Ennio Macchi

Ennio Macchi
Politecnico di Milano | Polimi · Department of Energy

full professor
scientific consultant of industrial and public organizations

About

135
Publications
43,946
Reads
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4,325
Citations
Citations since 2017
25 Research Items
2533 Citations
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20172018201920202021202220230100200300400
20172018201920202021202220230100200300400
20172018201920202021202220230100200300400
Additional affiliations
October 1969 - present
Politecnico di Milano
Position
  • Professor (Full)
Description
  • A fundamental course for Master in Energy Engineering
February 1968 - May 2016
Politecnico di Milano
Position
  • Head of Department
Description
  • full professor since 1980 - first director of the department of energy, since its foundation (1998) to december 2012

Publications

Publications (135)
Article
This paper focuses on the thermodynamic performance and techno-economic assessment of a novel electrical energy storage technology using carbon dioxide as a working fluid. This technology, named CO2 battery and recently patented by Energy Dome SpA., addresses an energy market which has a great need for energy storage solutions able to handle the in...
Conference Paper
This paper focuses on the thermodynamic performance and techno-economic assessment of a novel electrical energy storage technology using carbon dioxide as working fluid. This technology, named CO2 battery and recently patented by Energy Dome SpA., addresses to an energy market which has great need of energy storage solutions able to handle the incr...
Article
Full-text available
This paper focuses on the potential of supercritical carbon dioxide closed cycle for waste heat recovery applications. The valorization of waste heat released from glass, steel and cement production facilities is recognized as one of the most effective solutions for the reduction of carbon footprint of the industrial sector. Common solutions rely o...
Article
Full-text available
Stirling units are a viable option for micro-cogeneration applications, but they operate often with multiple daily startups and shutdowns due to the variability of load profiles. This work focused on the experimental and numerical study of a small-size commercial Stirling unit when subjected to cycling operations. First, experimental data about ene...
Article
Full-text available
In the near future, a significant increase of the fraction of electricity produced by variable renewable energy sources (wind and PV) is expected. In this scenario, concentrating solar power (CSP) plants, thanks to the implementation of cost-competitive thermal energy storage, can provide zero-emission backup power improving system stability. Advan...
Conference Paper
Full-text available
a radial outflow multistage expander has been developed, buit and installed for ORC applications.
Conference Paper
Full-text available
The present work deals with the study of the part-load performance and operating strategies of a coal-fired sCO 2 power plant. In sCO 2 cycles the compression phase generally starts very close to the fluid critical point in a region characterized by significant real gas effects, so that depressurization, that is the typical operating strategy adopt...
Conference Paper
Full-text available
Supercritical CO2 cycles (sCO2) are recognized as a promising solution for the exploitation of different energy sources: from fossil fuel combustion and nuclear energy to solar energy and waste heat recovery. The large range of possible applications and the possible scarcity of water for sCO2 systems makes the use of direct air-cooled heat rejectio...
Conference Paper
Full-text available
Supercritical CO2 cycles for power generation are gaining a large interest from industry, institutions and academia as demonstrated by the large amount of investments, founded projects and research papers. This attention is motivated by the potential of sCO2 technology of replacing conventional steam plants in a number of applications and likely to...
Article
The present work aims to investigate the potential advantages in using a novel wet and dry configuration for heat rejection units in ORC power plants. The reference case is a geothermal power plant that exploits a low temperature brine and uses a closed loop of cooling water to release the condensation heat to the ambient. In the calculations, the...
Article
Off-grid microgrids constitute an increasingly viable alternative to grid extension for rural electrification. Thanks to significant reductions in hardware cost, energy cost for off-grid users in areas sparsely covered by the national grid has become competitive with grid-connection once infrastructural costs are accounted for. Microgrids offer adv...
Article
Low-medium temperature heat sources in the range 5–50 MWth are made available by many industrial fields but they may also be of interest for biomass, geothermal and solar energy applications. ORC has been proposed in the last 20 years as a reliable solution for the exploitation of these energy sources since the alternative represented by steam cycl...
Article
The application of CO2 power cycles has proved to be particularly advantageous to exploit high-temperature heat sources (500–800 °C) in the case of available low-temperature heat sinks (15–25 °C). Otherwise, the efficiency of these cycles is strongly reduced when cold sink temperatures are higher than 25 °C. This is the case, for example, of solar...
Article
The calculation of the performance of an ORC (Organic Rankine Cycle) and its components (in particularly the turbine) is generally not a trivial task because of the lack of a proper instrumentation, the inaccuracy of the available measurements and the uncertainty on fluid thermodynamic properties calculation. These limitations can greatly affect th...
Article
Natural Gas (NG) is constantly increasing its importance and widening its penetration in the world energy mix, so that the topic of its reliable and efficient transportation represents an enduring challenge of utmost importance. Within this framework, the design and operation of NG compression stations is a key aspect, significantly influencing the...
Article
A rolling-horizon algorithm is proposed for optimizing the operating schedule of a given cogeneration energy system while taking into account time-variable loads, tariffs and ambient conditions, as well as yearly fiscal incentives. The presented algorithm is based on the Mixed Integer Linear Programming (MILP) model developed by the authors for opt...
Article
In this study, we investigated the possible synergies between desalination technologies and solar energy in a remote energy system modelled as a small-size island with the goal to increase system sustainability. The solar systems implemented are photovoltaic panels (PV) and a Concentrating Solar Power system coupled with an Organic Rankine Cycle (C...
Article
Full-text available
The present work aims to investigate the potential advantages in using a novel wet and dry configuration for heat rejection units in ORC power plants. The reference case is a geothermal power plant that exploits a medium temperature brine and uses a closed loop of cooling water to release the condensation heat. In the calculations, the off-design o...
Article
Full-text available
The application of CO2 power cycles is advantageous to exploit high-temperature sources (500-800°C) in the case of available low-temperature heat sinks (15-25°C). However, their efficiency is strongly reduced for higher heat sink temperatures. At these temperatures, due to the low-critical temperature of CO2 (about 31°C), CO2 is in fact compressed...
Article
Full-text available
This paper focuses on the design and the optimization of Organic Rankine Cycle (ORC) for LNG regasification plants. This technology is a promising solution with large benefits attainable in terms of primary energy savings compared to both Open Rack Vaporizer (ORV) and Submerged Combustion Vaporizer (SCV) technologies. Different cycle configurations...
Article
Full-text available
This paper, after a brief description of the radial outflow turbine and of its main features, discloses the field performances evaluation of two operating geothermal ORC (Organic Rankine Cycle) plants installed by Exergy Spa in Turkey. The work describes the test procedure, the measurements and calculation methods used to obtain the turbine efficie...
Article
Full-text available
Low-medium temperature heat sources in the range 5 - 50 MWth are made available by many industrial fields but they may also be of interest for biomass and solar energy applications. ORC has been proposed in the last 20 years as a reliable solution for the exploitation of these energy sources since the alternative represented by steam cycles leads t...
Article
Hybrid microgrids are expected to play an important role in the expansion of access to electricity in developing countries. While most of these systems are operated with dispatch strategies which do not make use of predictions about the load or about the availability of renewable energy resources, forecast-based strategies have recently gained atte...
Chapter
This chapter aims to define a set of general correlations for the estimation of axial-flow turbine efficiency in the Organic Rankine Cycle (ORC) field. A dedicated numerical tool is used for the optimization of several hundreds of turbines and the results are presented in terms of specific parameters (SP, Vr, and Ns) according to similarity rules....
Chapter
This chapter aims to define a set of general correlations for the estimation of axial-flow turbine efficiency in the Organic Rankine Cycle (ORC) field. A dedicated numerical tool is used for the optimization of several hundreds of turbines and the results are presented in terms of specific parameters (SP, Vr, and Ns) according to similarity rules....
Article
This paper investigates the coupling of parabolic dish concentrator with air micro gas turbine engine (net power output equal to 32.9 kWel). With the aim of increasing the conversion efficiency of the incoming solar radiation, a high temperature system (up to 1100 °C) has been considered: this solution implies the adoption of a ceramic expander cou...
Book
Organic Rankine Cycle (ORC) Power Systems: Technologies and Applications provides a systematic and detailed description of organic Rankine cycle technologies and the way they are increasingly of interest for cost-effective sustainable energy generation. Popular applications include cogeneration from biomass and electricity generation from geotherma...
Article
This paper investigates the smart integration of a 500 ha microalgae culturing facility with a large scale coal power plant (758.6 MWe): a fraction of the CO2 contained in the coal plant flue gases is used for the algal cultivation, a fraction of the low-temperature flue gas heat available is used for the biomass drying, finally the produced biomas...
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
The presented work compares two optimization models for combined heat and power (CHP) energy systems scheduling. Both models are focused on the evaluation of the best operating strategy to run a defined cogeneration system that is dealing with time-variable loads and tariffs. The simultaneous usage of different prime movers operating in parallel is...
Article
This paper focuses on the design optimization of a stand-alone hybrid microgrid serving a 2000 inhabitants community located in a rural area of Bihar (India) and it investigates the potential of the use of wood biomass for electricity generation. The economic performance of the different power generation configurations is evaluated simulating the...
Article
As a consequence of growing energy demand and expanded use of fossil fuels, CO2 level in the atmosphere has risen in the last couple of centuries. The principal effect of these anthropologic emissions of greenhouse gases is global warming. In the last years, there has been much effort on finding a long term solution to this problem, mostly based on...
Article
Full-text available
Stirling engines are a promising candidate for micro-cogeneration in residential and small-scale tertiary applications. Due to the variability of energy demand profiles and electricity tariffs, real applications often require to operate the cogeneration unit with multiple daily starts and stops, especially during summer and intermediate seasons. Th...
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
A rolling-horizon algorithm is proposed for optimizing the operating schedule of a given tri-generation energy system while taking into account time-variable loads, tariffs and ambient conditions, as well as financial incentives given on a yearly basis.The algorithm is based on an extension of the Mixed Integer Linear Programming (MILP) model recen...
Article
Full-text available
Micro-cogeneration Stirling units are promising for residential applications because of high total efficiencies, favorable ratios of thermal to electrical powers and low CO as well as NOx emissions. This work focuses on the experimental and the numerical analysis of a commercial unit generating 8 kW of hot water (up to 15 kW with an auxiliary burne...
Conference Paper
Full-text available
This paper is focused on the design of a stand-alone microgrid for rural electrification. The aim of this work is to define the best mix of energy sources and the optimal size of the energy storage for a small isolated village on the Ghana seaside. We obtain the optimal solution by simulating one year of operation for several different combinations...
Article
Full-text available
The performance of a 5MWel indirect ORC cycle coupled to linear solar collectors with different technologies is assessed, aiming at evaluating the effect of different control strategies on annual electricity output. Two different solutions are considered for solar collectors: a state-of-the-art parabolic trough collector with Therminol VP1 as heat...
Article
Full-text available
Micro-cogeneration Stirling engines are considered promising for residential applications. The present work covers the experimental and numerical analysis of a commercial Stirling unit capable of 8 kW of hot water and 1 kW of electricity. A previously concluded experimental campaign that focused on external measurements is extended here to include...
Article
Full-text available
ScienceDirect 1876-6102 © 2014 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/). Peer-review under responsibility of the Organizing Committee of ICAE2014 Abstract Micro-cogeneration Stirling engines are promising for residential applications. Thi...
Article
This work discusses the design and the development of a Laboratory of Micro-Cogeneration (LMC) at Politecnico di Milano. The LMC laboratory is a unique structure devoted to small-scale power generation, with the main goals of testing and improving the performance of systems that produce or utilize electric and thermal (hot and/or cold) power in a v...
Article
A detailed optimization model is presented for planning the short-term operation of combined cooling, heat and power (CCHP) energy systems. The purpose is, given the design of a cogeneration system, to determine an operating schedule that minimizes the total operating and maintenance costs minus the revenue due to the electricity sold to the grid,...
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...
Article
Post combustion CO2 capture (PCC) with amine solvents is seen as one of the possible technologies which can be implemented in the near term to significantly reduce CO2 emissions from fossil fuel power plants. One of the major concerns for its implementation at large scale in power plants is the high capital and operating costs of the technology. Th...
Conference Paper
This work compares two optimization approaches for combined cooling, heating and power (CCHP or Tri-generation) energy systems scheduling. Both approaches are developed through dedicated software codes and are based on simulation models capable of evaluating of the best operating strategy (both economically and energy-wise) to run a given trigenera...
Article
This study focuses on the application of Pd-based membranes for CO2 capture in coal fuelled power plants. In particular, membranes are applied to Integrated Gasification Combined Cycle with two innovative feeding systems. In the first feeding system investigated, CO2 is used both as fuel carrier and back-flushing gas for the candle filters, while i...
Poster
Full-text available
Nowadays, supercritical carbon dioxide (S-CO2) Brayton cycles offer the potential of equivalent or higher cycle efficiency compared to supercritical or reheated steam cycles at turbine inlet temperatures relevant for nuclear, solar and geothermal energy conversion systems. The economy of S-CO2 cycles could be improved if the working fluid is conden...
Article
This two-part paper investigates the potential of ORC (Organic Rankine Cycles) for the exploitation of low-medium enthalpy geothermal brines. Part A deals with thermodynamic analysis and optimization, while Part B focuses on economic optimization. In this part, an economic model was defined and implemented in the Matlab® code previously developed....
Article
Full-text available
In the FP7 project CAESAR, Air Products, BP, ECN, SINTEF and Politecnico di Milano worked together in the further development of the SEWGS process with the objective to reduce the energy penalty and the costs per ton of CO2 avoided to less than €25 through optimization of sorbent materials, reactor and process design and smart integration of the SE...
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...
Conference Paper
Full-text available
This study considers the integration of Pd-based H 2 -selective membranes in integrated gasifier combined cycles (IGCC) from both technical and economical point of view. The selected gasification system is based on Shell technology. Two different dry feeding systems are investigated: the first is a state-of-f f the-art nitrogen-based lock hopper ch...
Article
This two part-paper investigates the performance of SEWGS (Sorption Enhanced Water Gas Shift), an innovative reactor for CO2 capture, applied to an Integrated Gasification Combined Cycle (IGCC).In part-A, different SEWGS working conditions are investigated outlining several advantages and performance differences. A comparison of two sorbents is als...
Article
This two part-paper investigates the performance of SEWGS (Sorption Enhanced Water Gas Shift), an innovative system for CO2 capture, applied to a coal fuelled Integrated Gasification Combined Cycle (IGCC). Firstly, two reference cases based on dry feed slagging Shell gasifier, with and without CO2 capture, are defined. Conventional pulverized coal...
Article
Pre-combustion capture applied to an integrated gasification combined cycle is a promising solution for greenhouse gas emission’s mitigation. For optimal design and operation of this cycle, detailed simulation of entrained flow gasifiers and their integration in the flowsheet analysis is required. This paper describes the development of a reduced o...
Article
Full-text available
An innovative process for CO2 capture named SEWGS (sorption enhanced water gas shift) was investigated from technical and economic point of view when applied to natural gas power plants. This activity was carried out under the FP7 project CAESAR financed by the EU community. The SEWGS working conditions were optimized in terms of carbon capture rat...
Article
This two part-paper investigates the adoption of an innovative CO2 capture concept named SEWGS (sorption enhanced water gas shift) in natural gas combined cycle. In Part A, SEWGS working conditions were optimized in terms of carbon capture ratio as well as CO2 purity and two different sorbent performances were analyzed. Part B presents the economic...
Article
This paper analyzes the performance of multi-MW wind turbines by means of a specific numerical model, with the aim of evaluating the application of an advanced hydrostatic transmission in a conventional state-of-the-art machine. The interest for such a solution is mainly related to the potential increase of reliability and reduction of maintenance...
Conference Paper
Full-text available
Many alternatives are being investigated for the carbon capture, but none appears to have been proved as the choice for full-scale applications. This work considers the Chilled Ammonia Process for coal-fired Ultra Super Critical power plants. Three layouts are simulated with Aspen Plus and the Extended UNIQUAC thermodynamic model. Compared to a tra...
Article
In view of a possible hydrogen infrastructure a number of studies on large-scale hydrogen liquefiers state that conventional plant efficiencies may be substantially increased. Generally those studies consider different (i) working conditions, (ii) operational unit performances and (iii) thermodynamic models, making it difficult to compare their res...
Article
Solar thermal plants are among the most promising technologies to replace fossil fuel stationary applications, and within solar thermal technologies, parabolic troughs are considered the most mature application in the market. This paper compares different solar field technologies, in terms of both performance at design conditions and annual energy...
Article
Post-combustion carbon capture is attracting much attention due to the fact that it can be retrofitted on existing coal power plants. Among the most interesting technologies is the one that employs aqueous ammonia solutions to absorb the generated carbon dioxide. The evaluation of such process requires the modeling of electrolyte solutions. In this...
Article
This paper deals with the development and testing of an innovative code for the performance prediction of solar trough based concentrated solar power (CSP) plants in off-design conditions. Off-design calculation starts from data obtained through the on-design algorithm and considers steady-state situations. The model is implemented in flexible soft...
Article
Full-text available
As carbon dioxide anthropogenic generation and climate change appear to be correlated, carbon capture becomes necessary, in particular if applied to coal-fired power plants. The Chilled Ammonia Process (CAP) is a promising technology to be proved for the purpose. This work investigates the integration of Ultra Super Critical (USC) power plants with...
Article
Full-text available
This paper investigates the performance of SEWGS (Sorption Enhanced Water Gas Shift), an innovative reactor for CO2 capture, applied to Integrated Gasification Combined Cycle (IGCC). Firstly, two IGCC reference cases based on dry feed slagging Shell gasifier, with and without CO2 capture, are defined. Then, two different integrations of SEWGS are i...
Article
This paper presents the development and testing of an innovative code for the prediction of thermodynamic performances at nominal conditions, as well as a preliminary plant sizing and investment costs estimation for different parabolic trough solar fields. Part A of the paper presented in detail the model and validated it toward existing plants. Th...
Article
This paper presents an innovative code for predicting performances, as well as preliminary plant sizing and investment costs estimation, for different parabolic trough solar fields operating at nominal conditions. The code allows a preliminary design of the solar field lay-out, the sizing of the main components of the plant and the optimization of...
Article
This two part-paper investigates the performance of different integration options of an innovative reactor for CO2 capture named SEWGS (Sorption-Enhanced Water Gas Shift) in a natural gas combined cycle. This activity was carried out under the FP7 project CAESAR financed by the EU community. In Part-A, several plant layouts starting from a complete...
Article
This two part-paper investigates the performance of different integration possibilities in a Natural Gas Combined Cycle of an innovative reactor for CO2 capture named SEWGS (Sorption Enhanced Water Gas Shift). This activity is carried out under the FP7 project CAESAR financed by the EU community. In part A, several plant layouts starting from compl...
Article
A combined concentrating solar power system and a geothermal binary plant based on an Organic Rankine Cycle (ORC) is analyzed. Given a supercritical ORC, designed for the optimal utilization of an intermediate enthalpy geothermal source, a solar parabolic trough field was included in the plant, introducing an additional high temperature heat source...
Article
The paper deals with the preliminary design and optimization of cogenerative solar thermodynamic plants for industrial users. The considered plants are all based on proven parabolic trough technology, but different schemes have been analyzed: from a conventional configuration with indirect steam cycle and a heat transfer fluid such as synthetic oil...
Article
As carbon dioxide anthropogenic generation and climate change appear to be correlated, carbon capture becomes advisable, in particular if applied to coal-fired power plants. The Chilled Ammonia Process (CAP) is a promising technology to be proved for the purpose. Continuing an ongoing study, this work examines the integration of Ultra Super Critica...