Significant Fuel Savings and EmissionReductions by Improving Vehicle Air ConditioningJohn RughNational Renewable Energy LaboratoryValerie HovlandMesoscopic DevicesStephen O. AndersenU.S.Environmental Protection Agency15thAnnual Earth Technologies Forum andMobile Air Conditioning SummitApril 15, 2004Outline•Modeling approach•Thermal comfort-based ACfuel use prediction•Model updates•Fuel saved forup to 30%drop in AC power (equal to a43% increase in COP)•Per vehicle (cars, light trucks)•By climate•Total savings and CO2reductions across California,U.S., EU, and Japan101419)(1.8 billion gallons)(0.5 billion gallons)26 billion liters (7 billion gallons6.9 billion liters1.7 billion liters101419Predicting Fuel Used for AC•–2)––State ATMYMonthTCTHPPDTimePPDVMTw/ACMPGMPGGal forAC/RegGal/StateAprJuly00055101015152025(C) ifModel0510152025

i i ime1500( )

i ( )iiiUse Multiple Models/Inputs/Data SetsEnvironmental Conditions (Temp, RH, W/mThermal Comfort ModelVehicle Simulations (Fuel Economy Reduction with AC)City BCity XCity Aw/ ACw/o ACvehTotal12-6am6-9am9am-1pm1-4pm 4-7pm7-10pm10pm-12amJanFebMarMayJuneAugSeptOctNovDecTemper atur e n Denver, CO

MonthTi me o DayThermalComfort12-6am6-9am9am-1pm 1-4pm4-7pm7-10pm10pm-12amHour of the Day

Percentage of Travel Occurr ng dur ng that T0.01.02.03.04.05.06.010002000 2500 3000 3500Compressor Speed rpm

System Power Consumpt on kWFixed D sp 210Fixed D sp 180Var D sp 125Defrost 210Defrost 180Defrost 125Model Updates•Updates to U.S. study, Summer 2003–Mean Radiant Temperature varieswith vehicle type (car, truck)•Therefore usage PPD varies with type–Thermal comfort: use one assumption for clothing and soak (MRT)–Include demisting–AC power consumption = f(type, compressor speed)State ATMYMonthTCTHPPDTimePPDVMTw/ACMPGMPGGal forAC/RegGal/StateDemistCity BCity XCity Aw/ ACw/o ACvehTotalEnvironmental Conditions:Phoenix, AZ: TemperatureState ATMYMonthTCTHPPDPPDVMTMPGMPGAC/RegJanFebMarAprJuneAugSeptOctNovDec101015151515202025253035

MonthTemperature,humidity,solar radiationCity BTimeCity XCity Aw/ACw/ACw/o ACGal forvehTot Gal/State12-6am6-9am9am-1pm1-4pm 4-7pm7-10pm10pm-12amMayJulyTemperature (C) in Phoenix, AZTime of DayMean Radiant Temperature Models•MRT varies with vehicle type (car, truck)•Vehicle data used to generate models•Ford Crown Victoria• Ford Explorer (White)• Ward Atkinson – Phoenix 2002•Plymouth Breeze• Ford Explorer (Black)• Bill Hill – GM Data•Jeep Grand Cherokee• Lincoln Navigator•Dodge Grand CaravanModelsMRT(car, time) =* Radiation(t)/1000W/m2+ Tambient(t)MRT(truck, time) =24°C2+ Tambient(t)27°C* Radiation(t)/1000W/mMean Radiant Temperature by CityJanFebMarAprJuneAugSeptOctNovDec101020202020303030405060Mean Radiant Temperature (C) in Phoenix, AZ

MonthMayJuly12-6am 6-9am9am-1pm1-4pm 4-7pm 7-10pm10pm-12amTime of DayThermal Comfort Model:Percent of People Using AC-3-2-101230102030405060708090100

PPDThermal Comfort Model,+ 3+ 2+ 10Slightly Cool-2l-3ldPMVThermal SensationState ATMYMonthTCTHPPDPPDVMTMPGMPGAC/RegThermal Sensation VoteWarmCoolPPD from PMVHotWarmSlightly WarmNeutral- 1CooCoCity BTimeCity XCity Aw/ACw/ACw/o ACGal forvehTot Gal/StateAC Usage for CoolingPredicted Percent Dissatisfied (%) in Phoenix, AZClothing: 0.6, Velocity: 0.1, MRT: Ambient+RiseDec101

MonthNovOctSeptAugJulyJuneMayAprMarFebJan1111010102020303040405060708090AC Off100% of PeopleHave AC On12-6am6-9am9am-1pm1-4pm 4-7pm7-10pm10pm-12amTime of DayAC Usage for DemistingAC used for demist if:Temperature is between 1.7-12.8°C (35-55°F), and Relative Humidity > 80%

MonthDemist Percent Usage in Brussels, BELDecNovOctSeptAugJulyJuneMayAprMarFebJan1110No Demist Usage20203030404050506060707080809090100% Demist Usage12-6am6-9am9am-1pm1-4pm 4-7pm7-10pm10pm-12amTime of DayVehicle Usage with Time of Day, MonthState ATMYMonthTCTHPPDPPDVMTMPGMPGAC/RegCity BTimeCity XCity Aw/ACw/ACw/o ACGal forvehTot Gal/State1015202570% Daily Travel Percentage of Travel Occurring in that Month98765432SummerMonths: May ­SeptemberAverage

Percentage of Travel Occurring during that Time12-6am6-9am9am-1pm1-4pm 4-7pm7-10pm10pm-12am1002 4 6 81012Hour of the DayMonth of the Year05152717251831264940235017264240252141322319261938185233202437285030333225232669415721295843436Percent of Time AC is On:Cooling + DemistState ATMYMonthTCTHPPDPPDVMTMPGMPGAC/RegCity BTimeCity XCity Aw/ACw/ACw/o ACGal forvehTot Gal/State101419152717251831264940235017264240252141322319261938185233202437281650303332252326694157282121295843436ifi iPercent of TimeAC for Cooling+ Dehumid cat on6.3 to 17.917.9 to 19.619.6 to 22.922.9 to 25.125.1 to 25.925.9 to 28.428.4 to 32.132.1 to 37.837.8 to 41.441.4 to 49.249.2 to 57.357.3 to 69.3232423212325262727252425232724252326252524262527262423262725272525252726272422302717Climate during AC UseTemperature, Humidity10141927262425272324232123252627272527242523272425232625262524262527262424232623272527252525252726272524242230272717Average TemperatureDuring AC Use (C)16.9 to 22.822.8 to 23.523.5 to 24.124.1 to 24.624.6 to 24.924.9 to 25.125.1 to 25.525.5 to 26.226.2 to 26.726.7 to 26.726.7 to 27.327.3 to 30.2U.S. Average: 25°C5077587077376974637071715669726752426931766774477574717181756974713771737480476832727667Climate during AC UseTemperature,Humidity1014197773575077775870773769746370717156697267524269317667744775747371577171817569747137717374807273476832727667Average RelativeHumidity DuringAC Use (%)31 to 4747 to 5656 to 6767 to 6969 to 7070 to 7171 to 7272 to 7373 to 7474 to 7676 to 7777 to 81U.S. Average: 66% RHPercent of TimeAC in UseCooling andDemistingingdomilandI landFiiclgariaiAC is ii istUnited KTurkeySw tzerlandSwedenSpainRomaniaPortugalPoNorwayNetherlandsJapanItalyreHungaryGreeceGermanyFrancenlandDenmarkCzech RepublBuBelg umAustriaPercent of Timen UseCool ng + Dem19.4 to 28.628.6 to 32.732.7 to 37.037.0 to 41.541.5 to 44.244.2 to 44.744.7 to 45.945.9 to 50.650.6 to 58.8Fuel Economy Impact: Vehicle SimulationsState ATMYMonthTCTHPPDPPDVMTMPGMPGAC/RegCity BTimeCity XCity Aw/ACw/ACw/o ACGal forvehTot Gal/StateUS CarUS TruckEU VehicleFuel Economy no AC22.018.830.4Fuel Economy with AC18.016.227.3Fuel Economy defrost21.118.129.0US CarUS TruckEU VehicleFE Drop with AC18% 14% 10%FTP drive cycleFE Drop with defrost4% 4% 4%Hot initialconditionsUS car and truck based on existing fleet0144162155131933101211711161291442591316123243240Vehicle RegistrationsState ACity BTMYMonthTCTHPPDTimePPDCity XCity AVMTw/ACMPGw/ACMPGw/o ACGal forAC/vehRegTot Gal/State1014194430144162155131933101211711161244914543259131612133243240Million VehicleRegistrations0.4 to 0.70.7 to 1.01.0 to 1.41.4 to 1.81.8 to 2.82.8 to 3.33.3 to 3.93.9 to 4.44.4 to 6.06.0 to 9.29.2 to 12.512.5 to 23.9TotalMillionVehiclesUS213.0Distance Traveled per YearSources:•2002 World RoadStatistics from theInternational RoadFederation•International RoadTraffic and AccidentDatabase•Ward’s AutomotiveYearbook, 2001EU and JapanSpainlItalyFiiclUnited KingdomTurkeySwitzerlandSwedenRomaniaPortugalPolandNorwayNether andsJapanIrelandHungaryGreeceGermanyFrancenlandDenmarkCzech RepublBulgariaBelgiumAustriaVehic e KilometersTraveled6500 to 98039803 to 1073810738 to 1332113321 to 1496414964 to 1753717537 to 20015U.S.:•Car: 11,850 miles(19,070 km)•Truck: 11,958miles (19,244km)7377864918743735179171271566109229273615216722401221917851448618621118176957514224226686825175376730216861671National Fuel Used for ACState ACity BTMYMonthTCTHPPDTimePPDCity XCity AVMTw/ACMPGw/ACMPGw/o ACGal forAC/vehRegTot Gal/State• 7.0billiongallons used forair conditioningannually• 5.5%total fuelconsumption• 62billion kg CO2• 9.5%importedcrude oil1014192387377864918743735179171271523866109229273615216722401221917851448618621118861769575142242266868251753196176730216861671Million GallonsCooling &Dehumidification1 to 1717 to 2626 to 5252 to 6868 to 7878 to 8686 to 142142 to 176176 to 216216 to 242242 to 730730 to 753Total Fuel Use for AC for Cooling andDemistingi iSwiSpainPolItalyIiclgariaBeli8 to 12TotalsDehumid +CoolingBillionGallonsBillionLitersBillion kgCO2Percent of TotalConsumptionEU 100% Market1.8 6.916.03.2%Japan 100% Market0.45 1.74.03.5%Un ted K ngdomTurkeytzerlandSwedenRomaniaPortugalandNorwayNetherlandsJapanrelandHungaryGreeceGermanyFranceFinlandDenmarkCzech RepublBugiumAustriaMillion GallonsCooling &Dehumid fication12 to 1414 to 1616 to 2323 to 2525 to 4141 to 5353 to 7575 to 258258 to 303303 to 450450 to 450-AC-1234567865% 70% 80% 85% 95% 100% 105%010203040506070U.S. Fuel Saved & CO2Reducedby Reducing AC Consumption1014195.5%Vs. Total Consump.3.6%0.50.91.31.72.5Consumption0.12.1CO2ReducedAC FuelSaved75%90%AC Power Consumption: Percent of Baseline

Billion Gallons Billion kg CO25.49.46.45.06.011.910.117.914.28.316.37.59.47.714.08.78.716.412.59.27.110.06.97.116.611.97.97.410.617.812.19.99.38.728.28.311.022.814.715.30.4Fuel Saved per Vehicle by Climate30% Reduction in AC Power10141913.17.610.99.414.021.95.49.46.45.06.011.910.117.914.28.316.37.59.47.714.08.78.716.412.59.27.110.06.913.17.116.611.97.97.67.410.66.617.810.912.19.99.38.79.428.214.021.910.27.98.311.022.814.715.30.4Gallons Saved/Vehicle/Year,30% Reductionin AC Power0.4 to 6.66.6 to 7.57.5 to 7.97.9 to 8.78.7 to 9.49.4 to 10.110.1 to 11.911.9 to 13.113.1 to 14.714.7 to 16.616.6 to 21.921.9 to 28.2-0246810121465% 70% 75%85% 90%100% 105%li/il/li/Per Vehicle Fuel Saved byReducing AC Consumption1014192.03.95.67.59.411.00.380%95%AC Power Consumption: Percent of Baseline

Gallons Saved/YearCar: Base ne Use 33.7 gal yearTruck: Basel ne Use 26.8 ga yearAverage: Base ne Use 30.8 gal yearU.S.Fuel Savings Taking into AccountNew Technology Penetration•Assumptions–15% and 30% reductions615%AC PowerAC Power3.7 bil gal/yrSaved by 2025Reduction inReduction in30%in AC power–Power reductions begin5in 20104–Fleet grows through time(DOE’s Vision model)3•234 million in 20102•293 million in 20501–Fleet turnover in 16years02010 2015 2020 2025 2030 2035 2040 2045 2050Time (year)–VMT increases over time•13,500 miles in 2010•19,950 miles in 2050 Billion Gallons per Year SavedPer Vehicle Savings from an Improved MAC$0

Savings from an Improved HFC-134a A/C System (2004 $)-/-­ One A/­­-$50$100$150$200$250$300$350$400$450Assumptions:30% reduction in A C energy11 gallons of fuel per year savedC service avoided in year 8Cost of service charge = $107Cost of fuel = 1.75 $/galCosts rise at rate of inflation0246810 12 14 16Vehicle Life (years)Al70%80% 85%95%ili

Billion Gallons-24681012141618il iBilEU Fuel Saved by ReducingAC Power Consumption3.2%Vs. Total Consump.2.2%0.020.090.190.280.370.460.56EU ACConsumptionC Fue SavedCO2 Reduced0.00.20.40.60.81.01.21.41.61.82.065%75%90%100% 105%AC Power Consumpt on: Percent of Base ne Billion kg CO2EU AC Consumpt onEU AC Fue Sav ngskg CO2 Savedil65% 70% 75% 80% 85% 90% 95% 100% 105%iline

Billion Gallons- BilliJapan Fuel Saved by ReducingAC Power Consumption3.4%Vs. Total Consump.2.4%0.0050.020.050.070.090.110.14Japan ACConsumpt onAC Fue SavedCO2 Reduced0.000.050.100.150.200.250.300.350.400.450.50AC Power Consumpt on: Percent of Base0.51.01.52.02.53.03.54.0 on kg CO2Conclusions•MAC fuel use & CO2 emissions are strong functions of:–Vehicle design–Vehicle use–Environment•Solutions to reduce fuel consumed by MACs–Reduce the thermal load – improve vehicle design–Improve delivery – design for occupant thermal comfort–Improve equipment–Educate consumers on impactsof driver behavior on MAC fueluseConclusions (cont.)•Thermal comfort-based AC fuel use predictionUSEUJapanAC Fuel Use, Billion Gallons7.01.820.45AC Fuel Use, Percent of TotalConsumption5.5%3.2%3.4%•Reducing AC fuel use has the potential to greatly benefit the nation•Reduce imported oil•Reduce CO2•Per vehicle savings allow calculation of payback time30% Reduction in PowerUnitsUSCaliforniaEUJapanSavings per Vehiclegal/year11.011.02.52.2Reference Total Consumptiongal/year30.830.58.07.2Savings of Total Consumption%2.0%-1.0%1.0%Fuel SavedBil Gallons2.50.260.560.14Fuel SavedBil Liters9.51.02.10.5Emissions ReducedBil k G CO222.12.34.91.2•Impact of incremental reduction in AC power: states, nations, worldFuel Savings across the WorldBillion Gallons: Savings with 30%Drop in AC PowerCO2Reduction across the WorldBillion kg CO2: Reduction with 30%Drop in AC PowerThank you!Thank you!•John Rugh–Ph: 303-275-4413–Email: john_rugh@nrel.gov•Valerie Hovland–Email: vhovland@mesoscopic.com•Stephen Andersen–Ph: 202-343-9069–Email: andersen.stephen@epa.govBack UpWhy So Much Fuel for A/C?150 WattsMetabolic HeatA/C Cooling3-6 kWth!GenerationCities Used from TMY Data Base• Plymouth Breeze• July 12• Golden, CO• Jeep Grand Cherokee• July 12• Golden, CO1020304050607080905:307:309:30 11:30 13:30 15:30 17:30Time

Temperature (C)TrimSeatAirGlazingIPHeadlinerAmbientModel1020304050607080905:307:309:30 11:30 13:30 15:30 17:30Time

Temperature (C)TrimSeatAirGlazingIPHeadlinerAmbientModelCar & Truck MRTVehicle Modeling in ADVISOR• 115 kW SI engine, 1300 kg• 144 kW SI, 1924 kgicle• 91 kW compressionignition diesel, 1220 kggasoline equivalent fuelconsumption2from fuel consumption•2/liter fuel1000200030004000050100150200250300350)

(ici• U.S. Car• U.S. Truck• EU Veh• Fuel economy expressed in• COemissions determined2.33 kg COSpeed (rpm

Torque Nm)Engine Eff encyMercedes 1.7L Diesel Engine f/ ORNL0.050.10.150.20.250.30.350.350.40.45Series5AC Modeling•HFC-134a•U.S. trucks: 210 cc fixed•U.S. cars: 180 cc fixed•EU vehicle: 125 ccvariable displacement•Compressor powerconsumption based onDelphi compressorcurves•Total power = Pcompressor+Pblower1000 1500 2000( )

i )Fi iFi ii0.00.51.01.52.02.53.03.54.02500 3000 3500Compressor Speed rpm

System Power Consumpt on (kW0.00.71.32.02.73.44.04.75.4 Horsepowerxed D sp 210xed D sp 180Var D sp 125Defrost 210Defrost 180Defrost 125•Pblower= 120 WCurves based on work by Forrest at Delphi•Engine speed/compressor• Cooling mode: 27°C, 60% RHspeed ratio = 0.64• Demist mode: 16°C, 80% RHConservative Estimate ofFuel Used for AC•Fanger’s thermal comfort modelexcludes:–Sun hitting a driver–Thermal asymmetry–Sitting on a hot seat–High humidity impacts•Model excludes AC use due to–Automatic Temperature Control•EU compressor powerSeries5Incremental Reduction in AC Power1000 1500 20003500)

i )

.Fi iFi iFi i85% of Baseline Power70% of Baseline Power0.00.51.01.52.02.53.03.54.02500 3000Compressor Speed (rpm

System Power Consumpt on (kW0.00.71.32.02.73.44.04.75.4 Horsepowerxed D sp 210xed D sp 210 * 0.85xed D sp 210 * 0.7EU/Japan Per Vehicle Fuel Saved byReducing AC Consumption65% 70% 80% 90% 95% 105%ili

Gallons Saved/Year/Vehicle Liters Saved/Year/Vehicleli lli l0.080.40.81.21.62.12.50.00.51.01.52.02.53.075% 85%100%AC Power Consumpt on: Percent of Base ne0.02.04.06.08.010.0EU Base ne: 8.0 gal onsJapan Base ne: 7.2 gal ons