Metodologie di analisi energetica nei supermercati e negli ipermercati, con l’obiettivo della ottimizzazione della domanda elettrica ed energetica globale, casi studio per la Regione Siciliana.

Ottimizzazione energetica nel settore dei supermercati e degli ipermercati - Congelazione Rapida degli alimenti

Advanced refrigerating plants based on transcritical cycles working with carbon dioxide for commercial refrigeration

Supermarkets and hypermarkets require a huge amount of energy to maintain chilled and frozen food in product display cases and cold storage rooms and thermal comfort in the whole building. Systems exploited require very large refrigerant charges for operation and suffer significant leakages. The challenge for advanced systems, based on equipment which reduce TEWI, suggests the proposal of carbon dioxide: a natural working fluid. This paper deals with a feasibility study of a refrigerating system for a big hypermarket in Sicily based on a three-stage transcritical cycle working with carbon dioxide which is compared with an alternative system composed of two cycles operating as a binary refri…

A Solar Pond for Feeding a Thermoelectric Generator or an Organic Rankine Cycle System

The world energy demand is continuously growing, which means an increase in consumption for all modern fuels or stronger effort on the development and improvement of renewable technologies. Moreover, Developing Countries claims more energy and they have often wide unutilized or unusable lands. The solar energy represents a useful opportunity for these Countries. The Solar Pond is both a solar collector and a thermal storage for long period and is suitable to use in wide sunny areas. Solar pond technology is able to supply heat for several applications requiring low-grade thermal energy or for electrical power production. In order to produce electrical energy from solar ponds it is necessary…

I letti fluidizzati e le loro applicazioni

A testing facility for refrigerating plants equipment working with new fluids

Celle a combustibile per applicazioni stazionarie cogenerative

Studio di fattibilità di un impianto di climatizzazione con accumulo di caldo e freddo con ghiaccio per un grosso ipermercato ubicato in Sicilia

Esperimenti sulle prestazioni di fluidi sostitutivi dell’R22 negli impianti frigoriferi

Schema del Piano Energetico Regionale della Regione Siciliana, Rapporto di Sintesi

Energy Saving with Absorption Equipment: a Case Study

The paper deals with the results of a feasibility study performed at DREAM which is related to the possibility of using reject heat from an Electric Utility (which has a Combined Cycle Unit with Gas and Steam turbines belonging with ENEL Pro. at Termini Imerese, Palermo). The Utility lies near an Industrial District where there has need for feeding a Cooling Plant for Foodstuff Stocking at two different temperature levels: 0 °C and -18°C. The feasibility study covers both technical feasibility of a suitable cooling plant which use two separate absorption equipment, working with the pair Ammonia-Water, and economic feasibility of the venture. The feasibility study pertains: to the optimal de…

Caso studio - Determinazione del quadro complessivo relativo alla utilizzazione del Gas Naturale nel territorio della Regione Siciliana

Organic Rankine Cycle fed by flat-plate solar collectors: a case study

L'attuale tendenza dell’utilizzo di sistemi di risorse energetiche distribuite (sistemi DER), insieme con il crescente sviluppo tecnologico, incoraggia l'uso di tecnologie capaci di recuperare efficacemente energia da fonti di calore a temperatura bassa o moderata, che rappresentano un'opzione essenziale per affrontare le problematiche energetiche ed ambientali. In questo contesto, i cicli Rankine a fluido organico (ORC) si stanno affermando come una tecnologia molto promettente tra quelle attualmente disponibili, in particolare per bassi valori di temperatura. I principi di funzionamento dei sistemi ORC sono essenzialmente gli stessi di quelli del ciclo Rankine. Nei sistemi ORC, l’acqua è …

Modelling heat transfer-controlled cooling and freezing times: a comparison between computational values and experimental results

Modelling of heat transfer-controlled cooling and freezing time predictions are very important for a good preservation of foodstuffs. In that regard, we used a computer code based on the finite-element method that allowed us to analyse the phase-change of various foodstuffs during their freezing. The model was exercised to predict process times. The results can be used to design high efficiency plants. In this work, the results predicted by the FEM program are compared with the experimental values given in technical literature.

A mesh less approch based upon Radial basis function Hermite collocation method for predicting the cooling and the freezing times of foods

This work presents a meshless numerical scheme for the solution of time dependent non linear heat transfer problems in terms of a radial basis function Hermite collocation approach. The proposed scheme is applied to foodstuff's samples during freezing process; evaluation of the time evolution of the temperature profile along the sample, as well as at the core, is carried out. The moving phase-change zone is identified in the domain and plotted at several timesteps. The robustness of the proposed scheme is tested by a comparison of the obtained numerical results with those found using a Finite Volume Method and with experimental results.

Trasmissione del calore nei letti fluidizzati con gas sino a medie temperature

Ottimizzazione energetica e razionalizzazione della domanda elettrica dei supermercati e degli ipermercati.

ENERGY RECOVERY FROM REGASIFICATION OF LNG

The international forecasts on energy consumption in the next future show an increasing trend due also to growing markets, and among this the leading emerging economies connected to BRICS countries (Brazil, Russia, India, China and South Africa). We need more and more energy. On the other side the environmental problem is arising and the climate change is a more and more pressing emergency. The latest environmental disasters, as the oil spill in the Gulf of Mexico in 2010 and the earthquake with the following tsunami in Japan in 2011, struck the public opinion and so, as in many European countries, the nuclear program is under a deep revision or even stopped. So it is necessary to utilize a…

Numerical Solution of Foodstuff Freezing Problems Using Radial Basis Functions

This work presents a novel numerical approach for the solution of time dependent non-linear freezing processes in terms of radial basis function Hermite approach. The proposed scheme is applied to a mashed potato sample during its freezing; evaluation of time evolution of the temperature profile at the core of the sample is carried out. Food thermal properties are highly dependent on temperature and the mathematical problem becomes highly non-linear and therefore particularly difficult to solve. Incorporating a Kirchhoff transformation significantly reduces the non-linearity. The robustness of the scheme is tested by comparison with experimental results available in literature.

La Life Cycle Assessment come strumento di supporto per le piccole e medie imprese: un caso studio siciliano

L’Unione Europea mira ad orientare il mercato verso una crescente domanda di prodotti e servizi ecoefficienti ed eco-sostenibili. Le PMI, per essere competitive sul mercato, hanno la necessità di superare il gap tecnologico e di competenze che spesso le caratterizza ed avviare processi produttivi eco-orientati. In tale contesto nasce il Centro di Ricerca Italo-Maltese per la Sostenibilità Ambientale e le Fonti Rinnovabili (CRIM-SAFRI), che si propone di offrire una significativa opportunità di crescita e sviluppo per il tessuto produttivo dell’area del Mediterraneo, contribuire a ridurre i consumi energetici, le emissioni di gas serra e di altre sostanze inquinanti connessi ai processi prod…

Trasmissione del calore nei letti fluidizzati con gas ad alte temperature

Trasmissione del calore nei letti fluidizzati con liquidi

Lo studio dei fenomeni relativi all’idrodinamica ed allo scambio termico nei letti fluidizzati è di grande interesse nell’Energetica industriale. Infatti è necessaria la loro comprensione per proporre modelli affidabili ai fini della progettazione e della simulazione del funzionamento delle tante apparecchiature nelle quali essi si manifestano. In molti processi industriali i contatti e le interazioni tra fluidi, siano essi liquidi o gas, e particolati solidi consentono una grande varietà di utili applicazioni. Si tratta del campo dell’ingegneria della fluidizzazione, che ha suscitato un ampio interesse fin dalla realizzazione, durante la Seconda Guerra Mondiale, dei reattori a letto fluido…

Safety study of an LNG regasification plant using an FMECA and HAZOP integrated methodology

Abstract A safety analysis was performed to determine possible accidental events in the storage system used in the liquefied natural gas regasification plant using the integrated application of failure modes, effects and criticality analysis (FMECA) and hazard and operability analysis (HAZOP) methodologies. The goal of the FMECA technique is the estimation of component failure modes and their major effects, whereas HAZOP is a structured and systematic technique that provides an identification of the hazards and the operability problems using logical sequences of cause-deviation-consequence of process parameters. The proposed FMECA and HAZOP integrated analysis (FHIA) has been designed as a …

Regimi di fluidizzazione e dimensioni dei particolati

The importance of reliable climatic data in the energy evaluation

Abstract In the last few years, more and more attention has been focused on energy issues, as it is pointed out, for example, by the Directive 2002/91/EC on the Energy Performance of Buildings and Directive 2009/28/EC on the promotion of the use of energy from renewable sources. However, in order to do that, reliable tools for technicians to design systems for such topics should be provided. Nowadays, several software are available; the weak point is the availability of reliable climatic data and, above all, the ones referring to solar radiation. In this work, after a short overview of the world climatic databases, a description of three statistical methods for the elaboration of a climatic…

Optimization of a thermoelectric system for power generation realized by ‘‘hidden’’ components

Abstract Today the utilization of renewable energy sources is very important to support the traditional ones, and also in order to reach the objectives fixed by the Kyoto Protocol. In this context, also well-known technologies related to the electric energy production, formerly not suitable – due to the poor technological level of the components or due to the high costs linked to the system efficiency – may now find a suitable collocation. Among these technologies, the thermoelectric effect may be very advantageous in some particular applications of small power. A power generation system utilizing this technology has been studied by the authors. This system utilizes the thermal difference b…

Schema del Piano Energetico Regionale della Regione Siciliana, Rapporto Finale

Comparing different control strategies for indoor thermal comfort aimed at the evaluation of the energy cost of quality of building

Abstract The rapid improvement in the standard of living requires more detailed and sophisticated methods of evaluating comfort conditions. But, maintaining thermal comfort conditions in confined environments may require complex regulation procedures and the proper management of heating, ventilating and air conditioning (HVAC) systems. In turn, the requirements for indoor thermal comfort do not necessarily coincide with those of energy saving purposes, which in the last years are becoming a crucial issue owing to the enactment of the European Energy Performance of Buildings Directive (EPBD). The aim of this work is to compare different indoor control thermal comfort strategies in view of th…

Analysis of Air Cycle and Efficiency Evaluation for a Blast Freezing Tunnel Plant

Air refrigerating systems offer a suitable alternative to vapour compression systems. Air can be used as working fluid in gas compression cycles for refrigeration, air conditioning and heat pump systems. This paper gives some results of theoretical investigation into improved air cycles for refrigeration systems and a comparison is made with their performances. The case-study relates to a dual purpose refrigerating plant. A blast freezing tunnel gives the coldest air stream and, in cascade, the air coming out from the tunnel is used in a channel network for feeding a lot of chilling cells. The case-study analysed indicates that there is a real possibility to build plants which will be equip…

Performance Enhancement of Vapour-Compression Refrigeration Systems Using Nanoparticles: An Experimental Study

In recent years, the development and characterization of new refrigerants with higher energetic efficiency have gained considerable interest [1], with a particular emphasis on the energetic performance of suitable replacements. Nanofluids have been proposed as possible alternative due to their role in enhancing the thermophysical proprieties of traditional refrigerants [2]. The comprehensive review in [2] suggests that thermal conductivity of nanofluid increases with temperature and volume concentration, but it is dependent on nanoparticle size distribution; specific heat is also increased if nanoparticles are added to the refrigerant.

Applicazioni dell'effetto termoelettrico: un caso studio

Riveste sempre maggiore importanza l’utilizzo di fonti rinnovabili di energia da affiancare alle fonti tradizionali, anche per l’ottenimento degli obiettivi sottoscritti con l’adesione al Protocollo di Kyoto. In questo contesto anche tecnologie note per la produzione di energia elettrica ma precedentemente non convenienti - sia per il livello tecnologico dei componenti o per gli elevati costi rapportati all’efficienza ottenibile dai sistemi sviluppabili - potrebbero trovare una adeguata collocazione. Tra queste tecnologie l’effetto termoelettrico potrebbe essere vantaggioso in alcune particolari applicazioni di piccola potenza. I principali sistemi per la produzione di energia elettrica da …

A Testing Facility for Refrigerating Plants Equipment Working with New Fluids

A test rig was built in the department of energy, in laboratory of refrigerating engineering for test runs with a lot of fluid and equipment of various kind for commercial refrigeration. The facility has been continuously improved during the past years and allows to perform experiments aiming to assess the performance characteristics both of conventional and new equipment for commercial refrigeration. In the test rig can be tested a lot of cooling loop filled with a secondary fluid for simulation of their behavior in industrial and commercial plants (e.g.: during exploitation in supermarket and hypermarket for refrigeration of foodstuffs in cold store, display cases and cabinets, etc.). The…

Caso Studio relativo ad un ipermercato ubicato in Sicilia, opportunità di risparmio energetico, studi di fattibilità

Energia incorporata negli edifici a energia netta zero

Absorption equipment for energy savings: A case study in Sicily

Abstract This paper considers a feasibility study on the recovery of the reject heat available from an electric utility with two units operating with 120-MW gas turbines; these units have a heat recovery system that feeds the district heating pipeline of an industrial consortium. Thus, feeding the expeller of the absorption equipment installed in a cooling plant for foodstuff stocking represents an opportunity for the feasibility study. This plant operates at both 0 °C and −18 °C. The feasibility study covers two aspects: (1) the technical feasibility of a suitable absorption cooling plant that uses two separate pieces of absorption equipment working with the pair ammonia–water and (2) the …

Il Progetto “Mentori per la didattica” dell’Università di Palermo dopo sei anni dalla nascita e le iniziative future

L’Ateneo di Palermo sta portando avanti diverse iniziative di miglioramento della qualità della didattica. In particolare, il progetto “Mentori per la didattica” nasce nel 2013 su iniziativa di alcuni docenti di ingegneria con l’obiettivo di migliorare la qualità della didattica dei partecipanti grazie a due strumenti chiave: l’aiuto dei mentori e una serie di incontri di riflessione e approfondimento. Ogni docente (mentee) che aderisce al progetto ha due mentori che hanno il compito di aiutarlo a migliorare la qualità della sua didattica. Inoltre, egli stesso svolge il ruolo di mentore a favore di altri due colleghi, cosicché ciascuno è mentore e mentee allo stesso tempo. I mentori assisto…

Celle a combustibile per applicazioni stazionarie cogenerative (5.2.5.11) - Celle a Combustibile (wp1)

Accordo di Programma MSE-CNR - Gruppo tematico: Celle a Combustibile (wp1) Responsabile scientifico del Progetto Vincenzo Antonucci - Accordo di Collaborazione tra CNR Dipartimento Energia e Trasporti (DET) e Dipartimento Ricerche Energetiche e Ambientali (DREAM) dell’ Università di Palermo - Attività di ricerca nell’ambito del Progetto: “Celle a combustibile per applicazioni stazionarie cogenerative – Sviluppo di celle ad ossidi solidi per la co-generazione di energia elettrica e calore (freddo)” - ATTIVITA’ ANNO 2009. Attività di sviluppo di un modello di simulazione matematico fenomenologico di sistemi di generazione elettrica con taglie di potenza 100-200 kW - Report finale. Palermo: DREAM.

Comportamento idrodinamico dei letti fluidizzati e stima della porosità

The importance of reliable climatic data in the urban energy policy

In the last years, more and more attention has been focused on energy issues, in particular at urban level, as it is pointed out by the Directive 2002/91/EC on the Energy Performance of Buildings. In fact, the building sector encompasses nearly 30% of the energy whole consumptions. To try to limit such consumptions, both central and local governments should plan effective policies, such as promoting the use of renewable sources and of more energy efficient buildings (e.g. by means of green coverings). But in order to do that, local administrations should provide reliable tools for engineers and technicians to plan such systems. Nowadays, several software are available; the weak point is the…

Optimization of a thermoelectric system for power generation

Nowadays the utilization of renewable energy sources is very important to support the traditional ones, and besides in order to achieve the objectives fixed by the Kyoto Protocol. In this context also well known technologies related to the electric energy production, formerly not suitable - due to the technological level of the components or due to the high costs linked to the system efficiency -, may found a suitable collocation. Among these technologies, the thermoelectric effect may be very advantageous in some particular applications of small power. A power generation system utilizing this technology was studied by the Authors. This system utilizes the thermal difference between a lower…

Accordo di Programma MSE-CNR. Gruppo tematico: Celle a Combustibile (wp1). Responsabile scientifico del Progetto Vincenzo Antonucci. Accordo di Collaborazione tra CNR Dipartimento Energia e Trasporti (DET) e Dipartimento dell’Energia (DE) dell’Università di Palermo. Responsabile Scientifico: Celidonio Dispenza sino al 31.10.2010, Vincenzo La Rocca dall’1.11.2010. Attività di ricerca nell’ambito del Progetto: “Celle a combustibile per applicazioni stazionarie cogenerative: Analisi comparative delle tecnologie in studio con sistemi energetici concorrenti”. ATTIVITA’ ANNO 2010-2011. Palermo. Dipartimento dell’Energia

Accordo di Programma MSE-CNR - Gruppo tematico: Celle a Combustibile (wp1) Responsabile scientifico del Progetto Vincenzo Antonucci - Accordo di Collaborazione tra CNR Dipartimento Energia e Trasporti (DET) e Dipartimento Ricerche Energetiche e Ambientali (DREAM) dell’ Università di Palermo - Responsabile Scientifico DREAM: Celidonio Dispenza - Attività di ricerca nell’ambito del Progetto: “Celle a combustibile per applicazioni stazionarie cogenerative” - ATTIVITA’ ANNO 2009

PERFORMANCE ENHANCEMENT OF VAPOUR COMPRESSION REFRIGERATION SYSTEMS USING NANOPARTICLES: AN EXPERIMENTAL STUDY

In recent years, the development and characterization of new refrigerants with higher energetic efficiency have gained considerable interest [1], with a particular emphasis on the energetic performance of suitable replacements. Nanofluids have been proposed as possible alternative due to their role in enhancing the thermophysical proprieties of traditional refrigerants [2]. The comprehensive review in [2] suggests that thermal conductivity of nanofluid increases with temperature and volume concentration but it is dependent on nanoparticle size distribution; specific heat is also increased if nanoparticles are added to the refrigerant. As consequence, the improved heat transfer coefficients …

The DREAM experimental facility for testing Equipment for Refrigerating Plants working with new fluids

Embodied energy and environmental impacts of a biomass boiler: a life cycle approach

The 2030 policy framework for climate and energy, proposed by the European Commission, aims towards the reduction of European greenhouse gas emissions by 40% in comparison to the 1990 level and to increase the share of renewable energy of at least the 27% of the European's energy consumption of 2030. The use of biomass as sustainable and renewable energy source may be a viable tool for achieving the above goals. However, renewable energy technologies are not totally clean because they cause energy and environmental impacts during their life cycle, and in particular they are responsible of air pollutant emissions. In this context, the paper assesses the energy and environmental impacts of a …

Una metodologia per la stima dei coefficienti di scambio termico nei letti fluidi circolanti