Valutazioni energetiche ed economiche relative all’utilizzo di un sistema frigorifero ad assorbimento alimentato da collettori parabolici

Assessing Methane Emission and Economic Viability of Energy Exploitation in a Typical Sicilian Municipal Solid Waste Landfill

Sanitary landfills for municipal solid waste (MSW) represent one of the major anthropogenic source of GHGs emissions and are directly responsible of the climate changes we are facing nowadays. Indeed, the biodegradable organic matter of MSW undergoes anaerobic digestion producing the landfill gas (LFG), whose main components are CH4 and CO2. Therefore, biomethane energy exploitation in MSW landfills will reduce GHGs emission positively affecting the global warming. The aim of the present study was to assess the methane production in a Sicilian landfill by comparing the results from field measurements of methane emission and the estimates achieved by applying different mathematical models. A…

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…

Energetic recovery from regasification plants for desalination processe and cold chain applications

Upgrade of citrus waste as a biofuel via slow pyrolysis

Abstract Slow pyrolysis (200–650 °C) experiments on citrus residues (orange peel waste “OP” and lemon peel waste “LP”) were carried out in lab scale fixed bed batch reactor. Bio-oil and bio-char obtained by thermal degradation are more stable, more homogeneous and higher energy content fuels when compared to the parent feedstock. Thermogravimetric analysis (TGA) showed higher stability of LP waste, which appears related to the higher lignin content . Mass and energy yields of solid and liquid products (i.e., char and oil) were measured to determine the effects of peak temperature on feedstock. A linear correlation between Gross Calorific Value (GCV), peak temperatures and mass loss (ML) all…

Il riutilizzo dei materiali di scarto provenienti dai processi industriali di estrazione e lavorazione del marmo nella tecnica delle costruzioni stradali

Evaluation of the optimal activation parameters for almond shell bio-char production for capacitive deionization

Abstract A study on a possible new biomass waste to be used as electrode material for capacitive deionization (CDI) processes was performed. Raw almond shells were pyrolyzed at 800, 900 and 1000 °C and then activated through CO2. Carbon activation is used to develop porosity inside the material, increasing the specific surface area and the adsorption performances. In this work, authors tried to correlate the effects of pyrolysis and activation temperature on the ion storage capacity. Results from the desalination tests indicated that the best performance in terms of ion adsorption was obtained when the bio-char was activated at the temperature of 900 °C. Brunauer-Emmet-Teller (BET) and Barr…

Use of HFC fluids as suitable replacements in low-temperature refrigeration plants

An experimental investigation of the performance of a low-temperature refrigerating unit working with R22 and a comparison of its performance when operating with replacement HFC fluids in accordance with the European Regulation CE-1005/2009 are presented in this paper. Plant working efficiency was tested with R22, as baseline, and then compared with four different HFC fluids: R413A, R417A, R422A and R422D. The refrigerating unit was a vapour-compression plant equipped with a reciprocating double-cylinder compressor able to keep the cold room at -20ºC. Lower values of the temperature at the end of compression and polytrophic exponent can be achieved with the HFC tested. Substituting the R22 …

Cogeneration plant in a pasta factory: Energy saving and environmental benefit

Abstract Italy produces approximately 4,520,000 tons of pasta annually, which is about 67% of its total productive potential. As factories need electric and thermal energy simultaneously, combined heat and power (CHP) systems are the most suitable. This paper describes a feasibility study of a CHP plant in a pasta factory in Italy while analyzing energy saving and environmental benefits. Commercially available CHP systems suitable for the power range of energy demand in pasta production use reciprocating engines or gas turbines. This study demonstrates how their use can reduce both energy costs and CO2 equivalent greenhouse gas emission in the environment. An economic analysis was performed…

ENERGY AND ECONOMIC ASSESSMENT OF A SOLAR ABSORPTION REFRIGERATION PLANT IN A FISH PROCESSING FACTORY: A CASE STUDY IN SICILY

Numerical Analysis of Piezoelectric Active Repair in the Presence of Frictional Contact Conditions

The increasing development of smart materials, such as piezoelectric and shape memory alloys, has opened new opportunities for improving repair techniques. Particularly, active repairs, based on the converse piezoelectric effect, can increase the life of a structure by reducing the crack opening. A deep characterization of the electromechanical behavior of delaminated composite structures, actively repaired by piezoelectric patches, can be achieved by considering the adhesive layer between the host structure and the repair and by taking into account the frictional contact between the crack surfaces. In this paper, Boundary Element (BE) analyses performed on delaminated composite structures …

PERFORMANCE EVALUATION OF CASCADE REFRIGERATION SYSTEMS USING DIFFERENT REFRIGERANTS

Due to the negative effects of synthetic refrigerants on the environment, natural refrigerants have obtained again interest as alternative refrigerants for different applications because of their zero ODP and negligible GWP. This paper presents a thermodynamic analysis of different two-stage cascade refrigeration systems using as refrigerant carbon dioxide (R744) in low-temperature circuit, and, respectively, ammonia (R717), propane (R290), butane (R600), R404A, R410A and R134a in high-temperature circuit. The operating parameters considered in this study include condensing and evaporating temperatures in high-temperature circuit, temperature difference in the cascade heat exchanger, and e…

Wind Turbines to Power Telecommunication Systems: A Case Study in Sicily

The ever increasing problems related to air pollution and the difficulties for power lines to reach inaccessible areas are pushing to find new solutions for powering telecommunications equipments (TLC). The renewable energy sys- tems, although relatively expensive, have the required characteristics. The purpose of this work is to find a solution based on a low power wind turbine to serve a real telecommunication site located near Palermo, the main city of Sicily (Italy).

Multi-Energy School System for Seasonal Use in the Mediterranean Area

School buildings represent an energy-consuming sector of real estate where different efficiency actions are necessary. The literature shows how the design of a multi-energy system offers numerous advantages, however, there are problems related to the integration of cogeneration units with renewable energy sources due to the low flexibility of the first one and the high degree of uncertainty of the latter. The authors provide an alternative solution through the analysis of a case study consisting of a multiple energy system in three Sicilian schools, focusing on the system&rsquo

VALUTAZIONI ENERGETICHE ED ECONOMICHE RELATIVE ALL’UTILIZZO DI UN SISTEMA FRIGORIFERO AD ASSORBIMENTO ALIMENTATO DA COLLETTORI PARABOLICI IN SOSTITUZIONE DI UN SISTEMA FRIGORIFERO CONVENZIONALE A COMPRESSIONE DI VAPORE

A Novel Lab‐Scale Fixed‐Bed Pyrolysis Reactor for Biofuel Production from Agro‐Waste: Experimental Set‐up and Preliminary Life Cycle Assessment Study

The present study reports the features and set-up of a novel lab-scale fixed bed pyrolysis reactor for the production of solid and liquid bio-fuels from waste biomass. The fixed bed reactor is tested by carrying out pyrolysis experiments using two different waste biomasses. Olive tree trimmings (OT) and olive pulp (OP), olive cultivation and olive mill industries residues respectively, are pyrolyzed, under nitrogen atmosphere, between 200 and 650 °C for a residence time of 0.5 h. The OT and OP pyrolysis chars were characterized in terms of mass yields, high calorific values (HHVs), proximate and elemental analysis. Char mass yields, on a dry basis (d.b.), decreased from 91 to 23 wt% and fro…

La cogenerazione con microturbine a gas nei pastifici

Usi energetici dei residui agricoli della coltivazione cerealicola in associazione con colture no food di rotazione: un caso studio nel Comprensorio Madonita mediante GIS

A numerical solution that determines the temperature field inside phase change materials: application in buildings

The use of novel building materials that contain active thermal components would be a major advancement in achieving significant heating and cooling energy savings. In the last 40 years, Phase Change Materials or PCMs have been tested as thermal mass components in buildings, and most studies have found that PCMs enhance the building energy performance. The use of PCMs as an energy storage device is due to their relatively high fusion latent heat; during the melting and/or solidification phase, a PCM is capable of storing or releasing a large amount of energy. PCMs in a wall layer store solar energy during the warmer hours of the day and release it during the night, thereby decreasing and sh…

Energy Recovery in Water Distribution Networks. Implementation of Pumps as Turbine in a Dynamic Numerical Model

In complex networks characterized by the presence of private tanks, water managers usually apply intermittent distribution, thus reducing the water volumes supplied to the users, or use Pressure Reduction Valves (PRV) for controlling pressure in the network. The application of Pump As Turbines (PATs) appears as an alternative and sustainable solution to either control network pressure as well as to produce energy. In the present paper, the hydrodynamic model, already presented by De Marchis et al. (2011) was further developed introducing the dynamic analysis of PATs. The model was applied to a district of Palermo network (Italy) characterized by intermittent distribution and by inequities a…

Recupero energetico da termovalorizzazione di rsu e dissalazione, un connubio possibile

Life Cycle Assessment della pirolisi di biomasse residuali dal settore agro – alimentare

Il presente studio si propone di valutare gli impatti energetico - ambientali connessi al processo di pirolisi di rifiuti agro – alimentari attraverso l’applicazione della metodologia Life Cycle Assessment seguendo un approccio dalla culla al cancello. Il sistema analizzato consiste in un reattore di pirolisi al quarzo a letto fisso realizzato a scala di laboratorio. L’unità funzionale per l’analisi è 1 MJ di energia termica potenzialmente generata dalla combustione del bio-char prodotto dalla pirolisi di residui della potatura di olivi e dei residui della spremitura delle arance a tre diverse temperature (400 °C, 500 °C e 650 °C). Lo studio fornisce un ampio set di indicatori ambientali e …

Technical and economical feasibility of biomass use for power generation in Sicily

Biomass can provide a reliable support for production ofbiofuels while contributing to sustainable management of natural resources. Many countries, including Italy, have introduced important incentive schemes to support the use of biomass for electricity, heat and transportation. This has raised considerable interest towards the use of biomass for energy generation purposes. Nonetheless, the design and installation ofbiomass-fuelled power plants present several critical issues, such as choice and availability of biomass, choice of technology, power plant localization and logistics. The case study tackled in this paper evaluates the economies originated by a 1MW el Organic Rankine Cycle (ORC…

LNG cold energy use in agro-food industry: A case study in Sicily

Abstract It is known how the complete gasification of liquefied natural gas (LNG) can return about 230 kWh/t of energy. Nevertheless out of fifty-one gasification plants in the world, only thirty-one of them are equipped with systems for the partial recovery of the available energy. At the moment most of these plants mainly produce electric energy; however the employment of the cold energy results very interesting, in fact, it can be recovered for agro-food transformation and conservation as well as for some loops in the cold chain. Cold energy at low temperatures requires high amounts of mechanical energy and it unavoidably increases as the required temperature diminishes. Cold energy reco…

Seawater desalination utilizing thermal energy from MSW

Reducing Air Pollutants through Road Innovative Intersections

Road pollutant emissions are correlated mainly to infrastructural capacity and to traffic intensity and typology. With the aim to improve road intersections performances in the last years was designed many new geometric layouts, like turbo roundabouts and flower roundabouts. The main objective of this paper is carried out a comparative analysis between conventional and innovative roundabouts in terms of CO, CO2, NO and PM2,5 vehicular emissions, evaluated by means of COPERT Software which is developed as a European tool for the calculation of emissions from the road transport sector.

Assessment of bio-combustibles production via slow pyrolysis of wine industry residues

With the aim of evaluating the potential production of high energy solid and liquid bio-fuels, a laboratory scale fixed bed reactor (FBR) derived from the standard Gray-King (GK) assay test on coal was used to carry out fixed bed pyrolysis experiments on wine industry by-products. The present study provides results on the pyrolysis of grape marc, residual from wine-making process, consisting of 50% by weight of grape seeds and 50% by weight of grape skins, at temperature between 150 and 500 °C, holding time of 30 minutes. Pyrolysis mass yields of solid (char) and liquid (tar) products and their corresponding energy properties, as a function of reaction temperature, are reported and discusse…

Valorizzazione energetica delle biomasse: un caso studio mediante GIS

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.

Potential applications using LNG cold energy in Sicily

According to previsions, natural gas could be the main energy source worldwide, inducing relevant geopolitical changes. Most likely, such problems will be solved with the development of a gas transportation mode alternative to traditional pipelines: liquefied natural gas (LNG). The global LNG trade has increased rapidly during recent years. A significant amount of energy is consumed to produce low-temperature LNG, which has plenty of cryogenic exergy/ energy. Therefore, the effective utilization of the cryogenic energy associated with LNG vaporization is very important. Sicily, with more than five million inhabitants, is the second biggest region of Italy and in this region will be realized…

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.

Outcome dei pazienti con sindrome da intestino corto. valutazione da una casistica nazionale multicentrica

Gli Autori presentano i risultati di una ricerca nazionale multicentrica retrospettiva sulla Sindrome da Intestino Corto (SIC)

Analisi di cicli frigoriferi a cascata e confronto con cicli frigoriferi a doppio stadio

The Application of Different Model of Multi-Layer Perceptrons in the Estimation of Wind Speed

Wind speed forecasting is essential for effective planning of wind energy exploitation projects. The ability to predict short-term wind speed is a prerequisite for all the operators of the wind energy sector. Consequently it is essential to identify an efficient method for forecasts. In this paper, the wind speed in the province of Trapani (Sicily) is modeled by artificial neural network. Several model of neural network were generated and compared through error measures. Simulation results show that the estimated values of wind speed are in good agreement with the values measured by anemometers..

Performance evaluation of hybrid RO/MEE systems powered by a WTE plant

Abstract The solid waste management is, in different contexts, a very critical issue. The use of landfills can no longer be considered a satisfactory environmental solution, therefore new methods have to be chosen and waste-to-energy (WTE) plants would provide an answer. Today's WTE plants are a far cry from their polluting predecessors. Using modern combustion and pollution control technology, WTE plants are able to retrieve considerable amounts of energy from waste combustion while minimizing emissions. As we know, is possible to recover thermal energy by combusting municipal solid waste (MSW) for electricity generation and district heating. However, with everincreasing population and rap…

Estimation of air pollutant emissions in flower roundabouts and in conventional roundabouts

Abstract The road pollutant emissions, above all in urban context, are correlated to many infrastructural parameters and to traffic intensity and typology. The research work on road junction geometry, carried out in European research centres, has recently allowed to design new road intersection types which are of undoubted interest, especially in terms of traffic functionality and safety, like the flower roundabouts (in which right-turn manoeuvres do not conflict with the circulating flow). The main objective of this paper is to propose a model for the estimation the capacity, delay, levels of service and the pollutant emissions into flower roundabouts. A comparative analysis between conven…

Municipal waste management in Sicily: practices and challenges.

There are numerous problems yet to be solved in waste management and although efforts towards waste recovery and recycling have been made, landfills are still the most common method used in the EU and many other industrialised countries. Thermal disposal, particularly incineration, is a tested and viable alternative. In 2004, only 11% of the annual waste production of Italy was incinerated. Sicily, with over five million inhabitants, is the second largest region in Italy where waste management is now a critical problem. The use of landfills can no longer be considered a satisfactory environmental solution; therefore, new methods have to be chosen and waste-toenergy plants could provide an a…

Efficienza energetica ed ambientale delle aree industriali- un caso studio di simbiosi industriale nella provincia di Palermo

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…

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…

Energy saving analysis in industrial processes by heat pump systems with ammonia as refrigerant: the case of a cheese factory

In the last few years, the consumption of energy has been the heart of many papers about future developments of refrigerating engines. The studies regard especially refrigerating systems used in industrial fields, where their operation can cause direct and indirect effects on our environment. In order to set a limit to the harms induced by the use of synthetic refrigerants and in order to follow up energy saving, it is very important to investigate new solutions. This paper reports a feasibility study on the plants of a cheese factory by means of addition of an heat pump with ammonia as refrigerant in order to recover the termic reject of two refrigerating units and to supply the required h…

Il Mercato del Risparmio Energetico: Nuove Opportunità

LA TERMOVALORIZZAZIONE DEI RIFIUTI SOLIDI URBANI E IL TERRITORIO: IL CASO DELLA REGIONE SICILIANA.

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 …

Rigassificatori: e se l’Italia diventasse lo snodo d’Europa?

Solare per la conservazione alimentare

Incentivi per il fotovoltaico: il nuovo conto energia

Reactivity of cellulose during hydrothermal carbonization of lignocellulosic biomass

Abstract Hydrothermal carbonization (HTC) of pure cellulose (CE) and birchwood (BW) samples was carried out at temperatures between 160 and 280 °C, 0.5 h residence time and biomass-to-water ratio 1:5, to investigate the reactivity of cellulose in lignocellulosic biomass. Thermogravimetric analysis (TGA) and Fourier transform infrared spectroscopy (FTIR) showed that the CE samples remained unaltered at temperatures up to 220 °C, but were significantly decomposed at 230 °C producing a thermal recalcitrant aromatic and high energy-dense material. FTIR showed that dehydration and aromatization reactions occurred at temperature equal or higher than 230 °C for the CE samples while a similar incre…

La Nuova Gestione Strategica dei Rifiuti Solidi Urbani in Sicilia

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 …

Environmental assessment of a waste-to-energy practice: The pyrolysis of agro-industrial biomass residues

Abstract The bio-wastes pyrolysis is a waste to energy strategy that converts bio-wastes into valuable products (bio-char, bio-oil) with wide use in the agri-food sector. However, limited efforts are paid to the investigation of its environmental sustainability: in this context, the study contributes the need towards the assessment of a wide range of environmental impacts for the pyrolysis process of different types of bio-wastes under different operating conditions. The study estimates the potential environmental impacts related to bio-char production from the pyrolysis of several different agro-industrial residues and different temperatures and identifies the process “hot spots”. The anal…

Il Contributo dei biocarburanti alla Sostenibilità Ambientale

Riscaldamento globale: prospettive di impiego dei fluidi frigorigeni

Energy and Environmental Assessment of a Hybrid Dish-Stirling Concentrating Solar Power Plant

Although the 2019 global pandemic slowed the growing trend of CO2 concentrations in the atmosphere, it has since resumed its rise, prompting world leaders to accelerate the generation of electricity from renewable sources. The study presented in this paper is focused on the evaluation of the energy and environmental benefits corresponding to the hypothesis of hybridizing a dish-Stirling plant installed on the university campus of Palermo (Italy). These analyses were carried out by means of dynamic simulations based on an accurate energy model validated with the experimental data collected during the measurement campaign that occurred during the period of operation of the reference plant. As…

Riscaldamento globale: il Rapporto IPCC/TEAP

Usi energetici dei residui agricoli della coltivazione cerealicola in associazione con colture no food di rotazione: Studio nel Comprensorio Madonita mediante GIS

VALUTAZIONI ENERGETICHE ED ECONOMICHE RELATIVE ALL’UTILIZZO DI UN SISTEMA DI REFRIGERAZIONE AD ASSORBIMENTO ALIMENTATO DA COLLETTORI PARABOLICI

Evaluating the Performances of Small Wind Turbines: A Case Study in the South of Italy

AbstractAmong renewable energy resources, wind energy became more attractive in the last decade. Wind farms installations dramatically increased in areas where climatic conditions, topography and environment have allowed their development. The installation of wind turbines, usually carried out in remote areas, recently began to cover areas identified by a complex terrain such as urban and suburban zones. Although these new sites’ choices are characterized by lower productivity there is increasing interest in wind energy production in both urban and suburban area. In this work the authors have carried out an energy analysis developed from a sample of small wind turbines available on the mark…