21-07-2012, 04:01 PM
compressed air car
compressed air car.pptx (Size: 284.47 KB / Downloads: 66)
Introduction :
A compressed air car is a car that uses a motor powered by compressed air.
The car can be powered solely by air.
This can also be powered by the combination of air with gasoline ,diesel, ethanol or an electric plant with regenerative braking.
ENGINE Setup :
These cars are powered by engines fueled by compressed air, which is stored in a tank at high pressure such as 30 MPa (4500 psi or 300 bar).
Compressed air cars use the expansion of compressed air, in a similar manner to the expansion of steam in a steam engine.
Storage tanks are often made of carbon-fiber for weight reduction while maintaining strength.
There have been prototype cars since the 1920s and compressed air has been used in torpedo propulsion as well.
Storage tanks :
The major manufacturers that are developing air cars have designed safety features into their cylinders.
It was reported on Seven Network’s Beyond Tomorrow that on its own , carbon-fiber is brittle and can split under sufficient stress, but creates no shrapnel when it does so.
Carbon-fiber tanks safely hold air at a pressure somewhere around 4500 psi, making them comparable to steel tanks.
Compressed air is also relatively space inefficient of storing energy when compared to conventional gasoline. Air at 30 MPa (4,500 psi) contains about 50 Wh of energy per liter. Gasoline contains about 9411 Wh per liter.
Emission :
Compressed air cars are emission-free at the exhaust.
Since a compressed air car’s source of energy is usually electricity, its total environmental impact depends on how clean the source of this electricity is.
Different regions can have very different sources of power, ranging from high-emission power sources such as coal to zero-emission power sources such as wind.
A given region can also update its electrical power sources over time, thereby improving or worsening total emissions.
ENERGY DENSITY :
Compressed air has relatively low energy density.
The energy density of a compressed air system can be more than doubled if the air is heated prior to expansion.
In order to increase energy density, some systems may use gases that can be liquified or solidified.
"CO2” offers far greater compressibility than air when it transitions from gaseous to supercritical form.
ADVANTAGES :
Refueling can be done at home using an air compressor or at service stations.
Reduction or elimination of hazardous chemicals such as gasoline or battery acids/metals.
Compressed air engines reduce the cost of vehicle production, because there is no need to build a cooling system, spark plugs, starter motor, or mufflers.
Expansion of the compressed air lowers its temperature; this may be exploited for use as air conditioning.
DISADVANTAGES :
The overall efficiency of a vehicle using compressed air energy storage is low (50% to 70%).
When air expands in the engine it cools dramatically (Charles's law) and must be heated to ambient temperature using a heat exchanger.
Conversely, when air is compressed to fill the tank it heats up. If the stored air is not cooled as the tank is filled, it cools off later and pressure decreases and energy also decreases.
Refueling the compressed air container using at home may take as long as 4 hours.
compressed air car.pptx (Size: 284.47 KB / Downloads: 66)
Introduction :
A compressed air car is a car that uses a motor powered by compressed air.
The car can be powered solely by air.
This can also be powered by the combination of air with gasoline ,diesel, ethanol or an electric plant with regenerative braking.
ENGINE Setup :
These cars are powered by engines fueled by compressed air, which is stored in a tank at high pressure such as 30 MPa (4500 psi or 300 bar).
Compressed air cars use the expansion of compressed air, in a similar manner to the expansion of steam in a steam engine.
Storage tanks are often made of carbon-fiber for weight reduction while maintaining strength.
There have been prototype cars since the 1920s and compressed air has been used in torpedo propulsion as well.
Storage tanks :
The major manufacturers that are developing air cars have designed safety features into their cylinders.
It was reported on Seven Network’s Beyond Tomorrow that on its own , carbon-fiber is brittle and can split under sufficient stress, but creates no shrapnel when it does so.
Carbon-fiber tanks safely hold air at a pressure somewhere around 4500 psi, making them comparable to steel tanks.
Compressed air is also relatively space inefficient of storing energy when compared to conventional gasoline. Air at 30 MPa (4,500 psi) contains about 50 Wh of energy per liter. Gasoline contains about 9411 Wh per liter.
Emission :
Compressed air cars are emission-free at the exhaust.
Since a compressed air car’s source of energy is usually electricity, its total environmental impact depends on how clean the source of this electricity is.
Different regions can have very different sources of power, ranging from high-emission power sources such as coal to zero-emission power sources such as wind.
A given region can also update its electrical power sources over time, thereby improving or worsening total emissions.
ENERGY DENSITY :
Compressed air has relatively low energy density.
The energy density of a compressed air system can be more than doubled if the air is heated prior to expansion.
In order to increase energy density, some systems may use gases that can be liquified or solidified.
"CO2” offers far greater compressibility than air when it transitions from gaseous to supercritical form.
ADVANTAGES :
Refueling can be done at home using an air compressor or at service stations.
Reduction or elimination of hazardous chemicals such as gasoline or battery acids/metals.
Compressed air engines reduce the cost of vehicle production, because there is no need to build a cooling system, spark plugs, starter motor, or mufflers.
Expansion of the compressed air lowers its temperature; this may be exploited for use as air conditioning.
DISADVANTAGES :
The overall efficiency of a vehicle using compressed air energy storage is low (50% to 70%).
When air expands in the engine it cools dramatically (Charles's law) and must be heated to ambient temperature using a heat exchanger.
Conversely, when air is compressed to fill the tank it heats up. If the stored air is not cooled as the tank is filled, it cools off later and pressure decreases and energy also decreases.
Refueling the compressed air container using at home may take as long as 4 hours.