Ankit Kumar Verma MTechCAD 3 rd Sem SR NO 73410 Roll No 6004540001 Guided By Sri Rahul Gupta Associate Professor MED HBTI Kanpur Topics of Interest Introduction to the liquid nitrogen vehicle ID: 935334
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Slide1
A Seminar OnA Liquid Nitrogen Vehicle
Ankit Kumar VermaM.Tech[CAD], 3rd Sem SR NO. 734/10Roll No. 6004540001
Guided By:
Sri. Rahul Gupta
(Associate Professor)
MED
HBTI Kanpur
Slide2Topics of InterestIntroduction to the liquid nitrogen vehicleHistoryJustifying the use of liquid nitrogen vehicleCryogenic heat enginesProduction of liquid nitrogenMain componentsPrinciple of operationOpen Rankine cycle
Slide3Topics of Interest Contd.Advantages Drawbacks Solutions to drawbacksEfficiencyReason for not being commercializedConclusion and Reference
Slide4What is Liquid Nitrogen Vehicle?It is a vehicle which uses Cryogenic fluid(liquid nitrogen) as a working fluid.Propulsion system is a cryogenic heat engine in which a cryogenic substance is used as a heat sink.CRYOGENICSCryogenic can be defined as the branch of the physics that deals with the study of the production of very low temperature (below −150 °C, −238 °F or 123 K) and the behavior of materials at those temperatures
.
Slide5HistoryIn 1997, the liquid nitrogen powered vehicles was independently developed by University of North Texas (UNT) and University of Washington (UW).The propulsion systems in these vehicles were cryogenic heat engines in which a cryogenic substance is used as a heat sink for heat engine. The vehicle (car) was named as LN2000.It was a converted 1984 Grumman-Olson Kubvan mail delivery van.
Slide6A liquid nitrogen propelled car(LN2000)
Slide7Why Nitrogen as a Vehicle Fuel?High cost and limited availability of fossil fuels like petrol and diesel.Due to high level of pollution associated with the combustion of fossil fuels the need of ZEV has been generated. (presently the battery powered electric vehicle is the only commercially available ZEV but not successful due to high initial cost, slow recharge and limited range).And the most important is the huge availability of Nitrogen gas(78% of air is nitrogen).Note: According to Petroleum Conservation and Research Association petroleum production will be at its peak in 2012 and is likely to decrease after that.
Slide8Cryogenic Heat Engine It is a engine which uses very cold substances to produce useful energy.There is always some heat input to the working fluid during the expansion process.
Slide9Liquid Nitrogen(LN2)Liquid Nitrogen is the cheapest, widely produced and most common cryogen.It is mass produced in air liquefaction plantsThe liquefaction process is very simple. Normal, atmospheric air is passed through dust precipitator and pre-cooled.
Slide10P-T Chart showing Nitrogen Liquification
Slide11Atmospheric Air passesFractional Distillation
Dust
Precipitator
Inter cooler
Nozzle
LN
2
Insulated chamber
Expansion
Turbo
pumps
Dewar Flask
Nitrogen cycle showing the production of liquid nitrogen
Slide12It is then compressed inside large turbo pumps to about 100 atmospheres(10.13 MPa).Once the air has been cooled to room temperature it is allowed to expand rapidly through a nozzle into an insulated chamber.
By running several cycles the temperature of the chamber becomes low enough. The air entering it starts to liquefy.Liquid nitrogen is removed from the chamber by fractional distillation and is stored inside well-insulated Dewar flasks .
Slide13Main Components of the Engine:A pressurized tank(24 gallon) to store liquid nitrogen.Pressurant bottles of N2 gas substitute for a pump. The gas pushes the liquid nitrogen out of the Dewar that serves as a fuel tank.
A primary heat exchanger that heats (using atmospheric heat) LN2 to form N2 gas, then heats gas under pressure to near atmospheric temperature.
An Expander to provide work to the drive shaft of the vehicle.
An economizer or a secondary heat exchanger, which preheats the liquid N
2
coming out from the pressurized tank taking heat from the exhaust.
Slide14Major components of the Nitrogen powered car
Slide15Setup position of various components of nitrogen powered car
Slide16Principle of Operation:LN2 at –320oF (-196oC) is pressurized and then vaporized in a heat exchanger by ambient temperature of the surrounding air.
This heat exchanger is like the radiator of a car but instead of using air to cool water, it uses air to heat and boil liquid nitrogen.Liquid N2
passing through the primary heat exchanger quickly reaches its boiling point.
The N
2
expands to a gas with a pressure of 150 KPa.
Slide17Liquid nitrogen energy conversion system
Slide18The pressurized N2 gas drives the motor.The only exhaust is nitrogen, which is major constituent of our atmosphere.Energy+N2(l)-->N2(g)
Hence, there is no pollution produced by running this car.
Slide19Open Rankine Cycle Process The work done for simple adiabatic expansion with no heat admitted during expansion,Wadiabatic =KrTa [1-(P2 / P1) K-1/K]/
(K-1) Where Ta = 300K, ambient temperature and K = 1.4, the ratio of specific heats for nitrogen.The resulting Wadiabatic is 180KJ/Kg of Nitrogen exhausted at 150KPa.
Slide20Another limiting process is isothermal expansion from 3.3 MPa to 120KPa and the work can be easily computed as
Wisothermal = r Ta ln (P
2
/P
1
)
r = 0.2968 (KJ/KgK) for nitrogen gas and T
a
= 300K.
The result for Nitrogen is 291.59 KJ/Kg.
Slide21Note: The Availability of working fluid N2 relative to ambient conditions (Ta = 300 K) is 768 KJ/Kg.The available energy of the liquid N2 is given by [|h|×(Ta – T0)]/Ta which is equal to 570.88 KJ/Kg.
This available energy is almost 4 times the specific energy of Pb-acid batteries which is 144KJ/Kg ,where Ta and T0 are the ambient and temperature of liquid nitrogen
Slide22(a) T-P chart of a single stage nitrogen expansion
Total work achieved is 180 KJ/Kg
(b) Specific work of various fluids in adiabatic and isothermal expanders
Slide23Advantages over electric cars:A liquid nitrogen car is much lighter and refilling its tank takes only about 10-15 minutes.The exhaust produced by the car is environmental friendly.A cryogenic car could have three times the range of an electric car of the same weight and no battery disposal concerns .
Slide24Drawbacks:The N2 passing through the tubes of the heat exchanger is so cold that the moisture in the surrounding air would condense on the outside of the tubes, obstructing the air flow.Then there's the safety issue. Should a nitrogen car be kept in a poorly ventilated space and, if the Nitrogen leaks off, it could prove fatal.
Turning N2 gas into a liquid requires a lot of energy. So while cryogenic cars have zero emissions, they rely on energy produced at emission generating power plants.
Slide25Probable Solutions:A tube within a tube design.N2 passes back and forth inside a set of three nested tubes. By the time it reaches the outermost tubes, the N2 is warm enough that the exterior wall of the tube remains above the freezing point of water. Route the exhaust from the fossil fuel power plants through cryogenic plants, so that the pollutants and the greenhouse gases could be condensed for later disposal
Slide26Efficiency:The LN2 car can travel 79 miles(127.58 km) on a full 24 gallon(90 liter) tank of liquid nitrogen going 20 MPH.Its maximum speed is over 35 MPH.
Slide27Why not commercialized? Even though the technology is 10 to 12 years old, still it has not come to the market for two reasons. Safety issues have not been sorted out as yet.Lack of funds for research.
Slide28Conclusion:In a real sense, the more such vehicles are used, the cleaner the air will become.In addition to the environmental impact of these vehicles, refueling using current technology can take only a few minutes, which is very similar to current gas refueling times.Extra research work is needed to utilize the most of the available energy
Slide29References: http://www.pcra.org/ “Petroleum conservation research association” "cryogenics" Encyclopædia Britannica http://search.eb.com/eb/article?eu=28520]. Knowlen, C., Hertzberg, A., Mattick
, A.T., “Automotive Propulsion Using Liquid Nitrogen,” AIAA 94-3349, 1994.M.C. Plummer, C.A. Ordonez, R.F. Reidy, “Liquid Nitrogen as a Non-Polluting Vehicle Fuel”, C. Knowlen, A.T. Mattick, A.P. Bruckner and A. Hertzberg, “High Efficiency Energy Conversion Systems for Liquid Nitrogen Automobiles” Paper serial no.981898
http://www.autoexpo.in/
“ Auto expo 2012”
Thomas B. North “Liquid nitrogen propulsion systems for automotive applications”
Slide30THANK YOU