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Lingbao Wang - One of the best experts on this subject based on the ideXlab platform.
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thermoeconomic evaluation and optimization of libr h2o double absorption heat transformer driven by flat plate collector
Energy Conversion and Management, 2018Co-Authors: Lingbao Wang, Hanzhi WangAbstract:Abstract In this paper, a solar double absorption heat transformer (SDAHT) operating with the LiBr-H2O solution is proposed to provide high Temperature energy. The flat plate collector (FPC) is used to supply the demanded heat input in the present configuration, which will greatly broaden the application scope of the FPCs. The thermoeconomic concept is applied to the evaluation and optimization of the SDAHT, aimed at minimizing its annual capital cost per kilowatt heat capacity (CPK) and payback period (PP). A dedicated computer model in the software Engineering Equation Solver was developed to conduct the study by means of a parametric analysis. The results show that there exists an optimum absorber/Evaporator Temperature at which CPK and PP can obtain the minimum values. With solar radiation intensity at 600 W/m2, generation (evaporation) Temperature at 75 °C, condensation Temperature at 38 °C, absorption Temperature at 135 °C and economizer efficiency set to 0.8, the optimum absorber/Evaporator Temperature and corresponding CPK and PP are 104.0 °C, 928.1 euros/kW and 4.0 years, respectively. The cost of the FPCs takes the major part of CPK. Moreover, the effects of the operating parameters such as the generation (evaporation), condensation, absorption Temperatures and design parameters including the first and second economizer efficiencies on the optimum absorber/Evaporator Temperature and corresponding CPK and PP have been analyzed in detail. Besides, some suggestions derived from the results are also given to assist the engineers in estimation of the economic performance.
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effects of the generator and Evaporator Temperature differences on a double absorption heat transformer different control strategies on utilizing heat sources
Energy Conversion and Management, 2017Co-Authors: Hanzhi Wang, Lingbao WangAbstract:Abstract The combination of the absorption heat transformer with renewable energy systems, like solar thermal systems, is raising more and more concern. In those combined systems the strategies on utilizing heat sources can affect system thermodynamic performance significantly. Therefore, this study presents a detailed analysis on the effect of the heat source Temperature and different heat source flow patterns on the performance of a double absorption heat transformer (DAHT). A detailed comparative study is carried out to clarify the impact of the generator and Evaporator Temperature differences (GETD) on the coefficient of performance (COP), exergy efficient (ECOP), exergy destruction rates in the individual components and heat transfer areas needed for each component. The results show that the generator, condenser and absorber-Evaporator are responsible for most of the exergy destruction rate in the DAHT system; the parallel-flow configuration (the generator Temperature is equal to the Evaporator Temperature) performs better under the high gross Temperature lift conditions; in the case of the counter-flow configuration (the generator Temperature is relatively higher), better performance can be obtained in both the COP and ECOP under the proper heat source Temperature (85 and 95 °C); the fair-flow configuration (higher Temperature in the Evaporator) is not recommended in this paper due to no advantages found in either thermodynamic performance or system size.
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optimum performance of a double absorption heat transformer
Energy Conversion and Management, 2016Co-Authors: Hanzhi Wang, Lingbao WangAbstract:Abstract Double absorption heat transformer (DAHT) is a promising device in reducing the use of fossil fuels since it can utilize renewable sources or waste heat to provide high Temperature energy. The absorber-Evaporator is an important component in the DAHT system, and there exists an optimum absorber-Evaporator Temperature (OAET) at which the maximum coefficient of performance (COP) and exergy efficiency (ECOP) can be obtained simultaneously. In this paper, an optimization study is carried out by means of a parametric analysis, using a mathematical model developed in the software Engineering Equation Solver. The effects of the operating parameters such as the absorber, condenser, Evaporator and generator Temperatures and design parameters including the first and second economizer efficiencies on the OAET and corresponding maximum COP and ECOP have been analyzed in detail. Besides, some suggestions derived from the results are also given.
Hadi Rostamzadeh - One of the best experts on this subject based on the ideXlab platform.
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proposal and assessment of a new geothermal based multigeneration system for cooling heating power and hydrogen production using lng cold energy recovery
Renewable Energy, 2019Co-Authors: Mohammad Ebadollahi, Hadi Ghaebi, Hadi Rostamzadeh, Mona Zamani Pedram, Majid AmidpourAbstract:Abstract Multigeneration systems (MGSs) driven by renewable sources are proved as cutting-edge technologies for multiple productions purposes to curb greenhouse gas emissions. With this regard, a novel geothermal-based MGS is proposed to produce multiple commodities of cooling, heating, power, and hydrogen, simultaneously, using liquefied natural gas (LNG) as cold energy recovery. The system is composed of an organic Rankine cycle (ORC), an ejector refrigeration cycle (ERC), an LNG power generation system, and a proton exchange membrane (PEM) electrolyzer system. To demonstrate the feasibility of the proposed MGS, energy, exergy, and exergoeconomic analysis are employed as the most effective tools for the performance assessment of the system. It is found that the proposed MGS can produce cooling capacity, heating capacity, net output power, and hydrogen of 1020 kW, 334.8 kW, 1060 kW, and 5.43 kg/h, respectively. In this case, the thermal efficiency, exergy efficiency and total SUCP (sum unit cost of the product) of the MGS are calculated 38.33%, 28.91%, and 347.9 $/GJ, respectively. Furthermore, condenser 2 is introduced as the main source of irreversibility of the proposed MGS by exergy destruction ratio of 58.98%. Moreover, a comprehensive parametric study is carried out and it is concluded that the SUCP of the system can be optimized based on the geothermal inlet Temperature. In addition, it is demonstrated that a higher thermal efficiency can be obtained by increasing the turbine 2 expansion ratio, Evaporator Temperature, and geothermal Temperature or decreasing of the generator terminal Temperature difference, turbine 1 expansion ratio, pump 3 pressure ratio, and condenser Temperature. In the same vein, a higher exergy efficiency can be attained at high turbine 1 expansion ratio, turbine 2 expansion ratio, Evaporator Temperature, and pump 3 pressure ratio or low generator terminal Temperature difference, geothermal inlet Temperature, and condenser Temperature.
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a novel geothermal combined cooling and power cycle based on the absorption power cycle energy exergy and exergoeconomic analysis
Energy, 2018Co-Authors: Towhid Parikhani, Hadi Ghaebi, Hadi RostamzadehAbstract:Abstract Energy, exergy, and exergoeconomic analysis of a novel combined cooling and power (CCP) system for producing cooling and power outputs are presented based on the absorption power cycle (APC), using geothermal energy as low-Temperature heat source. A comprehensive thermodynamic modeling of the proposed CCP system is carried out leading to determine the main source of irreversibility and performance characteristics of the system for a better thermal design purpose. In the parametric study, the effect of key thermodynamic parameters (i.e., generator hot pinch point Temperature difference (PPTD), generator cold PPTD, ammonia concentration, absorber minimum Temperature difference, condenser minimum Temperature difference, Evaporator Temperature, and geothermal Temperature) on the key performance parameters (i.e., net output power, cooling capacity, thermal efficiency, exergy efficiency, and sum unit cost of product (SUCP) of system) are investigated. It is found that the proposed system can produce cooling capacity and net output power of 221.4 kW and 161.2 kW, respectively, under supplying 2333 kW heat from the geothermal source. In this case, the overall thermal efficiency, exergy efficiency, and SUCP of system are calculated by 16.4%, 28.95% and 93.87 $/GJ, respectively. From exergy analysis it is understood that among all components, absorber accounted for the largest contribution of exergy destruction which constituted around 39.89% of the overall exergy destruction of system. In addition, the highest cost of exergy destruction corresponded to the absorber which is followed by the condenser. Finally, parametric study revealed that the exergy efficiency of the proposed system can be maximized based upon the ammonia concentration and Evaporator Temperature. Moreover, it is shown that the thermal efficiency of system can be increased by increasing of the generator hot PPTD and Evaporator Temperature or decreasing ammonia concentration, absorber and condenser minimum Temperature differences, and geothermal Temperature. While, it is also found that the SUCP of system can be decreased by increasing the generator cold PPTD, condenser minimum Temperature difference, and geothermal Temperature or decreasing the generator hot PPTD, absorber minimum Temperature difference, and Evaporator Temperature.
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a novel trigeneration system using geothermal heat source and liquefied natural gas cold energy recovery energy exergy and exergoeconomic analysis
Renewable Energy, 2018Co-Authors: Hadi Ghaebi, Towhid Parikhani, Hadi RostamzadehAbstract:This paper deals with the energy, exergy, and exergoeconomic analysis of a novel trigeneration system working with geothermal heat source and liquefied natural gas (LNG) cold energy recovery as thermal sink. The proposed trigeneration system is constructed based on the absorption refrigeration cycle (ARC). Due to the high ammonia concentration at condenser outlet of ARC, a heat pump system is employed for heating production, while LNG cold energy is used for recovering the latent heat of the basic solution from the condenser as heat source as well as for producing power output. A comprehensive thermodynamic modeling of the proposed system is presented and the performance of the system is investigated based on the following performance criteria: net power output, cooling output, heating output, thermal efficiency, exergy efficiency and sum unit cost of the product (SUCP) of the system. In this respect, the simulation revealed that the net power output, cooling output, heating capacity, thermal efficiency, exergy efficiency and total SUCP of the system can be calculated 405.1 kW, 1109 kW, 35.3 kW, 85.92%, 18.52%, and 68.76 $/GJ, respectively, under the proposed constrain variables. In addition, the irreversibility of each component and overall system are presented showing that condenser accounts for the highest exergy destruction among all components which constitutes around 55.51% of the overall exergy destruction rate of the system. Moreover, a comprehensive parametric study is conducted to investigate the effects of some key parameters on the main performance criteria. It is observed that one can obtain a higher thermal efficiency at high Evaporator Temperature or at low condenser Temperature, heating unit Temperature and absorber Temperature; while a higher exergy efficiency can be obtained at high Evaporator Temperature or at low absorber and condenser Temperatures. In addition, a lower total cost of product of the system can be obtained at high heating unit and Evaporator Temperatures or low absorber and condenser Temperatures. Moreover, it is found that the overall performance of system can be optimized based on the generator hot pinch point Temperature difference as well as geothermal inlet Temperature.
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proposal and assessment of a novel geothermal combined cooling and power cycle based on kalina and ejector refrigeration cycles
Applied Thermal Engineering, 2018Co-Authors: Hadi Ghaebi, Towhid Parikhani, Hadi Rostamzadeh, Behzad FarhangAbstract:Abstract This paper aims at introducing a new combined cooling and power (CCP) cycle, using geothermal energy as low-Temperature heat source. The proposed cycle is integrated from a Kalina cycle (KC) and an ejector refrigeration cycle (ERC) to produce a simultaneous refrigeration and power outputs. To enhance performance operation of the proposed CCP cycle, turbine exhaust is extracted for more power production purposes by employing a feed fluid heater (FFH). Energy and exergy assessments of the proposed CCP cycle are conducted using Engineering Equation Solver (EES) software. In addition, considering the thermal efficiency and exergy efficiency as objective functions, single- and multi-objective optimizations are carried out by genetic algorithm (GA), leading to determination of the optimum design variables including basic ammonia concentration, geothermal inlet Temperature, Evaporator Temperature, turbine inlet pressure, mass extraction ratio (MER), FFH pressure, terminal Temperature difference (TTD) of vapor generator, and pinch point Temperature differences of vapor generator and recuperators. In this case, the optimum net output power, refrigeration, thermal efficiency and exergy efficiency are calculated 2319 kW, 1133 kW, 15% and 47.8%, respectively. Moreover, among all components condenser 1 accounts for the biggest exergy destruction rate (589.6 kW) followed by vapor generator (422.1 kW). To better understand the effect of various parameters on system performance, a comprehensive parametric study of some key parameters (including turbine inlet pressure, geothermal inlet Temperature, feed fluid heater pressure, Evaporator Temperature, basic ammonia concentration, and mass extraction ratio) on the performance criteria is carried out. It is shown that the exergy efficiency of system can be maximized based on the turbine inlet pressure, feed fluid heater pressure, basic ammonia concentration, and mass extraction ratio. In addition, the thermal efficiency of system can be maximized by feed fluid heater pressure, while refrigeration output can be maximized by mass extraction ratio. Also, it is shown that a higher power output can be obtained at lower turbine inlet and feed fluid heater pressures as well as higher geothermal inlet Temperature, basic ammonia concentration, and mass extraction ratio. Moreover, a higher refrigeration output can be resulted at higher turbine inlet pressure and Evaporator Temperature, as well as lower feed fluid heater pressure and basic ammonia concentration.
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thermodynamic and thermoeconomic analysis and optimization of a novel combined cooling and power ccp cycle by integrating of ejector refrigeration and kalina cycles
Energy, 2017Co-Authors: Hadi Ghaebi, Towhid Parikhani, Hadi Rostamzadeh, Behzad FarhangAbstract:Abstract In the present work, a novel combined power and ejector refrigeration cycle is proposed by an appropriate combination of a Kalina cycle (KC) and an ejector refrigeration cycle (ERC) to produce power output and cooling output, simultaneously. The exhaust of the turbine is fed to the ejector as a primary flow to draw the secondary flow into the ejector. Energy, exergy, and exergoeconomic analysis of the proposed cycle are carried out using Engineering Equation Solver (EES) software. In addition, considering the thermal efficiency, exergy efficiency, and sum unit cost of the product (SUCP) of the system as objective functions, single- and multi-objective optimizations are carried out by genetic algorithm (GA) leading to determination the optimum design variables including the vapor generator pressure, Evaporator Temperature, condenser pinch point Temperature, heat source Temperature, ammonia concentration, and expander ratio. The results of the optimization demonstrated that the proposed cycle performs in an optimum state based on the selected objective functions when vapor generator pressure, Evaporator Temperature, condenser pinch point Temperature, heat source Temperature, ammonia concentration, and expander ratio work at 17.5 bar, 285 K, 8 K, 473 K, 15%, and 2.5, respectively. In this case, the optimum thermal efficiency, exergy efficiency, SUCP of the system are calculated 20.4%, 16.69%, and 2466.36 $/MWh, respectively. Moreover, it is demonstrated that the thermal efficiency can be maximized for the proposed cycle with respect to the vapor generator pressure, vapor generator Temperature, and heat source Temperature. Furthermore, it is shown that ejector has the main contribution in the exergy losses which is followed by the condenser. At the end, the effect of some key parameters on the main thermodynamic performance criteria are examined. It is shown that one can obtain a higher thermal and exergy efficiencies at lower ammonia concentration and condenser pinch point Temperature as well as at higher Evaporator Temperature.
Hanzhi Wang - One of the best experts on this subject based on the ideXlab platform.
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thermoeconomic evaluation and optimization of libr h2o double absorption heat transformer driven by flat plate collector
Energy Conversion and Management, 2018Co-Authors: Lingbao Wang, Hanzhi WangAbstract:Abstract In this paper, a solar double absorption heat transformer (SDAHT) operating with the LiBr-H2O solution is proposed to provide high Temperature energy. The flat plate collector (FPC) is used to supply the demanded heat input in the present configuration, which will greatly broaden the application scope of the FPCs. The thermoeconomic concept is applied to the evaluation and optimization of the SDAHT, aimed at minimizing its annual capital cost per kilowatt heat capacity (CPK) and payback period (PP). A dedicated computer model in the software Engineering Equation Solver was developed to conduct the study by means of a parametric analysis. The results show that there exists an optimum absorber/Evaporator Temperature at which CPK and PP can obtain the minimum values. With solar radiation intensity at 600 W/m2, generation (evaporation) Temperature at 75 °C, condensation Temperature at 38 °C, absorption Temperature at 135 °C and economizer efficiency set to 0.8, the optimum absorber/Evaporator Temperature and corresponding CPK and PP are 104.0 °C, 928.1 euros/kW and 4.0 years, respectively. The cost of the FPCs takes the major part of CPK. Moreover, the effects of the operating parameters such as the generation (evaporation), condensation, absorption Temperatures and design parameters including the first and second economizer efficiencies on the optimum absorber/Evaporator Temperature and corresponding CPK and PP have been analyzed in detail. Besides, some suggestions derived from the results are also given to assist the engineers in estimation of the economic performance.
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effects of the generator and Evaporator Temperature differences on a double absorption heat transformer different control strategies on utilizing heat sources
Energy Conversion and Management, 2017Co-Authors: Hanzhi Wang, Lingbao WangAbstract:Abstract The combination of the absorption heat transformer with renewable energy systems, like solar thermal systems, is raising more and more concern. In those combined systems the strategies on utilizing heat sources can affect system thermodynamic performance significantly. Therefore, this study presents a detailed analysis on the effect of the heat source Temperature and different heat source flow patterns on the performance of a double absorption heat transformer (DAHT). A detailed comparative study is carried out to clarify the impact of the generator and Evaporator Temperature differences (GETD) on the coefficient of performance (COP), exergy efficient (ECOP), exergy destruction rates in the individual components and heat transfer areas needed for each component. The results show that the generator, condenser and absorber-Evaporator are responsible for most of the exergy destruction rate in the DAHT system; the parallel-flow configuration (the generator Temperature is equal to the Evaporator Temperature) performs better under the high gross Temperature lift conditions; in the case of the counter-flow configuration (the generator Temperature is relatively higher), better performance can be obtained in both the COP and ECOP under the proper heat source Temperature (85 and 95 °C); the fair-flow configuration (higher Temperature in the Evaporator) is not recommended in this paper due to no advantages found in either thermodynamic performance or system size.
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optimum performance of a double absorption heat transformer
Energy Conversion and Management, 2016Co-Authors: Hanzhi Wang, Lingbao WangAbstract:Abstract Double absorption heat transformer (DAHT) is a promising device in reducing the use of fossil fuels since it can utilize renewable sources or waste heat to provide high Temperature energy. The absorber-Evaporator is an important component in the DAHT system, and there exists an optimum absorber-Evaporator Temperature (OAET) at which the maximum coefficient of performance (COP) and exergy efficiency (ECOP) can be obtained simultaneously. In this paper, an optimization study is carried out by means of a parametric analysis, using a mathematical model developed in the software Engineering Equation Solver. The effects of the operating parameters such as the absorber, condenser, Evaporator and generator Temperatures and design parameters including the first and second economizer efficiencies on the OAET and corresponding maximum COP and ECOP have been analyzed in detail. Besides, some suggestions derived from the results are also given.
Abdul Khaliq - One of the best experts on this subject based on the ideXlab platform.
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exergy analysis of industrial waste heat recovery based ejector vapour compression refrigeration system
Journal of The Energy Institute, 2011Co-Authors: Rajesh Kumar, Abdul KhaliqAbstract:AbstractThis communication employed a thermodynamic analysis through energy and exergy for the performance evaluation of waste heat recovery based ejector compression refrigeration in which internal heat exchanger and cooler are used to enhance the performance of the cycle. The system is an integration of the Rankine power cycle and the compression refrigeration cycle. A comprehensive parametric study is performed to investigate the effects of exhaust gas inlet Temperature, pinch point (PP) and Evaporator Temperature on the energetic and exergetic coefficient of performance (COP) of the system as well on the exergy destruction in each component. It is shown that the exergetic COP of the system decreases significantly with the increase in exhaust gas Temperature and PP, while the energetic COP increases slightly. The effect of Evaporator Temperature also shows a similar behaviour. It is further shown that the exergetic coefficient of performance of the system is ∼75% lower than the COP of the same system. ...
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exergy analysis of gas turbine trigeneration system for combined production of power heat and refrigeration
International Journal of Refrigeration-revue Internationale Du Froid, 2009Co-Authors: Abdul KhaliqAbstract:A conceptual trigeneration system is proposed based on the conventional gas turbine cycle for the high Temperature heat addition while adopting the heat recovery steam generator for process heat and vapor absorption refrigeration for the cold production. Combined first and second law approach is applied and computational analysis is performed to investigate the effects of overall pressure ratio, turbine inlet Temperature, pressure drop in combustor and heat recovery steam generator, and Evaporator Temperature on the exergy destruction in each component, first law efficiency, electrical to thermal energy ratio, and second law efficiency of the system. Thermodynamic analysis indicates that exergy destruction in combustion chamber and HRSG is significantly affected by the pressure ratio and turbine inlet Temperature, and not at all affected by pressure drop and Evaporator Temperature. The process heat pressure and Evaporator Temperature causes significant exergy destruction in various components of vapor absorption refrigeration cycle and HRSG. It also indicates that maximum exergy is destroyed during the combustion and steam generation process; which represents over 80% of the total exergy destruction in the overall system. The first law efficiency, electrical to thermal energy ratio and second law efficiency of the trigeneration, cogeneration, and gas turbine cycle significantly varies with the change in overall pressure ratio and turbine inlet Temperature, but the change in pressure drop, process heat pressure, and Evaporator Temperature shows small variations in these parameters. Decision makers should find the methodology contained in this paper useful in the comparison and selection of advanced heat recovery systems.
Rafet Yapici - One of the best experts on this subject based on the ideXlab platform.
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experimental investigation of performance of vapor ejector refrigeration system using refrigerant r123
Energy Conversion and Management, 2008Co-Authors: Rafet YapiciAbstract:Abstract In the present study, a novel ejector was designed based on a constant area ejector model and manufactured in order to investigate the performance of an ejector refrigeration system in a wider operating range. The ejector, with movable primary nozzle, was mounted on the system that was previously constructed for low pressure refrigerants. The modified refrigeration system has been tested using hot water as driving fluid and R123 as working fluid. The effects of the operating Temperatures on the cooling capacity and performance coefficient of the system were investigated experimentally when the primary nozzle position was optimum at the ejector area ratio of 9.97. As a result, a performance coefficient of 0.39 was obtained at the vapor generator Temperature 98 °C, the Evaporator Temperature 10 °C and critical condenser pressure 129 kPa.
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experimental study on ejector refrigeration system powered by low grade heat
Energy Conversion and Management, 2007Co-Authors: Rafet Yapici, C C YetisenAbstract:Abstract An ejector refrigeration system has been designed and constructed to operate with hot water. Such a refrigeration system, designed for low pressure refrigerants, can be operated using energy sources such as solar energy, geothermal energy and waste heat. In this study, the effects of the main operating parameters on system performance were experimentally investigated using R-11 as the working fluid and keeping constant the position of the primary nozzle end at the inlet plane of the mixing chamber section of the ejector. The experimental study was performed over a range of vapor generator Temperatures from about 90 to 102 °C, Evaporator Temperatures from 0 to 16 °C and condenser pressures from 114 to 143 kPa, and a COP up to 0.25 was obtained. It was seen that if higher cooling capacity and also lower Evaporator Temperature are desired from the system, the vapor generator Temperature should be increased considerably.
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Performance characteristics of the ejector refrigeration system based on the constant area ejector flow model
Energy Conversion and Management, 2005Co-Authors: Rafet Yapici, H.k. ErsoyAbstract:A theoretical analysis of the ejector refrigeration system based on the constant area ejector flow model is performed. Optimised results for R-123 are presented. It is determined that the variations in condenser and Evaporator Temperature have a greater effect on the optimum coefficient of performance (COP) than the variation in generator Temperature. At the same operating Temperatures of the ejector refrigeration system, the optimum COP and area ratio determined in this study using the constant area flow model are greater than the values given in the literature for the constant pressure flow model. For the same area ratio, the COP for the system with the constant pressure ejector is relatively higher than that with the constant area ejector. In this case, however, the condenser Temperature should be lowered. In addition, the refrigeration systems have almost the same COP values at lower Evaporator or higher condenser Temperatures.