Research ObjectivesMEEM4200

Group 1

Are compressed air

powered vehicles a

viable automotive propulsion alternative?

How far can you go and how

hard is it to refuel a

compressed air vehicle?

What is the fossil fuel-to-motor output

serial efficiency for a

compressed air vehicle?

Are compressed air vehicles a

“green” propulsion

technology?

How do compressed air

vehicles compare in cost

to other vehicles?

Car photo: http://www.popularmechanics.com/cars/news/preview-concept/4251491

1

Seth BrezeeStephen BuckleyAlfred PiggottAndrew Schorfhaar

12/10/2010

Compressed Air Vehicle - Basics

Image Source: http://www.mdi.lu/english http://zeropollutionmotors.us/, http://www.google.com/patents

,

Vehicle

Energy Storage

Pneumatic Motor

Compressed Air Tanks

2

Compressed Air Vehicle – Analysis

V

P

n=1Isothermal

1<n<k

n=k

IsentropicP2

P1

V

P

n=1Isothermal

1<n<k

n=k

IsentropicP2

P1

V

P

n=1Isothermal

1<n<k

n=k

IsentropicP2

P1

V

P

n=1Isothermal

1<n<k

n=k

IsentropicP2

P1

1

22

1

21 ln

p

pV

p

ppWisothermal

Time

p

pV

p

pp

Powerisothermal

1

22

1

21 ln

48.0InputPowerElectric

OutputPowerAircompressor

PVU2

3

Isothermal Compression and Expansion

Compressed Air Internal Energy

Serial Efficiency

Isothermal Power

31.0InputPowerAirCompressed

OutputPowerShaftMotorPneumatic

35.0AveragePlantPower

935.0GridElectric

0487.0)31.0)(48.0)(935.0)(35.0( serial

2211 VpVp

Image Source: <http://www.me.mtu.edu/~jstallen/courses/MEEM4200>

UWQ

First Law Air Compression

3

Battery Electric Vehicle - Basics

Propelled by:

Nissan Leaf

Charging Station(source www.GE.com)

Lithium Ion BatteryCapacity = 24 kWh

Motor Controller 80 kW Motor

(source www.nissanusa.com)

4Fuel Economy Label

(source www.nytimes.com)

Range = 73 miles

Battery Electric Vehicle - Analysis

Electric Power Plant (0.35)

Transmission Grid (0.935)

Charging Station (0.86)

AC/DC Converter (0.90)

Battery Charge Efficiency (0.99)

Battery Storage Efficiency (1.0)

Battery Discharge

Efficiency (0.99)

Motor Controller (0.96)

Electric Motor (0.804)

Fossil Fuel

Power Out

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/kWh5

Gasoline Powered Vehicle - Analysis

Serial Efficiency of Gasoline Power:

Fossil Fuel Engine out = 18%

A gasoline powered vehicle that was rated for around 30MPG was used for comparison.

Gasoline Engine Cost in Dollars 4000Technology Cost 28.25

Vehicle Power Output in kW 141.55

dollars dollars

kW kW

Technology Cost for Gasoline Power:

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

Gasoline Powered Vehicle Cont…

44Carbon Content 2,241 0.99 8.8

12

grams amu kg

gallon amu gallon

8.8 8.8

Carbon Footprint 1.74

. 33.7 0.15

kg kggallon gallon kg

kWhkWh kWhEFF

gallon gallon

Carbon Footprint for Gasoline Power:

Energy Density of Gasoline:

66 3 3 3

1 1Energy Density 122 10 32, 230

10 3.7854 10

Joules MJ gallon MJx

gallon J x m m

Vehicle Range :

Vehicle Range 30 16 480miles gallons miles

gallon tank tank

7

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>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>

8

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 /literSerial 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^3Calculation: 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.pdf3. 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. http://www.bankrate.com/brm/news/auto/20030804a1.asp4. Web. 09 Dec. 2010. http://www.evworld.com/library/energy_numbers.pdf 9

Summary – Energy Efficiency

Diesel

Gasoline

Battery Electric

Compressed Air

0.000.050.100.150.200.250.300.350.40

0.40

0.15

0.19

0.05

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

Summary – Carbon Emissions

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)

Diesel

Gasoline

Battery Electric

Compressed Air

0 2 4 6 8 10 12 14

1.7

1.7

3.2

12.5

Carbon Footprint (kg / KWh)

Conclusion: Compressed air vehicles produce lots of CO2 when powered by fossil fueled power plants 11

Summary – Energy Volumetric Density

Diesel

Gasoline

Battery Electric

Compressed Air

0 10,000 20,000 30,000 40,000

36,400

32,230

1,080

47

Energy Density (MJ/meter cubed)

Conclusion: Compressed air energy storage systems are not able to store a great deal of energy, limiting their range.

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Summary – Technology Cost Analysis

Diesel

Gasoline

Battery Electric

Compressed Air

$0 $20

$40

$60

$80

$100

$120

$140

$160

$180

$39

$28

$62

$167

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.

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Summary – Cost and Range

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.

Compressed Air

Battery Electric

Gasoline Diesel

Vehicle Cost $4600-$17,800 $32,780 $22,000 $20,000

Overall Vehicle Cost Summary:

Compressed Air

Battery Electric

Gasoline Diesel

Vehicle Range 29 miles 73 miles 480 miles 504 miles

Vehicle Range Summary:

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Technology Comparison – Customer Focus

Customer Metric

Compressed Air

Battery Electric Gasoline Diesel

Co2 Emissions? Relocates CO2 emissions, but creates more

Relocates CO2 emissions, but creates more

Emits CO2 at place of operation

Emits CO2 at place of operation

Easy to Refuel? No, need air compressor, large power draw

No, takes too long, expensive charger required

Refuel quickly with large refueling infrastructure

Refuel quickly with large refueling infrastructure

Costly to Own? Not likely, but exact figures unknown

Expensive to buy, lower cost to operate

Inexpensive to buy, costly to operate

Slightly more costly to buy, same as gas to operate

Future Promise? May be charged at home, reduce dependence on oil

May be charged at home, reduce dependence on oil

Most convenient to own, limited future for low cost oil

Most efficient to own, limited future for low cost oil

Future Hurdles? Must improve efficiency, on board energy storage, and infrastructure

Efficiency improving but must still increase on board storage and charging infrastructure

Fuel will continue to increase in cost, raising operating costs

Fuel will continue to increase in cost, but can be modified to use bio fuels

Green Factor High, clean power if charged by renewable sources

High, clean power if charged by renewable sources

Low, bad reputation for increasing air pollution

Low, bad reputation for increasing air pollution, fine particles

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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

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