The document presents information on Cryocar, a vehicle that uses liquid nitrogen as fuel. It discusses the history of liquid nitrogen propulsion research. The key components of a liquid nitrogen propulsion system are described including the cryogen storage vessel, pump, economizer, heat exchanger, and expander engine. The open Rankine power cycle is explained. Advantages include reduced emissions, but disadvantages include energy needed to liquefy nitrogen and potential safety issues if nitrogen leaks. The LN2000 vehicle developed at the University of Washington is provided as an example.

1. Technical Seminar presentation on
CRYOCARCRYOCAR
Presented by
Chethan S A 4BB13ME015
Under the Guidance of
Mr.Theju H.S. B.E., M.tech.,
Assistant Professor
DEPARTMENT OF MECHANICAL ENGINEERINGDEPARTMENT OF MECHANICAL ENGINEERING
Bahubali College of Engineering
Shravanabelgola-573 135
2016-17
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2. CONTENTSCONTENTS
1. Introduction
2. History
3. LN2000’s Liquid Nitrogen Propulsion System
4. Parts of a Liquid Nitrogen Propulsion System
5. Power Cycle
6. Advantages
7. Disadvantages
8. LN2000 Vehicle
9. Conclusion
10. References
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3. INTRODUCTIONINTRODUCTION
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The importance of cars in the present world is increasing day
by day.
There are various factors that influence the choice of the car.
These include performance, fuel consumption, pollution etc.
As the prices for fuels are increasing and the availability is
decreasing we have to go for alternative choice.
Here an automotive propulsion concept is presented which
utilizes liquid nitrogen as the working fluid.

4. HISTORYHISTORY
Researchers at the University of Washington are developing a
new zero-emission automobile propulsion concept.
That uses liquid nitrogen as the fuel. The principle of operation
is like that of a steam engine(open Rankine cycle).
In this liquid nitrogen at –320° F (–196° C) is pressurized and
then vaporized in a heat exchanger.
This heat exchanger is like the radiator of a car.
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5. LN2000’S LIQUID NITROGEN PROPULSIONLN2000’S LIQUID NITROGEN PROPULSION
SYSTEMSYSTEM
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Fig. No. 1: LN2000’s Liquid Nitrogen Propulsion System

6. PARTS OF A LIQUID NITROGEN PROPULSIONPARTS OF A LIQUID NITROGEN PROPULSION
SYSTEMSYSTEM
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The main parts of a liquid nitrogen propulsion system are:
1. Cryogen Storage Vessel.
2. Pump.
3. Economizer.
4. Expander Engine.
5. Heat exchanger.

7. 1. CRYOGEN STORAGE VESSEL1. CRYOGEN STORAGE VESSEL
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 It is a storage tank which is used to store and insulate the
liquid nitrogen at -196°c.
It should have Resistance to deceleration forces, low boil-off
rate, minimum size and mass, reasonable cost etc.
It is generally made up of titanium or aluminum alloys for the
inner and outer vessels.
Moderately high vacuum with super insulation type vessel is
used prevent boil-off rates.

8. 2. PUMP2. PUMP
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The pump is used to pump the liquid nitrogen into the engine.
The pump which are used for this purpose have an operating
pressure ranging between 500 – 600 Psi (35-42 bars).
As the pump, pumps liquid instead of gas, it is noticed that the
efficiency is high.

9. 3. ECONOMIZER3. ECONOMIZER
A pre heater, called an economizer, uses leftover heat in the
engine's exhaust to preheat the liquid nitrogen.
Hence the economizer acts as a heat exchanger between the
incoming liquid nitrogen and the exhaust gas which is left out.
This is similar to the regenerative process which is done in
steam power plant.
Hence with the use of the economizer, the efficiency can be
improved.
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LN2 at -320°F(-196°C) is pressurized and then vaporized in a
heat exchanger by ambient temperature of atmosphere.
The heat exchanger used is similar to radiator of car but instead
of using air to cool water, it uses air to heat and boil LN2.
Liquid LN2 passing through the primary heat exchanger
quickly reaches its boiling point.
Heat exchanger is made up of aluminum tubes with outside
diameter of 10mm and wall thickness of 1mm.
4. HEAT EXCHANGER4. HEAT EXCHANGER

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The maximum work output of the LN2 engine results from an
isothermal expansion stroke.
Thus, engines having expansion chambers with high surface-
to-volume ratios are favored for this application.
Rotary expanders such as the Wankel may also be well suited.
 A secondary fluid could be circulated through the engine
block to help keep the cylinder walls as warm as possible.
5. EXPANDER5. EXPANDER

12. POWER CYCLEPOWER CYCLE
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Fig. No. 2: Temperature Entropy Diagram For Open Rankine Cycle

13. Cont...Cont...
There are many thermodynamic cycles available for utilizing
the thermal potential of liquid nitrogen.
These range from the Brayton cycle, to using two and even
three fluid topping cycles.
The easiest to implement, however, and the one chosen for this
study, is shown in figure 2.(Rankine cycle).
State 1 is the cryogenic liquid in storage at 0.1 MPa and 77 K.
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14. Cont...Cont...
The liquid is pumped up to system pressure of 4 MPa
(supercritical) at state 2 and then enters the economizer.
State 3 indicates N2 properties after it is being preheated by the
exhaust gas.
Further heat exchange with ambient air brings to N2 300k at
state 4
Isothermal expansion to 0.11 MPa at state 5 would result in the
N2 exhaust having enough enthalpy to heat the LN2
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15. ADVANTAGESADVANTAGES
 The process to manufacture liquid nitrogen in large quantities
can be environmentally very friendly (Liquification).
 Produces no or less air pollution and pollutants to atmosphere
results in greater environmental benefits.
 The operating cost is very less as compared to cost of fossil
fuels.
 LN2 powered car offer many safety advantages over
commercial cars.
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16. DISADVANTAGESDISADVANTAGES
The N2 passing through the tubes of the heat exchanger obstruct
the air flow (Icing problem).
The 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.
The principal disadvantage is the inefficient use of primary
energy.
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17. LN2000 VEHICLELN2000 VEHICLE
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Fig. No. 3: Inner Components of LN2000
Fig. No. 4: LN2000 Vehicle

18. CONCLUSIONCONCLUSION
The potential for utilizing the available energy of liquid
nitrogen for automotive propulsion looks very promising.
Time to recharge (refuel), infrastructure investment, and
environmental impact are among the issues to consider.
The convenience of pumping a fluid into the storage tank is
very attractive.
Manufacturing LN2 from ambient air inherently removes small
quantities of atmospheric pollutants
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19. REFERENCESREFERENCES
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JOURNALS
[1] Abilash Vijayrao Nishane, (2016) “Cryogenic Liquid Nitrogen as a Fuel
for Zero Emission Vehicles (Z.E.V)”, International Journal and Magazine
of Engineering, Technology, Management and Research.
[2] Rahul Singh Choudhary, (2015) “Hydrogen as a Non-Polluting Fuel”,
International Journal of Advance Research, IJOAR.org.
[3] Akil Garg, Kartik Jakhu, Kishan Singh, (2015) “Cryogenic Technology
and Rocket Engines” International Journal of Aerospace and Mechanical
Engineering.
[4] Pankaj Soni, Gopal Sahu, Prakash Kumar Sen, Ritesh Sharma, (2014ss)
“A Review on Cryogenic Engine” International Journal for Research in
Science and Engineering Technology (IJRASET).

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