Compressed air system with a PCM heat exchanger prototype by Dr. Reza Alizade Evrin from Ontario Tech University.Compressed air system with a PCM heat exchanger prototype diagram
A compressed-air vehicle (CAV) is a transport mechanism fueled by tanks of pressurized atmosphericgas and propelled by the release and expansion of the gas within a pneumatic motor.
Compressed-air propulsion may also be incorporated in hybrid systems, such as with battery electric propulsion. This kind of system is called a hybrid-pneumatic electric propulsion. Additionally, regenerative braking can also be used in conjunction with this system.
Compressed-air engines
In principle, any pneumatic motor can be used for a compressed-air vehicle, but some engines were specifically developed for this application and/or have specific advantages.
di pietro engine
Dipietro eccentric shaft, rotary vane air engine
There have been several dubious claims with undisclosed information. However, the "di pietro" engine has been partially tested with CAD and finite element analysis program and published in scientific papers by Jarosław Zwierzchowski from Lodz University of Technology in 2017,[4] which is an eccentric shaft vane motor that uses low air pressure.
Liquidpiston
LiquidPiston rotary engine
Another recent engine that could be adapted to compressed air is Liquidpiston rotary engine.[5]
Compressed-air tanks and collision safety
Hyundai nexo high-pressure hydrogen tank safetyDuraStor consortium Thermoplastic composite pressure vessels for hydrogen vehicles
The pressure vessels or air storage tanks that can be used in compressed-air vehicles can be made of low pressure (9 atm) or high pressure (+240 atm), and can be made of composite materials like thermoplastic and fiber reinforced thermoplastics,[6][8] that means that the price can drop by using recycled or biobased thermoplastics using rotational molding and they are much lighter than lithium-iron batteries and 70% lighter compared to steel tanks, also they have more lifespan and don't need much maintenance.
To reduce vehicle weight further the air tanks can be used as structural storage so the tank is the main part of the vehicle chassis while using appropriate impact isolation, however fiber reinforced thermoplastic tanks only have ruptures in case of collision and don't explode. Some advances in pressure vessels for vehicles have been developed for hydrogen vehicles with high compression pressure vessels. Automobile designer Hyundai states:[9]
Hydrogen tanks require ‘High Strength’ to prevent rupture and ‘High Stiffness’ for durability. Strength is defined as the level of resistance to an influence of an external force. Stiffness is the level of resistance maintaining its original shape. The carbon fiber materials used in making hydrogen fuel tanks is as light as a plastic but has six and four times the strength and stiffness of steel, respectively. “When a bullet penetrates a hydrogen tank, it does not explode. Instead, hydrogen leaks out through the bullet hole. In a standard collision test, not even a tiny amount of hydrogen was detected because none had leaked out.
Compressed-air production, storage and energy efficiency and density
Wind Turbine Air Compressor posted Fieldlines.com: The Otherpower discussion board wind turbine powered hydraulic pump with Open Accumulator for Isothermal Compressed Air Energy Storage ICAES System
Compressed air can be produced by attaching an air compressor or hydraulic pump to a wind turbine[10][11] or using river, tidal, wave hydropower turbine with only a conversion from mechanical to pneumatic energy, eliminating electricity from the loop which gives higher efficiency overall.
Since the compressed air is filtered to protect the compressor machinery, the air discharged has less suspended dust in it, though there may be carry-over of lubricants used in the compressor or engine. This can be mitigated by using oil-free air compressors.
Resource consumption
The recent developments of composite pressure vessels and pneumatic components means that compressed-air vehicles can be part of the circular industry with biobased or recycled components. Also by cutting electric energy from the loop there is no need for electric grid and the metals used like cooper, iron in magnets, etc.
History
Gotthardbahn: Pneumatic Locomotive with attached pressure container.
During the construction of the Gotthardbahn from 1872 to 1882, pneumatic locomotives were used in the construction of the Gotthard Rail Tunnel and other tunnels of the Gotthardbahn.
In 1903, the Liquid Air Company located in London, United Kingdom, manufactured a number of compressed-air and liquified-air cars. The major problem with these cars and all compressed-air cars is the lack of torque produced by the "engines" and the cost of compressing the air.[13]
Since 2010, several companies have started to develop compressed air cars, including hybrid types that also include a petrol-driven engine; none has been released to the public, or have been tested by third parties.[citation needed]
Energy density compared to lithium-ion, Isothermal compressed air energy storage ICAES energy density can be at least 2.7MJ/kg or 3.6MJ/m3, 4 times [3] of lithium-ion batteries, which can be improved with high-pressure vessels and heat exchanger systems.
Structural weight, the low weight of composite pressure vessels relative to lithium-ionbattery and also compared to steel tanks (70% lighter),[8] which that can be reduced by using the tanks as vehicle chassis structure with appropriate impact isolation, also the low weight of wheel hub motor rotary engines.
Energy synergy with the available pneumatic energy, so all vehicle mechatronics systems can be powered by small air motors, and also the vehicle can use active pneumatic suspension, pneumatic steering or pneumatic shock absorption bumpers,[14] also there can be provided air conditioning or climate control with the using the low temperature created during air expansion.
Low noise of pistonless rotary engines while using compressed air, which can also being soundproofed because the low temperature in which it works.
Zero fire hazard, which makes it one of the few transportation systems that cannot produce spontaneous or after-collision fire or explosions like in the case of petrol, ethanol, hydrogen and also battery vehicles.
While batteries can somewhat maintain their voltage throughout their discharge and chemical fuel tanks provide the same power densities from the first to the last litre, the pressure of compressed air tanks falls as air is drawn off, reducing available power.
Possible improvements
It may be possible to store compressed air at lower pressure using an absorption material within the tank. Absorption materials like Activated carbon,[15] or a metal organic framework[16] is used for storing compressed natural gas at 500 psi instead of 4500 psi, which amounts to a large energy saving.
Vehicles
Compressed-air locomotive used in boring the Rove canal tunnel in France
This section needs to be updated. Please help update this article to reflect recent events or newly available information.(February 2013)
Several companies are investigating and producing prototypes including hybrid compressed-air/gasoline-combustion vehicles. As of August 2017, none of the developers have yet gone into production, although Tata has indicated they will begin selling vehicles from 2020[17] and MDI's US distributor Zero Pollution Motors says production of the AIRPod will commence in Europe in 2018.[18]
Experimental cars and bikes
In 2008, a compressed air and natural gas powered vehicle designed by engineering students at Deakin University in Australia was joint winner of the Ford Motor Company T2 competition to produce a car with a 200km range and an estimated cost of less than $7,000.[19][20]
Australian company Engineair has produced a number of vehicle types - moped, small car, small carrier, go-cart - around the rotary compressed air engine created by Angelo Di Pietro.
A compressed-air powered motorcycle, called the Green Speed Air Powered Motorcycle was made by Edwin Yi Yuan, based on the Suzuki GP100 and using the Angelo Di Pietro compressed-air engine.[21]
Three mechanical engineering students from San Jose State University; Daniel Mekis, Dennis Schaaf and Andrew Merovich, designed and built a bike that runs on compressed air. The total cost of the prototype was under $1000 and was sponsored by Sunshops (on the Boardwalk in Santa Cruz, California) and NO DIG NO RIDE (from Aptos, California.). The top speed of the maiden voyage in May 2009 was 23mph. While their design was simple, these three pioneers of compressed air powered vehicles helped pave the way[citation needed] for French automaker Peugeot Citroën to invent a brand new air-powered hybrid. The 'Hybrid Air' system uses compressed air to move the car's wheels when driving under 43mph. Peugeot said the new hybrid system should get up to 141 miles per gallon of gas. Models were claimed to start rolling out as early as 2016 . However, the head of the project left Peugeot in 2014 and in 2015 the company said it had been unable to find a partner to share the development costs, effectively ending the project.[22]
"Ku:Rin" named air-compressed three-wheeler vehicle was created by Toyota in 2011. The speciality about this vehicle is it has registered a record-breaking highest speed 129.2km/h (80mph) even if it has engine which uses only compressed air. This car was developed by the company's "Dream car workshop". This car is nicknamed as "sleek rocket", or "pencil shaped rocket".[23]
As part of the TV-show Planet Mechanics, Jem Stansfield and Dick Strawbridge converted a regular scooter to a compressed air moped.[24] This has been done by equipping the scooter with a compressed-air engine and air tank.[25]
In 2010, Honda presented the Honda Air concept car at the LA Auto Show.[26]
Since 2008 the former Bosch Rexroth, now Emerson is organizing the Emerson's International AVENTICS Pneumobile Competition in Eger, Hungary. It is a competition for students in the higher education to build racing vehicles propelled by compressed air.[27]
Óbuda University PowAir Pneumobil Team
There is an international conference related to the event organized by Óbuda University, Department of Bánki Donát Mechanical and Safety Engineering.[28]
Trains, Trams, Boats and Planes
Preserved Nantes compressed-air tramcar at the AMTUIR museum
Compressed-air locomotives are a kind of fireless locomotive and have been used in mining[29] and tunnel boring.[30]
Currently, no water or air vehicles exist that make use of the compressed-air engine. Historically certain torpedoes were propelled by compressed-air engines.
An engine or motor is a machine designed to convert one or more forms of energy into mechanical energy.
In an internal combustion engine, a turbocharger is a forced induction device that is powered by the flow of exhaust gases. It uses this energy to compress the intake air, forcing more air into the engine in order to produce more power for a given displacement.
A gas turbine, gas turbine engine, or also known by its old name internal combustion turbine, is a type of continuous flow internal combustion engine. The main parts common to all gas turbine engines form the power-producing part and are, in the direction of flow:
A starter is a device used to rotate (crank) an internal-combustion engine so as to initiate the engine's operation under its own power. Starters can be electric, pneumatic, or hydraulic. The starter can also be another internal-combustion engine in the case, for instance, of very large engines, or diesel engines in agricultural or excavation applications.
A hybrid vehicle is one that uses two or more distinct types of power, such as submarines that use diesel when surfaced and batteries when submerged. Other means to store energy include pressurized fluid in hydraulic hybrids.
A compressed-air car is a compressed-air vehicle powered by pressure vessels filled with compressed air. It is propelled by the release and expansion of the air within a motor adapted to compressed air. The car might be powered solely by air, or combined with other fuels such as gasoline, diesel, or an electric plant with regenerative braking.
An air compressor is a machine that takes ambient air from the surroundings and discharges it at a higher pressure. It is an application of a gas compressor and a pneumatic device that converts mechanical power into potential energy stored in compressed air, which has many uses. A common application is to compress air into a storage tank, for immediate or later use. When the delivery pressure reaches its set upper limit, the compressor is shut off, or the excess air is released through an overpressure valve. The compressed air is stored in the tank until it is needed. The pressure energy provided by the compressed air can be used for a variety of applications such as pneumatic tools as it is released. When tank pressure reaches its lower limit, the air compressor turns on again and re-pressurizes the tank. A compressor is different from a pump because it works on a gas, while pumps work on a liquid.
The Brayton cycle, also known as the Joule cycle, is a thermodynamic cycle that describes the operation of certain heat engines that have air or some other gas as their working fluid. It is characterized by isentropic compression and expansion, and isobaric heat addition and rejection, though practical engines have adiabatic rather than isentropic steps.
Compressed-air energy storage (CAES) is a way to store energy for later use using compressed air. At a utility scale, energy generated during periods of low demand can be released during peak load periods.
A compressor is a mechanical device that increases the pressure of a gas by reducing its volume. An air compressor is a specific type of gas compressor.
A chiller is a machine that removes heat from a liquid coolant via a vapor-compression, absorption refrigeration, or absorption refrigeration cycles. This liquid can then be circulated through a heat exchanger to cool equipment, or another process stream. As a necessary by-product, refrigeration creates waste heat that must be exhausted to ambience, or for greater efficiency, recovered for heating purposes. Vapor compression chillers may use any of a number of different types of compressors. Most common today are the hermetic scroll, semi-hermetic screw, or centrifugal compressors. The condensing side of the chiller can be either air or water cooled. Even when liquid cooled, the chiller is often cooled by an induced or forced draft cooling tower. Absorption and adsorption chillers require a heat source to function.
Grid energy storage is a collection of methods used for energy storage on a large scale within an electrical power grid. Electrical energy is stored during times when electricity is plentiful and inexpensive or when demand is low, and later returned to the grid when demand is high, and electricity prices tend to be higher.
Capstone Green Energy, formerly Capstone Turbine Corporation, was incorporated in 1988 as a California based gas turbine manufacturer that specializes in microturbine power along with heating and cooling cogeneration systems. Key to the Capstone design is its use of air bearings, which provides maintenance and fluid-free operation for the lifetime of the turbine and reduces the system to a single moving part. This also eliminates the need for any cooling or other secondary systems. The Capstone microturbine is a versatile and dispatchable technology that is fuel flexible and scalable enough to fit a variety of applications.
A pneumatic motor, or compressed-air engine, is a type of motor which does mechanical work by expanding compressed air. Pneumatic motors generally convert the compressed-air energy to mechanical work through either linear or rotary motion. Linear motion can come from either a diaphragm or piston actuator, while rotary motion is supplied by either a vane type air motor, piston air motor, air turbine or gear type motor.
A rotary-screw compressor is a type of gas compressor, such as an air compressor, that uses a rotary-type positive-displacement mechanism. These compressors are common in industrial applications and replace more traditional piston compressors where larger volumes of compressed gas are needed, e.g. for large refrigeration cycles such as chillers, or for compressed air systems to operate air-driven tools such as jackhammers and impact wrenches. For smaller rotor sizes the inherent leakage in the rotors becomes much more significant, leading to this type of mechanism being less suitable for smaller compressors than piston compressors.
Hydrogen technologies are technologies that relate to the production and use of hydrogen as a part hydrogen economy. Hydrogen technologies are applicable for many uses.
An alternative fuel vehicle is a motor vehicle that runs on alternative fuel rather than traditional petroleum fuels. The term also refers to any technology powering an engine that does not solely involve petroleum. Because of a combination of factors, such as environmental and health concerns including climate change and air pollution, high oil-prices and the potential for peak oil, development of cleaner alternative fuels and advanced power systems for vehicles has become a high priority for many governments and vehicle manufacturers around the world.
A free-piston engine is a linear, 'crankless' internal combustion engine, in which the piston motion is not controlled by a crankshaft but determined by the interaction of forces from the combustion chamber gases, a rebound device and a load device.
A liquid nitrogen engine is powered by liquid nitrogen, which is stored in a tank. Traditional nitrogen engine designs work by heating the liquid nitrogen in a heat exchanger, extracting heat from the ambient air and using the resulting pressurized gas to operate a piston or rotary motor. Vehicles propelled by liquid nitrogen have been demonstrated, but are not used commercially. One such vehicle, Liquid Air, was demonstrated in 1902.
An internal combustion engine is a heat engine in which the combustion of a fuel occurs with an oxidizer in a combustion chamber that is an integral part of the working fluid flow circuit. In an internal combustion engine, the expansion of the high-temperature and high-pressure gases produced by combustion applies direct force to some component of the engine. The force is typically applied to pistons, turbine blades, a rotor, or a nozzle. This force moves the component over a distance, transforming chemical energy into kinetic energy which is used to propel, move or power whatever the engine is attached to.
↑ Ma Shengqian (2008). "Metal-Organic Framework from an Anthracene Derivative Containing Nanoscopic Cages Exhibiting High Methane Uptake". Journal of the American Chemical Society. 130 (3): 1012–1016. doi:10.1021/ja0771639. PMID18163628.
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