Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy, 2009
In this article, a novel method of inlet air cooling is proposed to enhance the performance of a ... more In this article, a novel method of inlet air cooling is proposed to enhance the performance of a gas turbine operating in hot climates. The intake air at the compressor bell-mouth is cooled by an air Brayton refrigerator driven by the gas turbine, and the refrigerator uses air as the working fluid. Introducing the air refrigeration cycle provides the advantage of quite low temperatures close to 0 °C and even lower. This is not possible with other methods of intake air cooling, namely evaporative cooling or use of waste heat-driven absorption machines. A thermodynamic analysis through energy and exergy is employed, and a comprehensive parametric study is performed to investigate the effects of extraction pressure ratio, extracted mass rate, turbine inlet temperature (TIT), and ambient relative humidity (RH) on increase in net work output, first law efficiency, and second law efficiency of a compressor inlet air-cooled gas turbine cycle using a Joule—Brayton refrigerator. The analysis...
Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy, 2006
Abstract A finite-time thermodynamic analysis based on a new kind of optimization criterion has b... more Abstract A finite-time thermodynamic analysis based on a new kind of optimization criterion has been carried out for an endoreversible and regenerative Joule-Brayton power cycle coupled with variable temperature thermal reservoirs. The optimal performance and design parameters that maximize the ecological function are investigated. In this context, the optimal temperatures of the working fluid, the optimum power output, the optimum thermal efficiency, and the optimum second-law efficiency are determined in terms of technical parameters. Results are reported for the effect of regeneration, hot-cold temperature ratio, and the number of heat transfer units in hot and cold exchangers on the optimal performance parameters. The power and efficiency at maximum ecological function are found to be less than the maximum power and Curzon-Ahlborn efficiency. Power output increases significantly with increasing hot-cold side temperature ratio. However, it slightly increased as the number of heat transfer units in the regenerator increases. The optimization of ecological function leads to the improvement in exergetic efficiency and thermal efficiency, especially for low hot-cold side temperature ratios. Moreover, the thermal efficiency at maximum ecological function is less than the average of the finite time or maximum power efficiency and reversible Carnot efficiency.
ABSTRACT In this study, a novel trigeneration system is proposed as an idea for future research b... more ABSTRACT In this study, a novel trigeneration system is proposed as an idea for future research based on the industrial waste heat recovery operated steam generator for process heat, and produces both power and refrigeration simultaneously with stack gases, using ammonia?water mixture as the working fluid. An extensive review of various energy and exergy based approach used in the analysis of different cogeneration and trigeneration cycles is reported. Energy and exergy efficiencies have been defined, and computational analysis is performed to investigate the effects of exhaust gas inlet temperature and gas composition on first law efficiency, electrical/thermal energy ratio and exergy efficiency of an industrial waste heat recovery based trigeneration system. The variation in specific heat with exhaust gas composition and temperature is accounted in the analysis for further discussion. The first law (energy) efficiency increases while electrical/thermal energy ratio and exergy efficiency decrease with increasing exhaust gas inlet temperature. Exergy efficiency significantly varies with gas composition and oxygen content of the exhaust gas. Approximating the exhaust gas as air and the air standard analysis leads to either underestimation or overestimation of proposed trigeneration cycle from the point of view of exergy analysis. The present analysis will provide a convenient and practical tool for engineers and researchers dealing with the energy efficiency improvements in a sustainable manner.
In this paper, energy and exergy analyses of a new solar-driven triple-staged refrigeration cycle... more In this paper, energy and exergy analyses of a new solar-driven triple-staged refrigeration cycle using Duratherm 600 oil as the heat transfer fluid are performed. The proposed cycle is an integration of absorption refrigeration cycle (ARC), ejector (EJE) refrigeration cycle (ERC), and ejector expansion Joule–Thomson (EJT) refrigeration cryogenic cycles which could produce refrigeration output of different magnitude at different temperature simultaneously. Both exergy destruction and losses in each component and hence in the overall system are determined to identify the causes and locations of the thermodynamic imperfection. Several design parameters, including the hot oil outlet temperature, refrigerant turbine inlet pressure, and the evaporator temperature of ERC and EJT cycle are also tested to evaluate their effects on energy and exergy performance. It is observed that largest contribution to cycle irreversibility comes from the central receiver and heliostat field with the heat...
The growth and nutrition of maize (Zea mays L.) grown with and without the soil application of ph... more The growth and nutrition of maize (Zea mays L.) grown with and without the soil application of phosphorus (P) fertilizer and/or mycorrhizal inoculum was studied in pots placed under field environments. Inoculation enhanced the growth of maize significantly (up to 81.8%) during the early stages but response gradually disappeared during the later stages of growth. Addition of phosphate increased plant growth, but suppressed mycorrhizal infection. In the first half of the season, the stimulation in plant growth was related to higher rates of P uptake by the inoculated plants, but later a decline of growth in these treatments was most probably due to fungal parasitism as a result of high root densities.
Journal of Engineering for Gas Turbines and Power, 2007
A conceptual gas turbine based cogeneration cycle with compressor inlet air cooling and evaporati... more A conceptual gas turbine based cogeneration cycle with compressor inlet air cooling and evaporative aftercooling of the compressor discharge is proposed to increase the cycle performance significantly and render it practically insensitive to seasonal temperature fluctuations. Combined first and second-law approach is applied for a cogeneration system having intercooled reheat regeneration in a gas turbine as well as inlet air cooling and evaporative aftercooling of the compressor discharge. Computational analysis is performed to investigate the effects of the overall pressure ratio rp, turbine inlet temperature (TIT), and ambient relative humidity φ on the exergy destruction in each component, first-law efficiency, power-to-heat ratio, and second-law efficiency of the cycle. Thermodynamic analysis indicates that exergy destruction in various components of the cogeneration cycle is significantly affected by overall pressure ratio and turbine inlet temperature, and not at all affected...
Journal of Engineering for Gas Turbines and Power, 2008
The thermodynamic performance of the combustion gas turbine trigeneration system has been studied... more The thermodynamic performance of the combustion gas turbine trigeneration system has been studied based on first law as well as second law analysis. The effects of overall pressure ratio and process heat pressure on fuel utilization efficiency, electrical to thermal energy ratio, second law efficiency, and exergy destruction in each component are examined. Results for gas turbine cycle, cogeneration cycle, and trigeneration cycle are compared. Thermodynamic analysis 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 trigeneration system, cogeneration system, and gas turbine cycle significantly varies with the change in overall pressure ratio but the change in process heat pressure shows small variations in these parameters. Results clearly show that performance evaluatio...
In this paper, a novel industrial waste heat recovery based cogeneration is proposed for the comb... more In this paper, a novel industrial waste heat recovery based cogeneration is proposed for the combined production of power and refrigeration. The system is an integration of Rankine power cycle and absorption refrigeration cycle. A thermodynamic analysis through energy and exergy is employed, and a comprehensive parametric study is performed to investigate the effects of exhaust gas inlet temperature, pinch-point, and gas composition on energy efficiency, power-to-cold ratio, and exergy efficiency of the cogeneration cycle and exergy destruction in each component. The variation in specific heat with exhaust gas composition and temperature is accounted in the analysis for further discussion. The first-law efficiency decreases while power-to-cold ratio and exergy efficiency increase with increasing exhaust gas inlet temperature. The parameters, such as power-to-cold ratio and second-law efficiency, decrease while first-law efficiency increases with increasing pinch-point. Exergy effici...
In this study, first and second law analyses of a new combined power cycle based on wet ethanol f... more In this study, first and second law analyses of a new combined power cycle based on wet ethanol fuelled homogeneous charge compression ignition (HCCI) engine and an organic Rankine cycle are presented. A computational analysis is performed to evaluate first and second law efficiencies, with the latter providing good guidance for performance improvement. The effect of changing turbocharger pressure ratio, organic Rankine cycle (ORC) evaporator pinch point temperature, turbocharger compressor efficiency, and ambient temperature have been observed on cycle’s first law efficiency, second law efficiency, and exergy destruction in each of its component. A first law efficiency of 41.5% and second law efficiency of 36.9% were obtained for the operating conditions (T0 = 300 K, rp = 3, ηT = 80%). The first law efficiency and second law efficiency of the combined power cycle significantly vary with the change in the turbocharger pressure ratio, but the change in pinch point temperature, turboc...
This paper investigates the effects of change in cycle pressure ratio and maximum cycle temperatu... more This paper investigates the effects of change in cycle pressure ratio and maximum cycle temperature as well as the change in refrigerant in organic Rankine cycle (ORC) on energy and exergy performance of biomass-driven triple-power cycle. The results show that both first and second law efficiencies of the proposed triple-power cycle decreases with the increase in pressure ratio and increases with the increase in the maximum cycle temperature. The effect of change in the refrigerant in ORC is found to be marginal. Second law assessment of the cycle reveals that combustor, heat recovery steam generator (HRSG), and gasifier are the three main sources of irreversibility, where it is shown that out of the 100% fuel exergy input; around 25% of exergy is destructed in the combustor, 19% in HRSG, and 7.6% in the gasifier. Investigations show that the triple-power cycle has better thermodynamic performance than the combined power cycle driven by biomass.
ABSTRACT In this paper, combined first and second law approach is applied to investigate the effe... more ABSTRACT In this paper, combined first and second law approach is applied to investigate the effects of percent excess air and ambient temperature on the energy and exergy efficiency of the hydrogen-fuelled homogeneous charge compression ignition engine. A maximum energy efficiency of 45% and an exergy efficiency of 37% are obtained at the excess air of 25%. A narrow range of 42–40% energy efficiency and a wide range of 25–45% exergy efficiency were achieved between the 20–40% excess air and an ambient temperature of 300 K. Close range of variation for energy efficiency (48–44%) and exergy efficiency (32–36%) were achieved between the ambient temperatures of 13°C and 41°C. Exergy analysis indicates that 52% of the fuel hydrogen exergy is destroyed due to various irreversible processes of the engine, around 40% is available as a useful work output, and 7.83% is lost via engine exhaust.
... Biographical notes: Dr. Abdul Khaliq received his Bachelor's Degree in Mechanical Engine... more ... Biographical notes: Dr. Abdul Khaliq received his Bachelor's Degree in Mechanical Engineering in 1994 from the ZH College of Engineering and ... He received his PhD Degree on Second Law Analysis of Thermal Power Cycles and Thermofluid Systems from IIT Delhi in 2003. ...
Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy, 2009
In this article, a novel method of inlet air cooling is proposed to enhance the performance of a ... more In this article, a novel method of inlet air cooling is proposed to enhance the performance of a gas turbine operating in hot climates. The intake air at the compressor bell-mouth is cooled by an air Brayton refrigerator driven by the gas turbine, and the refrigerator uses air as the working fluid. Introducing the air refrigeration cycle provides the advantage of quite low temperatures close to 0 °C and even lower. This is not possible with other methods of intake air cooling, namely evaporative cooling or use of waste heat-driven absorption machines. A thermodynamic analysis through energy and exergy is employed, and a comprehensive parametric study is performed to investigate the effects of extraction pressure ratio, extracted mass rate, turbine inlet temperature (TIT), and ambient relative humidity (RH) on increase in net work output, first law efficiency, and second law efficiency of a compressor inlet air-cooled gas turbine cycle using a Joule—Brayton refrigerator. The analysis...
Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy, 2006
Abstract A finite-time thermodynamic analysis based on a new kind of optimization criterion has b... more Abstract A finite-time thermodynamic analysis based on a new kind of optimization criterion has been carried out for an endoreversible and regenerative Joule-Brayton power cycle coupled with variable temperature thermal reservoirs. The optimal performance and design parameters that maximize the ecological function are investigated. In this context, the optimal temperatures of the working fluid, the optimum power output, the optimum thermal efficiency, and the optimum second-law efficiency are determined in terms of technical parameters. Results are reported for the effect of regeneration, hot-cold temperature ratio, and the number of heat transfer units in hot and cold exchangers on the optimal performance parameters. The power and efficiency at maximum ecological function are found to be less than the maximum power and Curzon-Ahlborn efficiency. Power output increases significantly with increasing hot-cold side temperature ratio. However, it slightly increased as the number of heat transfer units in the regenerator increases. The optimization of ecological function leads to the improvement in exergetic efficiency and thermal efficiency, especially for low hot-cold side temperature ratios. Moreover, the thermal efficiency at maximum ecological function is less than the average of the finite time or maximum power efficiency and reversible Carnot efficiency.
ABSTRACT In this study, a novel trigeneration system is proposed as an idea for future research b... more ABSTRACT In this study, a novel trigeneration system is proposed as an idea for future research based on the industrial waste heat recovery operated steam generator for process heat, and produces both power and refrigeration simultaneously with stack gases, using ammonia?water mixture as the working fluid. An extensive review of various energy and exergy based approach used in the analysis of different cogeneration and trigeneration cycles is reported. Energy and exergy efficiencies have been defined, and computational analysis is performed to investigate the effects of exhaust gas inlet temperature and gas composition on first law efficiency, electrical/thermal energy ratio and exergy efficiency of an industrial waste heat recovery based trigeneration system. The variation in specific heat with exhaust gas composition and temperature is accounted in the analysis for further discussion. The first law (energy) efficiency increases while electrical/thermal energy ratio and exergy efficiency decrease with increasing exhaust gas inlet temperature. Exergy efficiency significantly varies with gas composition and oxygen content of the exhaust gas. Approximating the exhaust gas as air and the air standard analysis leads to either underestimation or overestimation of proposed trigeneration cycle from the point of view of exergy analysis. The present analysis will provide a convenient and practical tool for engineers and researchers dealing with the energy efficiency improvements in a sustainable manner.
In this paper, energy and exergy analyses of a new solar-driven triple-staged refrigeration cycle... more In this paper, energy and exergy analyses of a new solar-driven triple-staged refrigeration cycle using Duratherm 600 oil as the heat transfer fluid are performed. The proposed cycle is an integration of absorption refrigeration cycle (ARC), ejector (EJE) refrigeration cycle (ERC), and ejector expansion Joule–Thomson (EJT) refrigeration cryogenic cycles which could produce refrigeration output of different magnitude at different temperature simultaneously. Both exergy destruction and losses in each component and hence in the overall system are determined to identify the causes and locations of the thermodynamic imperfection. Several design parameters, including the hot oil outlet temperature, refrigerant turbine inlet pressure, and the evaporator temperature of ERC and EJT cycle are also tested to evaluate their effects on energy and exergy performance. It is observed that largest contribution to cycle irreversibility comes from the central receiver and heliostat field with the heat...
The growth and nutrition of maize (Zea mays L.) grown with and without the soil application of ph... more The growth and nutrition of maize (Zea mays L.) grown with and without the soil application of phosphorus (P) fertilizer and/or mycorrhizal inoculum was studied in pots placed under field environments. Inoculation enhanced the growth of maize significantly (up to 81.8%) during the early stages but response gradually disappeared during the later stages of growth. Addition of phosphate increased plant growth, but suppressed mycorrhizal infection. In the first half of the season, the stimulation in plant growth was related to higher rates of P uptake by the inoculated plants, but later a decline of growth in these treatments was most probably due to fungal parasitism as a result of high root densities.
Journal of Engineering for Gas Turbines and Power, 2007
A conceptual gas turbine based cogeneration cycle with compressor inlet air cooling and evaporati... more A conceptual gas turbine based cogeneration cycle with compressor inlet air cooling and evaporative aftercooling of the compressor discharge is proposed to increase the cycle performance significantly and render it practically insensitive to seasonal temperature fluctuations. Combined first and second-law approach is applied for a cogeneration system having intercooled reheat regeneration in a gas turbine as well as inlet air cooling and evaporative aftercooling of the compressor discharge. Computational analysis is performed to investigate the effects of the overall pressure ratio rp, turbine inlet temperature (TIT), and ambient relative humidity φ on the exergy destruction in each component, first-law efficiency, power-to-heat ratio, and second-law efficiency of the cycle. Thermodynamic analysis indicates that exergy destruction in various components of the cogeneration cycle is significantly affected by overall pressure ratio and turbine inlet temperature, and not at all affected...
Journal of Engineering for Gas Turbines and Power, 2008
The thermodynamic performance of the combustion gas turbine trigeneration system has been studied... more The thermodynamic performance of the combustion gas turbine trigeneration system has been studied based on first law as well as second law analysis. The effects of overall pressure ratio and process heat pressure on fuel utilization efficiency, electrical to thermal energy ratio, second law efficiency, and exergy destruction in each component are examined. Results for gas turbine cycle, cogeneration cycle, and trigeneration cycle are compared. Thermodynamic analysis 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 trigeneration system, cogeneration system, and gas turbine cycle significantly varies with the change in overall pressure ratio but the change in process heat pressure shows small variations in these parameters. Results clearly show that performance evaluatio...
In this paper, a novel industrial waste heat recovery based cogeneration is proposed for the comb... more In this paper, a novel industrial waste heat recovery based cogeneration is proposed for the combined production of power and refrigeration. The system is an integration of Rankine power cycle and absorption refrigeration cycle. A thermodynamic analysis through energy and exergy is employed, and a comprehensive parametric study is performed to investigate the effects of exhaust gas inlet temperature, pinch-point, and gas composition on energy efficiency, power-to-cold ratio, and exergy efficiency of the cogeneration cycle and exergy destruction in each component. The variation in specific heat with exhaust gas composition and temperature is accounted in the analysis for further discussion. The first-law efficiency decreases while power-to-cold ratio and exergy efficiency increase with increasing exhaust gas inlet temperature. The parameters, such as power-to-cold ratio and second-law efficiency, decrease while first-law efficiency increases with increasing pinch-point. Exergy effici...
In this study, first and second law analyses of a new combined power cycle based on wet ethanol f... more In this study, first and second law analyses of a new combined power cycle based on wet ethanol fuelled homogeneous charge compression ignition (HCCI) engine and an organic Rankine cycle are presented. A computational analysis is performed to evaluate first and second law efficiencies, with the latter providing good guidance for performance improvement. The effect of changing turbocharger pressure ratio, organic Rankine cycle (ORC) evaporator pinch point temperature, turbocharger compressor efficiency, and ambient temperature have been observed on cycle’s first law efficiency, second law efficiency, and exergy destruction in each of its component. A first law efficiency of 41.5% and second law efficiency of 36.9% were obtained for the operating conditions (T0 = 300 K, rp = 3, ηT = 80%). The first law efficiency and second law efficiency of the combined power cycle significantly vary with the change in the turbocharger pressure ratio, but the change in pinch point temperature, turboc...
This paper investigates the effects of change in cycle pressure ratio and maximum cycle temperatu... more This paper investigates the effects of change in cycle pressure ratio and maximum cycle temperature as well as the change in refrigerant in organic Rankine cycle (ORC) on energy and exergy performance of biomass-driven triple-power cycle. The results show that both first and second law efficiencies of the proposed triple-power cycle decreases with the increase in pressure ratio and increases with the increase in the maximum cycle temperature. The effect of change in the refrigerant in ORC is found to be marginal. Second law assessment of the cycle reveals that combustor, heat recovery steam generator (HRSG), and gasifier are the three main sources of irreversibility, where it is shown that out of the 100% fuel exergy input; around 25% of exergy is destructed in the combustor, 19% in HRSG, and 7.6% in the gasifier. Investigations show that the triple-power cycle has better thermodynamic performance than the combined power cycle driven by biomass.
ABSTRACT In this paper, combined first and second law approach is applied to investigate the effe... more ABSTRACT In this paper, combined first and second law approach is applied to investigate the effects of percent excess air and ambient temperature on the energy and exergy efficiency of the hydrogen-fuelled homogeneous charge compression ignition engine. A maximum energy efficiency of 45% and an exergy efficiency of 37% are obtained at the excess air of 25%. A narrow range of 42–40% energy efficiency and a wide range of 25–45% exergy efficiency were achieved between the 20–40% excess air and an ambient temperature of 300 K. Close range of variation for energy efficiency (48–44%) and exergy efficiency (32–36%) were achieved between the ambient temperatures of 13°C and 41°C. Exergy analysis indicates that 52% of the fuel hydrogen exergy is destroyed due to various irreversible processes of the engine, around 40% is available as a useful work output, and 7.83% is lost via engine exhaust.
... Biographical notes: Dr. Abdul Khaliq received his Bachelor's Degree in Mechanical Engine... more ... Biographical notes: Dr. Abdul Khaliq received his Bachelor's Degree in Mechanical Engineering in 1994 from the ZH College of Engineering and ... He received his PhD Degree on Second Law Analysis of Thermal Power Cycles and Thermofluid Systems from IIT Delhi in 2003. ...
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