The European Union has indicated in the combined heat and power production one of the most promising high efficiency technologies, fixing an ambitious "18% share of the total EU electricity production by CHP" target to be achieved at 2010 (COM/97/0514). Although it is not possible to actually achieve such results (at 2005 "only" a 12% CHP penetration was observed), efforts are being still made to promote cogeneration, due to its relevant potential in achieving primary and pollutant/GWC emissions savings with respect to he separate production of electricity and heat. Also, further benefits are related to the concept of Distributed Generation (DG), primarily in terms of reduction in transmission losses and increased safety of power supply. Today a relevant share of the CHP market is covered by large/medium size plants integrated within industrial districts or individual manufacturing processes, due to the possibility to operate conveniently the CHP unit (and, consequently, to achieve a profitable operation) where regular load profiles are concerned; currently, in Italy the average size of CHP units is in the order of 10 MWe, including the large gas or backpressure steam turbines or the even larger combined cycles. However, when depicting future scenarios concerning polygeneration market the scientific literature has been recently assigning a primary role to micro/small/medium scale CHP for applications in the civil sector (especially in the tertiary and, in some way, also the residential users); this growing interest is testified by the explicit focus of the Directive 2004/8/EC (fixing common criteria for the high efficiency CHP assessment) on "micro cogeneration" and "small scale cogeneration", defined with respect to the maximum 50 kWe and 1 MWe installed capacity, respectively. The Italian Legislative Decree n. 20/07, which pursues the goal declared in the aforementioned Directive, promotes "increases in the energetic efficiency and a higher reliability of energy supply" by defining a set of provisions concerning high efficiency polygeneration "based on a useful heat demand and on primary energy saving" (to avoid non cogenerative plants to be assessed as efficient cogeneration), basing on the specific climatic conditions in Italy. Among others, the following technologies are supported: • Reciprocate engines, either natural gas or diesel oil fuelled; • Micro gas turbines; • Stirling engines; • Fuel cells. In spite of this relevant and universally recognized potential, the installed small/micro -scale CHP capacity is still low, due to a number of obstacles; among them, a main role is probably played by a continuously changing legislative framework, which concur to increase the risk of any investment, and by the absence of specific knowledge on design and operation criteria for CHCP plants and the consequent difficulty in achieving economic viability. This research project is oriented to define a detailed knowledge on the performance of small/micro-scale CHP plants for applications in the civil sector and to elaborate methods and criteria for the optimization of design and operation. The research will involve different levels of analysis, like the modelization of several CHP technologies adopting both experimental and theoretical approaches and an in-depth understanding of the influence of components' integration on their individual performance (this aspect will be investigated for different plant lay-outs, design and boundary conditions as concerns legislative provisions and energy prices). For a full exploitation of the existing potential for polygeneration in the civil sector, different users will be considered: • Detached or semi-detached dwellings, to be supplied with heat, cooling and power by commercial micro-scale CHP units, where a primary role is played by the integration with small heat storage tanks or with electric heat pumps; • Large buildings, like hospitals, hotels or commercial centres, where an installed capacity up to 2-3 MWe can be required. This kind of applications can be covered by a variety of technologies, either "traditional" or "innovative" (like high/medium temperature fuel cells); • Clusters of large building situated over a small area, where the creation of a CHCP-based µ-grid, i.e. the fractioning of the capacity into a number of large CHCP plants to be installed in buildings' proximity and interconnected by a fluid distribution network, can be evaluated.

L'Unione Europea ha individuato nella produzione combinata di energia elettrica e calore una delle tecnologie ad alta efficienza di maggior interesse, fissando per il 2010 il target del 18% della produzione elettrica totale dell'Unione da sistemi cogenerativi (COM/97/0514). Dati recenti rivelano la non attualità di tale target (al 2005 si è raggiunto il 12% di penetrazione); rimane tuttavia evidente la volontà, esistente sia a livello comunitario che in molti Stati Membri, di perseguire la via della promozione della poligenerazione. Le ragioni di questo interesse sono evidenti: l'elevata efficienza di conversione garantita dal recupero dei cascami termici di un ciclo diretto consente, a parità di vettori energetici prodotti, una significativa riduzione dei consumi energetici rispetto alla produzione separata di energia elettrica e calore e, conseguentemente, un abbattimento delle emissioni inquinanti. A questi benefici se ne affiancano degli ulteriori, connessi al principio di generazione distribuita e rappresentati dalla riduzione delle perdite di trasmissione e dall'accresciuta affidabilità nell'alimentazione delle utenze elettriche. Una buona frazione dell'odierno mercato cogenerativo è rappresentata dai sistemi di media/grossa potenza integrati con attività industriali, a causa della regolarità dei profili di carico elettrico e termico di tali utenze che favorisce un elevato sfruttamento annuo dell'impianto CHP e, pertanto, contribuisce al rapido ammortamento del suo costo; la taglia media dei sistemi installati oggi in Italia si assesta intorno ai 10 MWel, comprendendo impianti turbogas e cicli a vapore in contropressione nonché sistemi di taglia ancora superiore a ciclo combinato. Nell'individuare scenari di elevata diffusione della generazione distribuita la letteratura scientifica ha evidenziato il significativo potenziale della cogenerazione e della trigenerazione di piccola e media taglia per utenze del settore civile; tale attenzione è ancora testimoniata dallo specifico riferimento che la Direttiva quadro in materia di riconoscimento dei sistemi CHP ad alta efficienza (Dir. 2004/8/EC) fa alla "micro-cogenerazione" ed alla "cogenerazione di piccola taglia", definite rispettivamente con riferimento alle soglie di potenza installata di 50 kWe ed 1 MWe. Il D. Lgs. 8 febbraio 2007 n. 20, attuativo della suddetta Direttiva, intende "accrescere l'efficienza energetica e migliorare la sicurezza dell'approvvigionamento", definendo misure atte a promuovere e sviluppare la cogenerazione ad alto rendimento di calore ed energia, basata sulla domanda di calore utile e sul risparmio di energia primaria, con particolare riferimento alle condizioni climatiche nazionali. Tra le tecnologie relative alla micro-cogenerazione ed alla cogenerazione di piccola taglia, il Decreto fa riferimento a: - Motori a combustione interna; - Microturbine a gas; - Motori Stirling; - Pile a combustibile. A fronte dell'elevato potenziale unanimemente riconosciuto, la capacità small/micro-scale CHP installata risulta ancora limitata, a causa di numerosi fattori; tra questi, si possono considerare preminenti la presenza di un quadro legislativo non stabile e l'assenza di competenze specifiche, a livello di piccoli/medi operatori di mercato, dei criteri di scelta e gestione di piccoli sistemi poligenerativi e delle opportunità offerte dalle odierne tecnologie CHP. Il presente progetto di ricerca è volto a fornire un quadro conoscitivo dettagliato e ad elaborare metodi per l'ottimizzazione di sistemi poligenerativi per applicazioni di piccola e media scala nel settore civile (terziario e residenziale). La ricerca dovrà coinvolgere diversi livelli, tra i quali lo studio, su base teorica per le tecnologie già affermate e sperimentale per quelle più innovative, del comportamento dei diversi componenti d'impianto e l'analisi delle interazioni tra questi al variare del lay-out, dei parametri di progetto e delle condizioni tariffarie e normative che influenzano le possibili condizioni d'esercizio. Lo sfruttamento del potenziale di produzione combinata esistente richiede inoltre l'analisi di diverse tipologie di utenza, tra le quali si considereranno: - abitazioni singole, da servire a mezzo di gruppi cogenerativi di piccolissima taglia già ampiamente disponibili in commercio, per le quali riveste un ruolo fondamentale l'accumulo termico; - edifici singoli di grosse dimensioni -alberghi, ospedali o centri commerciali- nei quali le potenze in gioco, che possono raggiungere i 2-3 MWe, consentono di esplorare scenari relativi a diverse tecnologie CHP, innovative (come le celle a combustibile a media e ad alta temperatura) e non; - i complessi di edifici, nei quali è possibile pensare alla creazione di µ-grids energetiche, ossia a reti di sistemi trigenerativi interconnessi tramite una rete di distribuzione dei fluidi termovettori.

Cardona, F., Piacentino, A. (2011). Criteri e metodi per l'ottimizzazione di sistemi di poligenerazione di piccola e media taglia - Criteria and methodologies for the optimization of small/medium scale polygeneration systems. Palermo : F. Cardona, E. Piacentino.

Criteri e metodi per l'ottimizzazione di sistemi di poligenerazione di piccola e media taglia - Criteria and methodologies for the optimization of small/medium scale polygeneration systems

CARDONA, Fabio;PIACENTINO, Antonio
2011-01-01

Abstract

The European Union has indicated in the combined heat and power production one of the most promising high efficiency technologies, fixing an ambitious "18% share of the total EU electricity production by CHP" target to be achieved at 2010 (COM/97/0514). Although it is not possible to actually achieve such results (at 2005 "only" a 12% CHP penetration was observed), efforts are being still made to promote cogeneration, due to its relevant potential in achieving primary and pollutant/GWC emissions savings with respect to he separate production of electricity and heat. Also, further benefits are related to the concept of Distributed Generation (DG), primarily in terms of reduction in transmission losses and increased safety of power supply. Today a relevant share of the CHP market is covered by large/medium size plants integrated within industrial districts or individual manufacturing processes, due to the possibility to operate conveniently the CHP unit (and, consequently, to achieve a profitable operation) where regular load profiles are concerned; currently, in Italy the average size of CHP units is in the order of 10 MWe, including the large gas or backpressure steam turbines or the even larger combined cycles. However, when depicting future scenarios concerning polygeneration market the scientific literature has been recently assigning a primary role to micro/small/medium scale CHP for applications in the civil sector (especially in the tertiary and, in some way, also the residential users); this growing interest is testified by the explicit focus of the Directive 2004/8/EC (fixing common criteria for the high efficiency CHP assessment) on "micro cogeneration" and "small scale cogeneration", defined with respect to the maximum 50 kWe and 1 MWe installed capacity, respectively. The Italian Legislative Decree n. 20/07, which pursues the goal declared in the aforementioned Directive, promotes "increases in the energetic efficiency and a higher reliability of energy supply" by defining a set of provisions concerning high efficiency polygeneration "based on a useful heat demand and on primary energy saving" (to avoid non cogenerative plants to be assessed as efficient cogeneration), basing on the specific climatic conditions in Italy. Among others, the following technologies are supported: • Reciprocate engines, either natural gas or diesel oil fuelled; • Micro gas turbines; • Stirling engines; • Fuel cells. In spite of this relevant and universally recognized potential, the installed small/micro -scale CHP capacity is still low, due to a number of obstacles; among them, a main role is probably played by a continuously changing legislative framework, which concur to increase the risk of any investment, and by the absence of specific knowledge on design and operation criteria for CHCP plants and the consequent difficulty in achieving economic viability. This research project is oriented to define a detailed knowledge on the performance of small/micro-scale CHP plants for applications in the civil sector and to elaborate methods and criteria for the optimization of design and operation. The research will involve different levels of analysis, like the modelization of several CHP technologies adopting both experimental and theoretical approaches and an in-depth understanding of the influence of components' integration on their individual performance (this aspect will be investigated for different plant lay-outs, design and boundary conditions as concerns legislative provisions and energy prices). For a full exploitation of the existing potential for polygeneration in the civil sector, different users will be considered: • Detached or semi-detached dwellings, to be supplied with heat, cooling and power by commercial micro-scale CHP units, where a primary role is played by the integration with small heat storage tanks or with electric heat pumps; • Large buildings, like hospitals, hotels or commercial centres, where an installed capacity up to 2-3 MWe can be required. This kind of applications can be covered by a variety of technologies, either "traditional" or "innovative" (like high/medium temperature fuel cells); • Clusters of large building situated over a small area, where the creation of a CHCP-based µ-grid, i.e. the fractioning of the capacity into a number of large CHCP plants to be installed in buildings' proximity and interconnected by a fluid distribution network, can be evaluated.
2011
Settore ING-IND/10 - Fisica Tecnica Industriale
Cardona, F., Piacentino, A. (2011). Criteri e metodi per l'ottimizzazione di sistemi di poligenerazione di piccola e media taglia - Criteria and methodologies for the optimization of small/medium scale polygeneration systems. Palermo : F. Cardona, E. Piacentino.
File in questo prodotto:
Non ci sono file associati a questo prodotto.

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/10447/76418
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus ND
  • ???jsp.display-item.citation.isi??? ND
social impact