The Experts below are selected from a list of 3609 Experts worldwide ranked by ideXlab platform
Alok Ku Mohapatra - One of the best experts on this subject based on the ideXlab platform.
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comparative analysis of Inlet air cooling techniques integrated to cooled gas turbine plant
Journal of The Energy Institute, 2015Co-Authors: Alok Ku MohapatraAbstract:Abstract The current article is focused on assessing the comparison of two different means of Inlet air cooling (evaporative cooing and vapor compression cooling) integrated to a cooled gas turbine power plant. Air film cooling has been adopted as the cooling technique for gas turbine buckets. A parametric study of the effect of pressure ratio (r p,c ), Compressor Inlet Temperature (CIT), turbine Inlet Temperature (TIT), Inlet Temperature ratio (r IT ), ambient relative humidity and ambient Temperature on performance parameters of plant has been carried out. It has been observed that the integration of the Inlet air cooling system to the gas turbine cycle improves the overall performance, the improvement being higher at higher ambient Temperature and ambient relative humidity. At a TIT = 1700 K, r p,c = 23, RH a = 0.2 and T a = 313 K, vapor compression Inlet air cooling has been observed to improve the plant specific work by 18.4% and efficiency by 4.18%, compared to 10.48% and 4.6% respectively for evaporative cooling. In geographical regions having low ambient relative humidity and low ambient Temperature however, evaporative Inlet air cooling should be preferred over vapor compression cooling in terms of higher plant efficiency.. The adoption of higher turbine Inlet Temperature has a more pronounced effect on vapor compression cooled gas turbine in terms of enhancement in plant performance parameters as compared to evaporative cooling. The work ratio increases with increase in value of r IT upto5.6 after which it decreases.
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thermodynamic assessment of impact of Inlet air cooling techniques on gas turbine and combined cycle performance
Energy, 2014Co-Authors: Alok Ku MohapatraAbstract:The article is focused on the comparison of impact of two different methods of Inlet air cooling (vapor compression and vapor absorption cooling) integrated to a cooled gas turbine based combined cycle plant. Air-film cooling has been adopted as the cooling technique for gas turbine blades. A parametric study of the effect of Compressor pressure ratio, Compressor Inlet Temperature (Ti,C), turbine Inlet Temperature (Ti,T), ambient relative humidity and ambient Temperature on performance parameters of plant has been carried out. Optimum Ti,T corresponding to maximum plant efficiency of combined cycle increases by 100 °C due to the integration of Inlet air cooling. It has been observed that vapor compression cooling improves the efficiency of gas turbine cycle by 4.88% and work output by 14.77%. In case of vapor absorption cooling an improvement of 17.2% in gas cycle work output and 9.47% in gas cycle efficiency has been observed. For combined cycle configuration, however, vapor compression cooling should be preferred over absorption cooling in terms of higher plant performance. The optimum value of Compressor Inlet Temperature has been observed to be 20 °C for the chosen set of conditions for both the Inlet air cooling schemes.
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analysis of parameters affecting the performance of gas turbines and combined cycle plants with vapor absorption Inlet air cooling
International Journal of Energy Research, 2014Co-Authors: Alok Ku MohapatraAbstract:SUMMARY The integration of an aqua-ammonia Inlet air-cooling scheme to a cooled gas turbine-based combined cycle has been analyzed. The heat energy of the exhaust gas prior to the exit of the heat recovery steam generator has been chosen to power the Inlet air-cooling system. Dual pressure reheat heat recovery steam generator is chosen as the combined cycle configuration. Air film cooling has been adopted as the cooling technique for gas turbine blades. A parametric study of the effect of Compressor–pressure ratio, Compressor Inlet Temperature, turbine Inlet Temperature, ambient relative humidity, and ambient Temperature on performance parameters of plants has been carried out. It has been observed that vapor absorption Inlet air cooling improves the efficiency of gas turbine by upto 7.48% and specific work by more than 18%, respectively. However, on the adoption of this scheme for combined cycles, the plant efficiency has been observed to be adversely affected, although the addition of absorption Inlet air cooling results in an increase in plant output by more than 7%. The optimum value of Compressor Inlet Temperature for maximum specific work output has been observed to be 25 °C for the chosen set of conditions. Further reduction of Compressor Inlet Temperature below this optimum value has been observed to adversely affect plant efficiency. Copyright © 2013 John Wiley & Sons, Ltd.
Kun Wang - One of the best experts on this subject based on the ideXlab platform.
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a systematic comparison of different s co2 brayton cycle layouts based on multi objective optimization for applications in solar power tower plants
Applied Energy, 2018Co-Authors: Kun Wang, Ming-jia Li, Peiwen LiAbstract:Supercritical CO2 (S-CO2) Brayton cycles are recently proposed to be integrated into the solar power tower (SPT) due to their high efficiency and compactness. Comparison of different S-CO2 Brayton cycle layouts is of great significance for selecting a suitable one in the SPT plant. Both of the efficiency and specific work are important performance criteria for the SPT plant. However, previous studies compared only one individual criterion, or both of them just separately. This paper puts forward a systematic comparison of different S-CO2 Brayton cycle layouts based on multi-objective optimizations. The two performance criteria are compared simultaneously between different S-CO2 cycle layouts by comparing the Pareto optimal fronts obtained from multi-objective optimizations. The results suggest that the inter-cooling cycle layout and the partial-cooling cycle layout can generally yield the most excellent performances, and followed by the recompression cycle layout and the pre-compression cycle layout, while the simple recuperation cycle layout has the worst performances. The advantages of the partial-cooling cycle layout and the inter-cooling cycle layout are more prominent compared with the other cycle layouts in the case of high Compressor Inlet Temperature. The provided systematic comparison can be helpful in selecting the most suitable cycle layout for the application in SPT when there are specified requirements for the efficiency and the specific work. In addition, novel salts with high upper limit Temperature (higher than 650 °C) are recommended to be developed as the heat transfer fluid for improving system performances.
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integration between supercritical co2 brayton cycles and molten salt solar power towers a review and a comprehensive comparison of different cycle layouts
Applied Energy, 2017Co-Authors: Kun Wang, Hanhui ZhuAbstract:Abstract In the present study, several current S-CO 2 Brayton cycle layouts are reviewed, and considered to be integrated into the existing mature molten salt solar power tower (SPT) systems. The SPT systems integrated with S-CO 2 Brayton cycles are completely modeled by an integrative approach. The performances of these different cycles are compared comprehensively for applications in molten salt SPT systems from the aspects of the efficiency, the specific work, and the incorporation ability with the thermal energy storage indicated by the molten salt Temperature difference across the solar receiver. The results indicate: (1) The intercooling cycle can generally offer the highest efficiency, followed by the partial-cooling cycle, and the recompression cycle; The precompression cycle can yield higher efficiency than the recompression cycle when the Compressor Inlet Temperature is high; The increase in the hot salt Temperature cannot always result in the efficiency improvement of the SPT systems. (2) The partial-cooling cycle can offer the largest specific work, while the recompression cycle and the split expansion cycle yield the lowest specific work. (3) The molten salt Temperature differences of SPT systems with the simple recuperation cycle, the partial-cooling cycle, and the precompression cycle are slightly larger than those of SPT systems with the recompression cycle, the split expansion cycle, and the intercooling cycle. (4) As a classical approach to improve efficiency, reheating can decrease the system efficiency in the cases with high hot molten salt Temperature; SPT systems without reheating can yield larger molten salt Temperature difference than those with reheating. (5) Although the current S-CO 2 Brayton cycle layouts can offer high efficiency, there are still several challenges for integrating them into the SPT systems: the specific work is relatively small, and the Temperature difference across the solar receiver is narrow. Further work remains to build novel S-CO 2 cycle layouts with high efficiency, large specific work, and wide Temperature difference.
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thermodynamic analysis and optimization of a molten salt solar power tower integrated with a recompression supercritical co2 brayton cycle based on integrated modeling
Energy Conversion and Management, 2017Co-Authors: Kun Wang, Yaling HeAbstract:Abstract In the present study, a molten salt solar power tower (SPT) system integrated with a S-CO 2 Brayton cycle is presented. An integrated model is developed for the integrated SPT system including the heliostat field, the molten salt solar receiver, the molten salt thermal storage, and the S-CO 2 recompression Brayton cycle with reheating. Parametric analysis is conducted to investigate the effects of some key thermodynamic parameters (e.g. hot salt Temperature, cycle high pressure, cycle low pressure, intermediate pressure, and the split ratio) on the integrated SPT system in terms of exergy efficiency. The parameter optimization is performed by using genetic algorithm in order to obtain the highest overall exergy efficiency. The effects of the component performance and the Compressor Inlet Temperature on the optimum parameters are also discussed. The results indicate that the optimum hot salt Temperature is 565 °C which is its maximum allowable Temperature when the solar salt is used as the heat transfer fluid and the thermal storage media. Besides, the optimum cycle low pressure is in the range of 7.80–10.0 MPa which means that the cycle low pressure is not mandatory to be close to the critical pressure. The increase in the Compressor Inlet Temperature leads to both the decrease in maximum exergy efficiency and the variation of the optimum thermodynamic parameters. The component performances have significant effects on the maximum exergy efficiency, but slight effects on optimum thermodynamic parameters. A novel salt with a higher maximum allowable Temperature is indispensable for further improving the system efficiency. The maximum allowable Temperature of 680 °C is recommended for novel salts to be used in the SPT system integrated with S-CO 2 recompression Brayton cycle from the viewpoint of exergy efficiency under the present conditions.
Peiwen Li - One of the best experts on this subject based on the ideXlab platform.
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a systematic comparison of different s co2 brayton cycle layouts based on multi objective optimization for applications in solar power tower plants
Applied Energy, 2018Co-Authors: Kun Wang, Ming-jia Li, Peiwen LiAbstract:Supercritical CO2 (S-CO2) Brayton cycles are recently proposed to be integrated into the solar power tower (SPT) due to their high efficiency and compactness. Comparison of different S-CO2 Brayton cycle layouts is of great significance for selecting a suitable one in the SPT plant. Both of the efficiency and specific work are important performance criteria for the SPT plant. However, previous studies compared only one individual criterion, or both of them just separately. This paper puts forward a systematic comparison of different S-CO2 Brayton cycle layouts based on multi-objective optimizations. The two performance criteria are compared simultaneously between different S-CO2 cycle layouts by comparing the Pareto optimal fronts obtained from multi-objective optimizations. The results suggest that the inter-cooling cycle layout and the partial-cooling cycle layout can generally yield the most excellent performances, and followed by the recompression cycle layout and the pre-compression cycle layout, while the simple recuperation cycle layout has the worst performances. The advantages of the partial-cooling cycle layout and the inter-cooling cycle layout are more prominent compared with the other cycle layouts in the case of high Compressor Inlet Temperature. The provided systematic comparison can be helpful in selecting the most suitable cycle layout for the application in SPT when there are specified requirements for the efficiency and the specific work. In addition, novel salts with high upper limit Temperature (higher than 650 °C) are recommended to be developed as the heat transfer fluid for improving system performances.
Gary E Rochau - One of the best experts on this subject based on the ideXlab platform.
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Dry-Cooled Supercritical CO2 Power for Advanced Nuclear Reactors
Journal of Engineering for Gas Turbines and Power, 2014Co-Authors: Thomas M. Conboy, Matthew D. Carlson, Gary E RochauAbstract:Currently, waste heat rejection from electrical power systems accounts for the largest fraction of water withdrawals from the U.S. fresh water table. Siting of nuclear power plants is limited to areas with access to a large natural supply of fresh or sea water. Due to a rise in energy needs and increased concern over environmental impact, dry air cooling systems are poised to play a large role in the future energy economy. In practice, the implementation of dry air-cooled condensing systems at steam plants has proven to be capital-intensive and requires the power cycle to take a significant efficiency penalty. These shortcomings are fundamental to dry-air steam condensation, which must occur at a fixed Temperature. Closed-cycle gas turbines are an alternative to the conventional steam Rankine plant that allows for much improved dry heat rejection compatibility. Recent research into advanced nuclear energy systems has identified the supercritical CO2 (s-CO2) Brayton cycle in particular as a viable candidate for many proposed reactor types. The s-CO2 Brayton cycle can maintain superior thermal efficiency over a wide range of ambient Temperatures, making these power systems ideally suited for dry air cooling, even in warm climates. For a sodium fast reactor (SFR) operating at 550 °C, thermal efficiency is calculated to be 43% with a 50 °C Compressor Inlet Temperature. This is achieved by raising CO2 Compressor Inlet pressure in response to rising ambient Temperatures. Preliminary design studies have shown that s-CO2 power cycle hardware will be compact and therefore well-matched to near-term and advanced integral small modular reactor (SMR) designs. These advantages also extend to the cooling plant, where it is estimated that dry cooling towers for an SFR-coupled s-CO2 power cycle will be similar in cost and scale to the evaporative cooling tower for a light-water reactor (LWR). The projected benefits of the s-CO2 power cycle coupled to dry air heat rejection may enable the long-awaited rise of next-generation nuclear energy systems, while redrawing the map for siting of small and large nuclear energy systems.
Thomas M. Conboy - One of the best experts on this subject based on the ideXlab platform.
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Dry-Cooled Supercritical CO2 Power for Advanced Nuclear Reactors
Journal of Engineering for Gas Turbines and Power, 2014Co-Authors: Thomas M. Conboy, Matthew D. Carlson, Gary E RochauAbstract:Currently, waste heat rejection from electrical power systems accounts for the largest fraction of water withdrawals from the U.S. fresh water table. Siting of nuclear power plants is limited to areas with access to a large natural supply of fresh or sea water. Due to a rise in energy needs and increased concern over environmental impact, dry air cooling systems are poised to play a large role in the future energy economy. In practice, the implementation of dry air-cooled condensing systems at steam plants has proven to be capital-intensive and requires the power cycle to take a significant efficiency penalty. These shortcomings are fundamental to dry-air steam condensation, which must occur at a fixed Temperature. Closed-cycle gas turbines are an alternative to the conventional steam Rankine plant that allows for much improved dry heat rejection compatibility. Recent research into advanced nuclear energy systems has identified the supercritical CO2 (s-CO2) Brayton cycle in particular as a viable candidate for many proposed reactor types. The s-CO2 Brayton cycle can maintain superior thermal efficiency over a wide range of ambient Temperatures, making these power systems ideally suited for dry air cooling, even in warm climates. For a sodium fast reactor (SFR) operating at 550 °C, thermal efficiency is calculated to be 43% with a 50 °C Compressor Inlet Temperature. This is achieved by raising CO2 Compressor Inlet pressure in response to rising ambient Temperatures. Preliminary design studies have shown that s-CO2 power cycle hardware will be compact and therefore well-matched to near-term and advanced integral small modular reactor (SMR) designs. These advantages also extend to the cooling plant, where it is estimated that dry cooling towers for an SFR-coupled s-CO2 power cycle will be similar in cost and scale to the evaporative cooling tower for a light-water reactor (LWR). The projected benefits of the s-CO2 power cycle coupled to dry air heat rejection may enable the long-awaited rise of next-generation nuclear energy systems, while redrawing the map for siting of small and large nuclear energy systems.