Liquid nitrogen vehicle

A aqueous nitrogen car is powered by aqueous nitrogen, which is stored in a tank. The engine works by heating the aqueous nitrogen in a calefaction exchanger, extracting calefaction from the ambient air and application the consistent pressurized gas to accomplish a agent or rotary engine. Vehicles propelled by aqueous nitrogen accept been demonstrated, but are not acclimated commercially.

Liquid nitrogen propulsion may aswell be congenital in amalgam systems, e.g., array electric propulsion and ammunition tanks to recharge the batteries. This affectionate of arrangement is alleged a amalgam aqueous nitrogen-electric propulsion. Additionally, adorning braking can aswell be acclimated in affiliation with this system.

Description

Liquid nitrogen is generated by cryogenic or Stirling engine coolers that adulterate the capital basic of air, nitrogen (N2). The acknowledgment can be powered by electricity or through absolute automated plan from hydro or wind turbines.

Liquid nitrogen is broadcast and stored in cloistral containers. The insulation reduces calefaction breeze into the stored nitrogen; this is all-important because calefaction from the surrounding ambiance boils the liquid, which again transitions to a aerial state. Reducing flood calefaction reduces the accident of aqueous nitrogen in storage. The requirements of accumulator anticipate the use of pipelines as a agency of transport. Since long-distance pipelines would be cher due to the insulation requirements, it would be cher to use abroad activity sources for assembly of aqueous nitrogen. Petroleum affluence are about a all-inclusive ambit from burning but can be transferred at ambient temperatures.

Liquid nitrogen burning is in aspect assembly in reverse. The Stirling engine or cryogenic calefaction engine offers a way to ability cars and a agency to accomplish electricity. Aqueous nitrogen can aswell serve as a absolute coolant for refrigerators, electrical accessories and air conditioning units. The burning of aqueous nitrogen is in aftereffect baking and abiding the nitrogen to the atmosphere.

Criticisms

Cost of production

Liquid nitrogen assembly is an energy-intensive process. Currently applied algidity plants bearing a few tons/day of aqueous nitrogen accomplish at about 50% of Carnot efficiency.1

edit Activity body of aqueous nitrogen

Any action that relies on a phase-change of a actuality will accept abundant lower activity densities than processes involving a actinic acknowledgment in a substance, which in about-face accept lower activity densities than nuclear reactions. Aqueous nitrogen as an activity abundance has a low activity density. Aqueous hydrocarbon fuels by allegory accept a top activity density. A top activity body makes the acumen of carriage and accumulator added convenient. Convenience is an important agency in customer acceptance. The acceptable accumulator of petroleum fuels accumulated with its low bulk has led to an incomparable success. In addition, a petroleum ammunition is a primary activity source, not just an activity accumulator and carriage medium.

The activity body — acquired from nitrogen's isobaric calefaction of dehydration and specific calefaction in aerial accompaniment — that can be realised from aqueous nitrogen at atmospheric burden and aught degrees Celsius ambient temperature is about 97 watt-hours per kilogram (W-hr/kg). This compares with 100-250 W-hr/kg for a lithium-ion array and 3,000 W-hr/kg for a gasoline agitation engine active at 28% thermal efficiency, 30 times the body of aqueous nitrogen acclimated at the Carnot efficiency.2

For an isothermal amplification engine to accept a ambit commensurable to an centralized agitation engine, a 350-litre (92 US gal) cloistral onboard accumulator barge is required.2 A applied volume, but a apparent access over the archetypal 50-litre (13 US gal) gasoline tank. The accession of added circuitous ability cycles would abate this claim and advice accredit frost chargeless operation. However, no commercially applied instances of aqueous nitrogen use for car propulsion exist.

edit Frost formation

Unlike centralized agitation engines, application a cryogenic alive aqueous requires calefaction exchangers to balmy and air-conditioned the alive fluid. In a boiling environment, frost accumulation will anticipate calefaction breeze and appropriately represents an engineering challenge. To anticipate frost body up, assorted alive fluids can be used. This adds topping cycles to ensure the calefaction exchanger does not abatement beneath freezing. Additional calefaction exchangers, weight, complexity, ability loss, and expense, would be adapted to accredit frost chargeless operation.2

edit Safety

However able the insulation on the nitrogen ammunition tank, there will accordingly be losses by dehydration to the atmosphere. If a car is stored in a ailing aerial space, there is some accident that aperture nitrogen could abate the oxygen absorption in the air and could could cause asphyxiation. Since nitrogen is a achromatic and odourless gas that already makes up 78% of air, such a change would be difficult to detect.

Cryogenic liquids are chancy if spilled. Aqueous nitrogen can could could cause algidity and can accomplish some abstracts acutely brittle.

As aqueous N2 is colder than 90.2K, oxygen from the atmosphere can condense. Aqueous oxygen can spontaneously and berserk acknowledge with amoebic chemicals, including petroleum articles like asphalt.3

Since the aqueous to gas amplification arrangement of this actuality is 1:694, a amazing bulk of force can be generated if aqueous nitrogen is rapidly vaporized. In an adventure in 2006 at Texas A&M University, the pressure-relief accessories of a catchbasin of aqueous nitrogen were closed with assumption plugs. As a result, the catchbasin bootless catastrophically, and exploded.4

edit Tanks

The tanks have to be advised to assurance standards adapted for a burden vessel, such as ISO 11439.5

The accumulator catchbasin may be fabricated of:

steel

aluminium

carbon fiber

Kevlar

added materials, or combinations of the above.

The cilia abstracts are appreciably lighter than metals but about added expensive. Metal tanks can bear a ample amount of burden cycles, but have to be arrested for bane periodically. Aqueous nitrogen, LN2, is frequently transported in cloistral tanks, up to 50 litres, at atmospheric pressure. These tanks, getting non-pressure tanks they are not accountable to inspection. Very ample tanks for LN2 are sometimes pressurized to beneath than 25 psi to aid in appointment the aqueous at point of use.

edit Discharge output

Like added non-combustion activity accumulator technologies, a aqueous nitrogen car displaces the discharge antecedent from the vehicle's appendage aqueduct to the axial electrical breeding plant. Where emissions-free sources are available, net assembly of pollutants can be reduced. Discharge ascendancy measures at a axial breeding bulb may be added able and beneath cher than alleviative the emissions of broadly broadcast vehicles.

Advantages

Liquid nitrogen cars are commensurable in abounding means to electric vehicles, but use aqueous nitrogen to abundance the activity instead of batteries. Their abeyant advantages over added cars include:

Much like electrical vehicles, aqueous nitrogen cars would ultimately be powered through the electrical grid, which makes it easier to focus on abbreviation abuse from one source, as against to the millions of cars on the road.

Busline of the ammunition would not be appropriate due to cartoon ability off the electrical grid. This presents cogent amount benefits. Abuse created during ammunition busline would be eliminated.

Lower aliment costs

Aqueous nitrogen tanks can be disposed of or recycled with beneath abuse than batteries.

Aqueous nitrogen cars are airy by the abasement problems associated with accepted array systems.

The catchbasin may be able to be refilled added generally and in beneath time than batteries can be recharged, with re-fueling ante commensurable to aqueous fuels.

Disadvantages

The arch disadvantage is the inefficient use of primary energy. Activity is acclimated to adulterate nitrogen, which in about-face provides the activity to run the motor. Any about-face of activity has losses. For aqueous nitrogen cars, electrical activity is absent during the condensate action of nitrogen.

Liquid nitrogen is not accessible in accessible refueling stations nor is there a administration arrangement in place.