The Experts below are selected from a list of 198 Experts worldwide ranked by ideXlab platform
Jayanta S. Kapat - One of the best experts on this subject based on the ideXlab platform.
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Transient Thermodynamic Modeling of Air Cooler in Supercritical CO2 Brayton Cycle for Solar Molten Salt Application
Journal of Energy Resources Technology-transactions of The Asme, 2020Co-Authors: Ankur Deshmukh, Jayanta S. Kapat, Akshay KhadseAbstract:Abstract Supercritical carbon dioxide Brayton power cycle is getting commercially attractive for power generation due to numerous advantages like zero water usage, compactness, low environmental emission, and potential to reach high thermal efficiency at lower costs. A typical recuperated closed cycle consists of three Heat Exchangers (Main Heat Exchanger, cooler, and recuperator) and two turbomachinery (turbine and compressor). Rapid changes in ambient temperature, operating loads, start-ups, and shutdowns affect the performance and operation of the turbomachinery and Heat Exchangers. The purpose of this research article is to study the thermodynamic parameters of the air cooler during transient operations by running dynamic simulations. Magnitude of change in carbon dioxide temperature due to change in air temperature is calculated. The simulation is a setup by having a steady-state design of 100 MWe cycle with operating temperature of 700 °C and pressure of 250 bar. Dynamic simulations are done using lms amesim. Transients studied in this article include: (i) step variation, (ii) standard variation, and (iii) linear variation of air temperature. This study thus serves as a framework to develop a design and control basis governed by transient scenarios.
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Pinch Point Analysis of Air Cooler in Supercritical Carbon Dioxide Brayton Cycle Operating Over Ambient Temperature Range
Journal of Energy Resources Technology-transactions of The Asme, 2020Co-Authors: Ankur Deshmukh, Jayanta S. KapatAbstract:Abstract Supercritical Carbon Dioxide Brayton Power Cycle is getting commercially attractive for power generation due to its numerous advantages like zero water discharge, compactness, low environmental emission and potential to reach high thermal efficiency. A typical recuperated closed cycle consists of three Heat Exchangers (Main Heat Exchanger, cooler and recuperator) and two turbomachinery (turbine and compressor). The cooler using ambient air for cooling is the focus of this study. Steady state air cooler model is set up to study the effect of air cooler size on cycle efficiency. The effect of change in ambient air temperature on air cooler pinch point for different air cooler sizes is analyzed using transient air cooler model. The simulation is setup for design of approximately 100MWe cycle with operating temperature of 700°C and pressure of 250 bara. Transient calculations are done using LMS AMESim. LMS AMESim is Siemens PLM commercially available software. This work thus serves as a framework to develop a basis for design of air cooler in the power cycle as a function of transient operating conditions.
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Pinch Point Analysis of Air Cooler in sCO2 Brayton Cycle Operating Over Ambient Temperature Range
ASME 2019 Heat Transfer Summer Conference, 2019Co-Authors: Ankur Deshmukh, Jayanta S. KapatAbstract:Abstract Supercritical CO2 Brayton Power cycle is getting commercially attractive for power generation due to its numerous advantages like zero water discharge, compactness, low environmental emission and potential to reach high thermal efficiency. A typical recuperated sCO2 closed cycle consists of three Heat Exchangers (Main Heat Exchanger, cooler and recuperator) and two turbomachinery (sCO2 turbine and sCO2 compressor). The cooler using ambient air for cooling is the focus of this study. Steady state air cooler model is set up to study the effect of air cooler size on cycle efficiency. The effect of change in ambient air temperature on air cooler pinch point for different air cooler sizes is analyzed using transient air cooler model. The simulation is setup for design of approximately 100MWe sCO2 cycle with operating temperature of 700° C and pressure of 250 barA. Transient calculations are done using LMS AMESim. LMS AMESim is Siemens PLM commercially available software. This work thus serves as a framework to develop a design basis for air cooler in sCO2 cycle as a function of transient operating conditions.
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Transient Thermodynamic Modeling of Air Cooler in Supercritical CO2 Brayton Cycle for Solar Molten Salt Application
Volume 9: Oil and Gas Applications; Supercritical CO2 Power Cycles; Wind Energy, 2019Co-Authors: Ankur Deshmukh, Jayanta S. Kapat, Akshay KhadseAbstract:Abstract Supercritical CO2 Brayton power cycle is getting commercially attractive for power generation due to its numerous advantages like zero water discharge, compactness, low environmental emission and potential to reach high thermal efficiency at lower costs. A typical recuperated sCO2 closed cycle consists of three Heat Exchangers (Main Heat Exchanger, cooler and recuperator) and two turbomachinery (sCO2 turbine and sCO2 compressor). The cooler which can use air or water as Heat sink is the focus of this study. The purpose of the paper is investigation of behavior of thermodynamic parameters of cooler during transient operations. In this study, dynamic simulation is performed to analyze the transient behavior of air cooler in sCO2 cycle using molten salt as Heat source from solar energy. Transient study is critical to understand the thermodynamic behavior of each system with time. Rapid changes in ambient temperature, operating loads, start-ups and shutdowns affect the performance of the turbomachinery and Heat Exchangers. The change in the thermal performance of air cooler with the change in boundary conditions is demonstrated here. The simulation is setup by having a steady state design of 100MWe sCO2 cycle with operating temperature of 700°C and pressure of 250 barA. Dynamic calculations are done using LMS AMESim. Transients studied in this paper include (i) step variation (ii) standard variation (iii) linear variation of air temperature. This work thus serves as a framework to develop a design basis for sCO2 cycle components as a function of transient operating conditions.
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Thermal Analysis and Pressure Loss Modeling for an Optimized Heat Exchanger Used in a Recuperated CO2 Power Cycle
Volume 9: Oil and Gas Applications; Supercritical CO2 Power Cycles; Wind Energy, 2018Co-Authors: Husam Zawati, Jayanta S. Kapat, Michael Elmore, Narasimha NagaiahAbstract:A simple recuperated cycle is studied and optimized in this paper. Geometrical parameters for a novel recuperator design are then optimized to minimize area density. The recuperator is where the s-CO2 is analyzed and simulated for both hot and cold sides. The design of the cycle is obtained through a study of a 100 MW net power output s-CO2 cycle, where this cycle features a turbine inlet temperature of 1023 K. The Main objective of this paper is to couple a recuperated cycle with a Heat Exchanger. This is done through Pareto optimality to study the tradeoffs between conflicting variables. The geometry of the Heat Exchanger features two inlet headers attached to semirectangular channels. The thermal analysis used is based on one-dimensional finite enthalpy method, where discretization is made by equal Heat transferred per element. In addition, pressure drops are calculated at both sides of Main Heat Exchanger body. Optimized cycle based on practical parametric assumptions reveals an efficiency of 45.8% and specific power of 132.1 kJ/kg. Best design reveals channel side length of 7 mm with surrounding solid sidewall thickness of 1 mm. Pressure drops for the proposed design are 4.8% and 0.6% of the initial pressure for the hot and the cold sides, respectively. Overall length of the Heat Exchanger is found to be 10.7 m with an effectiveness of 96.2% and an area density of 363 m2/m3.
Ankur Deshmukh - One of the best experts on this subject based on the ideXlab platform.
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Transient Thermodynamic Modeling of Air Cooler in Supercritical CO2 Brayton Cycle for Solar Molten Salt Application
Journal of Energy Resources Technology-transactions of The Asme, 2020Co-Authors: Ankur Deshmukh, Jayanta S. Kapat, Akshay KhadseAbstract:Abstract Supercritical carbon dioxide Brayton power cycle is getting commercially attractive for power generation due to numerous advantages like zero water usage, compactness, low environmental emission, and potential to reach high thermal efficiency at lower costs. A typical recuperated closed cycle consists of three Heat Exchangers (Main Heat Exchanger, cooler, and recuperator) and two turbomachinery (turbine and compressor). Rapid changes in ambient temperature, operating loads, start-ups, and shutdowns affect the performance and operation of the turbomachinery and Heat Exchangers. The purpose of this research article is to study the thermodynamic parameters of the air cooler during transient operations by running dynamic simulations. Magnitude of change in carbon dioxide temperature due to change in air temperature is calculated. The simulation is a setup by having a steady-state design of 100 MWe cycle with operating temperature of 700 °C and pressure of 250 bar. Dynamic simulations are done using lms amesim. Transients studied in this article include: (i) step variation, (ii) standard variation, and (iii) linear variation of air temperature. This study thus serves as a framework to develop a design and control basis governed by transient scenarios.
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Pinch Point Analysis of Air Cooler in Supercritical Carbon Dioxide Brayton Cycle Operating Over Ambient Temperature Range
Journal of Energy Resources Technology-transactions of The Asme, 2020Co-Authors: Ankur Deshmukh, Jayanta S. KapatAbstract:Abstract Supercritical Carbon Dioxide Brayton Power Cycle is getting commercially attractive for power generation due to its numerous advantages like zero water discharge, compactness, low environmental emission and potential to reach high thermal efficiency. A typical recuperated closed cycle consists of three Heat Exchangers (Main Heat Exchanger, cooler and recuperator) and two turbomachinery (turbine and compressor). The cooler using ambient air for cooling is the focus of this study. Steady state air cooler model is set up to study the effect of air cooler size on cycle efficiency. The effect of change in ambient air temperature on air cooler pinch point for different air cooler sizes is analyzed using transient air cooler model. The simulation is setup for design of approximately 100MWe cycle with operating temperature of 700°C and pressure of 250 bara. Transient calculations are done using LMS AMESim. LMS AMESim is Siemens PLM commercially available software. This work thus serves as a framework to develop a basis for design of air cooler in the power cycle as a function of transient operating conditions.
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Pinch Point Analysis of Air Cooler in sCO2 Brayton Cycle Operating Over Ambient Temperature Range
ASME 2019 Heat Transfer Summer Conference, 2019Co-Authors: Ankur Deshmukh, Jayanta S. KapatAbstract:Abstract Supercritical CO2 Brayton Power cycle is getting commercially attractive for power generation due to its numerous advantages like zero water discharge, compactness, low environmental emission and potential to reach high thermal efficiency. A typical recuperated sCO2 closed cycle consists of three Heat Exchangers (Main Heat Exchanger, cooler and recuperator) and two turbomachinery (sCO2 turbine and sCO2 compressor). The cooler using ambient air for cooling is the focus of this study. Steady state air cooler model is set up to study the effect of air cooler size on cycle efficiency. The effect of change in ambient air temperature on air cooler pinch point for different air cooler sizes is analyzed using transient air cooler model. The simulation is setup for design of approximately 100MWe sCO2 cycle with operating temperature of 700° C and pressure of 250 barA. Transient calculations are done using LMS AMESim. LMS AMESim is Siemens PLM commercially available software. This work thus serves as a framework to develop a design basis for air cooler in sCO2 cycle as a function of transient operating conditions.
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Transient Thermodynamic Modeling of Air Cooler in Supercritical CO2 Brayton Cycle for Solar Molten Salt Application
Volume 9: Oil and Gas Applications; Supercritical CO2 Power Cycles; Wind Energy, 2019Co-Authors: Ankur Deshmukh, Jayanta S. Kapat, Akshay KhadseAbstract:Abstract Supercritical CO2 Brayton power cycle is getting commercially attractive for power generation due to its numerous advantages like zero water discharge, compactness, low environmental emission and potential to reach high thermal efficiency at lower costs. A typical recuperated sCO2 closed cycle consists of three Heat Exchangers (Main Heat Exchanger, cooler and recuperator) and two turbomachinery (sCO2 turbine and sCO2 compressor). The cooler which can use air or water as Heat sink is the focus of this study. The purpose of the paper is investigation of behavior of thermodynamic parameters of cooler during transient operations. In this study, dynamic simulation is performed to analyze the transient behavior of air cooler in sCO2 cycle using molten salt as Heat source from solar energy. Transient study is critical to understand the thermodynamic behavior of each system with time. Rapid changes in ambient temperature, operating loads, start-ups and shutdowns affect the performance of the turbomachinery and Heat Exchangers. The change in the thermal performance of air cooler with the change in boundary conditions is demonstrated here. The simulation is setup by having a steady state design of 100MWe sCO2 cycle with operating temperature of 700°C and pressure of 250 barA. Dynamic calculations are done using LMS AMESim. Transients studied in this paper include (i) step variation (ii) standard variation (iii) linear variation of air temperature. This work thus serves as a framework to develop a design basis for sCO2 cycle components as a function of transient operating conditions.
Akshay Khadse - One of the best experts on this subject based on the ideXlab platform.
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Transient Thermodynamic Modeling of Air Cooler in Supercritical CO2 Brayton Cycle for Solar Molten Salt Application
Journal of Energy Resources Technology-transactions of The Asme, 2020Co-Authors: Ankur Deshmukh, Jayanta S. Kapat, Akshay KhadseAbstract:Abstract Supercritical carbon dioxide Brayton power cycle is getting commercially attractive for power generation due to numerous advantages like zero water usage, compactness, low environmental emission, and potential to reach high thermal efficiency at lower costs. A typical recuperated closed cycle consists of three Heat Exchangers (Main Heat Exchanger, cooler, and recuperator) and two turbomachinery (turbine and compressor). Rapid changes in ambient temperature, operating loads, start-ups, and shutdowns affect the performance and operation of the turbomachinery and Heat Exchangers. The purpose of this research article is to study the thermodynamic parameters of the air cooler during transient operations by running dynamic simulations. Magnitude of change in carbon dioxide temperature due to change in air temperature is calculated. The simulation is a setup by having a steady-state design of 100 MWe cycle with operating temperature of 700 °C and pressure of 250 bar. Dynamic simulations are done using lms amesim. Transients studied in this article include: (i) step variation, (ii) standard variation, and (iii) linear variation of air temperature. This study thus serves as a framework to develop a design and control basis governed by transient scenarios.
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Transient Thermodynamic Modeling of Air Cooler in Supercritical CO2 Brayton Cycle for Solar Molten Salt Application
Volume 9: Oil and Gas Applications; Supercritical CO2 Power Cycles; Wind Energy, 2019Co-Authors: Ankur Deshmukh, Jayanta S. Kapat, Akshay KhadseAbstract:Abstract Supercritical CO2 Brayton power cycle is getting commercially attractive for power generation due to its numerous advantages like zero water discharge, compactness, low environmental emission and potential to reach high thermal efficiency at lower costs. A typical recuperated sCO2 closed cycle consists of three Heat Exchangers (Main Heat Exchanger, cooler and recuperator) and two turbomachinery (sCO2 turbine and sCO2 compressor). The cooler which can use air or water as Heat sink is the focus of this study. The purpose of the paper is investigation of behavior of thermodynamic parameters of cooler during transient operations. In this study, dynamic simulation is performed to analyze the transient behavior of air cooler in sCO2 cycle using molten salt as Heat source from solar energy. Transient study is critical to understand the thermodynamic behavior of each system with time. Rapid changes in ambient temperature, operating loads, start-ups and shutdowns affect the performance of the turbomachinery and Heat Exchangers. The change in the thermal performance of air cooler with the change in boundary conditions is demonstrated here. The simulation is setup by having a steady state design of 100MWe sCO2 cycle with operating temperature of 700°C and pressure of 250 barA. Dynamic calculations are done using LMS AMESim. Transients studied in this paper include (i) step variation (ii) standard variation (iii) linear variation of air temperature. This work thus serves as a framework to develop a design basis for sCO2 cycle components as a function of transient operating conditions.
Haibing Li - One of the best experts on this subject based on the ideXlab platform.
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an efficient pulse tube cryocooler for boil off gas reliquefaction in liquid natural gas tanks
Applied Energy, 2016Co-Authors: J.y. Hu, Ercang Luo, Weiwei Dai, Jianguo Zhu, L.m. Zhang, Shiyi Chen, Haibing LiAbstract:Small liquid natural gas (LNG) distribution stations require compact, highly efficient cryocoolers to reliquefy boil-off gas in the LNG tank. This paper describes a pulse tube cryocooler measuring 420mm×690mm×780mm and weighing 180kg. With low input electric power, the relative Carnot efficiency exceeded 20%. Increasing the power to 10kW, the cryocooler produced approximately 1.2kW of cooling at 120K. Approximately 295 normal cubic meters of boil-off natural gas per day can be condensed. If Heat transfer in the Main Heat Exchanger is improved, cooling power and efficiency could be further improved. This development offers an efficient, compact, and reliable configuration for energy saving in LNG distribution stations.
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An Efficient Pulse Tube Cryocooler for BOG Recondensation in LNG Tanks
Energy Procedia, 2015Co-Authors: Jianying Hu, Shiyi Chen, Haibing LiAbstract:Abstract Small liquid natural gas (LNG) distribution stations require compact, highly efficient cryocoolers to condense boil-off gas in the LNG tank. This paper reports a pulse tube cryocooler measuring 420*690*780 mm and weighing 180 kg. Using low input electric power, the relative Carnot efficiency was greater than 20%. Increasing the power to 11 kW, the cryocooler produced approximately 1.2 kW of cooling at 120 K. Approximately 293 normal cubic meters of boil-off NG per day can be condensed. If Heat transfer in the Main Heat Exchanger was improved, cooling power and efficiency could be improved. It presents a new efficient, compact and reliable configuration for the energy saving in LNG distribution stations.
Harald Klein - One of the best experts on this subject based on the ideXlab platform.
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Design of a test rig for the simulation of startup procedures in Main Heat Exchangers of air separation plants
Chemical Engineering Research & Design, 2019Co-Authors: Patrick Haider, Pascal Freko, Stefan Lochner, Thomas Reiter, Sebastian Rehfeldt, Harald KleinAbstract:Abstract Within the Kopernikus project “SynErgie”, the sub-project “FlexASU” investigates an enhancement of the load flexibility of air separation units with the goal of synchronizing their power consumption with the availability of renewable energy sources. The Main Heat Exchanger of these plants was identified as a key component for a dynamic plant operation, because startup, shutdown and load-change procedures can lead to thermal stress and an increased lifetime consumption of the apparatus. Aluminum-brazed plate-fin Heat Exchangers (PFHE) are used in these plants because of their high process integration, low production cost and compact design. The Main focus of this work, which is an extended version of Haider et al. (2018a) , is the transient behavior of PFHE. The temperature profiles within a PFHE can be calculated, and a FEM-based model is available for investigation of the thermal stress induced by dynamic temperature changes in the apparatus. Hence, the reduction in lifetime due to certain dynamic plant operating scenarios can be estimated, and critical operating modes can be identified. For the further development of the model, a PFHE test rig is designed which is representative of extreme operating conditions in air separation units. A test scenario matching the conditions of plant startup after extended downtime in a cold state has been designed. The scenario leads to thermal stress that is expected to damage the PFHE within a few weeks of testing. The location of maximum stress in the FEM-model matches typical cracks observed in PFHE which have been exposed to severe thermal stress.
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Design of a test rig for the simulation of startup procedures in Main Heat Exchangers of air separation plants
Chemical engineering transactions, 2018Co-Authors: Patrick Haider, Pascal Freko, Stefan Lochner, Thomas Reiter, Sebastian Rehfeldt, Harald KleinAbstract:The Kopernikus project “FlexASU” investigates an enhancement of the load flexibility of air separation units with the goal to synchronize their power consumption with the availability of renewable energy sources. The Main Heat Exchanger of these plants was identified as a key component for a dynamic plant operation because startup, shutdown and load change procedures can lead to thermal stress and an increased lifetime consumption of the apparatus. Aluminium brazed plate fin Heat Exchangers (PFHE) are used in these plants because of their high process integration, low production cost and compact design. Finding the optimum operating scheme for the rectification columns depends on detailed knowledge of their effect on the lifetime of the PFHE.The transient behavior of temperature profiles within a PFHE can be calculated and a FEM-based model is available to investigate the thermal stress induced by dynamic temperature changes in the apparatus. Hence, the reduction of lifetime due to certain dynamic plant operating scenarios can be estimated and critical operating modes can be identified. For further development of the model, a PFHE test rig is designed which is representative for extreme operating conditions in air separation units. A test scenario matching the conditions of plant startup after extended downtime in cold condition has been designed. To reach a level of thermal stress comparable to industrial sized plants, the PFHE weighing around 1.5 tons is Heated up to 50 °C before rapidly being cooled down by a stream of gaseous nitrogen at -173 °C in a cyclic operation scheme. This test scenario leads to thermal stress that is expected to damage the PFHE within a few weeks of testing and the location of maximum thermal stress in the FEM model matches typical cracks observed in PFHE of air separation units. The test rig is designed to gain a clearer understanding of the underlying damage mechanism and to evaluate measures for lowering thermal stress in further test series. The knowledge gained from the experimental investigations is crucial for maximizing the operation flexibility of an ASU plant.
