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The use of a binary cycle coupled to the complete reinjection of non-condensable gases could provide a valid answer to the improvement of the sustainability of geothermal plants. In recent years, the interest in the use of CO2 as a working fluid in transcritical cycles has increased. However, the low critical temperature of carbon dioxide (≈30 °C) requires the cooling cycle, temperatures below 15 °C, which are not always available. In this work, to overcome this limitation and obtain a higher critical temperature and a lower maximum pressure for more flexible applications of transcritical binary cycles, the possibility of using a second component, mixed with CO2, has been evaluated. For this purpose, the following fluids have been proposed: R1234yf, R1234ze(E), n-butane, n-hexane, n-pentane, and propane, with a minimum considered carbon dioxide molar content of 60%. To carry out a cycle analysis, the knowledge of the thermodynamic properties of CO2-mixtures is fundamental; however, suitable equations of state under the appropriate conditions for these blends have not been clearly defined yet. Therefore, in the first part of this paper, different EoS for predicting thermodynamic properties of pure CO2 and CO2-based mixtures are analyzed and compared with reference data obtained from works published in the literature. However, because of the lack of experimental data of the selected blends, the values of density, enthalpy and entropy, obtained with the selected EoS, are compared with NIST REFPROP results. The EoS involved in the evaluation are cubic-type (PR, PR-Twu, PRSV, RK, SRK, GCEOS), Virial-type (LKP, BWRS), Helmholtz-type (SW), and SAFT-type (PC-SAFT). In a power cycle, the fluid works under different conditions, involving several possible states across the components. So the influence of the different EoS on each power cycle's key component for pure CO2 and two selected CO2-based mixtures has been investigated. The thermodynamic results show that the CO2-based mixtures, in a transcritical configuration, can achieve efficiencies higher than the sCO2 power cycle.
Mattia Bertini; Daniele Fiaschi; Giampaolo Manfrida; Pouriya H Niknam; Lorenzo Talluri. Evaluation of the property methods for pure and mixture of CO2 for power cycles analysis. Energy Conversion and Management 2021, 245, 114568 .
AMA StyleMattia Bertini, Daniele Fiaschi, Giampaolo Manfrida, Pouriya H Niknam, Lorenzo Talluri. Evaluation of the property methods for pure and mixture of CO2 for power cycles analysis. Energy Conversion and Management. 2021; 245 ():114568.
Chicago/Turabian StyleMattia Bertini; Daniele Fiaschi; Giampaolo Manfrida; Pouriya H Niknam; Lorenzo Talluri. 2021. "Evaluation of the property methods for pure and mixture of CO2 for power cycles analysis." Energy Conversion and Management 245, no. : 114568.
A comprehensive cost correlation analysis was conducted based on available cost correlations, and new equipment cost correlation models were proposed based on QUE$TOR modeling. Cost correlations for various types of equipment such as pumps, compressors, heat exchangers, air coolers, and pressure vessels were generated on the basis of extracted cost data. The models were derived on the basis of robust multivariable regression with the aim of minimizing the residuals by using the genetic algorithm. The proposed compressor models for both centrifugal and reciprocating types showed that the Turton cost estimation for carbon steel compressor and Matche’s and Mhhe’s data were compatible with the generated model. According to the results, the cost trend in the Turton correlation for carbon steel had a somewhat lower estimation than these correlations. Further, the cost trend of the Turton correlation for carbon steel pressure vessels was close to the presented model trend for both bullet and sphere types. The Turton cost trend for U-tube shell-and-tube heat exchangers with carbon steel shell and stainless steel tube was close to the proposed heat exchanger model. Furthermore, the Turton cost trend for the flat-plate heat exchanger using carbon steel was similar to the proposed model with a slight difference.
Moein Shamoushaki; Pouriya Niknam; Lorenzo Talluri; Giampaolo Manfrida; Daniele Fiaschi. Development of Cost Correlations for the Economic Assessment of Power Plant Equipment. Energies 2021, 14, 2665 .
AMA StyleMoein Shamoushaki, Pouriya Niknam, Lorenzo Talluri, Giampaolo Manfrida, Daniele Fiaschi. Development of Cost Correlations for the Economic Assessment of Power Plant Equipment. Energies. 2021; 14 (9):2665.
Chicago/Turabian StyleMoein Shamoushaki; Pouriya Niknam; Lorenzo Talluri; Giampaolo Manfrida; Daniele Fiaschi. 2021. "Development of Cost Correlations for the Economic Assessment of Power Plant Equipment." Energies 14, no. 9: 2665.
In this paper, we assess using two alternative allocation schemes, namely exergy and primary energy saving (PES) to compare products generated in different combined heat and power (CHP) geothermal systems. In particular, the adequacy and feasibility of the schemes recommended for allocation are demonstrated by their application to three relevant and significantly different case studies of geothermal CHPs, i.e., (1) Chiusdino in Italy, (2) Altheim in Austria, and (3) Hellisheidi in Iceland. The results showed that, given the generally low temperature level of the cogenerated heat (80–100 °C, usually exploited in district heating), the use of exergy allocation largely marginalizes the importance of the heat byproduct, thus, becoming almost equivalent to electricity for the Chiusdino and Hellisheidi power plants. Therefore, the PES scheme is found to be the more appropriate allocation scheme. Additionally, the exergy scheme is mandatory for allocating power plants’ environmental impacts at a component level in CHP systems. The main drawback of the PES scheme is its country dependency due to the different fuels used, but reasonable and representative values can be achieved based on average EU heat and power generation efficiencies.
Daniele Fiaschi; Giampaolo Manfrida; Barbara Mendecka; Lorenzo Tosti; Maria Parisi. A Comparison of Different Approaches for Assessing Energy Outputs of Combined Heat and Power Geothermal Plants. Sustainability 2021, 13, 4527 .
AMA StyleDaniele Fiaschi, Giampaolo Manfrida, Barbara Mendecka, Lorenzo Tosti, Maria Parisi. A Comparison of Different Approaches for Assessing Energy Outputs of Combined Heat and Power Geothermal Plants. Sustainability. 2021; 13 (8):4527.
Chicago/Turabian StyleDaniele Fiaschi; Giampaolo Manfrida; Barbara Mendecka; Lorenzo Tosti; Maria Parisi. 2021. "A Comparison of Different Approaches for Assessing Energy Outputs of Combined Heat and Power Geothermal Plants." Sustainability 13, no. 8: 4527.
This paper reports a comprehensive survey of well drilling time and cost. The models include both specific correlations on various well types and generalised correlations for rough estimation. The models are derived from robust multivariable regression to minimise the residuals. Africa has the highest construction cost component in well drilling and the United States has the lowest. Data in various regions are compared with European and World average drilling data. Drilling time in Italy is similar to Europe and world averages. The proposed model directly estimates both the drilling cost and time to be used in fundamental research and feasibility studies for geothermal power plants applicable worldwide.
Moein Shamoushaki; Daniele Fiaschi; Giampaolo Manfrida; Pouriya H. Niknam; Lorenzo Talluri. Feasibility study and economic analysis of geothermal well drilling. International Journal of Environmental Studies 2021, 1 -15.
AMA StyleMoein Shamoushaki, Daniele Fiaschi, Giampaolo Manfrida, Pouriya H. Niknam, Lorenzo Talluri. Feasibility study and economic analysis of geothermal well drilling. International Journal of Environmental Studies. 2021; ():1-15.
Chicago/Turabian StyleMoein Shamoushaki; Daniele Fiaschi; Giampaolo Manfrida; Pouriya H. Niknam; Lorenzo Talluri. 2021. "Feasibility study and economic analysis of geothermal well drilling." International Journal of Environmental Studies , no. : 1-15.
The emissions associated with Geothermal power plant (GTPP) due to geothermal fluids represents a compelling challenge addressed in the last decades. The on-line measuring of pollutants generated by GTPP might result in a complicated task to handle. Simulation of GTPP has become an excellent tool to monitor and control the emission of pollutants. In the present work, the pollutant emissions of GTPP of Hellisheidi (Island), Chiusdino, and Castelnuovo (Italy) are modelled and developed with Unisim Design R480 using well understood thermodynamical models implemented in OLI. The presence of brine in the thermodynamical models has been taken into account. Carbon dioxide, methane, and hydrogen sulfide are the chemical pollutants considered for the process simulation. The AQ framework model in OLI is being used for binary mixtures and non-condensable gas. Furthermore, for liquid mixtures containing more than two components, the MSE-SRK Thermodynamic model is desirable depending on the original geothermal fluid source. The simulation process outcome agrees with experimental data for pressure between 30 and 100 bar within 5% deviation. A systematic study of the spatial distribution of the emissions has been made for the area surrounding the GTPP. Furthermore, an economic evaluation overview has been performed to highlight the equipment needed for maintenance and tool substitution.
Vitantonio Colucci; Angelo Damone; Giampaolo Manfrida; Daniele Fiaschi. Thermodynamic modelling and simulation of geothermal power plants: case studies and environmental impact. 2021, 1 .
AMA StyleVitantonio Colucci, Angelo Damone, Giampaolo Manfrida, Daniele Fiaschi. Thermodynamic modelling and simulation of geothermal power plants: case studies and environmental impact. . 2021; ():1.
Chicago/Turabian StyleVitantonio Colucci; Angelo Damone; Giampaolo Manfrida; Daniele Fiaschi. 2021. "Thermodynamic modelling and simulation of geothermal power plants: case studies and environmental impact." , no. : 1.
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 can be developed to a reasonable size (rotor of 0.1 to 0.25 m diameters), with acceptable rotational speeds (which range from 500 to 10000 rpm). The original concept was revisited, designing it for two-phase operation and considering not only the rotor configuration but the whole machine. The flow model was developed using complete real fluid assumptions including several new concepts such as bladed channels for the stator, labyrinth seals, and a rotating diffuser. Preliminary design sketches are presented, and results discussed and evaluated.
L. Talluri; P. Niknam; A. Copeta; M. Amato; P. Iora; S. Uberti; C. Invernizzi; G. Di Marcoberardino; L. Pacini; G. Manfrida; D. Fiaschi. A revised Tesla Turbine concept for 2-phase applications. E3S Web of Conferences 2021, 238, 10006 .
AMA StyleL. Talluri, P. Niknam, A. Copeta, M. Amato, P. Iora, S. Uberti, C. Invernizzi, G. Di Marcoberardino, L. Pacini, G. Manfrida, D. Fiaschi. A revised Tesla Turbine concept for 2-phase applications. E3S Web of Conferences. 2021; 238 ():10006.
Chicago/Turabian StyleL. Talluri; P. Niknam; A. Copeta; M. Amato; P. Iora; S. Uberti; C. Invernizzi; G. Di Marcoberardino; L. Pacini; G. Manfrida; D. Fiaschi. 2021. "A revised Tesla Turbine concept for 2-phase applications." E3S Web of Conferences 238, no. : 10006.
Emissions of contaminants and CO2 are becoming a relevant issue for the development of geothermal energy projects. Organic Rankine (ORC) Cycles present in this light particular appeal in the light of the possibility of total reinjection of the geothermal fluid resource including Non-Condensable Gases (NCGs). The Castelnuovo (IT) case study conditions are considered a saturated vapour resource at 10 bar pressure. The performance of the ORC cycle for power generation from this geothermal resource is evaluated through mass and energy balances, stepping up to exergy, Life Cycle Analysis (LCA) and Exergo-Environmental analyses (EEvA). The applied methodology allows to identify the most critical components of the system and to evaluate the environmental indicators of the system.
Daniele Fiaschi; Giampaolo Manfrida; Barbara Mendecka; Moein Shamoushaki; Lorenzo Talluri. Exergy and Exergo-Environmental analysis of an ORC for a geothermal application. E3S Web of Conferences 2021, 238, 01011 .
AMA StyleDaniele Fiaschi, Giampaolo Manfrida, Barbara Mendecka, Moein Shamoushaki, Lorenzo Talluri. Exergy and Exergo-Environmental analysis of an ORC for a geothermal application. E3S Web of Conferences. 2021; 238 ():01011.
Chicago/Turabian StyleDaniele Fiaschi; Giampaolo Manfrida; Barbara Mendecka; Moein Shamoushaki; Lorenzo Talluri. 2021. "Exergy and Exergo-Environmental analysis of an ORC for a geothermal application." E3S Web of Conferences 238, no. : 01011.
Geothermal energy is a clean resource, which could significantly contribute to the reduction of greenhouse and other gas emissions by replacing fossil fuels for power generation. In many geothermal sites, the resource contains substantial Non-Condensable Gases (NCGs: CO2 and contaminants), whose emissions can be limited to developing power plant schemes suitable for complete resource reinjection. Organic Rankine or other closed-loop cycles are definitely favored in this light. This work investigates a solution for complete NCG reinjection in the liquid-dominated reservoir conditions typical of the Monte Amiata area (Italy), referring to the specific site of Torre Alfina (IT) which presents a specific attractiveness because of its high pressurization. The solution considered avoids flashing the resource and thus presents an appealing environmental performance. The power plant models include energy and exergy balances, as well as exergo-environmental analysis. The overall environmental performance is evaluated by a simplified (preliminary) Life Cycle Analysis (LCA). Different solutions are compared, considering the possibility of sub- or super-critical power cycles.
Daniele Fiaschi; Martina Leveni; Giampaolo Manfrida; Barbara Mendecka; Lorenzo Talluri. Geothermal power plants with improved environmental performance: assessment of the potential for an Italian site. E3S Web of Conferences 2021, 238, 01010 .
AMA StyleDaniele Fiaschi, Martina Leveni, Giampaolo Manfrida, Barbara Mendecka, Lorenzo Talluri. Geothermal power plants with improved environmental performance: assessment of the potential for an Italian site. E3S Web of Conferences. 2021; 238 ():01010.
Chicago/Turabian StyleDaniele Fiaschi; Martina Leveni; Giampaolo Manfrida; Barbara Mendecka; Lorenzo Talluri. 2021. "Geothermal power plants with improved environmental performance: assessment of the potential for an Italian site." E3S Web of Conferences 238, no. : 01010.
The surface equipment design for a binary cycle geothermal power plant including facilities required for the power cycle and the complete reinjection process of two-phase geothermal fluid (H2O + non-condensable gases (NCGs)) in the Castelnuovo area of Larderello are modelled. The proposed scheme includes the configuration of closed-loop power plant, NCGs compression train and reinjection process at the wellhead. Steady-state and dynamic simulations are performed. The steady-state model is developed to find the correct operating solutions and conditions, while the dynamic model investigates the unsteady behavior of the system. The study includes a sensitivity analysis of surface equipment design, demonstrating the effect of internal and external variables on the system performance, including power cycle, compression train and reinjection process. The maximum compressor power consumption (at 60 bar reinjection pressure) is 176 kW at 8% CO2 mass fraction into the geothermal fluid. The unsteady system behavior at startup and its response to step-changes of flow stream condition is assessed: it is found that the average response-time is about 20 minutes. Also, the system requires a drain pressure higher than the saturation level for effective reinjection. A new Antoine – based correlation for water-CO2 mixture is proposed for geothermal applications.
Pouriya H. Niknam; Lorenzo Talluri; Daniele Fiaschi; Giampaolo Manfrida. Sensitivity analysis and dynamic modelling of the reinjection process in a binary cycle geothermal power plant of Larderello area. Energy 2020, 214, 118869 .
AMA StylePouriya H. Niknam, Lorenzo Talluri, Daniele Fiaschi, Giampaolo Manfrida. Sensitivity analysis and dynamic modelling of the reinjection process in a binary cycle geothermal power plant of Larderello area. Energy. 2020; 214 ():118869.
Chicago/Turabian StylePouriya H. Niknam; Lorenzo Talluri; Daniele Fiaschi; Giampaolo Manfrida. 2020. "Sensitivity analysis and dynamic modelling of the reinjection process in a binary cycle geothermal power plant of Larderello area." Energy 214, no. : 118869.
Geothermal energy could play a crucial role in the European energy market and future scenarios focused on sustainable development. Thanks to its constant supply of concentrated energy, it can support the transition towards a low-carbon economy. In the energy sector, the decision-making process should always be supported by a holistic science-based approach to allow a comprehensive environmental assessment of the technological system, such as the life cycle assessment (LCA) methodology. In the geothermal sector, the decision-making is particularly difficult due to the large variability of reported results on environmental performance across studies. This calls for harmonized guidelines on how to conduct LCAs of geothermal systems to enhance transparency and results comparability, by ensuring consistent methodological choices and providing indications for harmonized results reporting. This work identifies the main critical aspects of performing an LCA of geothermal systems and provides solutions and technical guidance to harmonize its application. The proposed methodological approach is based on experts’ knowledge from both the geothermal and LCA sectors. The recommendations cover all the life cycle phases of geothermal energy production (i.e., construction, operation, maintenance and end of life) as well as a selection of LCA key elements thus providing a thorough base for concerted LCA guidelines for the geothermal sector. The application of such harmonized LCA framework can ensure comparability among LCA results from different geothermal systems and other renewable energy technologies.
Maria Laura Parisi; Melanie Douziech; Lorenzo Tosti; Paula Pérez-López; Barbara Mendecka; Sergio Ulgiati; Daniele Fiaschi; Giampaolo Manfrida; Isabelle Blanc. Definition of LCA Guidelines in the Geothermal Sector to Enhance Result Comparability. Energies 2020, 13, 3534 .
AMA StyleMaria Laura Parisi, Melanie Douziech, Lorenzo Tosti, Paula Pérez-López, Barbara Mendecka, Sergio Ulgiati, Daniele Fiaschi, Giampaolo Manfrida, Isabelle Blanc. Definition of LCA Guidelines in the Geothermal Sector to Enhance Result Comparability. Energies. 2020; 13 (14):3534.
Chicago/Turabian StyleMaria Laura Parisi; Melanie Douziech; Lorenzo Tosti; Paula Pérez-López; Barbara Mendecka; Sergio Ulgiati; Daniele Fiaschi; Giampaolo Manfrida; Isabelle Blanc. 2020. "Definition of LCA Guidelines in the Geothermal Sector to Enhance Result Comparability." Energies 13, no. 14: 3534.
Renewable energies are often subject to stochastic resources and daily cycles. Energy storage systems are consequently applied to provide a solution for the mismatch between power production possibility and its utilization period. In this study, a solar integrated thermo-electric energy storage (S-TEES) is analyzed both from an economic and environmental point of view. The analyzed power plant with energy storage includes three main cycles, a supercritical CO2 power cycle, a heat pump and a refrigeration cycle, indirectly connected by sensible heat storages. The hot reservoir is pressurized water at 120/160 °C, while the cold reservoir is a mixture of water and ethylene glycol, maintained at −10/−20 °C. Additionally, the power cycle’s evaporator section rests on a solar-heated intermediate temperature (95/40 °C) heat reservoir. Exergo-economic and exergo-environmental analyses are performed to identify the most critical components of the system and to obtain the levelized cost of electricity (LCOE), as well as the environmental indicators of the system. Both economic and environmental analyses revealed that solar energy converting devices are burdened with the highest impact indicators. According to the results of exergo-economic analysis, it turned out that average annual LCOE of S-TEES can be more than two times higher than the regular electricity prices. However, the true features of the S-TEES system should be only fully assessed if the economic results are balanced with environmental analysis. Life cycle assessment (LCA) revealed that the proposed S-TEES system has about two times lower environmental impact than referential hydrogen storage systems compared in the study.
Daniele Fiaschi; Giampaolo Manfrida; Karolina Petela; Federico Rossi; Adalgisa Sinicropi; Lorenzo Talluri. Exergo-Economic and Environmental Analysis of a Solar Integrated Thermo-Electric Storage. Energies 2020, 13, 3484 .
AMA StyleDaniele Fiaschi, Giampaolo Manfrida, Karolina Petela, Federico Rossi, Adalgisa Sinicropi, Lorenzo Talluri. Exergo-Economic and Environmental Analysis of a Solar Integrated Thermo-Electric Storage. Energies. 2020; 13 (13):3484.
Chicago/Turabian StyleDaniele Fiaschi; Giampaolo Manfrida; Karolina Petela; Federico Rossi; Adalgisa Sinicropi; Lorenzo Talluri. 2020. "Exergo-Economic and Environmental Analysis of a Solar Integrated Thermo-Electric Storage." Energies 13, no. 13: 3484.
Geothermal energy is acknowledged globally as a renewable resource, which, unlike solar, wind or wave energy, can be continuously exploited. The geothermal fluids usually have some acid gas content, which needs to be precisely taken into account when predicting the actual potential of a power plant in dealing with an effective reinjection. One of the key parameters to assess is the solubility of the acid gas, as it influences the thermodynamic conditions (saturation pressure and temperature) of the fluid. Therefore, an enhanced solubility model for the CO2-H2S-water system is developed in this study, based on the mutual solubility of gases. The model covers a wide range of pressures and temperatures. The genetic algorithm is employed to calculate the correlation constants and corresponding solubility values of both CO2 and H2S as functions of pressure, temperature and the balance of the gas. The results are validated against previously published models and experimental data available in the literature. The proposed model estimates the pure gas solubility, which is also a feature of other models. The more innovative feature of the model is the solubility estimation of each CO2 or H2S in simultaneous presence, such as when the binary gas is injected into the pure water of the geothermal reinjection well. The proposed solubility model fits well with the available experimental data, with a mean deviation lower than 0.2%.
Pouriya H. Niknam; Lorenzo Talluri; Daniele Fiaschi; Giampaolo Manfrida. Improved Solubility Model for Pure Gas and Binary Mixture of CO2-H2S in Water: A Geothermal Case Study with Total Reinjection. Energies 2020, 13, 2883 .
AMA StylePouriya H. Niknam, Lorenzo Talluri, Daniele Fiaschi, Giampaolo Manfrida. Improved Solubility Model for Pure Gas and Binary Mixture of CO2-H2S in Water: A Geothermal Case Study with Total Reinjection. Energies. 2020; 13 (11):2883.
Chicago/Turabian StylePouriya H. Niknam; Lorenzo Talluri; Daniele Fiaschi; Giampaolo Manfrida. 2020. "Improved Solubility Model for Pure Gas and Binary Mixture of CO2-H2S in Water: A Geothermal Case Study with Total Reinjection." Energies 13, no. 11: 2883.
The increasing interest in micro power generation is pushing the research world to find new solutions for increasing the efficiency of micro Organic Rankine Cycles. One of their main issues is the efficiency and the reliability of the expander. The Tesla turbine is an old/new expander, which has found a renewed interest in the last years because of the increasing appeal towards distributed micro generation, where this expander becomes competitive. This peculiar technology seems adapted to micro generation in Organic Rankine Cycle thanks to its main characteristic, which is its simple structure that allows for high reliability and cheapness. In recent years, this expander has been analytically and numerically assessed when working with organic fluids. In this study, the experimental investigation of a Tesla turbine working with R1233zd(E) is presented. One of the main achievements was the assessment of the blockage effect of disks edges when the pressure drop through the machine is relevant as in case of Organic Rankine Cycles (e.g. higher than 3–4 bars), resulting into a relatively large amount of flow deviation through the clearances between the rotor disks package and the case, which implies a throttling effect thus resulting into a relevant performance loss. This effect was accounted by a model that well fitted the experimental data. The achieved results confirmed the validity and the large applications potential of this emerging technology, especially in the fields of micro power generation, low inlet temperature and low expansion ratios. A maximum net power output of 371 W was obtained, proving the feasibility of utilizing Tesla turbines in Organic Rankine Cycle applications. A maximum shaft efficiency of 9.62% and a maximum adiabatic efficiency of 30% were achieved. The results and the developed model of disks edge losses effects represent an important step ahead, in physical depiction of the phenomenology, over the currently available literature, fundamental for the improvement of the design procedure of Tesla turbines for Organic Rankine Cycles.
Lorenzo Talluri; Olivier Dumont; Giampaolo Manfrida; Vincent Lemort; Daniele Fiaschi. Experimental investigation of an Organic Rankine Cycle Tesla turbine working with R1233zd(E). Applied Thermal Engineering 2020, 174, 115293 .
AMA StyleLorenzo Talluri, Olivier Dumont, Giampaolo Manfrida, Vincent Lemort, Daniele Fiaschi. Experimental investigation of an Organic Rankine Cycle Tesla turbine working with R1233zd(E). Applied Thermal Engineering. 2020; 174 ():115293.
Chicago/Turabian StyleLorenzo Talluri; Olivier Dumont; Giampaolo Manfrida; Vincent Lemort; Daniele Fiaschi. 2020. "Experimental investigation of an Organic Rankine Cycle Tesla turbine working with R1233zd(E)." Applied Thermal Engineering 174, no. : 115293.
This paper presents research on the supersonic nozzle geometry with particular emphasis on the effect of the internal body of the nozzle that largely affects the separation efficiency. A numerical investigation of the supersonic nozzle with an internal solid body, which forms an annular flow inside the convergent–divergent nozzle is carried out. The present study revealed different hydrodynamic behaviors of the nozzle, exploring different shapes of the inner body, and the computational fluid dynamic simulations of the supersonic nozzle is utilized to find out the best geometrical design. Utilizing a coupled pressure–velocity scheme with high order of discretization of the governing equation yielded to find the shockwave positions in different conditions. The turbulent behavior of the fluid in the shockwave zone is well discussed and the phase‐change phenomena for the natural gas application are studied considering both water condensation and hydrocarbon condensation simultaneously. Different nozzle configuration elucidates the physical mechanisms of the supersonic flow inside the nozzle. Shockwave position, swirling velocity stability, and mass flow capacity are investigated. The lower the inner body radius, the less the change of shockwave position in the gas is found. Also, the higher stability of swirling velocity magnitude is found for the convergent–divergent inner body, which brings enhanced physical phase separation.
Pouriya H. Niknam; Daniele Fiaschi; Hamid Reza Mortaheb; Babak Mokhtarani. Numerical investigation of multiphase flow in supersonic separator considering inner body effect. Asia-Pacific Journal of Chemical Engineering 2019, 14, 1 .
AMA StylePouriya H. Niknam, Daniele Fiaschi, Hamid Reza Mortaheb, Babak Mokhtarani. Numerical investigation of multiphase flow in supersonic separator considering inner body effect. Asia-Pacific Journal of Chemical Engineering. 2019; 14 (6):1.
Chicago/Turabian StylePouriya H. Niknam; Daniele Fiaschi; Hamid Reza Mortaheb; Babak Mokhtarani. 2019. "Numerical investigation of multiphase flow in supersonic separator considering inner body effect." Asia-Pacific Journal of Chemical Engineering 14, no. 6: 1.
The Tesla turbine is a bladeless expander; which principle of operation is based on the conversion of the viscous forces, developed by the flow while expanding through the rotor, in mechanical energy. It is especially suitable for small/micro size distributed energy systems (kW scale), mainly due to its very low cost, which results from the simple structure of the machine. The Tesla turbine works well at relatively moderate expansion ratios. Therefore, it is fit for CO2 power cycles applications that are characterised by small expansion ratio, despite the high pressure involved. In this work, the design and off-design analysis of a Tesla turbine for small/micro power application utilizing CO2 cycles is proposed. The optimized design was targeted for an inlet temperature of 150 °C and an inlet pressure of 220 bar. The final optimized geometry of the expander was defined, achieving a 23.4 W per channel power output with a 63% isentropic efficiency, when working with a 10.1 bar pressure drop at 2000 rpm. Furthermore, the turbine placement on the Baljè diagram was performed in order to understand the direct competitors of this machine. Finally, starting from the design configuration, the maps of efficiency at variable load and flow coefficients and that of reduced mass flowrate at variable pressure ratio were realized. Through the merging of these curves, the off-design maps of the Tesla turbine were obtained, highlighting a very limited sensitivity of the efficiency to variable working conditions, if rotational speed is adequately adjusted.
Daniele Fiaschi; Lorenzo Talluri. Design and off-design analysis of a Tesla Turbine utilizing CO2 as working fluid. E3S Web of Conferences 2019, 113, 03008 .
AMA StyleDaniele Fiaschi, Lorenzo Talluri. Design and off-design analysis of a Tesla Turbine utilizing CO2 as working fluid. E3S Web of Conferences. 2019; 113 ():03008.
Chicago/Turabian StyleDaniele Fiaschi; Lorenzo Talluri. 2019. "Design and off-design analysis of a Tesla Turbine utilizing CO2 as working fluid." E3S Web of Conferences 113, no. : 03008.
Even though textile industry is not considered an energy intensive sector, it comprises a large number of plants consuming and wasting a significant amount of energy that could be, at least partially, conveniently recovered. The objective of this work is to assess the possibilities and convenience of energy recovery from waste heat of different processes of a dry industrial textile laundry. The various thermal wastes from the processes were identified and characterised, in order to estimate their potential recovery and conversion into electricity. A suitable system layout was conceived, in order to exploit the heat deriving from thermal waste of different machinery in the factory, having distinct temperature levels, to an ORC powerplant, which converts the recovered heat into electricity. The ORC cycle was optimized to maximize the thermoelectric efficiency, comparing different possible working fluids. The best fluid was RC318, from which 92.5 kW power output was achieved, at 9.2% efficiency. The economic analysis revealed, conservatively, a payback period of 7 years for the whole system, which is potentially very interesting. The amount of electricity produced by the waste heat recovery equipment is well matched to the company's electrical needs, resulting in a significant reduction of electricity consumption, greatly reducing the electrical withdrawal from the grid and the related costs. The case study, the proposed solutions and the methodology have general aspects and may be extended to a wide range of cases in the sector of industrial textile laundry.
Daniele Fiaschi; Lorenzo Talluri. Assessment of the thermoelectric conversion potential of low-temperature waste heat from textile dry-cleaning processes. E3S Web of Conferences 2019, 113, 03019 .
AMA StyleDaniele Fiaschi, Lorenzo Talluri. Assessment of the thermoelectric conversion potential of low-temperature waste heat from textile dry-cleaning processes. E3S Web of Conferences. 2019; 113 ():03019.
Chicago/Turabian StyleDaniele Fiaschi; Lorenzo Talluri. 2019. "Assessment of the thermoelectric conversion potential of low-temperature waste heat from textile dry-cleaning processes." E3S Web of Conferences 113, no. : 03019.
The proposed Thermo-Electric Energy Storage (TEES) system addresses the need for peak-load support (1–2 daily hours of operation) for small-distributed users who are often owners of small/medium size PV systems (4 to 50 kWe) and wish to introduce a reliable storage system able to compensate the productivity/load mismatch. The proposed thermoelectric system relies on sensible heat storage: a warm resource at 120/160 °C (a hot water reservoir system), and a cold resource at −10 /−20 °C (a cold reservoir system containing water and ethylene glycol). The power cycle operates through a trans-critical CO2 scheme including recuperation; in the storage mode, a supercritical heat pump restores heat to the hot reservoir, while a cooling cycle (using a suitable refrigerant) cools the cold reservoir. The power cycle and the heat pump benefit from geothermal heat integration at low-medium temperatures (80–120 °C), thereby allowing to achieve a marginal round-trip efficiency (electric-to-electric) in the range from 50 to 75% (not considering geothermal heat integration). The three systems are analyzed with different resource conditions and parameters setting (hot storage temperature, pressure levels for all cycles, ambient temperature…); exergy and exergo-economic analyses are performed to evaluate the economic competitiveness and in order to identify the critical items in the system. A sensitivity analysis on the main parameters affecting the produced power cost of the system per unit electric energy is carried out.
Lorenzo Talluri; Giampaolo Manfrida; Daniele Fiaschi. Thermoelectric energy storage with geothermal heat integration – Exergy and exergo-economic analysis. Energy Conversion and Management 2019, 199, 111883 .
AMA StyleLorenzo Talluri, Giampaolo Manfrida, Daniele Fiaschi. Thermoelectric energy storage with geothermal heat integration – Exergy and exergo-economic analysis. Energy Conversion and Management. 2019; 199 ():111883.
Chicago/Turabian StyleLorenzo Talluri; Giampaolo Manfrida; Daniele Fiaschi. 2019. "Thermoelectric energy storage with geothermal heat integration – Exergy and exergo-economic analysis." Energy Conversion and Management 199, no. : 111883.
The power production from the conversion of heat at low and medium temperature is a viable way to recover energy from several industrial and utility processes. In this context, small-medium expanders for Organic Rankine Cycles and two-phase expanders for energy recovery in heat pumps are gathering an increasing attention. The design and setup of flexible test benches to carry out experimental investigations on these devices has a primary importance to their performance optimization. In this study, a test rig based on a hot gas bypass cycle to test expanders for superheated and two-phase organic fluids is proposed. This configuration leads to numerous advantages like compact design, high flexibility and a fast transition to stable steady conditions. After an experimental campaign to assess the correct response of the test bench in design condition, a numerical model was developed to study the behavior of the cycle. The management of the test rig, both with and without the expanders, for performing the tests at different operating conditions was analyzed, with particular focus on the required setting of valves and compressor. The analysis allowed the determination of the operating limits of the rig, and showed the impact of using different fluids in the same test rig at several operating conditions. The working range of the test bench is related to the condenser power (designed for 25 kW and 30 bar maximum pressure) and the ambient temperature. With R404A, in the 17–30 bars condenser pressure range, superheated and saturated vapor expanders may be tested at different values of cycle minimum pressure (between 3.7–7.2 bar and 3.6–6.4 bar respectively). With R410A the working range is narrower, with the possibility of testing 2 phase expanders between 6.4 and 8.7 bars of cycle minimum pressure in the 21–23 bars interval of condenser pressure and superheated vapor expanders between 5.7 and 7.2 bars of cycle minimum pressure in the 23–30 bars interval of condenser pressure.
Giovanni Galoppi; Lorenzo Ferrari; Giovanni Ferrara; Daniele Fiaschi. Development and characterization of a compact rig to test expanders for superheated and saturated organic fluids. Energy Conversion and Management 2019, 188, 262 -275.
AMA StyleGiovanni Galoppi, Lorenzo Ferrari, Giovanni Ferrara, Daniele Fiaschi. Development and characterization of a compact rig to test expanders for superheated and saturated organic fluids. Energy Conversion and Management. 2019; 188 ():262-275.
Chicago/Turabian StyleGiovanni Galoppi; Lorenzo Ferrari; Giovanni Ferrara; Daniele Fiaschi. 2019. "Development and characterization of a compact rig to test expanders for superheated and saturated organic fluids." Energy Conversion and Management 188, no. : 262-275.
A Thermo-Electric Energy Storage (TEES) system is proposed to provide peak-load support (1–2 daily hours of operation) for distributed users using small/medium-size photovoltaic systems (4 to 50 kWe). The purpose is to complement the PV with a reliable storage system that cancompensate the produc tivity/load mismatch, aiming at off-grid operation. The proposed TEES applies sensible heat storage, using insulated warm-water reservoirs at 120/160 °C, and cold storage at −10/−20 °C (water and ethylene glycol). The power cycle is a trans-critical CO2 unit including recuperation; in the storage mode, a supercritical heat pump restores heat to the hot reservoir, while a cooling cycle cools the cold reservoir; both the heat pump and cooling cycle operate on photovoltaic (PV) energy, and benefit from solar heat integration at low–medium temperatures (80–120 °C). This allows the achievement of a marginal round-trip efficiency (electric-to-electric) in the range of 50% (not considering solar heat integration).The TEES system is analysed with different resource conditions and parameters settings (hot storage temperature, pressure levels for all cycles, ambient temperature, etc.), making reference to standard days of each month of the year; exergy and exergo-economic analyses are performed to identify the critical items in the complete system and the cost of stored electricity.
Daniele Fiaschi; Giampaolo Manfrida; Karolina Petela; Lorenzo Talluri. Thermo-Electric Energy Storage with Solar Heat Integration: Exergy and Exergo-Economic Analysis. Energies 2019, 12, 648 .
AMA StyleDaniele Fiaschi, Giampaolo Manfrida, Karolina Petela, Lorenzo Talluri. Thermo-Electric Energy Storage with Solar Heat Integration: Exergy and Exergo-Economic Analysis. Energies. 2019; 12 (4):648.
Chicago/Turabian StyleDaniele Fiaschi; Giampaolo Manfrida; Karolina Petela; Lorenzo Talluri. 2019. "Thermo-Electric Energy Storage with Solar Heat Integration: Exergy and Exergo-Economic Analysis." Energies 12, no. 4: 648.
Tesla expander is a bladeless turbine suited to low power range applications. In this article, a comparison between the performance prediction, as well as the assessment of the main flow characteristics, of a Tesla turbine working with organic fluids obtained through an in-house 2D code developed in EES environment and a simulation run with a computational fluid dynamics commercial software was done. Three working fluids (R404a, R134a and R245fa) were analysed in order to determine the related performance parameters. Various computations were carried out at several speeds of revolution, both with the laminar model and the Langtry-Menter transitional shear stress transport model for turbulence processing. High rotor efficiency was predicted for a small-scale prototype working with all analysed fluids (69% at 3000 rpm). The results obtained by the CFD simulations and by the in-house code showed an excellent matching. Finally, absolute and relative flow path lines were computed in order to determine fluid dynamics inside the channel and to analyse the fundamental flow phenomena.
L. Ciappi; D. Fiaschi; P.H. Niknam; L. Talluri. Computational investigation of the flow inside a Tesla turbine rotor. Energy 2019, 173, 207 -217.
AMA StyleL. Ciappi, D. Fiaschi, P.H. Niknam, L. Talluri. Computational investigation of the flow inside a Tesla turbine rotor. Energy. 2019; 173 ():207-217.
Chicago/Turabian StyleL. Ciappi; D. Fiaschi; P.H. Niknam; L. Talluri. 2019. "Computational investigation of the flow inside a Tesla turbine rotor." Energy 173, no. : 207-217.