LIQUID NITROGEN VEHICLE

Liquid Nitrogen is the cheapest, widely produced and most common cryogenic liquid.  It is mass produced in air liquefaction plants.  The liquefaction process is very simple in it normal, atmospheric air is passed through a dust precipitation and pre-cooled using conventional refrigeration techniques. It is then compressed inside large turbo pumps to about 100 atmospheres.  Once the air has reached 100 atmospheres and has been cooled to room temperature it is allowed to expand rapidly through a nozzle into an insulted chamber.  By running several cycles the temperate of the chamber reaches low enough temperatures the air entering it starts to liquefy.  Liquid nitrogen is removed form the chamber by fractional distillation and is stored inside well-insulated Dewar flasks.

In 1997, the University of North Texas (UNT) and University of Washington (UW) independently developed liquid nitrogen powered vehicles in which the propulsion systems in these vehicles are cryogenic heat engines in which a cryogenic substance is used as a heat sink for heat engine.

Advantages:

The energy density of liquid nitrogen is relatively low and better than readily available battery systems.

They have significant performance and environmental advantages over electric vehicles.

A liquid nitrogen car is much lighter and refilling its tank will only 10-15 minutes.

The exhaust produced by the car is environmental friendly.

Conclusion :

In a real sense, the more such vehicles are used, the cleaner the air will become if the liquefaction process is driven by non-polluting energy sources.  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.