Editing Compressed-air car (section)

==Advantages==

There can be a single conversion of mechanical energy to pneumatic or hydraulic energy.<ref name="researchgate.net"/> Therefore, compressed air can have high [[Energy efficiency (physics)|energy efficiency]] when using mechanical [[renewable energy]] such as wind turbines or hydropower. [[Thermal energy]] to [[mechanical energy]] conversion is possible, but less efficient due to Carnot conversion inefficiencies. Thermal storage of heat from a renewable solar source is also possible using a phase change material such as a [[molten salt]].

[[Energy conversion efficiency|Energy efficiency]] of the 2020 isothermal prototype vehicle was 59.4% of a [[lithium-ion]] vehicle.<ref name="Compressed air cars for urban transportation"/><ref name="Experimental investigation of a compressed air vehicle prototype with phase change materials for heat recovery"/>

Compressed air technology adapts to [[renewable energy]] and possibly a [[circular economy]], if [[Biobased economy|biobased]] or recycled composites can be used. Thus it is more sustainable than [[electric car]]s. For example, there is much less use of metals, or toxic [[Electric battery|battery]] chemistries. A centralized manufacturing and electric grid might be less necessary.

Efficiency is also helped by the [[Structural load|low weight]] of composite [[pressure vessel]]s relative to steel tanks or [[lithium-ion]] [[Electric battery|batteries]].<ref name="plastics.gl"/> Weight might be further reduced if the tanks support the car chassis. Pneumatic engines also have lower weights than electric engines.

Refueling is possible in many places using only wind, [[solar power]] or [[hydropower]] to move an [[air compressor]], [[hydraulic pump]] or [[Stirling engine]].

Pneumatic power has energy synergy, because it is well suited to automotive [[mechatronics]]. Many car systems can be powered by small air motors. For example, [[Air suspension|active pneumatic suspension]], pneumatic steering, or pneumatic shock absorbers.<ref>{{cite web|url=https://www.researchgate.net/publication/340022516 |title=Automated Pneumatic Bumper For Vehicle Safety |date=2012-05-01 |accessdate=2014-05-01}}</ref> Expansion of the compressed air creates cold temperatures, and can directly provide [[air conditioning]] or climate control.

[[Energy recovery]] systems with [[regenerative suspension]] and [[regenerative braking]] produce low pressure compressed air. This can be stored in a [[pressure vessel]].

[[Pistonless rotary engine|Pistonless engines]] using compressed air are very quiet.<ref>{{Cite web|url=https://www.ge.com/news/reports/20-09-2013pumping-up-the-silent-engine|title = Pumping up the silent engine &#124; GE News}}</ref>

There is no [[fire hazard]] after accidents, unlike systems that utilize combustion fuels or high power batteries.

Compressed air engines reduce the cost of car production, because there is no need to build a cooling system, spark plugs, starter motor, or mufflers.

The rate of [[self-discharge]] is very low compared to batteries. A fueled, compressed-air vehicle may be left unused for a longer time than an electric car.

They reduce or eliminate hazardous chemicals such as gasoline, battery acids and related metals such as lead.

Compressed air cars are safer in more situations:
* potentially explosive work atmospheres
* brush-fire areas
* the vicinity of strong magnetic electric fields
* [[radio quiet zone]]s