Costante Mario Invernizzi

Costante Mario Invernizzi
Università degli Studi di Brescia | UNIBS · Department of Mechanical and Industrial Engineering - DIMI

Doctor of Philosophy

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96
Publications
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Publications

Publications (96)
Article
Full-text available
Organic Rankine cycles are often the best solution for the conversion of thermal energy. The many working fluids include silicon oils. One crucial issue that determines the choice of a working fluid is its thermochemical stability, as this sets a limit to the maximum temperature at which the fluid can be used in a power plant. A second subject, muc...
Article
Full-text available
Nowadays supercritical CO2 cycles are considered as a promising alternative to the traditional steam cycle for the power block in CSP plants with the aim of enhancing the system efficiency and reducing costs. This work deals with the experimental characterisation of a CO2 blend as working fluid in transcritical cycle: the addition of C6F6 as a dopa...
Article
Full-text available
This paper focuses on the use of the CO2 + SO2 binary mixture as innovative working fluid for closed transcritical power cycles with a minimum temperature above 50 °C. Starting from a literature review of the available experimental data on the mixture, the PC-SAFT EoS is identified as a suitable model to characterize the mixture behavior. Once the...
Presentation
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The presentation was discussed in a conference organized by "B+LabNet", at the University of Brescia: Environment, Health, Sustainability, June 5th 2019.
Conference Paper
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Supercritical CO 2 cycles are a promising technology, but their performance drops for hot cold source, in hot and arid environments, typical of a CSP field. The adoption of CO 2 -based mixtures as working fluid can turn supercritical CO 2 cycles into transcritical cycles even at high temperatures, with performance improvement and significant power...
Article
Full-text available
The present paper explores the utilisation of dopants to increase the critical temperature of Carbon Dioxide (sCO2) as a solution towards maintaining the high thermal efficiencies of sCO2 cycles even when ambient temperatures compromise their feasibility. To this end, the impact of adopting CO2-based mixtures on the performance of power blocks repr...
Conference Paper
Full-text available
Supercritical Carbon Dioxide (sCO2) power cycles have been proposed for Concentrated Solar Power (CSP) applications as a means to increase the performance and reduce the cost of state-of-the-art CSP systems. Nevertheless, the sensitivity of sCO2 systems to the usually hot ambient temperatures found in solar sites compromises the actual thermodynami...
Article
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Some historical notes, some technical details and some examples about the "low temperature" thermodynamic conversion of the solar energy. An update.
Article
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The Tesla turbine is an original expander working on the principle of torque transmission by wall shear stress. The principle – demonstrated for air expanders at lab scale has some attractive features when applied to two-phase expanders: it is suitable for handling limited flow rates (as is the case for machines in the range from 500W to 5 kW), it...
Article
Nowadays supercritical CO2 cycles are considered as a promising alternative to the traditional steam cycle for the power block in CSP plants with the aim of enhancing the system efficiency and reducing costs. This work deals with the experimental characterisation of a CO2 blend as working fluid in transcritical cycle: the addition of C6F6 as a dopa...
Conference Paper
The future of Concentrated Solar Power technology relies on significant cost reduction to be competitive against both fossil fuel power stations and renewable technologies as photovoltaics and wind. Most of the research activity on concentrated solar power focuses on supercritical CO2 cycles to increase the solar plant efficiency together with a co...
Article
Full-text available
This study aims to provide a thermodynamic comparison between supercritical CO2 cycles and ORC cycles utilizing flue gases as waste heat source. Moreover, the possibility of using CO2 mixtures as working fluids in transcritical cycles to enhance the performance of the thermodynamic cycle is explored. ORCs operating with pure working fluids show hig...
Article
Full-text available
In the last years, several fluids have been proposed to replace steam as working fluid in power cycle for converting thermal power into electricity. This paper describes the procedure to be adopted for the selection of any innovative fluid which can be even mixtures of fluids. The first step consists of the working fluid characterization in terms o...
Article
Full-text available
This study investigates the use of pure and hydrocarbons binary mixtures as potential alternatives working fluids in a usual biomass powered organic Rankine cycle (ORC). A typical biomass combined heat and power plant installed in Cremona (Italy) is considered as the benchmark. Eight pure hydrocarbons (linear and cyclic) and four binary mixtures of...
Article
Full-text available
This work explores the possibility to adopt in organic Rankine cycle (ORC) plants mixtures of water (acting as solvent) plus an organic compound (acting as solute) as the working fluid. Initially an evaluation of the thermodynamic properties of the mixtures is performed, in order to assess their properties, and to point out the molar fractions whic...
Article
This paper discusses the adoption of CO2 mixtures for improving the thermal-to-power efficiency conversion in solar tower plants and reducing the Levelized Cost of Electricity. Two different fluids are considered for blending the CO2: N2O4 and TiCl4. The main advantage of the innovative mixtures relies in a higher critical temperature with respect...
Article
The competitiveness of concentrated solar power technology in the near-future electricity generation scenario, requires a substantial reduction of the Levelized Cost of Energy which can be achieved with an increase of the energy conversion efficiencies while maintaining or reducing the investment costs. This paper discusses the use of pure Dinitrog...
Conference Paper
One of the option to make concentrated solar power competitive from economic point of view consists of adopting innovative power cycle which can efficiently exploit temperature up to 700°C. This work assesses the potentiality of pure N2O4 and mixed with CO2 when applied to solar tower plant using liquid as heat transfer fluid. N2O4 has a high criti...
Article
A thermal stability test-rig for organic Rankine cycles working fluids was designed and commissioned at the Laboratory of Compressible-fluid dynamics for Renewable Energy Applications (CREA Lab) of Politecnico di Milano, in collaboration with the University of Brescia. The set-up is composed by a vessel containing the fluid, heated for about 80 h a...
Article
Full-text available
For developing a sustainable power system, the key is to maximize the use of available resources with a minimal impact on the environment. One technique for achieving this is exhaust heat recovery. In this paper, three gas turbine exhaust heat recovery supercritical carbon dioxide combined power cycles are presented. They are combined gas turbine-r...
Article
This paper addresses the optimal working fluid selection for organic Rankine cycle recovering heat from heavy-duty internal combustion engines. Four cases are considered featuring two different engine exhaust temperatures (245 °C vs 354 °C) and two scenarios (maximum recovery of mechanical power vs. cogeneration of low-temperature heat). The analys...
Article
Full-text available
Small-CHP (Combined Heat and Power) systems are generally considered a valuable technological option to the conventional boilers, in a technology developed context. If small-CHP systems are associated with the use of renewable energies (biomass, for example) they could play an important role in distributed generation even in developing countries or...
Article
Full-text available
This paper discusses the thermodynamic characteristics of the closed Brayton cycles in which the compression is placed near the critical point of the working fluid. Under these conditions, the specific volumes of the fluid during the compression are a fraction of the corresponding values under ideal gas conditions, and the cycle performances improv...
Article
Full-text available
Real time matching of electric power generation is a crucial aspect in off-grid systems as well as in case of use of renewable intermittent sources. In this paper, with reference to 1 MWel Turboden biomass ORC plants operating in off-grid systems, we study the possibility to store thermal energy in the form of sensible heat within a storage compose...
Article
Full-text available
The successful exploitation of geothermal energy for power production relies on to the availability of nearly zero emission and efficient technologies, able to provide flexible operation. It can be realized with the binary cycle technology. It consists of a closed power cycle coupled to a closed geothermal loop, whereby the closed power cycle is ge...
Article
Full-text available
A novel test-rig for studying the thermal stability of mixtures as working fluids for ORC applications was designed and commissioned at the Laboratory of Compressible-fluid dynamics for Renewable Energy Applications (CREA) of Politecnico di Milano, in collaboration with the University of Brescia. The set-up is a standard one, in which a vessel cont...
Article
Full-text available
This article focuses on the optimization of ORCs for heat recovery from heavy duty Internal Combustion Engines (ICEs), with particular attention to the optimal fluid selection. We considered two different ICEs featuring same power (10 MW) but different architectures: a two-stroke engine with exhaust temperature 250°C and a four-stroke engine with 3...
Article
Full-text available
The successful exploitation of geothermal energy for power production relies on the availability of nearly zero emission and efficient technologies. Two zero emission flash plant layouts, with full reinjection of the geothermal fluid (non-condensable gas included), are considered. This paper focusses on the CO2 issue, and therefore only the carbon...
Article
In this paper we investigate the thermal stability of three representative hydrocarbons used as working fluids in organic Rankine cycles (ORC): n-pentane, cyclo-pentane and toluene. The experimental used method is a “static” one, based on the recording of the pressure during the permanence of the fluid sample at constant temperature and on the meas...
Article
Full-text available
This article analyzed the potential energy recovery from rather small quantities of associated gas (<2000 m³/h), where the on-site electricity generation within the oil extraction field may represent a cost-effective solution as an alternative to flare combustion. Various power plant technologies were considered and compared from both the economic...
Article
This article analyzed the potential energy recovery from rather small quantities of associated gas (<2000 m3/h), where the on-site electricity generation within the oil extraction field may represent a cost-effective solution as an alternative to flare combustion. Various power plant technologies were considered and compared from both the economic...
Chapter
Each organic fluid is characterized by thermal decomposition above a specific temperature called the thermal stability limit. The correct evaluation of this limit is extremely important to avoid massive cracking phenomena which can cause the fouling of heat exchangers' surfaces, material erosion, and changes of fluid thermodynamic properties. After...
Article
In this paper, Titanium tetrachloride (TiCl4) is analyzed/assessed and proposed as a new potential working fluid in Rankine Cycles. Besides its good thermodynamic properties, TiCl4 is in fact a fairly low cost, non-carcinogenic fluid, with zero Global Warming Potential (GWP) and Ozone Depleting Potential (ODP) and it is currently employed in high t...
Article
In this paper we investigate the potential replacement of HFC-134a in ORC applications by two low-GWP refrigerant fluids, namely HFO-1234yf and HFO-1234ze(E). After revising and discussing their main thermo-physical properties, we adopted in our calculations the Peng Robinson EOS available in Aspen Plus v7.3, integrated with literature data. By ass...
Article
Full-text available
Power generation using Organic Rankine Cycle was studied in this paper in case of both low and high temperature cycles, exploiting respectively a geothermal heat source available at 167 °C, and heat available at 300 °C from the combustion of biomass. In particular we assess the feasibility of employing mixture of working fluids, in the case of repl...
Article
In this paper the possible replacement of conventional metallic heat exchangers with plastic components is investigated with reference to low size Organic Rankine Cycles, aiming at a reduction of the plant investment cost. A thermodynamic optimization of a 20. kW regenerative ORC plant, representative of a low temperature (<140. °C) heat recovery a...
Article
Full-text available
The thermal stability analysis of perfluorohexane (C6F14)is presented in this paper as a preliminary evaluation of the potential application of the binary mixture CO2 – C6F14 as innovative working fluid for transcritical-CO2 power cycles. After presentinga description of the experimental apparatus, saturation pressure models are compared and calibr...
Conference Paper
Binary cycles have drawn the attention as a technical solution for the geothermal power production. This attention is mainly due to the huge potential of medium-low temperature geothermal sources, typically exploited by means of a binary cycle, and the relevance of the environmental concern, which can be conveniently dealt with by means of a closed...
Article
There is a common interest in the distributed power generation: generally for the combined production of electrical and thermal energy and often, although not necessarily, in association with renewable energies as heat sources for the prime mover. For example, in the field of distributed concentrated solar power generation of small size, the gas en...
Article
The world trade in LNG (liquefied natural gas) has tripled in the last 15 years and the forecasts are for its further rapid expansion. Although the cryogenic exergy of the LNG could be used in many industrial processes, it is recognized also as a source for power cycles.When using the low temperature capacity of LNG for power production, several th...
Article
Full-text available
In this work we present an improved survey method for the evaluation of the thermal stability of working fluids for organic Rankine cycles. The method presented here represents an improvement of a test methodology already used in literature, based on the analysis of temperature and pressure measurements of a fluid subjected to increasing thermal st...
Article
With the aim of improving the performance of Stirling engines for applications with relatively low maximum temperatures (150 °C–300 °C), working fluids that have noticeable real gas effects have been considered. The simulation model developed for the preliminary analysis of Stirling engines takes into account the losses of mechanical power and the...
Conference Paper
The gas circuit and the drive mechanism are the main subsystems of a Stirling engine. Models can be used to study these subsystems. The numerical computing power currently available allows the development of models with fewer simplifying assumptions than was possible decades ago. Because all models must be validated experimentally, the benefit of t...
Technical Report
In questo documento sono riportate le attività svolte e attivate dal Dipartimento di Energia nell'ambito del progetto di ricerca dal titolo "Verifica del comportamento del TiCl4 come possibile fluido di lavoro" giunto al secondo anno di indagini. Le attività di questo secondo anno sono descritte in due rapporti distinti. La prima dal titolo "Propri...
Conference Paper
This work presents innovative cogenerative Organic Rankine Cycles operating with fluids at high temperature (up to 400 °C) coupled with a biomass-fired molten salts boiler, that allow to obtain an electrical efficiency over the threshold of 20 %. Two fluids have been considered in this study, namely PP9 and TiCl4. The power plants are modeled with...
Technical Report
Full-text available
l presente documento descrive le attività di ricerca svolte all’interno dell’Accordo di collaborazione “Definizione e studio di fluidi organici o loro miscele in grado di operare a temperature massime superiori a quelle attualmente in uso e valutazione dei cicli termodinamici” Responsabile scientifico ENEA: Roberta Roberto Responsabile scientifico...
Chapter
Chap. 3 is dedicated to Rankine cycles with organic fluids: the so-called organic Rankine cycles (ORC), which in recent years have had a large success on the market. After a brief historical review we discuss the characteristics that must have the potential working fluids to be used in an ORC engine. A large discussion is about the interactions bet...
Chapter
Today, the term “binary cycle” commonly refers to the organic fluid Rankine engines in geothermal systems, where a mass flow of geothermal brine is cooled in a recovery heat exchanger and the heat recovered is converted into electricity by means of an organic fluid engine (see Chap. 3, Sect. 3.6, and DiPippo [1]). In general, though, the term “bina...
Chapter
This chapter defines the heat engine and describes the most common closed power cycles: the steam cycle, the Brayton cycle, and the Stirling cycle. For each of them are discussed in detail the fundamental thermodynamic properties and the plant characteristics. Before the discussion of the conventional prime movers that operate in a closed cycle, wi...
Chapter
This chapter, preliminary to the subsequent chapters, summarises the thermodynamic properties of fluids, illustrates the Law of Corresponding States and define a parameter of molecular complexity for each working fluid. The chapter then discusses the influence of the compressibility, of the molecular complexity and of the molar mass of the working...
Chapter
In practice, all the mechanical energy produced by thermal engines is generated via cycles that use steam (see Sect. 1.6) or combustion products (in gas-turbines and internal combustion engines).
Article
Among the renewable energy sources, ocean energy is encountering an increasing interest. Several technologies can be applied in order to convert the ocean energy into electric power: among these, ocean thermal energy conversion (OTEC) is an interesting technology in the equatorial and tropical belt, where the temperature difference between surface...
Book
With the growing attention to the exploitation of renewable energies and heat recovery from industrial processes, the traditional steam and gas cycles are showing themselves often inadequate. The inadequacy is due to the great assortment of the required sizes power and of the large kind of heat sources. Closed Power Cycles: Thermodynamic Fundamenta...
Article
Closed Brayton gas and supercritical cycles operating with mixtures of carbon dioxide and hydrocarbons, in particular mixture with a low content (5-15%) of benzene, were studied. Totally supercritical cycles and condensation cycles were looked at and a comparison was made with pure carbon dioxide cycles with a minimal temperature around 40 − 50 ◦C...
Article
This article investigates the possibility to enhance the performance of a biomass organic Rankine cycle (ORC) plant by adding an externally fired gas turbine (EFGT), yielding a combined EFGT + ORC system. A typical ORC configuration is first modelled and validated on data available from an existing unit 1.5 MW reference plant. Then, different worki...
Article
When using the cooling capacity of LNG several thermodynamic schemes are proposable employing conventional and non conventional conversion cycles. All conventional systems make use of organic working fluids such as methane or propane in series of Rankine cycles used in a cascading mode. A simpler system is available, using a single cycle and a sing...
Article
Real gas effects typical of the critical region of working fluids are a powerful tool to increase the energy performances of Stirling cycles, mainly at low top temperatures. To carry out the compression near the critical region the working fluids must have a critical temperature near environmental conditions and the use of organic working substance...
Conference Paper
Full-text available
The paper describes a prototype of a low-budget, low-power Ringbom-Stirling engine which contains air as the working fluid. This solution is being investigated as it seems appropriate for electric energy production in non-grid-connected locations of developing countries. The engine is thought to be heated with biomass from agricultural wastes eithe...
Conference Paper
Full-text available
In this study the thermodynamics and geometry of a Ringbom-Stirling engine are analyzed through a mathematical model; moreover the use of innovative metal bellows to replace the pistons and cylinders is proposed. The bellows have the advantage of eliminating the friction of the piston seals and to allow, intrinsically, the hermetic sealing of the s...
Conference Paper
Full-text available
This paper compares the different incentive systems in support to the photovoltaic power generation in force in six countries of the European Union: Austria, France, Germany, Italy, Portugal and Spain. For the proper solar radiation of each location and two different plant sizes (one, from 1 to 3 kWp, typical of domestic installations, the other la...
Article
Liquefied natural gas (LNG) is recognized as a source of usable cryogenic exergy for power cycles. The performance of conventional cycles are calculated. A binary steam–Organic Rankine Cycle (ORC) at 550 °C has an efficiency of about 52%, somewhat higher than that of a nitrogen Brayton cycle (50.7% at 700 °C). Carbon dioxide is recognized as an alm...