micro hydro power plants are defined. The breakdown cost of 11 power plants, realized on adduction networks and found on the SILVIA database, will be used to understand the critical parameters. Indeed, the review of actual economical formulas for the estimation of electro-mechanical components will lead to the definition of a new model for micro-Pelton and Cross-Flow turbines. The second part of the thesis deals with water distribution networks. To improve their management, the use of micro-turbine instead of PRV has been shown to be a viable option both for energy recovery and pressure management improvement. The devices that potentially can be used have been collected in this chapters and a functioning chart has been created in order to help designers to select the proper device on the basis of boundary flow conditions. Then the optimization methods to improve the management of the WDN are described and compared. A case of study, which considers one of these methods, shows the improvement of the WDN management using some of the devices introduced. In the third part of the thesis, the assessment of the energy recovery at the works outfalls or inflows of wastewater treatment plants is carried out. The results of two case studies, using the model developed in the first part of the thesis, indicate that significant potential exist for energy recovery in the wastewater industry and could be exploited both technically and economically profitable.
Nell’industria idrica e in particolare nei sistemi di approvvigionamento esiste il potenziale per produzione idroelettrica a diverse scale, dal piccolo idro al micro, in differenti aree, dalla rete di adduzione al trattamento delle acque reflue. L’energia può essere recuperata nella rete nei punti caratterizzati da portate o pressioni eccessivamente alte. Posizioni adatte possono essere trovate in concomitanza con serbatoi e valvole mentre altre nuove e promettenti posizioni possono essere identificate usando un algoritmo di ricerca per l’ottimizzazione delle pressioni. La prima parte delle tesi considera le reti di adduzione. Dopo aver comparato le turbine utilizzabili ed avere valutato il potenziale idrico sfruttabile e attualmente sfruttato basandosi sui dati GIS e GSE, tutte le informazioni per la valutazione tecnica ed economica di un mini o micro impianto idroelettrico sono definite. Undici impianti realizzati su reti d’adduzione ricavati dal database SILVIA verranno usati per comprendere i parametri critici. Inoltre, la revisione delle attuali formule economiche per la stima delle componenti elettro-meccaniche porterà alla definizione di un nuovo modello per micro e mini turbine Pelton e Cross-Flow. La seconda parte della tesi tratta le reti di distribuzione. L’utilizzo di micro turbine invece di PRV è un opzione praticabile per il recupero energetico e il miglioramento della gestione delle pressioni. I dispositivi che potenzialmente possono essere utilizzati sono stati raccolti in questi capitoli e un diagramma funzionale è stato creato per aiutare i progettisti a selezionare il corretto dispositivo sulla base delle condizioni di flusso. Poi i metodi di ottimizzazione per migliorare la gestione delle reti di distribuzione sono descritti e comparati. Un caso di studio, che considera uno di questi metodi, mostra i miglioramenti nella gestione della rete utilizzando alcuni dei dispositivi introdotti. Nella terza parte della tesi è effettuata la valutazione dell’energia recuperabile allo sbocco o all’ingresso degli impianti di trattamento delle acque. I risultati di due casi di studio, utilizzando il modello sviluppato nella prima parte della tesi, indicano che un potenziale significativo esiste per il recupero energetico nell’ industria delle acque reflue e potrebbe essere sfruttata sia tecnicamente sia con profitto.
Energy recovery from water system
CASTELLINI, LORENZO
2016/2017
Abstract
Climate change has challenged the water sector to optimize the energy use and limit greenhouse gas emissions of their operations. In water industry and in particular in supply systems there is still a potential for hydropower production at several scales, from small hydro to micro and several areas from adduction to waste water treatment. Energy can be recovered from the network at locations of excessively high flow or pressure. Suitable locations may be found at break pressure tanks, storage reservoirs or pressure reducing valves, while other new promising positions can be identified using a search algorithm for optimization of pressure. The first part of the thesis is related to the water adduction networks. After a comparison among the used turbines and the evaluation of the exploitable hydraulic potential based on GIS and GSE data, all the information for the technical and economic assessment of a mini and micro hydro power plants are defined. The breakdown cost of 11 power plants, realized on adduction networks and found on the SILVIA database, will be used to understand the critical parameters. Indeed, the review of actual economical formulas for the estimation of electro-mechanical components will lead to the definition of a new model for micro-Pelton and Cross-Flow turbines. The second part of the thesis deals with water distribution networks. To improve their management, the use of micro-turbine instead of PRV has been shown to be a viable option both for energy recovery and pressure management improvement. The devices that potentially can be used have been collected in this chapters and a functioning chart has been created in order to help designers to select the proper device on the basis of boundary flow conditions. Then the optimization methods to improve the management of the WDN are described and compared. A case of study, which considers one of these methods, shows the improvement of the WDN management using some of the devices introduced. In the third part of the thesis, the assessment of the energy recovery at the works outfalls or inflows of wastewater treatment plants is carried out. The results of two case studies, using the model developed in the first part of the thesis, indicate that significant potential exist for energy recovery in the wastewater industry and could be exploited both technically and economically profitable.| File | Dimensione | Formato | |
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https://hdl.handle.net/10589/138739