This paper discussed the experimental results of the performance of an organic Rankine cycle(ORC)system with an ultra-low temperature heat source.The low boiling point working medium R134a was adopted in the system.Th...This paper discussed the experimental results of the performance of an organic Rankine cycle(ORC)system with an ultra-low temperature heat source.The low boiling point working medium R134a was adopted in the system.The simulated heat source temperature(SHST)in this work was set from 39.51°C to 48.60°C by the simulated heat source module.The influence of load percentage of simulated heat source(LPSHS)between 50%and 70%,the rotary valve opening(RVO)between 20%and 100%,the resistive load between 36Ωand 180Ωor the no-load of the generator,as well as the autumn and winter ambient temperature on the system performance were studied.The results showed that the stability of the system was promoted when the generator had a resistive load.The power generation(PG)and generator speed(GS)of the system in autumn were better than in winter,but the expander pressure ratio(EPR)was lower than in winter.Keep RVO unchanged,the SHST,the mass flow rate(MFR)of the working medium,GS,and the PG of the system increased with the increasing of LPSHS for different generator resistance load values.When the RVO was 60%,LPSHS was 70%,the SHST was 44.15°C and the resistive load was 72Ω,the highest PG reached 15.11 W.Finally,a simulation formula was obtained for LPSHS,resistance load,and PG,and its correlation coefficient was between 0.9818 and 0.9901.The formula can accurately predict the PG.The experimental results showed that the standard deviation between the experimental and simulated values was below 0.0792,and the relative error was within±5%.展开更多
For efficient utilization of a limited geothermal resource in practical projects,the cycle parameters were comprehensively analyzed by combining with the heat transfer performance of the plate heat exchanger,with a va...For efficient utilization of a limited geothermal resource in practical projects,the cycle parameters were comprehensively analyzed by combining with the heat transfer performance of the plate heat exchanger,with a variation of flowrate of R245 fa.The influence of working fluid flowrate on a 500 W ORC system was investigated.Adjusting the working fluid flowrate to an optimal value results in the most efficient heat transfer and hence the optimal heat transfer parameters of the plate heat exchanger can be determined.Therefore,for the ORC systems,optimal working fluid flowrate should be controlled.Using different temperature hot water as the heat source,it is found that the optimal flowrate increases by 6-10 L/h with 5 ℃ increment of hot water inlet temperature.During experiment,lower degree of superheat of the working fluid at the outlet the plate heat exchanger may lead to unstable power generation.It is considered that the plate heat exchanger has a compact construction which makes its bulk so small that liquid mixture causes the unstable power generation.To avoid this phenomenon,the flow area of plate heat exchanger should be larger than the designed one.Alternatively,installing a small shell and tube heat exchanger between the outlet of plate heat exchanger and the inlet of expander can be another solution.展开更多
With increasing awareness of energy conservation and environmental protection, the Organic Rankine Cycle (ORC) system has gained significant attention. This technology enables the recovery of industrial waste heat, wa...With increasing awareness of energy conservation and environmental protection, the Organic Rankine Cycle (ORC) system has gained significant attention. This technology enables the recovery of industrial waste heat, waste incineration heat, and renewable energy sources such as geothermal heat, biomass energy, and solar energy at lower temperatures. However, the low-grade heat source utilized in ORC systems faces a challenge to achieving high power generation efficiency and output power. Therefore, enhancing the power generation capacity of ORC systems is a key research focus in this field. An entranced heat exchanger ORC system with the screw expander driven by the low-temperature heat source is established to investigate the relevant performance. Hot water temperature from 77°C to 132°C is adopted for performance analysis, while the environmental temperature is approximately 25°C. Refrigerant R245fa is selected as the working fluid, and the screw expander is employed for power generation. It is worth noting that the entranced heat exchanger ORC system has significant potential for low-temperature heat recovery. Experimental results indicate that the maximum power output is 12.83 kW, which is obtained at around 105°C hot water inlet temperature. Correspondingly, the average power output remains 11.75 kW, revealing the system’s high stability for power generation. The implementation of a plate heat exchanger for enhanced heat transfer has enabled a 50% reduction in system size compared to traditional shell-tube type ORC systems. Besides, economic calculations demonstrate substantial benefits associated with the ORC system. The calculations indicate an internal benefit of 560,000 RMB/year, accompanied by notable external benefits such as an energy saving and emission reduction potential of up to 784 t CO2 per year. Moreover, the payback period is 2.23 years. It shows a remarkable improvement in terms of performance and excellent economic benefits. As a result, the novel ORC presents a promising alternative for low-grade heat utilization as compared to conventional small-scale ORC systems.展开更多
Permanent loss of vital functions after central nervous system （CNS） injury, e.g., blindness in traumatic optic nerve （ON） injury or paralysis in spinal cord injury, occurs in part because axons in the adult mamma...Permanent loss of vital functions after central nervous system （CNS） injury, e.g., blindness in traumatic optic nerve （ON） injury or paralysis in spinal cord injury, occurs in part because axons in the adult mammalian CNS do not regenerate after injury. Growth failure is due to the diminished intrinsic regenerative capacity of mature neurons and the inhibitory environment of the adult CNS. Neutralizing extracellular inhibitory molecules genetically or pharmacologically yields only limited regeneration and functional recovery, highlighting the critical importance of neuron-intrinsic factors.展开更多
A novel dual-pressure organic Rankine cycle system(DPORC)with a dual-stage ejector(DE-DPORC)is proposed.The system incorporates a dual-stage ejector that utilizes a small amount of extraction steam from the highpressu...A novel dual-pressure organic Rankine cycle system(DPORC)with a dual-stage ejector(DE-DPORC)is proposed.The system incorporates a dual-stage ejector that utilizes a small amount of extraction steam from the highpressure expander to pressurize a large quantity of exhaust gas to performwork for the low-pressure expander.This innovative approach addresses condensing pressure limitations,reduces power consumption during pressurization,minimizes heat loss,and enhances the utilization efficiency of waste heat steam.A thermodynamic model is developed with net output work,thermal efficiency,and exergy efficiency(W_(net,ηt,ηex))as evaluation criteria,an economicmodel is established with levelized energy cost(LEC)as evaluation index,anenvironmentalmodel is created with annual equivalent carbon dioxide emission reduction(AER)as evaluation parameter.A comprehensive analysis is conducted on the impact of heat source temperature(T_(S,in)),evaporation temperature(T_(2)),entrainment ratio(E_(r1),E_(r2)),and working fluid pressure(P_(5),P_(6))on system performance.It compares the comprehensive performance of the DE-DPORC system with that of the DPORC system at TS,in of 433.15 K and T2 of 378.15 K.Furthermore,multi-objective optimization using the dragonfly algorithm is performed to determine optimal working conditions for the DE-DPORC system through the TOPSIS method.The findings indicate that the DEDPORC system exhibits a 5.34%increase inWnet andηex,a 58.06%increase inηt,a 5.61%increase in AER,and a reduction of 47.67%and 13.51%in the heat dissipation of the condenser andLEC,compared to theDPORCsystem,highlighting the advantages of this enhanced system.The optimal operating conditions are TS,in=426.74 K,T_(2)=389.37 K,E_(r1)=1.33,E_(r2)=3.17,P_(5)=0.39 MPa,P_(6)=1.32 MPa,which offer valuable technical support for engineering applications;however,they are approaching the peak thermodynamic and environmental performance while falling short of the highest economic performance.展开更多
目的以RNA干扰抑制血管平滑肌细胞(vascu lar smooth musc le cells,VSMCs)ORC1基因,探讨ORC1基因表达抑制后VSMCs增殖的变化。方法实验设置正常对照组、阴性siRNA组及阳性(ORC1+A、ORC1+B、ORC1+C)siR-NA组。应用W estern b lot检测ORC...目的以RNA干扰抑制血管平滑肌细胞(vascu lar smooth musc le cells,VSMCs)ORC1基因,探讨ORC1基因表达抑制后VSMCs增殖的变化。方法实验设置正常对照组、阴性siRNA组及阳性(ORC1+A、ORC1+B、ORC1+C)siR-NA组。应用W estern b lot检测ORC1基因表达的变化;应用MTT比色试验、3H-TdR掺入试验检测VSMCs增殖的情况。免疫细胞化学染色观察增殖细胞核抗原(proliferating cell nuc lear antigen,PCNA)表达。结果①siRNA转染后,3个阳性siRNA转染组ORC1基因表达水平均降低,尤以第2对阳性siRNA抑制效果最为显著,而空白对照组及阴性对照组间ORC1基因表达水平无显著差异。②siRNA转染使ORC1表达减弱后,VSMCs的MTT吸光度值3、H-TdR掺入量和PCNA表达量均较空白对照组及阴性对照组显著降低。结论RNA干扰介导的ORC1基因沉寂可显著抑制VSMCs增殖。展开更多
为降低CO_(2)排放,提高能源利用效率,该文建立超超临界二次再热-碳捕集集成系统。利用碳捕集汽轮机排汽为再沸器提供能量,并在集成系统基础上提出3种优化方法。结果表明,3种优化方案都提高了机组效率和热力性能,热效率分别提高0.508%、1...为降低CO_(2)排放,提高能源利用效率,该文建立超超临界二次再热-碳捕集集成系统。利用碳捕集汽轮机排汽为再沸器提供能量,并在集成系统基础上提出3种优化方法。结果表明,3种优化方案都提高了机组效率和热力性能,热效率分别提高0.508%、1.314%和4.817%,对应煤耗分别降低4.514g/(kW×h)、11.428g/(kW×h)、39.440g/(kW×h)。当设定碳捕集率为96%、CO_(2)再生能耗为3.8GJ/t时,对集成系统及3种优化系统进行技术经济性分析与㶲分析。通过分析可知,方案III的平均发电成本(the levelized cost of energy,LCOE)和CO_(2)减排成本最低;㶲分析表明高压加热器的㶲效率、㶲损普遍高于低压加热器。3种方案中,方案Ⅲ的高压加热器㶲效率明显高于方案Ⅰ与方案Ⅱ,从系统各设备㶲分析对比来看锅炉㶲效率最低。与锅炉相比较汽轮机的㶲损失相对较小,其中超高压缸和低压缸㶲损失所占比例相对较大。展开更多
基金This work was supported by Tianjin Natural Science Foundation(No.21JCZDJC00750).
文摘This paper discussed the experimental results of the performance of an organic Rankine cycle(ORC)system with an ultra-low temperature heat source.The low boiling point working medium R134a was adopted in the system.The simulated heat source temperature(SHST)in this work was set from 39.51°C to 48.60°C by the simulated heat source module.The influence of load percentage of simulated heat source(LPSHS)between 50%and 70%,the rotary valve opening(RVO)between 20%and 100%,the resistive load between 36Ωand 180Ωor the no-load of the generator,as well as the autumn and winter ambient temperature on the system performance were studied.The results showed that the stability of the system was promoted when the generator had a resistive load.The power generation(PG)and generator speed(GS)of the system in autumn were better than in winter,but the expander pressure ratio(EPR)was lower than in winter.Keep RVO unchanged,the SHST,the mass flow rate(MFR)of the working medium,GS,and the PG of the system increased with the increasing of LPSHS for different generator resistance load values.When the RVO was 60%,LPSHS was 70%,the SHST was 44.15°C and the resistive load was 72Ω,the highest PG reached 15.11 W.Finally,a simulation formula was obtained for LPSHS,resistance load,and PG,and its correlation coefficient was between 0.9818 and 0.9901.The formula can accurately predict the PG.The experimental results showed that the standard deviation between the experimental and simulated values was below 0.0792,and the relative error was within±5%.
基金Project (2012AA053001) supported by High-tech Research and Development Program of China
文摘For efficient utilization of a limited geothermal resource in practical projects,the cycle parameters were comprehensively analyzed by combining with the heat transfer performance of the plate heat exchanger,with a variation of flowrate of R245 fa.The influence of working fluid flowrate on a 500 W ORC system was investigated.Adjusting the working fluid flowrate to an optimal value results in the most efficient heat transfer and hence the optimal heat transfer parameters of the plate heat exchanger can be determined.Therefore,for the ORC systems,optimal working fluid flowrate should be controlled.Using different temperature hot water as the heat source,it is found that the optimal flowrate increases by 6-10 L/h with 5 ℃ increment of hot water inlet temperature.During experiment,lower degree of superheat of the working fluid at the outlet the plate heat exchanger may lead to unstable power generation.It is considered that the plate heat exchanger has a compact construction which makes its bulk so small that liquid mixture causes the unstable power generation.To avoid this phenomenon,the flow area of plate heat exchanger should be larger than the designed one.Alternatively,installing a small shell and tube heat exchanger between the outlet of plate heat exchanger and the inlet of expander can be another solution.
文摘With increasing awareness of energy conservation and environmental protection, the Organic Rankine Cycle (ORC) system has gained significant attention. This technology enables the recovery of industrial waste heat, waste incineration heat, and renewable energy sources such as geothermal heat, biomass energy, and solar energy at lower temperatures. However, the low-grade heat source utilized in ORC systems faces a challenge to achieving high power generation efficiency and output power. Therefore, enhancing the power generation capacity of ORC systems is a key research focus in this field. An entranced heat exchanger ORC system with the screw expander driven by the low-temperature heat source is established to investigate the relevant performance. Hot water temperature from 77°C to 132°C is adopted for performance analysis, while the environmental temperature is approximately 25°C. Refrigerant R245fa is selected as the working fluid, and the screw expander is employed for power generation. It is worth noting that the entranced heat exchanger ORC system has significant potential for low-temperature heat recovery. Experimental results indicate that the maximum power output is 12.83 kW, which is obtained at around 105°C hot water inlet temperature. Correspondingly, the average power output remains 11.75 kW, revealing the system’s high stability for power generation. The implementation of a plate heat exchanger for enhanced heat transfer has enabled a 50% reduction in system size compared to traditional shell-tube type ORC systems. Besides, economic calculations demonstrate substantial benefits associated with the ORC system. The calculations indicate an internal benefit of 560,000 RMB/year, accompanied by notable external benefits such as an energy saving and emission reduction potential of up to 784 t CO2 per year. Moreover, the payback period is 2.23 years. It shows a remarkable improvement in terms of performance and excellent economic benefits. As a result, the novel ORC presents a promising alternative for low-grade heat utilization as compared to conventional small-scale ORC systems.
基金supported by grants from National Eye Institute,Bright Focus Foundation and Shriners Hospital for Children
文摘Permanent loss of vital functions after central nervous system （CNS） injury, e.g., blindness in traumatic optic nerve （ON） injury or paralysis in spinal cord injury, occurs in part because axons in the adult mammalian CNS do not regenerate after injury. Growth failure is due to the diminished intrinsic regenerative capacity of mature neurons and the inhibitory environment of the adult CNS. Neutralizing extracellular inhibitory molecules genetically or pharmacologically yields only limited regeneration and functional recovery, highlighting the critical importance of neuron-intrinsic factors.
基金supported by the Foundation of Liaoning Provincial Key Laboratory of Energy Storage and Utilization(Grant Nos.CNWK202304 and CNNK202315)the Introduction of TalentResearch Start-Up Funding Projects ofYingkou Institute of Technology(Grant No.YJRC202107).
文摘A novel dual-pressure organic Rankine cycle system(DPORC)with a dual-stage ejector(DE-DPORC)is proposed.The system incorporates a dual-stage ejector that utilizes a small amount of extraction steam from the highpressure expander to pressurize a large quantity of exhaust gas to performwork for the low-pressure expander.This innovative approach addresses condensing pressure limitations,reduces power consumption during pressurization,minimizes heat loss,and enhances the utilization efficiency of waste heat steam.A thermodynamic model is developed with net output work,thermal efficiency,and exergy efficiency(W_(net,ηt,ηex))as evaluation criteria,an economicmodel is established with levelized energy cost(LEC)as evaluation index,anenvironmentalmodel is created with annual equivalent carbon dioxide emission reduction(AER)as evaluation parameter.A comprehensive analysis is conducted on the impact of heat source temperature(T_(S,in)),evaporation temperature(T_(2)),entrainment ratio(E_(r1),E_(r2)),and working fluid pressure(P_(5),P_(6))on system performance.It compares the comprehensive performance of the DE-DPORC system with that of the DPORC system at TS,in of 433.15 K and T2 of 378.15 K.Furthermore,multi-objective optimization using the dragonfly algorithm is performed to determine optimal working conditions for the DE-DPORC system through the TOPSIS method.The findings indicate that the DEDPORC system exhibits a 5.34%increase inWnet andηex,a 58.06%increase inηt,a 5.61%increase in AER,and a reduction of 47.67%and 13.51%in the heat dissipation of the condenser andLEC,compared to theDPORCsystem,highlighting the advantages of this enhanced system.The optimal operating conditions are TS,in=426.74 K,T_(2)=389.37 K,E_(r1)=1.33,E_(r2)=3.17,P_(5)=0.39 MPa,P_(6)=1.32 MPa,which offer valuable technical support for engineering applications;however,they are approaching the peak thermodynamic and environmental performance while falling short of the highest economic performance.
文摘目的以RNA干扰抑制血管平滑肌细胞(vascu lar smooth musc le cells,VSMCs)ORC1基因,探讨ORC1基因表达抑制后VSMCs增殖的变化。方法实验设置正常对照组、阴性siRNA组及阳性(ORC1+A、ORC1+B、ORC1+C)siR-NA组。应用W estern b lot检测ORC1基因表达的变化;应用MTT比色试验、3H-TdR掺入试验检测VSMCs增殖的情况。免疫细胞化学染色观察增殖细胞核抗原(proliferating cell nuc lear antigen,PCNA)表达。结果①siRNA转染后,3个阳性siRNA转染组ORC1基因表达水平均降低,尤以第2对阳性siRNA抑制效果最为显著,而空白对照组及阴性对照组间ORC1基因表达水平无显著差异。②siRNA转染使ORC1表达减弱后,VSMCs的MTT吸光度值3、H-TdR掺入量和PCNA表达量均较空白对照组及阴性对照组显著降低。结论RNA干扰介导的ORC1基因沉寂可显著抑制VSMCs增殖。
文摘为降低CO_(2)排放,提高能源利用效率,该文建立超超临界二次再热-碳捕集集成系统。利用碳捕集汽轮机排汽为再沸器提供能量,并在集成系统基础上提出3种优化方法。结果表明,3种优化方案都提高了机组效率和热力性能,热效率分别提高0.508%、1.314%和4.817%,对应煤耗分别降低4.514g/(kW×h)、11.428g/(kW×h)、39.440g/(kW×h)。当设定碳捕集率为96%、CO_(2)再生能耗为3.8GJ/t时,对集成系统及3种优化系统进行技术经济性分析与㶲分析。通过分析可知,方案III的平均发电成本(the levelized cost of energy,LCOE)和CO_(2)减排成本最低;㶲分析表明高压加热器的㶲效率、㶲损普遍高于低压加热器。3种方案中,方案Ⅲ的高压加热器㶲效率明显高于方案Ⅰ与方案Ⅱ,从系统各设备㶲分析对比来看锅炉㶲效率最低。与锅炉相比较汽轮机的㶲损失相对较小,其中超高压缸和低压缸㶲损失所占比例相对较大。
