The Experts below are selected from a list of 165 Experts worldwide ranked by ideXlab platform
Amir Akbarzadeh - One of the best experts on this subject based on the ideXlab platform.
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experimental investigation of nozzle geometry effect on two phase nozzle performance through Trilateral Flash Cycle
Thermal science and engineering, 2020Co-Authors: Mahdi Ahmadi, Abhijit Date, Arbab Iqbal, Ahmadreza Faghih Khorasani, Amir AkbarzadehAbstract:Abstract This paper aims to elucidate the effect of the divergent geometry of a nozzle on its performance by experimentally estimating the force generated by high speed two-phase fluid leaving the nozzle exit. The experiments are carried out by using the nozzles with two diverging profiles of conical and bell and various divergent angles of 6°, 18° and 30° corresponding to the divergent lengths of 45 mm, 17 mm and 12 mm respectively. The nozzles are examined at inlet temperatures of 50 °C and 60 °C for Isopentane as working fluid. The experimental results are indicative of higher values for thrust force and consequently isentropic efficiency by increasing the inlet temperature from 50 °C to 60 °C for all examined nozzles. It is found through the experiments that the maximum efficiency is about 41% with inlet temperature of 60 °C for the bell shape nozzle with the corresponding divergent angle of 6°. Whereas, the 30° conical and bell nozzles have the least force and efficiency. The pressure measurements along the 6° conical and bell nozzles are indicative of a greater pressure drop after the nozzle throat for bell shape nozzle compared to conical nozzle. This paper presents empirical results that can be used in designing efficient nozzles.
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Experimental performance investigation and case study of combined desalination and power generation
2020Co-Authors: Abhijit Date, Amir Akbarzadeh, Ahmadi, Sayantan Ganguly, M KumarAbstract:This paper presents experimental performance data of a total flow combined desalination and power generation system. A twophase flow simple reaction turbine has been used in this system which operates on the Trilateral Flash Cycle. Hot saline water is used as the working fluid. The hot water supply temperature is varied from 80oC to 95oC, while the condenser is maintained at about 35oC to 45oC. This paper examines the concept of using the Trilateral Flash Cycle for combined desalination and power generation from saline water in the salt affected areas using geothermal energy. The basic working principle of the combined desalination and power generation system is presented followed by discussions of the governing equations and the thermodynamics of the proposed system. Experimental setup and the test results are briefly explained to give an idea of the performance of the proposed system in a laboratory scale. Later it is shown how a combined desalination and power generation system can be coupled with conventional solar water heaters to boost the fluid temperature when the geothermal resource is at low temperature. Following the introduction of this concept the preliminary design is presented for combined desalination and power generation plant that would use saline water from hot water springs in the western coast of India and provide drinking water for a small coastal village with 20 houses (i.e. approximately 80 people with drinking water need of around 3 L/day/person). Most of the hot water springs along the western coast of India have temperature of around 60oC and hence possibility of boosting the temperature using bio mass or solar thermal energy will also be explored. Attempts are also made to provide some information on the basic economics of such a system.
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Experimental investigation of nozzle geometry effect on two-phase nozzle performance through Trilateral Flash Cycle
Thermal science and engineering, 2020Co-Authors: Ahmadi, Arbab Iqbal, Abhijit Date, Ahmadreza Faghih Khorasani, Amir AkbarzadehAbstract:Abstract This paper aims to elucidate the effect of divergent geometry of nozzle on its performance by experimentally estimating the force generated by high speed two-phase fluid leaving the nozzle exit. The experiments are carried out by using the nozzles with two diverging profiles of conical and bell and various divergent angles of 6o, 18o and 30o corresponding to the divergent lengths of 45 mm, 17 mm and 12 mm respectively. The nozzles are examined at inlet temperatures of 50 °C and 60 °C for Isopentane as working fluid. The experimental results are indicative of higher values for thrust force and consequently isentropic efficiency by increasing the inlet temperature from 50 °C to 60 °C for all examined nozzles. It is found through the experiments that the maximum efficiency is about 41% with inlet temperature of 60 °C for the bell shape nozzle with the corresponding divergent angle of 6°. Whereas, the 30° conical and bell nozzles have the least force and efficiency. The pressure measurements along the 6° conical and bell nozzles are indicative of a greater pressure drop after the nozzle throat for bell shape nozzle compared to conical nozzle. This paper presents empirical results that can be used in designing efficient nozzles.
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experimental study on the prospect of low temperature heat to power generation using Trilateral Flash Cycle tfc
Applied Thermal Engineering, 2020Co-Authors: Arbab Iqbal, Abhijit Date, Mahdi Ahmadi, Sohel Rana, Amir AkbarzadehAbstract:Abstract In this paper, a Trilateral Flash Cycle (TFC) based system has been developed and studied to find out its prospect for utilizing more energy and enhancing the power generation capacity. To hold simplicity and minimize the cost of system construction, an impulse turbine and a converging-diverging (CD) stationary nozzle setup have been used as the expander. The experimental study introduced impulse turbine incorporates with a stationary CD nozzle and organic working fluid, which showed a promising power generation capability from a heat source below 80 °C in spite of the increasing size of the heat exchanger, condenser, and pump. In addition to the use of proper impulse turbines, however, the power generation capacity of such type of system is basically a function of the nozzle isentropic efficiency, which lies on the nozzle geometry and the alignment with respect to the turbine. A case study on the application of the TFC system for commercial power generation in associate with economic analysis has also been included in this study which shows a payback time less than 10 years with typical operational life of 20 years, considering only 40% nozzle isentropic efficiency and by using more efficient nozzle, the capital cost per unit power generation could be minimized.
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Trilateral Flash Cycle tfc a promising thermodynamic Cycle for low grade heat to power generation
Energy Procedia, 2019Co-Authors: Arbab Iqbal, Abhijit Date, Mahdi Ahmadi, Sohel Rana, Amir AkbarzadehAbstract:Abstract Energy crisis, fossil fuel depletion and growing environmental concern pushing not only for new source of energy but also developing advance technology for power generation. Besides conventional heat sources, low grade heat source of below 100 °C temperature like solar thermal, geothermal or waste heat has a good potential to become a sustainable source of power. Organic Rankine Cycle is the widely use thermodynamic power Cycle for low grade heat to power generation where low boiling point pressurised organic working fluid is vaporised and expands through a turbine fed generator thus outputting usable electrical energy. The used fluid then returns to a reservoir before it is condensed and forced through the same process again via a high-pressure pump. Another thermodynamic Cycle namely Trilateral Flash Cycle (TFC) which is nothing but a modified ORC where the organic working fluid is heated up to the saturation temperature under high pressure rather than evaporated. In this paper, an analytical comparative study on ORC and TFC shows that TFC has about at least 50% more power generation potential than that of conventional ORC for the same heat source and heat sink conditions if the heat source temperature is just below 100 °C. TFC even has the potential of power generation from the heat source below 80 °C where ORC is not economically viable.
Abhijit Date - One of the best experts on this subject based on the ideXlab platform.
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experimental investigation of nozzle geometry effect on two phase nozzle performance through Trilateral Flash Cycle
Thermal science and engineering, 2020Co-Authors: Mahdi Ahmadi, Abhijit Date, Arbab Iqbal, Ahmadreza Faghih Khorasani, Amir AkbarzadehAbstract:Abstract This paper aims to elucidate the effect of the divergent geometry of a nozzle on its performance by experimentally estimating the force generated by high speed two-phase fluid leaving the nozzle exit. The experiments are carried out by using the nozzles with two diverging profiles of conical and bell and various divergent angles of 6°, 18° and 30° corresponding to the divergent lengths of 45 mm, 17 mm and 12 mm respectively. The nozzles are examined at inlet temperatures of 50 °C and 60 °C for Isopentane as working fluid. The experimental results are indicative of higher values for thrust force and consequently isentropic efficiency by increasing the inlet temperature from 50 °C to 60 °C for all examined nozzles. It is found through the experiments that the maximum efficiency is about 41% with inlet temperature of 60 °C for the bell shape nozzle with the corresponding divergent angle of 6°. Whereas, the 30° conical and bell nozzles have the least force and efficiency. The pressure measurements along the 6° conical and bell nozzles are indicative of a greater pressure drop after the nozzle throat for bell shape nozzle compared to conical nozzle. This paper presents empirical results that can be used in designing efficient nozzles.
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Experimental performance investigation and case study of combined desalination and power generation
2020Co-Authors: Abhijit Date, Amir Akbarzadeh, Ahmadi, Sayantan Ganguly, M KumarAbstract:This paper presents experimental performance data of a total flow combined desalination and power generation system. A twophase flow simple reaction turbine has been used in this system which operates on the Trilateral Flash Cycle. Hot saline water is used as the working fluid. The hot water supply temperature is varied from 80oC to 95oC, while the condenser is maintained at about 35oC to 45oC. This paper examines the concept of using the Trilateral Flash Cycle for combined desalination and power generation from saline water in the salt affected areas using geothermal energy. The basic working principle of the combined desalination and power generation system is presented followed by discussions of the governing equations and the thermodynamics of the proposed system. Experimental setup and the test results are briefly explained to give an idea of the performance of the proposed system in a laboratory scale. Later it is shown how a combined desalination and power generation system can be coupled with conventional solar water heaters to boost the fluid temperature when the geothermal resource is at low temperature. Following the introduction of this concept the preliminary design is presented for combined desalination and power generation plant that would use saline water from hot water springs in the western coast of India and provide drinking water for a small coastal village with 20 houses (i.e. approximately 80 people with drinking water need of around 3 L/day/person). Most of the hot water springs along the western coast of India have temperature of around 60oC and hence possibility of boosting the temperature using bio mass or solar thermal energy will also be explored. Attempts are also made to provide some information on the basic economics of such a system.
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Experimental investigation of nozzle geometry effect on two-phase nozzle performance through Trilateral Flash Cycle
Thermal science and engineering, 2020Co-Authors: Ahmadi, Arbab Iqbal, Abhijit Date, Ahmadreza Faghih Khorasani, Amir AkbarzadehAbstract:Abstract This paper aims to elucidate the effect of divergent geometry of nozzle on its performance by experimentally estimating the force generated by high speed two-phase fluid leaving the nozzle exit. The experiments are carried out by using the nozzles with two diverging profiles of conical and bell and various divergent angles of 6o, 18o and 30o corresponding to the divergent lengths of 45 mm, 17 mm and 12 mm respectively. The nozzles are examined at inlet temperatures of 50 °C and 60 °C for Isopentane as working fluid. The experimental results are indicative of higher values for thrust force and consequently isentropic efficiency by increasing the inlet temperature from 50 °C to 60 °C for all examined nozzles. It is found through the experiments that the maximum efficiency is about 41% with inlet temperature of 60 °C for the bell shape nozzle with the corresponding divergent angle of 6°. Whereas, the 30° conical and bell nozzles have the least force and efficiency. The pressure measurements along the 6° conical and bell nozzles are indicative of a greater pressure drop after the nozzle throat for bell shape nozzle compared to conical nozzle. This paper presents empirical results that can be used in designing efficient nozzles.
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experimental study on the prospect of low temperature heat to power generation using Trilateral Flash Cycle tfc
Applied Thermal Engineering, 2020Co-Authors: Arbab Iqbal, Abhijit Date, Mahdi Ahmadi, Sohel Rana, Amir AkbarzadehAbstract:Abstract In this paper, a Trilateral Flash Cycle (TFC) based system has been developed and studied to find out its prospect for utilizing more energy and enhancing the power generation capacity. To hold simplicity and minimize the cost of system construction, an impulse turbine and a converging-diverging (CD) stationary nozzle setup have been used as the expander. The experimental study introduced impulse turbine incorporates with a stationary CD nozzle and organic working fluid, which showed a promising power generation capability from a heat source below 80 °C in spite of the increasing size of the heat exchanger, condenser, and pump. In addition to the use of proper impulse turbines, however, the power generation capacity of such type of system is basically a function of the nozzle isentropic efficiency, which lies on the nozzle geometry and the alignment with respect to the turbine. A case study on the application of the TFC system for commercial power generation in associate with economic analysis has also been included in this study which shows a payback time less than 10 years with typical operational life of 20 years, considering only 40% nozzle isentropic efficiency and by using more efficient nozzle, the capital cost per unit power generation could be minimized.
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Trilateral Flash Cycle tfc a promising thermodynamic Cycle for low grade heat to power generation
Energy Procedia, 2019Co-Authors: Arbab Iqbal, Abhijit Date, Mahdi Ahmadi, Sohel Rana, Amir AkbarzadehAbstract:Abstract Energy crisis, fossil fuel depletion and growing environmental concern pushing not only for new source of energy but also developing advance technology for power generation. Besides conventional heat sources, low grade heat source of below 100 °C temperature like solar thermal, geothermal or waste heat has a good potential to become a sustainable source of power. Organic Rankine Cycle is the widely use thermodynamic power Cycle for low grade heat to power generation where low boiling point pressurised organic working fluid is vaporised and expands through a turbine fed generator thus outputting usable electrical energy. The used fluid then returns to a reservoir before it is condensed and forced through the same process again via a high-pressure pump. Another thermodynamic Cycle namely Trilateral Flash Cycle (TFC) which is nothing but a modified ORC where the organic working fluid is heated up to the saturation temperature under high pressure rather than evaporated. In this paper, an analytical comparative study on ORC and TFC shows that TFC has about at least 50% more power generation potential than that of conventional ORC for the same heat source and heat sink conditions if the heat source temperature is just below 100 °C. TFC even has the potential of power generation from the heat source below 80 °C where ORC is not economically viable.
Jeremy Miller - One of the best experts on this subject based on the ideXlab platform.
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modelling and off design performance optimisation of a Trilateral Flash Cycle system using two phase twin screw expanders with variable built in volume ratio
Applied Thermal Engineering, 2020Co-Authors: Giuseppe Bianchi, Jeremy Miller, Matteo Marchionni, S A TassouAbstract:Abstract This research work presents a numerical chamber model of a two-phase twin-screw expander and its further integration in a one-dimensional model of a Trilateral Flash Cycle (TFC) system for low-grade heat to power conversion applications. The novel feature of the expander is the capability of changing the built-in volume ratio (BIVR) of the machine through a sliding valve in the casing that opens an additional suction port. Lowering the BIVR from 5.06 to 2.63 results in an improvement of the volumetric efficiency from 53% to 77% but also in a reduction of the specific indicated power from 4.77 kJ/kg to 3.56 kJ/kg. Parametric analysis on several degrees of freedom of the full TFC system concluded that expander speed and BIVR are the variables that mostly impact the net power output of the unit. An optimisation study enabled the net power output of the TFC system, at design point, to increase from 81 kW to 103 kW.
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one dimensional modelling of a Trilateral Flash Cycle system with two phase twin screw expanders for industrial low grade heat to power conversion
Designs, 2019Co-Authors: Giuseppe Bianchi, Stuart Kennedy, Jeremy Miller, Matteo Marchionni, S A TassouAbstract:This paper provides an overview of a one-dimensional modelling methodology for equipment and systems for heat to power conversion based on a staggered grid space discretization and implemented in the commercial software GT-SUITE®. Particular attention is given to a newly developed modelling procedure for twin-screw machines that is based on a chamber modelling approach and considers leakage paths between cells and with the casing. This methodology is then applied to a low-grade heat to power conversion system based on a Trilateral Flash Cycle (TFC) equipped with two parallel two-phase twin-screw expanders and a control valve upstream of the machines to adapt the fluid quality for an optimal expander operation. The standalone expander model is used to generate performance maps of the machine, which serve as inputs for the TFC system model. Parametric analyses are eventually carried out to assess the impact of several operating parameters of the TFC unit on the recovered power and Cycle thermal efficiency. The study shows that the most influencing factors on the TFC system’s performance are the inlet temperature of the heat source and the expander speed. While the first depends on the topping industrial process, the expander speed can be used to optimize and control the TFC system operation also in transient or off-design operating conditions.
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numerical investigations of a Trilateral Flash Cycle under system off design operating conditions
Energy Procedia, 2019Co-Authors: Matteo Marchionni, Giuseppe Bianchi, Obadah Zaher, S A Tassou, Jeremy MillerAbstract:Abstract The current research presents a comprehensive model of a 100 kWe Trilateral Flash Cycle TFC system composed of sub-modules for the plate heat exchangers and twin-screw expanders to assess and identify the operating parameters that mostly affect the TFC performance at off-design conditions. The modelling approach for heat exchangers and piping is based on 1D CFD while considering the operating maps for pump and expander. The simulation process takes into account variations of the heat source temperature and mass flow rate from the design point. The TFC performance is analysed in terms of efficiency and power output while the expander performance is discussed in terms of volumetric and isentropic efficiencies. A sensitivity analysis is carried out to assess the most suitable parameter for control purposes and system performance optimisation. The results point out a large sensitivity of the inlet quality at the expander due to the revolution speed of the machine but also the off-design behaviour of the heater.
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numerical modelling of a two phase twin screw expander for Trilateral Flash Cycle applications
International Journal of Refrigeration-revue Internationale Du Froid, 2018Co-Authors: Giuseppe Bianchi, Stuart Kennedy, Obadah Zaher, S A Tassou, Jeremy Miller, Hussam JouharaAbstract:Abstract This paper presents numerical investigations of a twin-screw expander for low grade (≤100 °C) heat to power conversion applications based on the bottoming Trilateral Flash Cycle. After a thorough description of the modeling procedure, a first set of simulations shows the effect of different inlet qualities of the R245fa working fluid and of the revolution speed on the expander performance. In particular, at 3750 RPM and an inlet absolute pressure of 5 bar, the volumetric and adiabatic efficiencies would increase from 24.8% and 37.6% to 61.2% and 83.1% if the inlet quality in the intake duct of the expander increased from 0 to 0.1. To further assess the effects of inlet quality, inlet pressure and revolution speed on the expander performance, parametric analyses are carried out in the ranges 0–1 inlet quality, 5–10 bar pressure and 1500–6000 RPM speed respectively.
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development and analysis of a packaged Trilateral Flash Cycle system for low grade heat to power conversion applications
Thermal science and engineering, 2017Co-Authors: Giuseppe Bianchi, Obadah Zaher, S A Tassou, Jeremy Miller, Rebecca Mcginty, David Oliver, Derek Brightman, Hussam JouharaAbstract:Abstract The current research tackles the energy trilemma of emissions reduction, security of supply and cost savings in industrial environments by presenting the development of a packaged, plug & play power unit for low-grade waste heat recovery applications. The heat to power conversion system is based on the Trilateral Flash Cycle (TFC), a bottoming thermodynamic Cycle particularly suitable for waste heat sources at temperatures below 100 °C which, on a European scale, account for 469 TWh in industry and are particularly concentrated in the chemical and petrochemical sectors. The industrial test case refers to a UK tire manufacturing company in which a 2 MW water stream at 85 °C involved in the rubber curing process was chosen as hot source of the TFC system while a pond was considered the heat sink. The design of the industrial scale power unit, which is presented at end of the manuscript, was carried out based on the outcomes of a theoretical modelling platform that allowed to investigate and optimize multiple design parameters using energy and exergy analyses. In particular, the model exploitation identified R1233zd(E) and R245fa as the most suitable pure working fluids for the current application, given the higher net power output and the lower ratio between pumping and expander powers. At nominal operating conditions, the designed TFC system is expected to recover 120 kWe and have an overall efficiency of 6%.
Giuseppe Bianchi - One of the best experts on this subject based on the ideXlab platform.
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modelling and off design performance optimisation of a Trilateral Flash Cycle system using two phase twin screw expanders with variable built in volume ratio
Applied Thermal Engineering, 2020Co-Authors: Giuseppe Bianchi, Jeremy Miller, Matteo Marchionni, S A TassouAbstract:Abstract This research work presents a numerical chamber model of a two-phase twin-screw expander and its further integration in a one-dimensional model of a Trilateral Flash Cycle (TFC) system for low-grade heat to power conversion applications. The novel feature of the expander is the capability of changing the built-in volume ratio (BIVR) of the machine through a sliding valve in the casing that opens an additional suction port. Lowering the BIVR from 5.06 to 2.63 results in an improvement of the volumetric efficiency from 53% to 77% but also in a reduction of the specific indicated power from 4.77 kJ/kg to 3.56 kJ/kg. Parametric analysis on several degrees of freedom of the full TFC system concluded that expander speed and BIVR are the variables that mostly impact the net power output of the unit. An optimisation study enabled the net power output of the TFC system, at design point, to increase from 81 kW to 103 kW.
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one dimensional modelling of a Trilateral Flash Cycle system with two phase twin screw expanders for industrial low grade heat to power conversion
Designs, 2019Co-Authors: Giuseppe Bianchi, Stuart Kennedy, Jeremy Miller, Matteo Marchionni, S A TassouAbstract:This paper provides an overview of a one-dimensional modelling methodology for equipment and systems for heat to power conversion based on a staggered grid space discretization and implemented in the commercial software GT-SUITE®. Particular attention is given to a newly developed modelling procedure for twin-screw machines that is based on a chamber modelling approach and considers leakage paths between cells and with the casing. This methodology is then applied to a low-grade heat to power conversion system based on a Trilateral Flash Cycle (TFC) equipped with two parallel two-phase twin-screw expanders and a control valve upstream of the machines to adapt the fluid quality for an optimal expander operation. The standalone expander model is used to generate performance maps of the machine, which serve as inputs for the TFC system model. Parametric analyses are eventually carried out to assess the impact of several operating parameters of the TFC unit on the recovered power and Cycle thermal efficiency. The study shows that the most influencing factors on the TFC system’s performance are the inlet temperature of the heat source and the expander speed. While the first depends on the topping industrial process, the expander speed can be used to optimize and control the TFC system operation also in transient or off-design operating conditions.
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numerical investigations of a Trilateral Flash Cycle under system off design operating conditions
Energy Procedia, 2019Co-Authors: Matteo Marchionni, Giuseppe Bianchi, Obadah Zaher, S A Tassou, Jeremy MillerAbstract:Abstract The current research presents a comprehensive model of a 100 kWe Trilateral Flash Cycle TFC system composed of sub-modules for the plate heat exchangers and twin-screw expanders to assess and identify the operating parameters that mostly affect the TFC performance at off-design conditions. The modelling approach for heat exchangers and piping is based on 1D CFD while considering the operating maps for pump and expander. The simulation process takes into account variations of the heat source temperature and mass flow rate from the design point. The TFC performance is analysed in terms of efficiency and power output while the expander performance is discussed in terms of volumetric and isentropic efficiencies. A sensitivity analysis is carried out to assess the most suitable parameter for control purposes and system performance optimisation. The results point out a large sensitivity of the inlet quality at the expander due to the revolution speed of the machine but also the off-design behaviour of the heater.
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numerical modelling of a two phase twin screw expander for Trilateral Flash Cycle applications
International Journal of Refrigeration-revue Internationale Du Froid, 2018Co-Authors: Giuseppe Bianchi, Stuart Kennedy, Obadah Zaher, S A Tassou, Jeremy Miller, Hussam JouharaAbstract:Abstract This paper presents numerical investigations of a twin-screw expander for low grade (≤100 °C) heat to power conversion applications based on the bottoming Trilateral Flash Cycle. After a thorough description of the modeling procedure, a first set of simulations shows the effect of different inlet qualities of the R245fa working fluid and of the revolution speed on the expander performance. In particular, at 3750 RPM and an inlet absolute pressure of 5 bar, the volumetric and adiabatic efficiencies would increase from 24.8% and 37.6% to 61.2% and 83.1% if the inlet quality in the intake duct of the expander increased from 0 to 0.1. To further assess the effects of inlet quality, inlet pressure and revolution speed on the expander performance, parametric analyses are carried out in the ranges 0–1 inlet quality, 5–10 bar pressure and 1500–6000 RPM speed respectively.
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development and analysis of a packaged Trilateral Flash Cycle system for low grade heat to power conversion applications
Thermal science and engineering, 2017Co-Authors: Giuseppe Bianchi, Obadah Zaher, S A Tassou, Jeremy Miller, Rebecca Mcginty, David Oliver, Derek Brightman, Hussam JouharaAbstract:Abstract The current research tackles the energy trilemma of emissions reduction, security of supply and cost savings in industrial environments by presenting the development of a packaged, plug & play power unit for low-grade waste heat recovery applications. The heat to power conversion system is based on the Trilateral Flash Cycle (TFC), a bottoming thermodynamic Cycle particularly suitable for waste heat sources at temperatures below 100 °C which, on a European scale, account for 469 TWh in industry and are particularly concentrated in the chemical and petrochemical sectors. The industrial test case refers to a UK tire manufacturing company in which a 2 MW water stream at 85 °C involved in the rubber curing process was chosen as hot source of the TFC system while a pond was considered the heat sink. The design of the industrial scale power unit, which is presented at end of the manuscript, was carried out based on the outcomes of a theoretical modelling platform that allowed to investigate and optimize multiple design parameters using energy and exergy analyses. In particular, the model exploitation identified R1233zd(E) and R245fa as the most suitable pure working fluids for the current application, given the higher net power output and the lower ratio between pumping and expander powers. At nominal operating conditions, the designed TFC system is expected to recover 120 kWe and have an overall efficiency of 6%.
S A Tassou - One of the best experts on this subject based on the ideXlab platform.
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modelling and off design performance optimisation of a Trilateral Flash Cycle system using two phase twin screw expanders with variable built in volume ratio
Applied Thermal Engineering, 2020Co-Authors: Giuseppe Bianchi, Jeremy Miller, Matteo Marchionni, S A TassouAbstract:Abstract This research work presents a numerical chamber model of a two-phase twin-screw expander and its further integration in a one-dimensional model of a Trilateral Flash Cycle (TFC) system for low-grade heat to power conversion applications. The novel feature of the expander is the capability of changing the built-in volume ratio (BIVR) of the machine through a sliding valve in the casing that opens an additional suction port. Lowering the BIVR from 5.06 to 2.63 results in an improvement of the volumetric efficiency from 53% to 77% but also in a reduction of the specific indicated power from 4.77 kJ/kg to 3.56 kJ/kg. Parametric analysis on several degrees of freedom of the full TFC system concluded that expander speed and BIVR are the variables that mostly impact the net power output of the unit. An optimisation study enabled the net power output of the TFC system, at design point, to increase from 81 kW to 103 kW.
-
one dimensional modelling of a Trilateral Flash Cycle system with two phase twin screw expanders for industrial low grade heat to power conversion
Designs, 2019Co-Authors: Giuseppe Bianchi, Stuart Kennedy, Jeremy Miller, Matteo Marchionni, S A TassouAbstract:This paper provides an overview of a one-dimensional modelling methodology for equipment and systems for heat to power conversion based on a staggered grid space discretization and implemented in the commercial software GT-SUITE®. Particular attention is given to a newly developed modelling procedure for twin-screw machines that is based on a chamber modelling approach and considers leakage paths between cells and with the casing. This methodology is then applied to a low-grade heat to power conversion system based on a Trilateral Flash Cycle (TFC) equipped with two parallel two-phase twin-screw expanders and a control valve upstream of the machines to adapt the fluid quality for an optimal expander operation. The standalone expander model is used to generate performance maps of the machine, which serve as inputs for the TFC system model. Parametric analyses are eventually carried out to assess the impact of several operating parameters of the TFC unit on the recovered power and Cycle thermal efficiency. The study shows that the most influencing factors on the TFC system’s performance are the inlet temperature of the heat source and the expander speed. While the first depends on the topping industrial process, the expander speed can be used to optimize and control the TFC system operation also in transient or off-design operating conditions.
-
numerical investigations of a Trilateral Flash Cycle under system off design operating conditions
Energy Procedia, 2019Co-Authors: Matteo Marchionni, Giuseppe Bianchi, Obadah Zaher, S A Tassou, Jeremy MillerAbstract:Abstract The current research presents a comprehensive model of a 100 kWe Trilateral Flash Cycle TFC system composed of sub-modules for the plate heat exchangers and twin-screw expanders to assess and identify the operating parameters that mostly affect the TFC performance at off-design conditions. The modelling approach for heat exchangers and piping is based on 1D CFD while considering the operating maps for pump and expander. The simulation process takes into account variations of the heat source temperature and mass flow rate from the design point. The TFC performance is analysed in terms of efficiency and power output while the expander performance is discussed in terms of volumetric and isentropic efficiencies. A sensitivity analysis is carried out to assess the most suitable parameter for control purposes and system performance optimisation. The results point out a large sensitivity of the inlet quality at the expander due to the revolution speed of the machine but also the off-design behaviour of the heater.
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numerical modelling of a two phase twin screw expander for Trilateral Flash Cycle applications
International Journal of Refrigeration-revue Internationale Du Froid, 2018Co-Authors: Giuseppe Bianchi, Stuart Kennedy, Obadah Zaher, S A Tassou, Jeremy Miller, Hussam JouharaAbstract:Abstract This paper presents numerical investigations of a twin-screw expander for low grade (≤100 °C) heat to power conversion applications based on the bottoming Trilateral Flash Cycle. After a thorough description of the modeling procedure, a first set of simulations shows the effect of different inlet qualities of the R245fa working fluid and of the revolution speed on the expander performance. In particular, at 3750 RPM and an inlet absolute pressure of 5 bar, the volumetric and adiabatic efficiencies would increase from 24.8% and 37.6% to 61.2% and 83.1% if the inlet quality in the intake duct of the expander increased from 0 to 0.1. To further assess the effects of inlet quality, inlet pressure and revolution speed on the expander performance, parametric analyses are carried out in the ranges 0–1 inlet quality, 5–10 bar pressure and 1500–6000 RPM speed respectively.
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development and analysis of a packaged Trilateral Flash Cycle system for low grade heat to power conversion applications
Thermal science and engineering, 2017Co-Authors: Giuseppe Bianchi, Obadah Zaher, S A Tassou, Jeremy Miller, Rebecca Mcginty, David Oliver, Derek Brightman, Hussam JouharaAbstract:Abstract The current research tackles the energy trilemma of emissions reduction, security of supply and cost savings in industrial environments by presenting the development of a packaged, plug & play power unit for low-grade waste heat recovery applications. The heat to power conversion system is based on the Trilateral Flash Cycle (TFC), a bottoming thermodynamic Cycle particularly suitable for waste heat sources at temperatures below 100 °C which, on a European scale, account for 469 TWh in industry and are particularly concentrated in the chemical and petrochemical sectors. The industrial test case refers to a UK tire manufacturing company in which a 2 MW water stream at 85 °C involved in the rubber curing process was chosen as hot source of the TFC system while a pond was considered the heat sink. The design of the industrial scale power unit, which is presented at end of the manuscript, was carried out based on the outcomes of a theoretical modelling platform that allowed to investigate and optimize multiple design parameters using energy and exergy analyses. In particular, the model exploitation identified R1233zd(E) and R245fa as the most suitable pure working fluids for the current application, given the higher net power output and the lower ratio between pumping and expander powers. At nominal operating conditions, the designed TFC system is expected to recover 120 kWe and have an overall efficiency of 6%.
