Compares Compressed Air Vehicles with Battery Electric, Gasoline and Diesel energy conversion using key metrics. Metrics are serial efficiency, volumetric energy density of the fuel (MJ/M3), cost per Kilowatt output ($/kW), and mass of CO2 per energy output (kg/kWh)

1. Seth Brezee
Stephen Buckley MEEM4200
Research Objectives Alfred Piggott
Andrew Schorfhaar
Group 1
Are
compressed air
powered
vehicles a
How do viable
How far can
compressed air automotive you go and how
vehicles propulsion hard is it to
compare in cost alternative? refuel a
to other compressed
vehicles? air vehicle?
What is the
Are compressed fossil fuel-to-
air vehicles a motor output
“green” serial efficiency
propulsion for a
technology? compressed air
vehicle?
Car photo:
12/10/2010
http://www.popularmechanics.com/cars/new
s/preview-concept/4251491
1

2. Compressed Air Vehicle - Basics
Vehicle Pneumatic Motor
Energy Storage
Compressed Air Tanks
Image Source: http://www.mdi.lu/english http://zeropollutionmotors.us/, http://www.google.com/patents
2

3. Compressed Air Vehicle – Analysis
Serial Efficiency Isothermal Compression and Expansion
P
Power Plant Average 0.35
P2
1
1<
n=k
n<
0.935
k Is
<k
Electric Grid
n
n=
I
Is
1
e t
ent
o
o
th
he
r
rop
erm
m
Air Power Output
i
ic
a
all
compressor 0.48
Electric Power Input P1
Shaft Power Output
Pneumatic Motor 0.31 V
Compressed Air Power Input
p2 p2
serial (0.35 )( 0.935 )( 0.48 )( 0.31) 0.0487 Wisothermal p1 V2 ln
p1 p1
Compressed Air Internal Energy
3 p1V1 p2V2
U PV
2 Isothermal Power
First Law Air Compression p2 p
p1 V2 ln 2
p1 p1
Q W U Powerisothermal
Time
Image Source: <http://www.me.mtu.edu/~jstallen/courses/MEEM4200> 3

4. Battery Electric Vehicle - Basics
Nissan Leaf
Propelled by:
(source www.nissanusa.com)
Lithium Ion Battery
Capacity = 24 kWh
Charging Station
(source www.GE.com)
Range = 73 miles
Fuel Economy Label
(source www.nytimes.com) Motor Controller 80 kW Motor 4

5. Battery Electric Vehicle - Analysis
Battery
Electric Power Battery Storage
Fossil Fuel Discharge
Plant (0.35) Efficiency (1.0)
Efficiency (0.99)
Transmission Battery Charge Motor Controller
Grid (0.935) Efficiency (0.99) (0.96)
Charging AC/DC Electric Motor Power Out
Station (0.86) Converter (0.90) (0.804)
Serial (0.35)(0.935)(0.86)(1.0)(0.99)(0.90)(0.99)(0.96)(0.804)
Efficiency = 0.192
Carbon 0.608 kg/kWh (CO2 for 1 kWh at plant)
Footprint 0.192 (serial efficiency) = 3.17 kg/kWh
5

6. Gasoline Powered Vehicle - Analysis
A gasoline powered vehicle that was rated for around 30MPG was used for
comparison.
Serial Efficiency of Gasoline Power:
Fossil Fuel Engine out = 18%
Technology Cost for Gasoline Power:
Gasoline Engine Cost in Dollars 4000dollars dollars
Technology Cost 28.25
Vehicle Power Output in kW 141.55kW kW
Vehicle Cost for Gasoline Power:
o An average sedan in the market, for example, a Chevrolet Malibu
has a base price of $22,000.
o The Malibu is rated at 23 MPG in town and 34MPG on the
Highway while powered by a stock 193 HP 2.4 liter 4-Cylinder
engine.
1. "Advanced Technologies & Energy Efficiency." Fuel Economy. Web. 05 Dec. 2010. <http://www.fueleconomy.gov/feg/atv.shtml>.
2. "2011 Chevy Malibu Sedan Specs and Features | Chevrolet." 2011 Cars, SUVs, Trucks, Crossovers & Vans | Chevrolet. Web. 09 Dec. 2010.
<http://www.chevrolet.com/malibu/features-specs/>.
6

7. Gasoline Powered Vehicle Cont…
Carbon Footprint for Gasoline Power:
grams 44amu kg
Carbon Content 2, 241 0.99 8.8
gallon 12amu gallon
kg kg
8.8 8.8
gallon gallon kg
Carbon Footprint 1.74
kWh kWh kWh
EFF . 33.7 0.15
gallon gallon
Energy Density of Gasoline:
Joules 1MJ 1gallon MJ
Energy Density 122 x106 32, 230
gallon 106 J 3.7854 x10 3 m3 m3
Vehicle Range :
miles gallons miles
Vehicle Range 30 16 480
gallon tank tank
7

8. Diesel Powered Vehicle - Analysis
Diesel Serial Efficiency Fossil Fuel-to-motor output:
Motor Efficiency = 40% = 0.40
Diesel Conversion Technology Cost
Cost = (Diesel Engine Cost)/(Engine Output)
Calculation: $5000 / 126.8 kW (2010 Jetta TDI) = $39.42/ kW
Diesel Vehicle Cost Comparison
• The average diesel vehicle costs about $1000 more than a comparable petrol model.
-2010 VW Jetta TDI (Diesel) starts at $22,000, 2010 VW Jetta (petrol) starts at $20,000
-2010 VW Jetta TDI gets 40/22 mpg (hwy/city), gas model gets 30/20 mpg (hwy/city)
1. Way, By The. "2010 Volkswagen Jetta TDI - Top Speed." Web. 10 Dec. 2010. <http://www.topspeed.com/cars/volkswagen/2010-volkswagen-jetta-tdi-ar75332.html>
8
2. "2010 VW Jetta TDI Buyers Guide Myturbodiesel.com - VW TDI Forum, Web. 10 Dec. 2010. <http://www.myturbodiesel.com/1000q/a5/2009-2010-VW-Jetta-TDI-checklist.htm>
3. "Gas Mileage of 2010 Volkswagen Jetta." Fuel Economy. Web. 10 Dec. 2010. <http://www.fueleconomy.gov/feg/bymodel/2010_Volkswagen_Jetta.shtml>

9. Diesel Powered Vehicle - Analysis
Carbon Footprint for Diesel Energy (Using Serial Efficiency for between Refinement and Motor Output.)
Diesel Carbon Content = 2.7 kg/liter, Diesel Energy Content = 10.1 kW-h /liter
Serial Efficiency = 40.0 %
Carbon Footprint (kg/ kW-h) = (Carbon Content) / (Energy Content * Serial Efficiency)
Calculation: 2.7/ (10.1*0.40) = 1.7 kg/ kW-h
Diesel Energy Density (Calculated for diesel with a density of 0.84 g/ ml)
Diesel Energy Content = 36.4 MJ/ liter; 1 liter = 1000 cm^3; 1 m^3 = 1,000,000 cm^3
Calculation: 36.4 * 100^3 / 1000 = 36.4 * 10^3 MJ/ m^3
Diesel Vehicle Range
As stated previously, the gas mileage of the 2010 VW Jetta TDI is 40 mpg highway. A
standard tank size for a mid to small size car is between 12 and 15 gallons. This would
put the range of the Jetta between 480 and 600 miles (504 used for comparison).
1. Lucy, By. "The Pros and Cons of Going Diesel." Mortgage Rates Credit Cards Refinance Home CD Rates by Bankrate.com.
2. US Environmental Protection Agency. Web. 09 Dec. 2010. http://www.epa.gov/otaq/models/ngm/may04/crc0304c.pdf
3. Lucy, By. "The Pros and Cons of Going Diesel." Mortgage Rates Credit Cards Refinance Home CD Rates by Bankrate.com. Web. 6. 09 Dec. 2010.
4.
http://www.bankrate.com/brm/news/auto/20030804a1.asp
Web. 09 Dec. 2010. http://www.evworld.com/library/energy_numbers.pdf 9

10. Summary – Energy Efficiency
Compressed Air 0.05
Battery Electric 0.19
Gasoline 0.15
Diesel 0.40
0.00 0.10 0.20 0.30 0.40
Efficiency (Fossil Fuel to Motor Out)
Conclusion: Compressed air vehicles are on the low end of
efficiency, diesel is unmatched for converting fossil fuel to
usable motor power 10

11. Summary – Carbon Emissions
Compressed Air 12.5
Battery Electric 3.2
Gasoline 1.7
Diesel 1.7
0 510 15
Carbon Footprint (kg / KWh)
For Battery and Air: C.F. = (0.608 kg / kW-hr) (1/serial efficiency)
For Gasoline: C.F. = (0.261 kg / kW-hr) (1/serial efficiency)
For Diesel: C.F. = (0.667 kg / kW-hr) (1/serial efficiency)
Conclusion: Compressed air vehicles produce lots of CO2 when powered by fossil
fueled power plants 11

12. Summary – Energy Volumetric Density
Compressed Air 46.5
Battery Electric 1080
Gasoline 32,230
Diesel 36,400
0
10,000 20,000 30,000 40,000
Energy Density (MJ/meter cubed)
Conclusion: Compressed air energy storage systems are not
able to store a great deal of energy, limiting their range.
12

13. Summary – Technology Cost Analysis
Compressed Air $167
Battery Electric $62
Gasoline $28
Diesel $39
$0 $50
$100 $150 $200
Technology Cost (Dollars/kW)
Conclusion: Compressed air vehicles are on the high end in
terms of cost to produce power due to low power output.
13

14. Summary – Cost and Range
Overall Vehicle Cost Summary:
Compressed Battery Gasoline Diesel
Air Electric
Vehicle Cost $4600-$17,800 $32,780 $22,000 $20,000
Vehicle Range Summary:
Compressed Battery Gasoline Diesel
Air Electric
Vehicle Range 29 miles 73 miles 480 miles 504 miles
Conclusion: Compressed air and electric vehicles will create
“range anxiety” condition with customers, they will be worried
about returning home before their energy reserve is depleted.
14

15. Technology Comparison – Customer Focus
Customer Compressed Battery Electric Gasoline Diesel
Metric Air
Co2 Emissions? Relocates CO2 Relocates CO2 Emits CO2 at place of Emits CO2 at place of
emissions, but creates emissions, but creates operation operation
more more
Easy to Refuel? No, need air No, takes too long, Refuel quickly with Refuel quickly with
compressor, large expensive charger large refueling large refueling
power draw required infrastructure infrastructure
Costly to Own? Not likely, but exact Expensive to buy, Inexpensive to buy, Slightly more costly to
figures unknown lower cost to operate costly to operate buy, same as gas to
operate
Future Promise? May be charged at May be charged at Most convenient to Most efficient to own,
home, reduce home, reduce own, limited future for limited future for low
dependence on oil dependence on oil low cost oil cost oil
Future Hurdles? Must improve Efficiency improving Fuel will continue to Fuel will continue to
efficiency, on board but must still increase increase in cost, increase in cost, but
energy storage, and on board storage and raising operating costs can be modified to
infrastructure charging infrastructure use bio fuels
Green Factor High, clean power if High, clean power if Low, bad reputation Low, bad reputation
charged by renewable charged by renewable for increasing air for increasing air
sources sources pollution pollution, fine particles
15

16. Conclusions
Compressed air vehicles are on the low end of
efficiency, cannot store enough energy, and have serious
infrastructure issues.
Diesel powered vehicles have the best efficiency overall
Battery electric vehicle green energy claims should be
challenged when they are powered by fossil fuel power plants
Both air and electric powered vehicles require a refueling
infrastructure to be viable
Gasoline and Diesel vehicles will continue to be popular for
their ability to refuel quickly and carry a massive amount of
chemical energy
16