NREL Presentation
Transcript of NREL Presentation
Reduction in Vehicle Temperatures and Fuel Use from
Cabin Ventilation, Solar-Reflective Paint, and a New Solar-Reflective
GlazingJohn P. Rugh, Lawrence Chaney, Jason Lustbader
National Renewable Energy LaboratoryJohn Meyer - VisteonMukesh Rustagi, Kurt Olson - PPG IndustriesRupert Kogler - Webasto AG
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OutlineImproved Mobile Air Conditioning Cooperative Research ProgramVehicle Thermal Soak TestThermal and Vehicle Fuel Use Analysis
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Improved Mobile Air Conditioning Cooperative Research Program
Demonstrate technologies to reduce direct (leakage) and indirect (tailpipe) HFC-134a refrigerant emissionsGovernment/Industry partnership28 Industry SponsorsAdministered by Society of Automotive Engineers (SAE)Four Teams
Reduce leakage during operationImproved COPReduce vehicle thermal loadReduce leakage during service
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2006 I-MAC Reduced Thermal Load Vehicle
Select the most promising technologies and test in a final configuration
Solar Powered Parked Car Ventilation
Solar Reflective Glazings
Solar Reflective Paint
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Solar Reflective Glazings: Sungate EPManufacturer: PPG IndustriesReflects IR portion of solar spectrum
Meets 70 % transmittance requirementGreater than 50% solar energy reflected
Reduces solar heat gainWindshield, sidelites, backlite
Solargreen® glass
Sungate® windshield
Sungate® EP
LTa 72% 72 71
TSET 44% 39 33
TSER 6% 31 47
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Solar Powered Parked Car Ventilation
Manufacturer: Webasto24 cell, 17 W PV panel in sunroofSix ~ 1.6 W fansCurrent configuration: Extracts hot air from cabin interiorSince STS already had a sunroof, a unique test install was required
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Solar Reflective Paint
Manufacturer: PPG IndustriesPrototype S2XMaintains color while reflecting IR portion of solar spectrumStandard clearcoat over IR reflective basecoatCooler skin temperatures reduce cabin heat gainNREL measured absorptance
Baseline 89.4%Solar reflective 82.1%
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I-MAC Vehicle Soak Test Procedure
Two nearly identical vehicles parked facing 160º, front/backEvaluate technologies that reduce thermal load
Modify test vehicleStart data acquisition system ~ 8:30 amStop data acquisition system ~ 16:30 am
Data analysisReport time-averaged temperature difference between identical locations between 12:30 and 13:30Eliminate cloudy daysAverage results with multiple “good” test days
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Cadillac STS & NREL Test Facility
Modified
Baseline
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Reduction in Air TemperaturesSolar reflective glazings all locationsSolar powered ventilationSolar reflective paint
20
25
30
35
40
45
50
55
60
65
70
9:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00 17:00Time
Tem
pera
ture
(o C
)
68
77
86
95
104
113
122
131
140
149
158
Tem
pera
ture
(o F)
air foot baselineair foot modifiedair breath baselineair breath modifiedair baselineair modifiedAmbient airSeries3
Breath
Average
Foot
Ambient air
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Solar Reflective Glass (All Locations), Paint, and Ventilation
5.6
12.0
8.8
16.8
6.0
10.3
11.9
20.4
0
5
10
15
20
25
Air-Foot Air-Breath Air Dashboard Roof Exterior Front DriverSeat
Front PassSeat
Windshield
Red
uctio
n in
Tem
pera
ture
(o C)
0
9
18
27
36
45
Red
uctio
n in
Tem
pera
ture
(o F)
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0
5
10
15
20
25
Air-Foot Air-Breath Air Dashboard Roof Exterior Front DriverSeat
Front PassSeat
Windshield
Red
uctio
n in
Tem
pera
ture
(o C)
0
9
18
27
36
45
Red
uctio
n in
Tem
pera
ture
(o F)
Solar Reflective Glass-all locations, Parked Car VentilationSolar Reflective Glass-all locationsSolar Reflective Windshield-BackliteSolar Reflective Windshield
Solar Reflective Paint-all tests
Comparison to Solar Reflective Glass only Data
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Solar Powered Ventilation Only
-2.9
7.1
2.1
6.2
1.5
0.70.3
2.3
3.0
8.3
5.6
8.3
1.0
6.0
5.3
2.3
-4
-2
0
2
4
6
8
10
Air-Foot Air-Breath Air Dashboard Roof Exterior Front DriverSeat
Front PassSeat
Windshield
Red
uctio
n in
Tem
pera
ture
(o C)
Air blown into vehicleAir pulled out of vehicle
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Solar Reflective Roof Film Only
0.5
1.20.8 0.9
6.7
0.4 0.4
-0.6-1
0
1
2
3
4
5
6
7
8
Air-Foot Air-Breath Air Dashboard Roof Exterior Front DriverSeat
Front PassSeat
Windshield
Red
uctio
n in
Tem
pera
ture
( o C
)
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Integrated ModelingAssessing the impact of Assessing the impact of advanced climate control advanced climate control
systems on vehicle fuel use systems on vehicle fuel use and human thermal comfort and human thermal comfort
in a Cadillac STSin a Cadillac STSCAD
RadTherm
ThermalComfort
AirConditioning
Cabin Thermal/Fluid
Vehicle
FuelEconomy
TailpipeEmissions
OccupantThermal Comfort
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Model temperatures Model temperatures and airflow in the cabinIntegrated Modeling and airflow in the cabin
CAD
RadTherm
ThermalComfort
AirConditioning
Cabin Thermal/Fluid
Vehicle
FuelEconomy
TailpipeEmissions
OccupantThermal Comfort
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Baseline Soak Results Comparison to Test Data
30
40
50
60
70
80
90
IP Left
IP right
Dr sea
t
Pa Sea
twindsh
ield
Backli
ghtDr s
ide light
Pa side l
ight
Pkg Shelf
Headlin
er
air fo
ot
air brea
thDataSimulation
-0.8
+1.4
+2.2
+7.2
-1.5
-2.6
+2.2
+1.7
-9.8
+7.0
+0.8
-2.9
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Soak Results Temperature Contours
Baseline Reduced Thermal LoadSolar Reflective Glazings
Solar Reflective PaintSolar Powered Parked Car Ventilation
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Simplified Thermal ModelRadTherm Fluent
136,000 Elements Full CFD model 900,000 Fluid Nodes
136,000 Elements Simplified model 8 Fluid Nodes
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35
45
55
65
75
85
0 5 10 15 20 25 30 35 40 45
Time (Minutes)
Tem
pera
ture
(o C)
Driver Seat (Simulation)Driver Seat (Data)Pass. Seat (Simulation)Pass. Seat (Data)
Driver Seat
Pass. Seat
Baseline Cool Down Results
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Adjust A/C Load in RadTherm to Achieve Equal 30 min. Cooldown
30
35
40
45
50
55
60
0 5 10 15 20 25 30
Minutes
Mas
s A
vera
ge T
empe
ratu
re (o C
)
Baseline (5.7kW)Reduced Thermal Load (4.0 kW)
30% Reduction in cooling load
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30 minute cool down• Heat Balance:
• Balanced with:Baseline – 5.7 kW cooling
Reduced Thermal Load – 4.0 kW cooling
• 29.8% Reduction in cooling load
∑∑∑∑=
=
=
=
=
=⎟⎠⎞
⎜⎝⎛ ∆=∆−∆−⎟
⎠⎞
⎜⎝⎛ ∆
30
0 Re,
.30
0
30
0 ,
. t
t alLoadducedThermAirp
SoakSolar
t
tSolar
t
t BaselineAirp TCmQQTCm
AirInletAirExit TTT −=∆
ducedLoadBaseline NetSolarNetSolarSolar QQQRe,, −=∆
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Integrated Modeling Model the STS over a drive Model the STS over a drive cycle and find the fuel usecycle and find the fuel use
CAD
RadTherm
ThermalComfort
AirConditioning
Cabin Thermal/Fluid
Vehicle
FuelEconomy
TailpipeEmissions
OccupantThermal Comfort
ADVISOR
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Impact on Fuel Economy
• Vehicle simulator used to assess impact of reduced AC load.
FTP Drive Cycle
Fuel Economy no AC 18.5Fuel Economy with Baseline AC 15.4Fuel Economy with 70% Baseline AC 16.1
Fuel Economy (mpg)
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Impact on Fuel Use
• US Average AC use - 32.6% (MAC Summit 2004)
• US Vehicle Miles Traveled - 11,998 (Wards 2005)
FTP Drive Cycle
Fuel Used with Baseline AC 42.6Fuel Used with 70% Baseline AC 31.4Fuel Savings per Vehicle 11.2
Annual Fuel Used per Vehicle for AC (gal)
26 % Reduction in AC fuel use for this vehicle
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ConclusionsSignificant reduction in cabin interior temperatures demonstrated 30% reduction in thermal loadPotential for lower power A/C system or A/C used less oftenReducing fuel use of vehicle air conditioning is within reach with current technology
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AcknowledgementsDOE
Lee SlezakEd Wall
NRELCharlie KingMatt KeyserAaron OakleySean Gooding
EPAStephen AndersenKaren ThundiyilKris Taddonio
NissanDavid Barwin
GMGreg MajorBill HillDavid Drapkin
WebastoJames Cowen
I-MAC Team 3Gary Pollak, SAEPaul Hoke, FordAl Reginaldo, ToyotaHashem Akbari, LBNL
AVLReinhard Tatschl
ThermoAnalytics, Inc.Craig MakensCraig Cless
BETA CAE SystemsGeorge Galaitsis