Organic Rankine Cycle(ORC)is one of the solutions to utilize a low temperature geothermal fluid for power generation.The ORC system can be placed at the exit of the separator to extract energy from brine.Furthermore,o...Organic Rankine Cycle(ORC)is one of the solutions to utilize a low temperature geothermal fluid for power generation.The ORC system can be placed at the exit of the separator to extract energy from brine.Furthermore,one of the main components of the system and very important is the pump.Therefore,in this research,the pump rotation is examined to investigate the effect on power output and energy efficiency for low temperature geothermal fluid.The rotation is determined by using an inverter with the following frequencies:7.5,10,12.5,15 and 17.5 Hz,respectively.R-134 working fluid is employed with 373.15 K evaporator temperature in relation to the low temperature of the geothermal fluid.Furthermore,the condenser temperature and fluid pressure were set up to 293.15 K and 5×10^(5) Pa,respectively.This research uses a DC generator with a maximum power of 750 Watt and the piping system is made from copper alloy C12200 ASTM B280 with size 1.905×10^(−2) m and a thickness of 8×10^(−4) m.The results showed that there is an increase in mass flow rate,enthalpy and generator power output along with increasing pump rotation.In addition,it showed that the maximum generator output power was 377.31 Watt at the highest pump rotation with a frequency of 17.5 Hz.展开更多
Charge-based studies,in particular investigations of mass distribution,are still almost absent,although the efficiency of the organic Rankine cycle(ORC)has attracted a great deal of scholarly attention.This paper aims...Charge-based studies,in particular investigations of mass distribution,are still almost absent,although the efficiency of the organic Rankine cycle(ORC)has attracted a great deal of scholarly attention.This paper aims to provide a new perspective on the intrinsic relationship among the mass distribution,phase-zone distribution in the heat exchanger(HEX),charge of working fuid(WF),rotation speed of the pump(RSP),and system performance.A comprehensive ORC simulation model is presented by linking each component's sub-models,including the independent models for HEX,pump,and expander in an object-oriented fashion.The visualization study of mass distribution of the WF in the system is investigated under different working conditions.Furthermore,the volume and mass of the gas phase,two-phase and liquid phase of WF in the HEX and their variation rules are analyzed in-depth.Finally,the strategies of charge reduction considering HEX areas and pipe sizes are investigated.The results show that the model based on the interior-point method provides high levels of accuracy and robustness.The mass ratio of the WF is concentrated in the liquid receiver,especially in the regenerator,which is 32.9%and 21.9%of the total mass,respectively.Furthermore,2.4 kg(6.9%)WF in the system gradually migrates to the high-temperature side as the RSP increases while 6.1 kg(17.4%)WF migrates to the low-temperature side,especially to the condenser,as the charge in the system increases.Output power and efficiency both decrease gradually after the peak due to changes in RSP and charge.Last,reducing heat transfer areas of the condenser and regenerator is the most effective way to reduce WF charge.展开更多
The organic Rankine cycle(ORC)is a promising technology for industrial waste heat recovery and renewable energy utilization.High temperature ORCs have attracted particular interest because of their high thermal effici...The organic Rankine cycle(ORC)is a promising technology for industrial waste heat recovery and renewable energy utilization.High temperature ORCs have attracted particular interest because of their high thermal efficiencies and outputs.The material compatibility of working fluid is a significant limitation for the working fluid selection and system design for high temperature ORCs.This work presents a method for studying the material compatibility of ORC working fluids based on the calculated conditions of the ORCs and matching of components,temperatures,and materials.Hexamethyldisiloxane(MM)was chosen as the test fluid.The experimental results show that 304 stainless steel has better compatibility with MM than copper as the material of evaporators.Fluoric rubber is not a suitable sealing material for high temperature ORCs with MM as the working fluids because of the bad compatibility.Mineral oil has better compatibility with MM than polyol ester(POE)lubricant as the lubricant for the fluid pump.展开更多
A novel combined power and heat generation system was investigated in this study. This system consists of a low-temperature geothermally-powered organic Rankine cycle (ORC) subsystem, an intermediate heat exchanger an...A novel combined power and heat generation system was investigated in this study. This system consists of a low-temperature geothermally-powered organic Rankine cycle (ORC) subsystem, an intermediate heat exchanger and a commercial R134a-based heat pump subsystem. The advantages of the novel combined power and heat generation system are free of using additional cooling water circling system for the power generation subsystem as well as maximizing the use of thermal energy in the low-temperature geothermal source. The main purpose is to identify suitable working fluids (wet, isentropic and dry flu-ids) which may yield high PPR (the ratio of power produced by the power generation subsystem to power consumed by the heat pump subsystem) value and QQR (the ratio of heat supplied to the user to heat produced by the geothermal source) value. Parameters under investigation were evaporating temperature, PPR value and QQR value. Results indicate that there exits an optimum evaporating temperature to maximize the PPR value and minimize the QQR value at the same time for individual fluid. And dry fluids show higher PPR values but lower QQR values. NH3 and R152a outstand among wet fluids. R134a out-stands among isentropic fluids. R236ea, R245ca, R245fa, R600 and R600a outstand among dry fluids. R236ea shows the highest PPR value among the recommended fluids.展开更多
Hot dry rock(HDR)is a kind of clean energy with significant potential.Since the 1970s,the United States,Japan,France,Australia,and other countries have attempted to conduct several HDR development research projects to...Hot dry rock(HDR)is a kind of clean energy with significant potential.Since the 1970s,the United States,Japan,France,Australia,and other countries have attempted to conduct several HDR development research projects to extract thermal energy by breaking through key technologies.However,up to now,the development of HDR is still in the research,development,and demonstration stage.An HDR exploration borehole(with 236℃ at a depth of 3705 m)was drilled into Triassic granite in the Gonghe Basin in northwest China in 2017.Subsequently,China Geological Survey(CGS)launched the HDR resources exploration and production demonstration project in 2019.After three years of efforts,a sequence of significant technological breakthroughs have been made,including the genetic model of deep heat sources,directional drilling and well completion in high-temperature hard rock,large-scale reservoir stimulation,reservoir characterization,and productivity evaluation,reservoir connectivity and flow circulation,efficient thermoelectric conversion,monitoring,and geological risk assessment,etc.Then the whole-process technological system for HDR exploration and production has been preliminarily established accordingly.The first power generation test was completed in November 2021.The results of this project will provide scientific support for HDR development and utilization in the future.展开更多
基金gratitude to LPPM UNS,for funding this research project titled“Increasing the Capacity of Geothermal Power Plants Using Exergy Analysis to Support Government Policy in the Development of a 35 Thousand MW Power Plant(Hibah Penelitian Unggulan UNS(PU-UNS))”.
文摘Organic Rankine Cycle(ORC)is one of the solutions to utilize a low temperature geothermal fluid for power generation.The ORC system can be placed at the exit of the separator to extract energy from brine.Furthermore,one of the main components of the system and very important is the pump.Therefore,in this research,the pump rotation is examined to investigate the effect on power output and energy efficiency for low temperature geothermal fluid.The rotation is determined by using an inverter with the following frequencies:7.5,10,12.5,15 and 17.5 Hz,respectively.R-134 working fluid is employed with 373.15 K evaporator temperature in relation to the low temperature of the geothermal fluid.Furthermore,the condenser temperature and fluid pressure were set up to 293.15 K and 5×10^(5) Pa,respectively.This research uses a DC generator with a maximum power of 750 Watt and the piping system is made from copper alloy C12200 ASTM B280 with size 1.905×10^(−2) m and a thickness of 8×10^(−4) m.The results showed that there is an increase in mass flow rate,enthalpy and generator power output along with increasing pump rotation.In addition,it showed that the maximum generator output power was 377.31 Watt at the highest pump rotation with a frequency of 17.5 Hz.
文摘Charge-based studies,in particular investigations of mass distribution,are still almost absent,although the efficiency of the organic Rankine cycle(ORC)has attracted a great deal of scholarly attention.This paper aims to provide a new perspective on the intrinsic relationship among the mass distribution,phase-zone distribution in the heat exchanger(HEX),charge of working fuid(WF),rotation speed of the pump(RSP),and system performance.A comprehensive ORC simulation model is presented by linking each component's sub-models,including the independent models for HEX,pump,and expander in an object-oriented fashion.The visualization study of mass distribution of the WF in the system is investigated under different working conditions.Furthermore,the volume and mass of the gas phase,two-phase and liquid phase of WF in the HEX and their variation rules are analyzed in-depth.Finally,the strategies of charge reduction considering HEX areas and pipe sizes are investigated.The results show that the model based on the interior-point method provides high levels of accuracy and robustness.The mass ratio of the WF is concentrated in the liquid receiver,especially in the regenerator,which is 32.9%and 21.9%of the total mass,respectively.Furthermore,2.4 kg(6.9%)WF in the system gradually migrates to the high-temperature side as the RSP increases while 6.1 kg(17.4%)WF migrates to the low-temperature side,especially to the condenser,as the charge in the system increases.Output power and efficiency both decrease gradually after the peak due to changes in RSP and charge.Last,reducing heat transfer areas of the condenser and regenerator is the most effective way to reduce WF charge.
基金supported by the National Natural Science Foundation of China (51806117, 51236004)China Postdoctoral Science Foundation funded project (2018M630155)the Science Fund for Creative Research Group (No. 51621062)
文摘The organic Rankine cycle(ORC)is a promising technology for industrial waste heat recovery and renewable energy utilization.High temperature ORCs have attracted particular interest because of their high thermal efficiencies and outputs.The material compatibility of working fluid is a significant limitation for the working fluid selection and system design for high temperature ORCs.This work presents a method for studying the material compatibility of ORC working fluids based on the calculated conditions of the ORCs and matching of components,temperatures,and materials.Hexamethyldisiloxane(MM)was chosen as the test fluid.The experimental results show that 304 stainless steel has better compatibility with MM than copper as the material of evaporators.Fluoric rubber is not a suitable sealing material for high temperature ORCs with MM as the working fluids because of the bad compatibility.Mineral oil has better compatibility with MM than polyol ester(POE)lubricant as the lubricant for the fluid pump.
基金supported by the National Natural Science Foundation of China (Grant No 50976079)
文摘A novel combined power and heat generation system was investigated in this study. This system consists of a low-temperature geothermally-powered organic Rankine cycle (ORC) subsystem, an intermediate heat exchanger and a commercial R134a-based heat pump subsystem. The advantages of the novel combined power and heat generation system are free of using additional cooling water circling system for the power generation subsystem as well as maximizing the use of thermal energy in the low-temperature geothermal source. The main purpose is to identify suitable working fluids (wet, isentropic and dry flu-ids) which may yield high PPR (the ratio of power produced by the power generation subsystem to power consumed by the heat pump subsystem) value and QQR (the ratio of heat supplied to the user to heat produced by the geothermal source) value. Parameters under investigation were evaporating temperature, PPR value and QQR value. Results indicate that there exits an optimum evaporating temperature to maximize the PPR value and minimize the QQR value at the same time for individual fluid. And dry fluids show higher PPR values but lower QQR values. NH3 and R152a outstand among wet fluids. R134a out-stands among isentropic fluids. R236ea, R245ca, R245fa, R600 and R600a outstand among dry fluids. R236ea shows the highest PPR value among the recommended fluids.
基金funded by the“Hot Dry Rock Resources Exploration and Production Demonstration Project”of the China Geological Survey(DD20190131,DD20190135,DD20211336).
文摘Hot dry rock(HDR)is a kind of clean energy with significant potential.Since the 1970s,the United States,Japan,France,Australia,and other countries have attempted to conduct several HDR development research projects to extract thermal energy by breaking through key technologies.However,up to now,the development of HDR is still in the research,development,and demonstration stage.An HDR exploration borehole(with 236℃ at a depth of 3705 m)was drilled into Triassic granite in the Gonghe Basin in northwest China in 2017.Subsequently,China Geological Survey(CGS)launched the HDR resources exploration and production demonstration project in 2019.After three years of efforts,a sequence of significant technological breakthroughs have been made,including the genetic model of deep heat sources,directional drilling and well completion in high-temperature hard rock,large-scale reservoir stimulation,reservoir characterization,and productivity evaluation,reservoir connectivity and flow circulation,efficient thermoelectric conversion,monitoring,and geological risk assessment,etc.Then the whole-process technological system for HDR exploration and production has been preliminarily established accordingly.The first power generation test was completed in November 2021.The results of this project will provide scientific support for HDR development and utilization in the future.
