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Re: Behold the CityCAT air car, powered by compressed air.
"Michael Pardee" <michaeltnull@cybertrails.com> wrote in message news:tYSdnRixCOsL5cXbnZ2dnUVZ_sOknZ2d@sedona.net.. . > > Worse than that, air (and most gases that have low boiling points) are not > very "elastic." Air has a ratio of specific heats of around 1.4, so about > 1/3 of the energy is lost just to the compression and expansion. Batteries > can do a lot better. The compressed air has to be used at raw pressure - > that's the point, after all - and it is very difficult to make motors that > can maintain efficiency over the range of pressures necessary to make the > system work. It's much more like charging a giant, lossy capacitor. I'd be > shocked at getting anything near 50% overall efficiency, something EVs do > with ease. > > Mike > > > Nevertheless, this type of thinking is what will save us from fossil fuels. The compressed air cars are doing pretty well, and if you use solar power to charge them up, it's free energy. The car I saw on NG channel, (maybe Discovery), was still in development, but the engine was also able to be the compressor, and he was developing an electric motor to make the car self-contained. If the technology was pushed to it's limits, it could do a lot better. Hey, if you put the car in reverse, and roll forward down a hill, it'll charge it's own tanks! Batteries are very very bad for the environment. |
Re: Behold the CityCAT air car, powered by compressed air.
"Michael Pardee" <michaeltnull@cybertrails.com> wrote in message news:tYSdnRixCOsL5cXbnZ2dnUVZ_sOknZ2d@sedona.net.. . > > Worse than that, air (and most gases that have low boiling points) are not > very "elastic." Air has a ratio of specific heats of around 1.4, so about > 1/3 of the energy is lost just to the compression and expansion. Batteries > can do a lot better. The compressed air has to be used at raw pressure - > that's the point, after all - and it is very difficult to make motors that > can maintain efficiency over the range of pressures necessary to make the > system work. It's much more like charging a giant, lossy capacitor. I'd be > shocked at getting anything near 50% overall efficiency, something EVs do > with ease. > > Mike > > > Nevertheless, this type of thinking is what will save us from fossil fuels. The compressed air cars are doing pretty well, and if you use solar power to charge them up, it's free energy. The car I saw on NG channel, (maybe Discovery), was still in development, but the engine was also able to be the compressor, and he was developing an electric motor to make the car self-contained. If the technology was pushed to it's limits, it could do a lot better. Hey, if you put the car in reverse, and roll forward down a hill, it'll charge it's own tanks! Batteries are very very bad for the environment. |
Re: Behold the CityCAT air car, powered by compressed air.
"Dan G" <none@12345.org> wrote in message
news:PoqdneiunIjcF8XbnZ2dneKdnZydnZ2d@comcast.com. .. > > "Michael Pardee" <michaeltnull@cybertrails.com> wrote in message > news:tYSdnRixCOsL5cXbnZ2dnUVZ_sOknZ2d@sedona.net.. . >> >> Worse than that, air (and most gases that have low boiling points) are >> not >> very "elastic." Air has a ratio of specific heats of around 1.4, so about >> 1/3 of the energy is lost just to the compression and expansion. >> Batteries >> can do a lot better. The compressed air has to be used at raw pressure - >> that's the point, after all - and it is very difficult to make motors >> that >> can maintain efficiency over the range of pressures necessary to make the >> system work. It's much more like charging a giant, lossy capacitor. I'd >> be >> shocked at getting anything near 50% overall efficiency, something EVs do >> with ease. >> >> Mike >> >> >> > > Nevertheless, this type of thinking is what will save us from fossil > fuels. > The compressed air cars are doing pretty well, and if you use solar power > to > charge them up, it's free energy. The car I saw on NG channel, (maybe > Discovery), was still in development, but the engine was also able to be > the > compressor, and he was developing an electric motor to make the car > self-contained. If the technology was pushed to it's limits, it could do a > lot better. Hey, if you put the car in reverse, and roll forward down a > hill, it'll charge it's own tanks! > > Batteries are very very bad for the environment. > > > The physics of the technology pretty much cap the energy storage efficiency at 50% max, and it's going to be hard to break the 35% barrier. The ratio of specific heats problem (the same thing that makes a basketball "deader" than a superball) won't go away as long as this universe is in existence. Adaptive air motors are possible but always tricky. Using only the "top half" of the pressure charge means hauling around a lot of dead weight. Batteries don't have to be bad for the environment at all. The heavy metals that are most to blame for batteries' bad rep are completely recyclable. The larger batteries get the less likely they will escape the recycling stream; even standard car batteries are rarely dumped any more. Air powered cars have been around longer than electric cars - there are reasons they haven't caught on. In a time when efficiency is seen as more important than ever, the inherent inefficiency of compressed air makes this a tough sell. Mike |
Re: Behold the CityCAT air car, powered by compressed air.
"Dan G" <none@12345.org> wrote in message
news:PoqdneiunIjcF8XbnZ2dneKdnZydnZ2d@comcast.com. .. > > "Michael Pardee" <michaeltnull@cybertrails.com> wrote in message > news:tYSdnRixCOsL5cXbnZ2dnUVZ_sOknZ2d@sedona.net.. . >> >> Worse than that, air (and most gases that have low boiling points) are >> not >> very "elastic." Air has a ratio of specific heats of around 1.4, so about >> 1/3 of the energy is lost just to the compression and expansion. >> Batteries >> can do a lot better. The compressed air has to be used at raw pressure - >> that's the point, after all - and it is very difficult to make motors >> that >> can maintain efficiency over the range of pressures necessary to make the >> system work. It's much more like charging a giant, lossy capacitor. I'd >> be >> shocked at getting anything near 50% overall efficiency, something EVs do >> with ease. >> >> Mike >> >> >> > > Nevertheless, this type of thinking is what will save us from fossil > fuels. > The compressed air cars are doing pretty well, and if you use solar power > to > charge them up, it's free energy. The car I saw on NG channel, (maybe > Discovery), was still in development, but the engine was also able to be > the > compressor, and he was developing an electric motor to make the car > self-contained. If the technology was pushed to it's limits, it could do a > lot better. Hey, if you put the car in reverse, and roll forward down a > hill, it'll charge it's own tanks! > > Batteries are very very bad for the environment. > > > The physics of the technology pretty much cap the energy storage efficiency at 50% max, and it's going to be hard to break the 35% barrier. The ratio of specific heats problem (the same thing that makes a basketball "deader" than a superball) won't go away as long as this universe is in existence. Adaptive air motors are possible but always tricky. Using only the "top half" of the pressure charge means hauling around a lot of dead weight. Batteries don't have to be bad for the environment at all. The heavy metals that are most to blame for batteries' bad rep are completely recyclable. The larger batteries get the less likely they will escape the recycling stream; even standard car batteries are rarely dumped any more. Air powered cars have been around longer than electric cars - there are reasons they haven't caught on. In a time when efficiency is seen as more important than ever, the inherent inefficiency of compressed air makes this a tough sell. Mike |
Re: Behold the CityCAT air car, powered by compressed air.
Fishface wrote: > Michael Pardee wrote: > > More spam by the tinfoil hat site. Gotta say, they advertise the > > normal stuff and leave teh weird subjects until you actually look > > at the site. > > So, skip right to the source: > http://youtube.com/watch?v=QmqpGZv0YT4 > A "Beyond Tomorrow" segment, worth the watch. Seen it before. It just shows how easy it is to pull the wool over the eyes of TV reporters. Graham |
Re: Behold the CityCAT air car, powered by compressed air.
Fishface wrote: > Michael Pardee wrote: > > More spam by the tinfoil hat site. Gotta say, they advertise the > > normal stuff and leave teh weird subjects until you actually look > > at the site. > > So, skip right to the source: > http://youtube.com/watch?v=QmqpGZv0YT4 > A "Beyond Tomorrow" segment, worth the watch. Seen it before. It just shows how easy it is to pull the wool over the eyes of TV reporters. Graham |
Re: Behold the CityCAT air car, powered by compressed air.
Dan G wrote: > Nevertheless, this type of thinking is what will save us from fossil fuels. No it won't. They are *less* efficient that EVs, so need MORE energy to keep them running. > The compressed air cars are doing pretty well, Where exactly ? Except in your fantasies ? > and if you use solar power to charge them up, it's free energy. Damn you're an ignorant prick of the first order. Use the same cutesy 'solar energy' in EVs and you'll easily go *TWICE* as far - probably more since EVs can reclaim energy by regenerative braking. Graham |
Re: Behold the CityCAT air car, powered by compressed air.
Dan G wrote: > Nevertheless, this type of thinking is what will save us from fossil fuels. No it won't. They are *less* efficient that EVs, so need MORE energy to keep them running. > The compressed air cars are doing pretty well, Where exactly ? Except in your fantasies ? > and if you use solar power to charge them up, it's free energy. Damn you're an ignorant prick of the first order. Use the same cutesy 'solar energy' in EVs and you'll easily go *TWICE* as far - probably more since EVs can reclaim energy by regenerative braking. Graham |
Re: Behold the CityCAT air car, powered by compressed air.
Michael Pardee wrote: > In a time when efficiency is seen as more important than ever, the inherent > inefficiency of compressed air makes this a tough sell. A *non-sell* for general road use. Graham |
Re: Behold the CityCAT air car, powered by compressed air.
Michael Pardee wrote: > In a time when efficiency is seen as more important than ever, the inherent > inefficiency of compressed air makes this a tough sell. A *non-sell* for general road use. Graham |
Re: Behold the CityCAT air car, powered by compressed air.
"Michael Pardee" <michaeltnull@cybertrails.com> wrote in message news:N9udnZhplYyEAcXbnZ2dnUVZ_q6vnZ2d@sedona.net.. . > > > > > The physics of the technology pretty much cap the energy storage efficiency > at 50% max, and it's going to be hard to break the 35% barrier. The ratio of > specific heats problem (the same thing that makes a basketball "deader" than > a superball) won't go away as long as this universe is in existence. > Adaptive air motors are possible but always tricky. Using only the "top > half" of the pressure charge means hauling around a lot of dead weight. > > Batteries don't have to be bad for the environment at all. The heavy metals > that are most to blame for batteries' bad rep are completely recyclable. The > larger batteries get the less likely they will escape the recycling stream; > even standard car batteries are rarely dumped any more. > > Air powered cars have been around longer than electric cars - there are > reasons they haven't caught on. In a time when efficiency is seen as more > important than ever, the inherent inefficiency of compressed air makes this > a tough sell. > > Mike > > All true, but batteries are every bit as heavy as air tanks, in their current state of development. Air is as good an alternative source of energy as any other, and it's the combination of various technologies that will save us, not one specific one. Air is perfectly clean and endlessly renewable, so efficiency can take a back seat till better options come along. Lord knows it's better than alcohol. It's "alternative thinking" that's important, not necessarily relative efficiency. In other words, don't shoot it down cause it's not perfect. What's most important at this point in time is that it's CLEAN. Unless you're off the grid on solar and wind, electricity is anything BUT clean. |
Re: Behold the CityCAT air car, powered by compressed air.
"Michael Pardee" <michaeltnull@cybertrails.com> wrote in message news:N9udnZhplYyEAcXbnZ2dnUVZ_q6vnZ2d@sedona.net.. . > > > > > The physics of the technology pretty much cap the energy storage efficiency > at 50% max, and it's going to be hard to break the 35% barrier. The ratio of > specific heats problem (the same thing that makes a basketball "deader" than > a superball) won't go away as long as this universe is in existence. > Adaptive air motors are possible but always tricky. Using only the "top > half" of the pressure charge means hauling around a lot of dead weight. > > Batteries don't have to be bad for the environment at all. The heavy metals > that are most to blame for batteries' bad rep are completely recyclable. The > larger batteries get the less likely they will escape the recycling stream; > even standard car batteries are rarely dumped any more. > > Air powered cars have been around longer than electric cars - there are > reasons they haven't caught on. In a time when efficiency is seen as more > important than ever, the inherent inefficiency of compressed air makes this > a tough sell. > > Mike > > All true, but batteries are every bit as heavy as air tanks, in their current state of development. Air is as good an alternative source of energy as any other, and it's the combination of various technologies that will save us, not one specific one. Air is perfectly clean and endlessly renewable, so efficiency can take a back seat till better options come along. Lord knows it's better than alcohol. It's "alternative thinking" that's important, not necessarily relative efficiency. In other words, don't shoot it down cause it's not perfect. What's most important at this point in time is that it's CLEAN. Unless you're off the grid on solar and wind, electricity is anything BUT clean. |
Re: Behold the CityCAT air car, powered by compressed air.
"Dan G" <none@12345.org> wrote in message
news:RbydnZKMnJO4KsXbnZ2dnUVZ_rOqnZ2d@comcast.com. .. > > > All true, but batteries are every bit as heavy as air tanks, in their > current state of development. Air is as good an alternative source of > energy > as any other, and it's the combination of various technologies that will > save us, not one specific one. Air is perfectly clean and endlessly > renewable, so efficiency can take a back seat till better options come > along. Lord knows it's better than alcohol. It's "alternative thinking" > that's important, not necessarily relative efficiency. In other words, > don't > shoot it down cause it's not perfect. What's most important at this point > in > time is that it's CLEAN. Unless you're off the grid on solar and wind, > electricity is anything BUT clean. > > > Compressed air is only a storage medium, just as batteries, hydrogen or flywheels are. According to the Wikipedia entry on energy density, http://en.wikipedia.org/wiki/Energy_density, it competes poorly in that category. Even excluding the weight of the tanks, just the weight of the air itself, it weighs 2-3 times as much as the equivalent capacity of Li-Ion batteries and has at least 7 times the loss. (The practical recovery efficiency of compressed air is given as 64%, which is the efficiency if the driven device is 100% efficient over the entire range of pressure. This requires the air pressure used not drop much below the 20 bar pressure they cite; darned Second Law of Thermodynamics!) It fares even worse in energy density against compressed hydrogen powering a fuel cell, which offers about 250 times the energy density of compressed air. Mike |
Re: Behold the CityCAT air car, powered by compressed air.
"Dan G" <none@12345.org> wrote in message
news:RbydnZKMnJO4KsXbnZ2dnUVZ_rOqnZ2d@comcast.com. .. > > > All true, but batteries are every bit as heavy as air tanks, in their > current state of development. Air is as good an alternative source of > energy > as any other, and it's the combination of various technologies that will > save us, not one specific one. Air is perfectly clean and endlessly > renewable, so efficiency can take a back seat till better options come > along. Lord knows it's better than alcohol. It's "alternative thinking" > that's important, not necessarily relative efficiency. In other words, > don't > shoot it down cause it's not perfect. What's most important at this point > in > time is that it's CLEAN. Unless you're off the grid on solar and wind, > electricity is anything BUT clean. > > > Compressed air is only a storage medium, just as batteries, hydrogen or flywheels are. According to the Wikipedia entry on energy density, http://en.wikipedia.org/wiki/Energy_density, it competes poorly in that category. Even excluding the weight of the tanks, just the weight of the air itself, it weighs 2-3 times as much as the equivalent capacity of Li-Ion batteries and has at least 7 times the loss. (The practical recovery efficiency of compressed air is given as 64%, which is the efficiency if the driven device is 100% efficient over the entire range of pressure. This requires the air pressure used not drop much below the 20 bar pressure they cite; darned Second Law of Thermodynamics!) It fares even worse in energy density against compressed hydrogen powering a fuel cell, which offers about 250 times the energy density of compressed air. Mike |
Re: Behold the CityCAT air car, powered by compressed air.
Michael Pardee said the following on 5/26/2007 8:23 PM:
> "Dan G" <none@12345.org> wrote in message > news:RbydnZKMnJO4KsXbnZ2dnUVZ_rOqnZ2d@comcast.com. .. >> >> All true, but batteries are every bit as heavy as air tanks, in their >> current state of development. Air is as good an alternative source of >> energy >> as any other, and it's the combination of various technologies that will >> save us, not one specific one. Air is perfectly clean and endlessly >> renewable, so efficiency can take a back seat till better options come >> along. Lord knows it's better than alcohol. It's "alternative thinking" >> that's important, not necessarily relative efficiency. In other words, >> don't >> shoot it down cause it's not perfect. What's most important at this point >> in >> time is that it's CLEAN. Unless you're off the grid on solar and wind, >> electricity is anything BUT clean. >> >> >> > Compressed air is only a storage medium, just as batteries, hydrogen or > flywheels are. According to the Wikipedia entry on energy density, > http://en.wikipedia.org/wiki/Energy_density, it competes poorly in that > category. Even excluding the weight of the tanks, just the weight of the air > itself, it weighs 2-3 times as much as the equivalent capacity of Li-Ion > batteries and has at least 7 times the loss. (The practical recovery > efficiency of compressed air is given as 64%, which is the efficiency if the > driven device is 100% efficient over the entire range of pressure. This > requires the air pressure used not drop much below the 20 bar pressure they > cite; darned Second Law of Thermodynamics!) It fares even worse in energy > density against compressed hydrogen powering a fuel cell, which offers about > 250 times the energy density of compressed air. > > Mike > > > Entropy just ain't what it used to be. |
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