高等工热-有机工质朗肯循环orc.ppt

Cliquez pour modifier les styles du texte du masque,Deuxime niveau,Troisime niveau,Quatrime niveau,Cinquime niveau,Cliquez pour modifier le style du titre,*,Cliquez pour modifier les styles du texte du masque,Deuxime niveau,Troisime niveau,Quatrime niveau,Cinquime niveau,Cliquez pour modifier le style du titre,单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,Research and Development Trends in Organic Rankine Cycle Systems,Vincent Lemort,Thermodynamics Laboratory,University of Lige,Belgium,A lecture given at the,Beijing Key Laboratory of New Energy and Renewable Energy,North China Electric Power University,August 3rd,Content of the lecture,Introduction,What is an Organic Rankine cycle?,ORC versus steam cycles,Applications of ORCs,Selection of the working fluid,Selection of the expansion machine,Experimental methods,Modeling features,Conclusions and perspectives,Introduction,What is an organic Rankine cycle?,Working principle of Organic Rankine cycle(ORC):,Same components and working principle as traditional water Rankine cycle.,Optional regenerator,Organic fluids such as refrigerants(R123,R245fa)or hydrocarbons(pentane,.),Main advantage of ORC:,Efficient conversion of low temperature heat source to mechanical power.,Introduction,What is an organic Rankine cycle?,Organic Rankine Cycle(ORC):Small scale,lower temperature,Application fields:Waste heat recovery,Solar sources,engine exhaust gases,biomass CHP,geothermy,.,Selection of the working fluid and optimization of the working conditions are key issues,The selection of the expansion machine depends on the selection of the working fluid(and the size of the installed power),Content of the lecture,Introduction,Applications of ORCs,Solar power plants,Biomass combined heat and power,Waste heat recovery,Cycle optimization,Selection of the working fluid,Selection of the expansion machine,Experimental methods,Modeling features,Conclusions and perspectives,Applications of ORCs,generalities,Cooling circuit,Heat source:biomass,waste heat recovery,solar energy,CHP or cooling tower,dry-cooler,Thermal oil/pressurized water/hot gas,Applications of ORCs,ORC vs steam cycles,ORC systems:more economically profitable than steam cycles for installed,power lower than 3MWe,(steam cycle require high P and high T),Heat source temperature range:,100C to 450C,Easy,to install module(one squid,already assembled),Boiler is less complex and less expensive,because,Heat up to 300C a thermal oil(at low pressure),In the case of steam,high pressure(60-70 bar)and necessity to superheat(450C),Lower,working fluid operating,pressure,(no damage threat for the turbine,For 1MWe and high temperature,20%,Applications of ORCs,ORC vs steam cycles,Lower boiler efficiency because high oil return t(300C vs 100C for feed water in a steam plant)=flue gas leave at higher t,Architecture of the system is modified,Applications of ORCs,Solar power plants,Solar collector+concentrator,collector,Transfers heat to a thermal oil,Linear or punctual(higher concentrator factor=high temperature applications:e.g.,solar tower associated with steam cycle or combined cycle,Solar dish,cylindrical-parabolic(CSP-trough),Fresnel,solar tower,ORCs:Fresnel and CSP lower temperature(300-400C),Example:Arizona:1MWe,20%,n-pentane,CSP(surface of 1 ha),Applications of ORCs,Solar power plants(MIT and STG International),small power:1 kWe,remote areas in Lesotho,replacement of diesel power supply,Applications of ORCs,Biomass(combined heat and power)production,Biomass:wood pellets,waste material,(agriculture),Ideally,local use,is considered:,low energy density of biomass(cost of transportation!),simultaneity between heat and electricity demand is on-site,Size lower than 1MWe(steam cycle not cost-effective in this power range),particularly suitable in the case of off-grid or unreliable grid connection,Thermal oil at 300C,Condensing temperature at 90C,Energy efficiency,15-20%,Combined heat and power is preferable,(since low electrical efficiency),water heated in the condenser at 80C-90C,If no heat demand,lower condensing temperature,Competing technology is,gasification,Applications of ORCs,Biomass(combined heat andpower)production,ORC systems:large investment cost but can be economically profitable when electricity is expensive:,e.g.:remote-areas not connected to the grid,ORCs between 50 kWe and 2 MWe is a good option,even better when area is fed with low-cost biomass,in replacement of diesel power generation(cost of diesel transport is high!),Applications of ORCs,Waste heat recovery,waste heat available in,Industry,at low temperature,such heat can be used internally(hot water production,building heating,)but not easily,a lot of possibilities:steal industry,cement industry,glass industry,e.g.:cement industry:40%of the heat is produced under the form of gas between 215 and 315C,Applications of ORCs,Waste heat recovery,Internal combustion engines,Convert 1/3 of fuel energy into mechanical power,Heat can be recovered in the,exhaust gas,(300-900C)and in the,cooling circuit,(80-90C),can increase the engine efficiency from 28.9%to 32.7%,Competing technologies:thermo-electricity and absorption air-conditioning,not a new idea:Mach Trucks in the 70s,Today:larger choice of working fluids and new developments in the field of,expansion machines,Control of the system,is complex because of transient operation,(source:Honda),Applications of ORCs,Waste heat recovery,(source:Honda),Biomass:wood pellets,waste material(agriculture),Could have been predicted introducing void fraction models in the condenser and evaporator,low energy density of biomass(cost of transportation!),Leakage loss,Content of the lecture,Selection of the working fluid and optimization of the working conditions are key issues,Applications of ORCsBiomass(combined heat and power)production,Applications of ORCs,Lower working fluid operating pressure(high efficiency,Case B:Low evaporation temperature without recuperator =high output power,Influence of the evaporation temperature,=12.5%,28 KW,=7.8%,71 KW,Biomass CHP,Solar power,Geothermy,Waste heat recovery,Applications of ORCs,Cycle optimization,In,waste heat recovery,cycle efficiency is not sufficient to evaluate the performance of the system.,Global efficiency,of a waste heat recovery system can be defined as the product of two terms:,The efficiency of heat recovery,The efficiency of heat conversion,Applications of ORCs,Medium and large-scale application:market overview,ORC manufacturers have been present on the market since the 70s,=broad range of power and temperature levels,ORCs is mature technology for waste heat,biomass and geothermy but in the MW range,Applications of ORCs,Medium and large-scale application:market overview,Content of the lecture,Introduction,Applications of ORCs,Selection of the working fluid,Optimal characteristics,Example,Selection of the expansion machine,Experimental methods,Modeling features,Conclusions and perspectives,Waste heat recovery,ButylBenzene,Propylbenzene,Ethylbenzene,Toluene,OMTS,Content of the lecture,need good efficiency,Concluding remarks and research perspectives,Leakage length,small power:1 kWe,Experimental methodsTesting steam scroll expanders,Applications of ORCsgeneralities,Modeling featuresModeling the expander(deterministic approach),Considered fluids,Conclusions and perspectives,Global efficiency of a waste heat recovery system can be defined as the product of two terms:,“Plug and play”rig to test expanders,Content of the lecture,Selection of the working fluid,Comparisons are usually performed:,For a given application,Maximizing the thermodynamic efficiency,Additional factors such as vapor density or pressure ratio are rarely taken into account,Author(s),Application,Cond.Temp.,Evap.Temp.,Considered fluids,Recommended fluids(in terms of efficiency and/or power),Saleh et al.,Geothermal,alkanes,fluorinated alkanes,ethers and fluorinated ethers,RE134,RE245,R600,R245fa,R245ca,R601,Maizza and Maizza(2001),n/a,35,80-110,Unconventional working fluids,R123,R124,Liu et al.(2004),Waste heat recovery,150,R123,iso-pentane,HFE7100,Benzene Toluene,p-xylene,Benzene,Toluene(,甲苯,),R123,El Chammas and Clodic(2005),ICE,(for water),60-,(150 for water),Water,R123,isopentane,R245ca,R245fa,butane,isobutene and R-152a,Water,R245-ca and isopentane,Drescher and Bruggemann(,2007),Biomass CHP,*,250-350C*,ButylBenzene,Propylbenzene,Ethylbenzene,Toluene,OMTS,AlkylBenzenes(,烷基苯,),Hettiarachchia et al.(2007),Geothermal,30C*,70,Ammonia,n-Pentane,R123,PF5050,Ammonia,Lemort et al.(2007),Waste heat recovery,60,R245fa,R123,R134a,n-pentane,R123,n-pentane,Hettiarachchia et al.(2007),Geothermal,30C*,70,Ammonia,n-Pentane,R123,PF5050,Ammonia,Lemort et al.(2007),Waste heat recovery,60,R245fa,R123,R134a,n-pentane,R123,n-pentane,Borsukiewicz-Gozdur and Nowak(2007),Geothermal,80,propylene,R227ea,RC318,R236fa,ibutane,R245fa,Propylene,（丙烯）,R227ea,R245fa,Fankam et al.(2009),Solar,60,Refrigerants,R152a,R600,R290,Selection of the working fluid,甲苯,庚烷,戊烷,Selection of the working fluid,Optimal characteristics,High thermodynamic performance,Positive or isentropic saturation vapor curve,High vapor density and low volume ratio,Acceptable pressures,High stability temperature,Good availability and low cost,Low environmental impact and high safety level(ODP,GWP,etc.),Content of the lecture,Introduction,Applications of ORCs,Selection of the working fluid,Selection of the expansion machine and pump,Expansion machine,Pump,Experimental methods,Modeling features,Conclusions and perspectives,Selection of the expansion machine and pump,Expansion machines,Volumetric expanders,Turbomachines,Scroll,Screw,Reciprocating,Axial,Radial,Selection of the expansion machine and pump,expansion machine,Screw expander,For each fluid,a type of machine is restricted by an operating map,Each expansion machine technology is adapted to a power range,Selection of the expansion machine and pump,Pump,Higher backwork ratio than with steam,need good efficiency,Cavitation!,Subcooler(but decreases cycle performance),Increase liquid column,Content of the lecture,Introduction,Applications of ORCs,Selection of the working fluid,Selection of the expansion machine,Experimental methods,Steam scroll expanders,First organic Rankine cycle test rig,Testing the performance of an hermetic scroll expander,Modeling features,Conclusions and perspectives,Experimental methods,Testing steam scroll expanders,Experimental methods,Testing steam scroll expanders,Air,R-404a,Rfrigration,R-134a,Mobile air-conditioning,A,C,B,Experimental methods,First ORC test rig,boilers,Asynchronous machine,Expander,Torque-meter,Experimental methods,First ORC test rig,Open-drive,oil-free,air scroll compressor,Only the cooling fan was removed,Kinematically rigid configuration(compliant),Tip seals,148 cm,3,in compressor mode,Steam,R123,Isentropic efficiency,Filling factor,Experimental methods,Achieved performance,Experimental methods,Hermetic scroll expander,Gas cycle test rig,few components,quick stabilization,“Plug and play”rig to test expanders,Experimental methods,Hermetic scroll expander,Content of the lecture,Introduction,Applications of ORCs,Selection of the working fluid,Selection of the expansion machine,Experimental methods,Modeling features,Modeling the expansion machine,Modeling the cycle,Dynamic modeling,Conclusions and perspectives,Modeling features,Why?,To better understand the measurements(comparison between predictions by the model and measurements could help,understanding the major physical processes,),Tool for defining and optimizing the design of the system and the operating conditions,Developed models should be accurate enough,numerically robust and allow extrapolation of performance for other operating conditions and design characteristics,Modeling features,Modeling the expander(semi-empirical approach),Under-expansion,Over-expansion,Modeling features,Modeling the expander(semi-empirical approach),8 parameters,Modeling features,Modeling the expander(semi-empirical approach),AU,amb,W/K,AU,su,W/K,AU,ex,W/K,kg/s,A,leak,mm,2,r,v,in,-,V,s,cm,3,d,su,mm,T,loss,N-m,6.4,21.2,34.2,0.12,4.6,4.05,36.54,5.91,0.47,Model validation,Modeling features,Modeling the expander(semi-empirical approach),Parametric study,Expander isentropic effectiveness,Expander shaft power,Suction pressure drop,Internal leakage,Modeling features,Modeling the expander(deterministic approach),Comprehensive model of the expander,Why a deterministic model?,-Better understand all the inherent physical processes(tune as little parameters as possible),Check physical meaning of the parameters of the semi-empirical model,Appropriate tool for investigating the variation of the expander performance with its geometry,More reliable tool for extrapolating the performance,Geometrical model+thermodynamic model,Modeling features,Modeling the expander(deterministic approach),Based on equation of the involute of a circle,Chambers volumes(+derivatives),Heat transfer areas,Leakage length,ports&opening areas,f(,),Modeling features,Modeling the expander(deterministic approach),Differential equations of variation of P and T(from Energy&Mass conservation),Numerically solved for each chamber,Internal leakages between chambers,Heat transfers between the fluid and the scroll wraps,Simple mechanical loss model,Spiral heat exchanger,Modeling features,Modeling the expander(deterministic approach),Modeling features,Modeling the expander(deterministic approach),Definition of the working chambers,Crank angle evolution of the volumes of the chambers,Modeling features,Modeling the expander(deterministic approach),Large supply pressure drop,Suction port blockage,Subdivision of suction chamber(end of suction),Modeling features,Modeling the expander(deterministic approach),Suction pressure drop,Leakage loss,rpm,Under-expansion loss is limited,Modeling features,Modeling the cycle(static approach),Could have been predicted introducing void fraction models in the condenser and evaporator,Modeling features,Modeling the cycle(dynamic approach),Goal:,Set a regulation strategy,To optimize the overall heat recovery efficiency for a variable heat source,Modeling features,Modeling the cycle(dynamic approach),Conservation of energy:,Conservation of mass:,Metal wall:,MODELING FEATURES,MODELING THE CYCLE(DYNAMIC APPROACH),Concluding remarks and research perspectives,ORC applications,particularly well adapted for low-grade heat recovery,mature market for large scale biomass,waste heat and geothermal applications,ORC market,:,Growing market,No largely commercialized products for the small-scale ORC system,Development of adapted positive displacement machines,Pump!,Experimental research,:,Better understanding of the behavior of the system(control,),Validation of simulation models,Point out unexpected problems(e.g.pump cavitation),Concluding remarks and research perspectives,Cycle design,:,maximize power output or cycle efficiency according to the application(solar,biomass,geothermal,heat recovery),not limit th