Recupero del freddo nella rigassificazione del GNL: produzione di energia elettrica

Caso studio - Risparmio energetico nella rigassificazione del GNL

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.

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…

Il metodo di Hermite applicato ad un caso studio di trasmissione di calore

Analisi del transitorio termico nei processi di surgelazione di derrate alimentari

Exergy Recovery during LNG Regasification: Electric Energy Production - Part Two

In liquefied natural gas (LNG) regasification facilities, for exergy recovery during regasification, an option could be the production of electric energy recovering the energy available as cold. In a previous paper, the authors propose an innovative process which uses a cryogenic stream of LNG during regasification as a cold source in an improved combined heat and power (CHP) plant. Considering the LNG regasification projects in progress all over the World, an appropriate design option could be based on a modular unit having a mean regasification capacity of 2 × 109 standard cubic meters/year. This paper deals with the results of feasibility studies, developed by the authors at DREAM in the…

I letti fluidizzati e le loro applicazioni

A testing facility for refrigerating plants equipment working with new fluids

Recupero e utilizzazione del freddo nella rigassificazione del GNL

Celle a combustibile per applicazioni stazionarie cogenerative

Energy and environmental impacts of Energy related products (ErP): a case study of biomass-fuelled systems

Abstract Energy-related Products (ErP) account for a large proportion of European energy and natural resource consumption. In 2007, ErP were responsible for the consumption of about 239 Mtoe of electricity and about 555 Mtoe of fuels. In order to reduce the energy and environmental impacts of these products, the European Commission published the Directive 2009/125/EC on the eco-design of ErP. This Directive represents a key component of European policy for improving the energy and environmental performances of products in the internal market. In this context, it is important to develop scientific research aimed at assessing the energy and environmental impacts of ErP, and at defining their …

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

CHP plants for production of electrical energy during regasification of LNG recovering exergy of cold.

The tranport of natural gas by pipeline from gas fiel tothe town or industrial sites in most case is impossible, so there is need to transport LNG by ship. At the terminal of arrival a regasification process of LNG, which is liquefied near well-head, returns it back to gas state before its transport in the pipelinenetwork. This paper deals with the results of feasibility studies on ventures based on an appropriate thermo-economic analysis of improved cycles (CHP Cycles: the top Cycle is a convevtional Gas Turbine open Cycle fed by natural gas and the bottom Cycle is an improved Gas Turbine closed cycle working with Helium or Nitrogen gas). The analysis shows the convenience and the profitab…

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

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

Cold recovery during regasification of LNG part one: Cold utilization far from the regasification facility

The paper deals with cold recovery during LNG regasification. The applications analyzed pertain to the use in deep freezing agro food industry and in space air conditioning facilities in commercial sector (Supermarkets and Hypermarkets) of cold recovered from the regasification process. A modular LNG regasification unit is proposed having the regasification capacity of 2 billion standard cubic meters/year of gas and it is based on use of a Power Cycle working with Ethane, this unit allows operation of cold energy transfer, contained in LNG to be regasified, in a range of temperatures suitable for multipurpose use of cold, reducing regasification process irreversibility. Some electric energy…

Graded Carrier Concentration Absorber Profile for High Efficiency CIGS Solar Cells

We demonstrate an innovative CIGS-based solar cells model with a graded doping concentration absorber profile, capable of achieving high efficiency values. In detail, we start with an in-depth discussion concerning the parametrical study of conventional CIGS solar cells structures. We have used the wxAMPS software in order to numerically simulate cell electrical behaviour. By means of simulations, we have studied the variation of relevant physical and chemical parameters-characteristic of such devices-with changing energy gap and doping density of the absorber layer. Our results show that, in uniform CIGS cell, the efficiency, the open circuit voltage, and short circuit current heavily depe…

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

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

CIGS PV Module Characteristic Curves Under Chemical Composition and Thickness Variations

This paper analyzes how the electrical characteristics of a CIGS photovoltaic module are affected by the chemical composition and by the thickness variations of the CIGS absorber. The electrical characteristics here considered are the short circuit current, the open circuit voltage, the efficiency and the power peak. The chemical composition is varied by tuning the ratio between gallium and indium. This analysis has been performed by means of the wxAMPS software, developed by the University of Illinois. The above variations have been taken into account on a PV module made of 72 cells. This analysis has been carried out employing a PV module mathematical model developed and implemented by th…

Life cycle assessment of solar communities

Abstract This study presents the comparison of the life cycle performance of two different urban energy systems, applied to a large mixed-use community, in Calgary (Canada). The two systems investigated consist of an energy efficient conventional system, using heat pumps for heating, cooling and domestic hot water; the second design widely deploys solar thermal panels coupled to district heating infrastructure and a borehole seasonal thermal storage. The analysis is based on the Life Cycle Assessment methodology and includes the stages of raw materials and energy supply, system manufacturing, use stage of the systems, generation and use of energy on-site, maintenance and components’ substit…

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.

Exergy recovery in regasification facilities – Cold utilization: A modular unit

Abstract The paper deals with the problem of cold recovery for direct utilization both in the site of regasification facility and far from it. A modular LNG regasification unit is proposed having the regasification capacity of 2 billion standard cubic meters/year of gas. The modular plant is based on use of a power cycle working with ethane or ethylene which allows operation of cold energy transfer, contained in LNG to be regasified, in a range of temperatures suitable for multipurpose use of cold, reducing regasification process irreversibility. Some electric energy is produced by the power cycle, but the own mission of modular unit proposed is addressed to deliver cold suitable for indust…

Trasmissione del calore nei letti fluidizzati con gas ad alte temperature

Ricerca sul risparmio energetico nella rigassificazione del GNL – Impianti CHP con ciclo di Botton ad elio o ad azoto. Innovazione tecnologica di impianti energetici: Studio teorico e sperimentale di metodologie per la progettazione e verifica.

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…

Regimi di fluidizzazione e dimensioni dei particolati

Impatti energetico-ambientali connessi alla produzione di energia elettrica in Sicilia

Negli ultimi anni l’attenzione verso le problematiche connesse al cambiamento climatico e all’approvvigionamento energetico è diventata sempre più rilevante. L’Unione Europea ha approvato il “pacchetto clima-energia” che mira, entro il 2030, a ridurre le emissioni di gas ad effetto serra del 40% rispetto al 1990 e ad incrementare la quota di energia prodotta da fonti rinnovabili almeno al 27%. Per iniziare a stimare i benefici indotti dall’incremento della produzione di elettricità da fonti rinnovabili, nel presente lavoro vengono stimati gli impatti energetico-ambientali connessi alla produzione di 1 kWh di energia elettrica in Sicilia nell’arco temporale 2000 – 2011, tramite l’applicazion…

Towards achieving net-zero energy communities: Investigation of design strategies and seasonal solar collection and storage net-zero

Abstract This paper explores a solar mixed-use community and its potential towards achieving net-zero energy status. This mixed-use community combines residential and commercial/institutional buildings. Energy performance of this neighbourhood is estimated in terms of energy consumption and generation potential by means of building integrated PV systems. A solar thermal collector system combined with a borehole thermal energy storage (BTES) is designed to investigate the impact on the overall performance of the neighbourhood. The design of solar thermal collectors and the sizing of short-term thermal energy storage is based on the analysis of the thermal loads for heating and domestic hot w…

Parametrical study of multilayer structures for CIGS solar cells

In this paper, a numerical analysis of relevant electrical parameters of multilayer structures for CIGS-based solar cells was carried out, employing the simulation software wxAMPS. In particular, we have focused on thin film cells having a ZnO:Al/ZnO/CdS/CIGS structure with a Molybdenum back contact. The aim of this work is to establish good theoretical reference values for an ongoing experimental activity, where our technology of choice is the single-step electrodeposition. In detail, we have analyzed how the main electrical properties change with the bang gap and the thickness of the absorber layer, for such a type of solar cell structure. Our results show that both efficiency and fill fa…

Studio per la redazione del Piano Energetico della Regione Siciliana, Casi studio – Risparmio energetico nella rigassificazione del GNL

Schema del Piano Energetico Regionale della Regione Siciliana, Rapporto Finale

Determinazione del quadro complessivo relativo alla utilizzazione del Gas Naturale nel territorio della Regione Siciliana. Relazione di sintesi

Energy and economic assessment of a small domestic wind turbine in Palermo

The cost effectiveness of micro-wind technology is closely linked to the annual energy production plants, which strongly depends on the wind characteristics and on the morphological properties of the installation site. The power curve of a wind turbine, supplied by manufacturers, characterizes the theoretical energy performance that it should have at a particular site. The behavior of a wind turbine in the field is affected by the speed but also by wind direction variations. At each change of direction and speed, the turbine will try to adapt to new conditions and the phase transition negatively influences the energy production. In order to experimentally confirm what above mentioned, the a…

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…

Characterization of Biodiesel from Vegetable Oil Using Comprehensive Two-Dimensional Gas Chromatography

Biodiesel from vegetable oils has been analyzed and its suitability for internal combustion engines has been assessed. The Standard biofuel’s characteristics have been investigated. Gas chromatography (GC) tests were carried out to characterize the fatty acid behavior. It was found that the mass percentage of saturated fatty acids did not change substantially with time, while unsaturated fatty acids increased with time for both B100 and B30. An increase in density for B100 and B30 with time was noted. Biodiesel density was within the standardization. The calorific values of biodiesel and its blend increased with time. Higher heating value for B100 increased from 41 to 43 MJ/kg while B30 inc…

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

Characterization of Biodiesel from Vegetable Oil Using Comprehensive Two-Dimensional Gas Chromatography

Biodiesel from vegetable oils has been analyzed and its suitability for internal combustion engines has been assessed. The Standard biofuel’s characteristics have been investigated. Gas chromatography (GC) tests were carried out to characterize the fatty acid behavior. It was found that the mass percentage of saturated fatty acids did not change substantially with time, while unsaturated fatty acids increased with time for both B100 and B30. An increase in density for B100 and B30 with time was noted. Biodiesel density was within the standardization. The calorific values of biodiesel and its blend increased with time. Higher heating value for B100 increased from 41 to 43 MJ/kg while B30 inc…

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 …

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

Ricerca sul risparmio energetico nella rigassificazione del GNL, Innovazione tecnologica di impianti energetici: Studio teorico e sperimentale di metodologie per la progettazione e la verifica Unità di Ricerca dell’Università di Palermo, Rapporto monografico risultati ricerca

Sintesi dello Studio del TEAM del PER per il forum con le parti sociali e Bozza dei Piani d’Azione

On-site Experimental Study of HCFC-22 Substitution with HFCs Refrigerants

Abstract The European Regulation no 2037/2000 has banned manufacturing HCFC refrigerants from January 1st 2010, although its use is allowed up to 2015 if the fluids come from a recycling process. This situation creates the need for developing new working fluids to replace the HCFC in the refrigeration plants now in operation. Among all the HCFCs the R22 is the most widely used in a wide range of applications, especially in air conditioning. This paper presents the results of an experimental analysis comparing the performance of a vapour compression refrigerating unit operating with R22, and its performance in comparison to some HFCs fluids, substituting the former. In particular, the plant …

Cold recovery during regasification of LNG part two: applications in an Agro Food Industry and a Hypermarket

Abstract The paper deals with the cold energy available during LNG regasification, which can be recovered and utilized both inside the LNG regasification area and at a distance, such as in deep freezing agro food industry facilities and for space conditioning in the commercial and residential sector (e.g. Supermarkets and Hypermarkets). The feasibility study of this kind of application has been carried out at DREAM, Palermo University, within the framework of a research program. The results of a feasibility study of the kind of venture proposed, starting from its conceptual design and with a thorough thermodynamic and economic analysis, demonstrated the suitability and the profitability of …

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.

Hypertonic Saline in Conjunction with High-Dose Furosemide Improves Dose-Response Curves in Worsening Refractory Congestive Heart Failure.

Introduction Diuretic responsiveness in patients with chronic heart failure (CHF) is better assessed by urine production per unit diuretic dose than by the absolute urine output or diuretic dose. Diuretic resistance arises over time when the plateau rate of sodium and water excretion is reached prior to optimal fluid elimination and may be overcome when hypertonic saline solution (HSS) is added to high doses of furosemide. Methods Forty-two consecutively hospitalized patients with refractory CHF were randomized in a 1:1:1 ratio to furosemide doses (125 mg, 250 mg, 500 mg) so that all patients received intravenous furosemide diluted in 150 ml of normal saline (0.9%) in the first step (0–24 h…

An experimental study of a refrigerating plant when replacing R22 with HFCs refrigerants

This paper presents the results of an experimental analysis comparing the performance of a vapour compression refrigerating unit operating with R22, and its performance in comparison to some HFCs fluids, substituting the former according to reg. n. 2037/2000. In particular, the plant working efficiency was first tested with R22 and then with three HFC fluids: R417A, R407C and R404A. The investigation verified that the performance with HFCs refrigerants did not result as efficient as when using R22. An environmental analysis also was performed.

Comportamento idrodinamico dei letti fluidizzati e stima della porosità

Thin Film CIGS Solar Cells, Photovoltaic Modules, and the Problems of Modeling

Starting from the results regarding a nonvacuum technique to fabricate CIGS thin films for solar cells by means of single-step electrodeposition, we focus on the methodological problems of modeling at cell structure and photovoltaic module levels. As a matter of fact, electrodeposition is known as a practical alternative to costly vacuum-based technologies for semiconductor processing in the photovoltaic device sector, but it can lead to quite different structural and electrical properties. For this reason, a greater effort is required to ensure that the perspectives of the electrical engineer and the material scientist are given an opportunity for a closer comparison and a common language.…

Environmental Implications of Traffic Flow Delays: a Model for Urban Streets

In this paper the problem of road's capacity is dealt in presence of perturbations of the vehicular flow. In particular, among the different disturbing causes, it is here considered the presence of vehicles parked along the road in relation to their parking activity. Having already established the delay, caused by those vehicles leaving their stationary positions and entering the traffic flow or by those who slow down the flow to park, it is possible to evaluate the changes in time running values. Related to these times delay, the extra pollutant emissions by a given urban running fleet is also evaluated, by utilizing emission factors depending on age, type, volume capacity and engine of th…

Experimental performance evaluation of a vapour compression refrigerating plant when replacing R22 with alternative refrigerants

Abstract This paper presents the results of an experimental analysis comparing the performance of a vapour compression refrigerating unit operating with R22, and its performance in comparison to a new HFC fluid, substituting the former according to Regulation No 2037/2000. In particular, the plant working efficiency was first tested with R22 and then with three new HFC fluids: R417A, R422A and R422D. The investigation verified that despite the case of substitution and the advantage of being able to continue to use mineral oil as a lubricant in the compressor, the performance with the new tested fluids did not result as efficient as when using R22.

Environmental Implications of Traffic Flow Delays: A Model for Urban Streets

In this paper the problem of road's capacity is dealt in presence of perturbations of the vehicular flow. In particular, among the different disturbing causes, it is here considered the presence of vehicles parked along the road in relation to their parking activity. Having already established the delay, caused by those vehicles leaving their stationary positions and entering the traffic flow or by those who slow down the flow to park, it is possible to evaluate the changes in time running values. Related to these times delay, the extra pollutant emissions by a given urban running fleet is also evaluated, by utilizing emission factors depending on age, type, volume capacity and engine of th…

Un innovativo metodo per modellare fenomeni fisici

Photovoltaic module characteristics from CIGS solar cell modelling

We describe our approach to the task of modelling, both at single cell structure and complete module levels, during the solar cell technology development process. This can give very helpful indications, in terms of global photovoltaic module characteristics, for the assessment of intermediate research results and planning of further experiments. We make reference specifically to the fabrication of thin film CIGS solar cells by means of single-step electrodeposition, a technique which appears fairly easy and low-cost but, at the same time, can lead to quite different structural and electrical properties.

Exergy recovery during LNG regasification: Electric energy production – Part one

Abstract In liquefied natural gas (LNG) regasification facilities, for exergy recovery during regasification, an option could be the production of electric energy recovering the energy available as cold. In a previous paper, the authors propose an innovative process which uses a cryogenic stream of LNG during regasification as a cold source in an improved combined heat and power (CHP) plant. Considering the LNG regasification projects in progress all over the World, an appropriate design option could be based on a modular unit having a mean regasification capacity of 2 × 109 standard cubic meters/year. This paper deals with the results of feasibility studies, developed by the authors at DRE…

Studio per la redazione del Piano Energetico della Regione Siciliana, Sintesi del Rapporto di Seconda e Terza Fase Rapporto di Terza fase e bozze dei piani di Azione

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 …

Experiments on heat transfer in evaporators for refrigerating plants working with new fluids and data correlation

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

Phase Change Materials Applications to Optimize Cooling Performance of Buildings in the Mediterranean Area: A Parametric Analysis

Abstract Building integrated thermal energy storage systems cover a wide range of techniques and solutions depending on technology applications and aims. They however all have in common the concept behind: being able to store energy for later use in order to reduce the time mismatch between energy availability and demand. In this context, Phase Change Materials (PCMs) fit the above description, since they would allow for mostly isothermal phase change within normal thermal comfort range. In order to face the typical challenges of the Mediterranean climate, the following concept was elaborated: the idea is to use the phase change mechanics as a substitute to the thermal inertia of massive wa…

Sviluppo di piattaforme innovative per il calcolo dell’energia incorporata nell’edilizia e di modelli per la quantificazione del potenziale Ventilative Cooling nell’edilizia

Il presente report si inserisce nell’ambito dell’accordo di Collaborazione tra ENEA e il Dipartimento di Energia, Ingegneria dell’informazione e Modelli Matematici (DEIM), per l’attività dal titolo “Sviluppo di piattaforme innovative per il calcolo dell’energia incorporata nell’edilizia e di modelli per la quantificazione del potenziale del ventilative cooling nell’edilizia”, nel contesto del Piano annuale di Realizzazione 2014 del progetto “Sviluppo di modelli per la realizzazione di interventi di efficienza energetica sul patrimonio immobiliare pubblico”. L’attività prevede due linee di ricerca interne, sviluppate, rispettivamente, nelle Parti A e B del presente report: “Sviluppo di piatt…