R744作为全球性解决方案的优点与可能性

R744 the Global Solution Advantages & PossibilitiesFrank Wolf Vice PresidentO BRIST E ngineering GmbHAUSTRIA f.wolf@obrist.atKjerstin Lien and Frank ObristPetter NeksåSenior Research Scientist SINTEF Energy ResearchNORWAYPetter.Neksa@sintef.noArmin HafnerContentSection ONEIntroduction; direct and indirect emissionsSection TWOIndirect emission improvements for A/C systemsSection THREEEfficiency advantages for R744Section FOURSummary and IntroductionGWP CO2= 1GWP CH4= 23GWP N2O = 310Green House Gas Shock to our PlanetChanges in greenhouse gases from ice-core and modern dataDiagrams from IPCC Climate Change 2007Direct Emissions R134a Shock1. Direct emissions:20% of produced R134a is eachyear emitted to the atmosphere*1.With an expected car sale of 81.5million vehicles in year 2017, the direct emissions of R134a from MAC alone may contribute to a total amount of 390 million tons CO 2equivalents only in 2017*2.*Data from DuPont’s presentations at 1I-MAC 30/50, Delhi /India, March 2005 and 2IEA Cooling Cars with less fuel, Paris /France, October 2006.¾R134a is not a sustainable solution ¾Not in Europe and not in the WorldIntroductionData from IPCC Climate Change 2001IntroductionData from IPCC Climate Change 2001Indirect Emissions2. Indirect emissions:Up to 15% of the worlds energy consumption is used for cooling *Large differences in fuel consumption by A/C use:o By low load and good engineering about 5% of the car’s fuel consumption is used for running the A/C **o At high load and lowest cost engineering the fuel consumption for the A/C can be up to 70% of the total fuel consumption **There are clearly large reduction potential for indirect emissions in the cooling sector and here especially in MACs.*OE estimates**HEAC Prototype: Comfort Improvement with Reduction of Impact on FuelConsumption,Carloandrea Malvicino, CRF, MAC Summit Washington April 2004ContentSection ONEIntroduction; direct and indirect emissions Section TWOIndirect emission improvements for A/C systems Section THREEEfficiency advantages for R744Section FOURSummaryIndirect Emission ImprovementsSystem related Strategies1. Improved Front End designBad Front End design, especially in small cars, lead to too highcondenser inlet temperatures. The problem is severe if air is flowing back to the condenser over the catalytic converter.2.Evaporator temperature control →avoids unnecessarycoolingBy reduced/ medium load can an increased Tevap from 2°C to 12°Cmake savings of up to 3kW possible. Unfortunately most new cars worldwide still do not use this technology. Temp. Glide is prohibitive 3.Automatic recirculation controlMost systems do not control the amount of re-circulated air and use in many cases too much of the hot outside air, which results in wasteuse of energy. Knowing RH, T and CO2concentration inside andtemperature and RH outside the system can be optimized.Indirect Emission ImprovementSystem related Strategies4. Optimized Sub-cooling and Super-heatingReduces several negative influences on the system efficiency 5. Reduced Oil Circulation / Oil Managementallows ≈1% increase of performance 1% reduction in OCRR134a6. Right system chargeOvercharging of systems can cause reduced overall efficiency7. IR reflective paint and glass8. Indirect Emissions from Fuel Fired Heaters and electricalHeaters are prohibitiveIndirect Emission ImprovementComponent and Refrigerant related Strategies9. Heat Exchangers adapted to the refrigerant10. Improved compressor efficiencyThe compressor efficiency influences the total efficiency considerably.Test Results Overall Compressor EfficiencyOverall Compressor EfficiencyTest Conditions R134asuction pressure = 3,0 bar, discharge pressure = 15,7 bar102030405060708090100100020003000400050006000700080009000nK [RPM]O v e r a l l E f f i c i e n c y [%] .R134a variable displacement compressorMarket LeaderContentSection ONEIntroduction; direct and indirect emissions Section TWOIndirect emission improvements for A/C systemsSection THREEEfficiency advantages for R744SAE ARCRP II (past)New compressor development (now)Compressor Expander (future)Section FOURSummaryResults already obtained with R744 MAC2002 UNEP RTOCR744 is comparable to R134a regarding cooling capacity and fuelconsumption (energy efficiency). Satisfies the EU requirements2005 SAE ARCRP II conclusionsAbout 10% less fuel consumption for the R744 system compared to R134a for averaged climates2005 IPCC/TEAP Special Report ”Safeguarding the ozone…”GHG emissions, quantified by TEWI (and LCCP) of R744 systems are significantly better than that of Improved R134a systems (30 to 45% lower emissions for respectively very hot and moderate climates)Small car resultsSeveral companies show R744 systems better than R134a2007 ARCRP II results of R744 Systemsbased on experimental data¾COP of R744 systems at medium ambient temperatures are considerably better than R134a:Vehicle Mid – size Full SizeDrive cycle NEDC US FTP 75Cycleduration1180 sec. 2138SystemDemandEnergy/ cycle [kJ] Energy/ cycle [kJ]R 134a* Base BaseR 152a -3% -7%R 744**Optimized Refrigerant Controls -11% -9%February 23-24,2005Saalfelden, AustriaBased on analysis of the accuracy and repeatability of the data,it is estimated that these values are within +/-6%.-10%R744 Compressor DesignNew Swivel Joint mechanism8 Piston DesignR134a compatible controllerNew Internal Oil ManagementNew type of bearing solutionImproved coolingmanagementLowest Oil Circulating RateLightweight clutchless plasticmaterial pulleyEfficiency improvementTest Results Overall Compressor EfficiencyCompressor Comparison - Overall EfficiencyComparable Test Conditions R134a; R744suction press. = 3;40 bar, discharge press. = 15,7;120 bar, suction temp= ~30 °C1020304050607080901000100020003000400050006000700080009000nK [RPM]O v e r a l l E f f i c i e n c y [%]R134a variable displacement compressor R744 variable displacement compressor+79%+28%+40%R744 Compressor DevelopmentSwivel Joint TechnologyCo-operation between OBRIST Engineering and DOOWON4.3kg Weight 9700Max. rpm Clutchless Clutch TypeΦ105x220mmSize28cc DisplacementVariable DisplacementDSP28Type MODEL2007 Compressor Expander and EjectorFuture possibility with great potential for R744¾Targets are; dramatically increased COP at high ambient temperatures and increased fuel efficiency under all operating conditions.¾Two options:1.Ejector system (in mass production for stationary systems.Possible MAC use)pressor Expander(development status for MAC)New system layouts for R744 will lead to furtherimproved COP also at high ambient temperatures Potential improvement for R744 >> R134a2007 Compressor ExpanderExperience¾Compressor Expander for fuel¾cell application NECAR I-IVhumid air / ionised waterKey Design Criteria¾~ zero gap design for high efficiency¾R744 refrigerant velocity below 10m/sec¾Good thermal insulationCompressor Expander SystemSystem configurationsEnh R134a : A R744: B R744 Expander-Comp: C ARCRP II ARCRP II New development22,533,544,555,52527293133353739414345Gascooler air inlet temperature [°C]C O PB R744A Enh R134aEnh R134a vs. R744 / ARCRPIITe0 = 10degC Control or Equal Capacity / Compressor Nc = 2500rpm COP (above 38°C) HFC134a >R744COP (below 38°C)R744 >HFC134aResults from Pega Hrnjak / Mac Summit 2006 page 6/15 & ARCRP IIAssumptions for the 3 systems Assumptions for the analysisHeat Exchangers:A andB from ARCRP IIC according to B of ARCRP IICompressor efficiencySystem A: Enhanced R134a ARCRP IISystem B: R744 ARCRP IISystem C: R744 Main Compressor 0.82 (test result) Expander:isentropic efficiency: 0.55 (test result)2. stage compressor driven by expanderisentropic efficiency: 0.65 (test result)22,533,544,555,52527293133353739414345Gascooler air inlet temperature [°C]C O PB R744A Enh R134aC R744 CoExpR744 Compressor Expander SystemTe0 = 10degC Control or Equal Capacity / Compressor Nc = 2500rpm Results from Pega Hrnjak / Mac Summit 2006 page 6/15 & ARCRP IICOP (below ~50°C)R744 >HFC134a+27%R744 Baseline Systema bcdf eR744 Compressor Expander System12346 758be23614578Advantages Compressor Expander SystemBest COP and therefore lowest indirect emission at all ambient temperaturesMain Compressor Discharge Temperatures and Pressures reducedNext Stepso Component optimizationo Extended system testingo Costing target System A = System B = System CContentSection ONEIntroduction; direct and indirect emissions Section TWOIndirect emission improvements for A/C systemsSection THREEEfficiency advantages for R744Section FOURSummary and SummaryBoth direct and indirect emissions of global warming gases must be reduced:1. Reduction of direct emission throughchange to lowest GWP refrigerant; R134a →R7442. Reduction of indirect emission throughA lot potential remains to improve the systems independent of therefrigerantWith a R744 systemo ARCRP II shows advantage for R744 (past)o Compressor overall efficiency is increased to 81% (now)o Ejector and Compressor Expander technology will improve system COP by up to 40%R744 outperforms R134a not only at medium,but also at high ambient conditionsSummaryR744 is the natural refrigerant for the global A/C market Sustainable technology¾best efficiency and COP over the total temperature range¾lowest additional fuel consumption¾weight reduction¾low costs¾low emissions¾heat pump application with highest COP10% overall vehicle emissions reduction is possibleThank you for you attentionFrank Wolf Petter NeksåArmin Hafner, Kjerstin Lien and Frank Obrist。