A novel power and cooling cogeneration system which combines a supercritical CO_(2) recompression cycle(SCRC), an ammonia-water absorption refrigeration cycle(AARC) and a Kalina cycle(KC) is proposed and investigated ...A novel power and cooling cogeneration system which combines a supercritical CO_(2) recompression cycle(SCRC), an ammonia-water absorption refrigeration cycle(AARC) and a Kalina cycle(KC) is proposed and investigated for the recovery of medium-temperature waste heat. The system is based on energy cascade utilization, and the waste heat can be fully converted through the simultaneous operation of the three sub-cycles. A steady-state mathematical model is built for further performance study of the proposed system. When the exhaust temperature is 505℃, it is shown that under designed conditions the thermal efficiency and exergy efficiency reach 30.74% and 61.55%, respectively. The exergy analysis results show that the main exergy destruction is concentrated in the heat recovery vapor generator(HRVG). Parametric study shows that the compressor inlet pressure, the SCRC pressure ratio, the main compressor and the turbine I inlet temperature, and the AARC generator pressure have significant effects on thermodynamic and economic performance of the combined system. The findings in this study could provide guidance for system design to achieve an efficient utilization of medium-temperature waste heat(e.g., exhaust heat from gas turbine, high-temperature fuel cells and internal combustion engine).展开更多
As an alternative to the conventional steam Rankine Cycle,Kalina Cycle has witnessed a growing interest over the past years for high-temperature applications(A working fluid temperature of 500◦C at the turbine inlet)....As an alternative to the conventional steam Rankine Cycle,Kalina Cycle has witnessed a growing interest over the past years for high-temperature applications(A working fluid temperature of 500◦C at the turbine inlet).However,the possibility of implementing an additional multi-phase expander on the weak ammonia-water solution loop of the Kalina cycle was hardly analyzed in the available literatures.In this research,two novel Kalina cycles(Kalina cycle-12A and Kalina cycle-12B)have been presented by integrating a multi-phase expander in addition to the turbine installed downstream of the Kalina evaporator.For Kalina cycle-12A,this additional multi-phase expander is positioned downstream of the Kalina separator and on the weak ammonia-water solution loop for Kalina Cycle-12B.A detailed mathematical model based on the thermodynamic laws has been developed to solve and optimize the Kalina Cycles.The influence of critical decision parameters,specifically the ammonia concentration on working fluid and evaporation pressure,were investigated.The optimization was performed based on the objective to maximize the net power output from the multi-phase expander under steady-state operating conditions.When the performance of the proposed Kalina cycles was compared with the conventional Kalina Cycle-12,both of them demonstrated superior performance,i.e.,net power output and peak thermal efficiency increased by a maximum value of 3.23%for the proposed Kalina Cycle-12A cycle and 3.94%for the proposed Kalina Cycle-12B cycle.In terms of second law efficiency,Kalina Cycle-12A is 3.68 percent more efficient than Kalina Cycle-12,while Kalina Cycle-12B is 4.04 percent more efficient.Furthermore,2nd law analysis also reveals,maximum destruction of exergy occurs at the condensers of the cycles.展开更多
Hot dry rock is a new type of geothermal resource which has a promising application prospect in China.This paper conducted a comparative research on performance evaluation of two eligible bottoming cycles for a hot dr...Hot dry rock is a new type of geothermal resource which has a promising application prospect in China.This paper conducted a comparative research on performance evaluation of two eligible bottoming cycles for a hot dry rock power plant in the Gonghe Basin.Based on the given heat production conditions,a Kalina cycle and three organic Rankine cycles were tested respectively with different ammonia-water mixtures of seven ammonia mass fractions and nine ecofriendly working fluids.The results show that the optimal ammonia mass fraction is 82%for the proposed bottoming Kalina cycle in view of maximum net power output.Thermodynamic analysis suggests that wet fluids should be supercritical while dry fluids should be saturated at the inlet of turbine,respectively.The maximum net power output of the organic Rankine cycle with dry fluids expanding from saturated state is higher than that of the other organic Rankine cycle combinations,and is far higher than the maximum net power output in all tested Kalina cycle cases.Under the given heat production conditions of hot dry rock resource in the Gonghe Basin,the saturated organic Rankine cycle with the dry fluid butane as working fluid generates the largest amount of net power.展开更多
In order to improve efficiency of a combined power system in which waste heat from exhaust gas could be efficiently recovered and cold energy of liquefied natural gas(LNG) could be fully utilized as well. A system sim...In order to improve efficiency of a combined power system in which waste heat from exhaust gas could be efficiently recovered and cold energy of liquefied natural gas(LNG) could be fully utilized as well. A system simulation and thermodynamic analysis were carried out,the Kalina cycle was reorganized by changing the concentration of "basic composition",so that a better thermal matching in the heat exchanger could be obtained and the irreversibility of the system was decreased. It was found that the Kalina cycle generally used in the bottom of combined power cycle could also be used to recover the cold energy of LNG. The results show that the exergy efficiency of 42.97% is obtained. Compared with the previous system attained the exergy efficiency of 39.76%,the improved system has a better performance.展开更多
基金supported by the Shandong Provincial Natural Science Foundation of China(No.ZR2019MEE045)the National Natural Science Foundation of China(No.51776203)the Key Project of National Natural Science Foundation of China(No.61733010)。
文摘A novel power and cooling cogeneration system which combines a supercritical CO_(2) recompression cycle(SCRC), an ammonia-water absorption refrigeration cycle(AARC) and a Kalina cycle(KC) is proposed and investigated for the recovery of medium-temperature waste heat. The system is based on energy cascade utilization, and the waste heat can be fully converted through the simultaneous operation of the three sub-cycles. A steady-state mathematical model is built for further performance study of the proposed system. When the exhaust temperature is 505℃, it is shown that under designed conditions the thermal efficiency and exergy efficiency reach 30.74% and 61.55%, respectively. The exergy analysis results show that the main exergy destruction is concentrated in the heat recovery vapor generator(HRVG). Parametric study shows that the compressor inlet pressure, the SCRC pressure ratio, the main compressor and the turbine I inlet temperature, and the AARC generator pressure have significant effects on thermodynamic and economic performance of the combined system. The findings in this study could provide guidance for system design to achieve an efficient utilization of medium-temperature waste heat(e.g., exhaust heat from gas turbine, high-temperature fuel cells and internal combustion engine).
文摘As an alternative to the conventional steam Rankine Cycle,Kalina Cycle has witnessed a growing interest over the past years for high-temperature applications(A working fluid temperature of 500◦C at the turbine inlet).However,the possibility of implementing an additional multi-phase expander on the weak ammonia-water solution loop of the Kalina cycle was hardly analyzed in the available literatures.In this research,two novel Kalina cycles(Kalina cycle-12A and Kalina cycle-12B)have been presented by integrating a multi-phase expander in addition to the turbine installed downstream of the Kalina evaporator.For Kalina cycle-12A,this additional multi-phase expander is positioned downstream of the Kalina separator and on the weak ammonia-water solution loop for Kalina Cycle-12B.A detailed mathematical model based on the thermodynamic laws has been developed to solve and optimize the Kalina Cycles.The influence of critical decision parameters,specifically the ammonia concentration on working fluid and evaporation pressure,were investigated.The optimization was performed based on the objective to maximize the net power output from the multi-phase expander under steady-state operating conditions.When the performance of the proposed Kalina cycles was compared with the conventional Kalina Cycle-12,both of them demonstrated superior performance,i.e.,net power output and peak thermal efficiency increased by a maximum value of 3.23%for the proposed Kalina Cycle-12A cycle and 3.94%for the proposed Kalina Cycle-12B cycle.In terms of second law efficiency,Kalina Cycle-12A is 3.68 percent more efficient than Kalina Cycle-12,while Kalina Cycle-12B is 4.04 percent more efficient.Furthermore,2nd law analysis also reveals,maximum destruction of exergy occurs at the condensers of the cycles.
基金the State Grid Technology Program(SGRI-DL-71-15-006)the Scientific and Technological Project of Qinghai Province,China(2018-ZJ-726).
文摘Hot dry rock is a new type of geothermal resource which has a promising application prospect in China.This paper conducted a comparative research on performance evaluation of two eligible bottoming cycles for a hot dry rock power plant in the Gonghe Basin.Based on the given heat production conditions,a Kalina cycle and three organic Rankine cycles were tested respectively with different ammonia-water mixtures of seven ammonia mass fractions and nine ecofriendly working fluids.The results show that the optimal ammonia mass fraction is 82%for the proposed bottoming Kalina cycle in view of maximum net power output.Thermodynamic analysis suggests that wet fluids should be supercritical while dry fluids should be saturated at the inlet of turbine,respectively.The maximum net power output of the organic Rankine cycle with dry fluids expanding from saturated state is higher than that of the other organic Rankine cycle combinations,and is far higher than the maximum net power output in all tested Kalina cycle cases.Under the given heat production conditions of hot dry rock resource in the Gonghe Basin,the saturated organic Rankine cycle with the dry fluid butane as working fluid generates the largest amount of net power.
基金Sponsored by the Liaoning Provincial Science and Technology Program Project(Grant No.2012219024)
文摘In order to improve efficiency of a combined power system in which waste heat from exhaust gas could be efficiently recovered and cold energy of liquefied natural gas(LNG) could be fully utilized as well. A system simulation and thermodynamic analysis were carried out,the Kalina cycle was reorganized by changing the concentration of "basic composition",so that a better thermal matching in the heat exchanger could be obtained and the irreversibility of the system was decreased. It was found that the Kalina cycle generally used in the bottom of combined power cycle could also be used to recover the cold energy of LNG. The results show that the exergy efficiency of 42.97% is obtained. Compared with the previous system attained the exergy efficiency of 39.76%,the improved system has a better performance.
