Exhaust waste heat recovery system based on organic Rankine cycle(ORC)has been considered as an effective method to achieve energy conservation and emissions reduction of engine.The performance of adiesel engine with ...Exhaust waste heat recovery system based on organic Rankine cycle(ORC)has been considered as an effective method to achieve energy conservation and emissions reduction of engine.The performance of adiesel engine with an on-board ORC exhaust heat recovery system was evaluated through simulations in this study.The combined system was optimized through controlling the exhaust gas mass flow rate entering the ORC system.The models of the engine with ORC system were developed in GT-suite and Simulink environment.The validation results showed high accuracy of the models.The performance of the system recovering heat from different exhaust gas mass flow rates was evaluated.The comparative analysis of the performance between the optimized and un-optimized system was also presented.The results indicated that the exhaust gas mass flow rate had significant effects on the system performance.Integration with the onboard ORC system could effectively improve the engine power performance.The power output of the engineORC combined system with optimization had further improvement,and the maximum improvement could reach up to 1.16 kW.展开更多
Seasonally flooded várzea forests of Western Amazonia are one of the most productive and biodiverse wetland forests in the world.However,data on their soil CO_(2)emissions,soil organic matter decomposition rates,...Seasonally flooded várzea forests of Western Amazonia are one of the most productive and biodiverse wetland forests in the world.However,data on their soil CO_(2)emissions,soil organic matter decomposition rates,and soil C stocks are scarce.This is a concern because hydrological changes are predicted to lead to increases in the height,extent,and duration of seasonal floods,which are likely to have a significant effect on soil C stocks and fluxes.However,with no empirical data,the impact of altered flood regimes on várzea soil C cycles remains uncertain.This study quantified the effects of maximum annual flood height and soil moisture on soil CO_(2)efflux rate(R_(s))and soil organic matter decomposition rate(k)in the várzea forests of Pacaya Samiria National Reserve,Peru.The study was conducted between May and August 2017.The results showed that R_(s)(10.6–182.7 mg C m^(-2)h^(-1))and k(0.016–0.078)varied between and within sites,and were considerably lower than the values reported for other tropical forests.In addition,R_(s)was negatively affected by flood height(P<0.01)and soil moisture(P<0.001),and it decreased with decreasing river levels post flooding(P<0.001).In contrast,k was not affected by any of the above-mentioned factors.Soil moisture was the dominant factor influencing R_(s),and it was significantly affected by maximum flood height,even after the floods had subsided(P<0.001).Consequently,we concluded that larger floods will likely lead to reduced R_(s),whilst k could remain unchanged but with decomposition processes becoming more anaerobic.展开更多
文摘Exhaust waste heat recovery system based on organic Rankine cycle(ORC)has been considered as an effective method to achieve energy conservation and emissions reduction of engine.The performance of adiesel engine with an on-board ORC exhaust heat recovery system was evaluated through simulations in this study.The combined system was optimized through controlling the exhaust gas mass flow rate entering the ORC system.The models of the engine with ORC system were developed in GT-suite and Simulink environment.The validation results showed high accuracy of the models.The performance of the system recovering heat from different exhaust gas mass flow rates was evaluated.The comparative analysis of the performance between the optimized and un-optimized system was also presented.The results indicated that the exhaust gas mass flow rate had significant effects on the system performance.Integration with the onboard ORC system could effectively improve the engine power performance.The power output of the engineORC combined system with optimization had further improvement,and the maximum improvement could reach up to 1.16 kW.
基金supported by Department of Geography and Earth Sciences(DGES)and Institute of Biological,Environmental and Rural Sciences(IBERS)at Aberystwyth University,Wales of UK。
文摘Seasonally flooded várzea forests of Western Amazonia are one of the most productive and biodiverse wetland forests in the world.However,data on their soil CO_(2)emissions,soil organic matter decomposition rates,and soil C stocks are scarce.This is a concern because hydrological changes are predicted to lead to increases in the height,extent,and duration of seasonal floods,which are likely to have a significant effect on soil C stocks and fluxes.However,with no empirical data,the impact of altered flood regimes on várzea soil C cycles remains uncertain.This study quantified the effects of maximum annual flood height and soil moisture on soil CO_(2)efflux rate(R_(s))and soil organic matter decomposition rate(k)in the várzea forests of Pacaya Samiria National Reserve,Peru.The study was conducted between May and August 2017.The results showed that R_(s)(10.6–182.7 mg C m^(-2)h^(-1))and k(0.016–0.078)varied between and within sites,and were considerably lower than the values reported for other tropical forests.In addition,R_(s)was negatively affected by flood height(P<0.01)and soil moisture(P<0.001),and it decreased with decreasing river levels post flooding(P<0.001).In contrast,k was not affected by any of the above-mentioned factors.Soil moisture was the dominant factor influencing R_(s),and it was significantly affected by maximum flood height,even after the floods had subsided(P<0.001).Consequently,we concluded that larger floods will likely lead to reduced R_(s),whilst k could remain unchanged but with decomposition processes becoming more anaerobic.
