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Fwd: SAfrica may produce squashed-air car

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  • Autymn D. C.
    Subject: SAfrica may produce squashed-air car From: David Haith, horizon@horizon.worldonline.co.uk An extraordinary new vehicle with a unique power
    Message 1 of 4 , Nov 1, 2000
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      Subject: SAfrica may produce squashed-air car
      From: David Haith, horizon@...

      An extraordinary new vehicle with a unique power source is lined up for
      production in South Africa, offering hope for those incensed by the cost
      of
      hydrocarbons.
      The car, called the Taxi ZerO Pollution (TOP), runs off motive energy
      stored as compressed air in tanks resembling those of scuba divers. The
      compressed air impels a piston engine. In effect, it's a serious versionof
      toys whose power source is emptying balloons.

      The TOP is the brainchild of a former French Formula One racing engineer,
      Guy Negre. It looks similar to the micro-minibuses recently introduced by
      the likes of Renault to the South African market.

      The compressed air is stored in tanks holding 300 litres and attached to
      the underside of the car. The body of the vehicle weighs only 700kg; the
      engine itself is a mere 35kg. This means that the vehicle can
      theoretically
      be driven for up to 10 hours in an urban environment at an average speed
      of
      80km/h.
      Plugged into a electrical power source, it can take as much as four hours
      for the car to "re-fuel" as air is compressed and forced into the storage
      tanks by a small compressor. But large-scale "air stations" could manage
      the
      task in just three minutes for companies running fleets of air-powered
      commercial vehicles.
      The projected cost in South Africa is around R74 000, near the bottom
      end of the market. The vehicle's range is 200km, at a phenomenal
      projected cost
      of just R2. If this scenario proves workable, the savings may well seduce
      many who might otherwise be put off by the range limitation.

      Details on the technology have yet to be revealed, but the concept is
      significantly simpler than others being pursued by developers of
      environmentally friendly transport, such as fuel cells and internal
      combustion-electric hybrids.

      Road tests of the prototypes have been done since 1998 in Brignoles,
      France. A hybrid version of the engine runs on normal fuel at speeds
      higher
      than 60km/h, still with extremely low energy consumption.

      But the car itself is not the only innovative part of the concept. The
      production has been designed to be extremely simple, allowing factories to
      be constructed for a minimal $8-million. Such a factory would produce 2
      000
      to 4 000 vehicles a year with a staff of 130. The factory concept is
      designed to be franchised, and easily transported to developing countries.

      The local branch of Zero Pollution Motors hopes to establish a production
      line in Gauteng next year, being in production by 2002.

      a.. Zero Pollution Motors was not answering calls.



      -- The Mail&Guardian, October 30, 2000.
      Here's a link about it
      http://www.mg.co.za/mg/za/archive/2000oct/features/30oct-aircar.html
    • Bob Dubner
      Not bloody likely! You d be better off sending your banking information to one of those Nigerian fax scam deals. And even if this *could* work, I don t want to
      Message 2 of 4 , Nov 1, 2000
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        Not bloody likely!

        You'd be better off sending your banking information to one of those
        Nigerian fax scam deals.

        And even if this *could* work, I don't want to be anywhere *near* one of
        those things, much less riding in one. There is a *lot* of energy in a
        compressed air tank; I once saw pictures of a SCUBA tank that fell over,
        broke the valve, flew 70 feet through the air and punched through a brick
        wall.

        But there isn't *that* much energy in there, not compared to gasoline.

        Ten hours at 80 km/hr is 800 km. I suspect that's a typo; in an urban
        environment you don't go 80 km/hr. Also, it is inconsistent with the figure
        that is has a range of 200 km.

        So, ignore the speed and ten hour figures. Use the 200km = 124 miles, which
        is what something needs to be useful as a taxicab. If the car could do 62
        miles per gallon with an efficient gasoline engine, then the compressed air
        has to be able to do the work of two gallons of gas.

        Two gallons of gas, burned with complete efficiency, represents about
        250,000 BTU. Figuring a car runs at about 40% efficiency, we can estimate
        that it requires about 100,000 BTU at 100% efficiency to propel our vehicle
        for those 124 miles.

        Okay -- let's figure out how much work we have to do, starting with air at 1
        atmosphere, to end up with 100,000 BTU in a 300 liter tank. 100,000 BTU is
        equal to about one million liter-atmospheres.

        The work done when compressing a volume of gas is the integral of P(V)dV. In
        this case, we figure P(V) by noting that P1V1=PV, where P1 is one
        atmosphere. We end up with the work done as being

        W = 1E6 = V1(ln(V1) - ln(300))

        I don't remember how to solve that one rigorously. A little fooling around
        with a calculator shows me that the initial volume needs to be something on
        the order of 170,000 liters.

        If you compress 170,000 liters down to 300 liters, and if you manage to do
        it reversibly (which is a good trick), the resulting pressure is 566
        atmospheres, which is about 8,000 pounds per square inch. SCUBA tanks are
        ordinarily filled to about 2100 pounds per square inch; modern firefighting
        oxygen bottles are filled to about 2,700 pounds per square inch, if memory
        holds.

        8,000 pounds per square inch is *DANGEROUS*.

        Oh, and about those tanks. Normal welding tanks (usually filled to about
        1,600 or so pounds per square inch) are about six inches in diameter. 300
        liters means that you'd need five tanks, each six inches in diameter, each
        TEN FEET LONG!! underneath this car, filled to 8,000 pounds per square inch.
        Be careful not to bump into anything when parallel parking. And don't even
        *think* about two of these cars colliding in an accident -- imagine all of
        the energy in four gallons of gas -- which is something like 20 sticks of
        dynamite -- all released at once.

        Not me, folks. I'd just as soon juggle live rattlesnakes; it's safer.

        It *has* to be a scam. Either that, or somebody's slipstick slipped the
        wrong way.

        "...Details on the technology have yet to be revealed..." -- you bet your
        arse they do.


        > -----Original Message-----
        > From:
        > sentto-4092-1694-973123819-rdubner=compuserve.com@...
        > [mailto:sentto-4092-1694-973123819-rdubner=compuserve.com@...
        > t.com]On Behalf Of Autymn D. C.
        > Sent: Wednesday, November 01, 2000 19:00
        > To: free_energy@egroups.com
        > Subject: [free_energy] Fwd: SAfrica may produce squashed-air car
        >
        >
        >
        > Subject: SAfrica may produce squashed-air car
        > From: David Haith, horizon@...
        >
        > An extraordinary new vehicle with a unique power source is lined up for
        > production in South Africa, offering hope for those incensed by the cost
        > of
        > hydrocarbons.
        > The car, called the Taxi ZerO Pollution (TOP), runs off motive energy
        > stored as compressed air in tanks resembling those of scuba divers. The
        > compressed air impels a piston engine. In effect, it's a serious versionof
        > toys whose power source is emptying balloons.
        >
        > The TOP is the brainchild of a former French Formula One racing engineer,
        > Guy Negre. It looks similar to the micro-minibuses recently introduced by
        > the likes of Renault to the South African market.
        >
        > The compressed air is stored in tanks holding 300 litres and attached to
        > the underside of the car. The body of the vehicle weighs only 700kg; the
        > engine itself is a mere 35kg. This means that the vehicle can
        > theoretically
        > be driven for up to 10 hours in an urban environment at an average speed
        > of
        > 80km/h.
        > Plugged into a electrical power source, it can take as much as four hours
        > for the car to "re-fuel" as air is compressed and forced into the storage
        > tanks by a small compressor. But large-scale "air stations" could manage
        > the
        > task in just three minutes for companies running fleets of air-powered
        > commercial vehicles.
        > The projected cost in South Africa is around R74 000, near the bottom
        > end of the market. The vehicle's range is 200km, at a phenomenal
        > projected cost
        > of just R2. If this scenario proves workable, the savings may well seduce
        > many who might otherwise be put off by the range limitation.
        >
        > Details on the technology have yet to be revealed, but the concept is
        > significantly simpler than others being pursued by developers of
        > environmentally friendly transport, such as fuel cells and internal
        > combustion-electric hybrids.
        >
        > Road tests of the prototypes have been done since 1998 in Brignoles,
        > France. A hybrid version of the engine runs on normal fuel at speeds
        > higher
        > than 60km/h, still with extremely low energy consumption.
        >
        > But the car itself is not the only innovative part of the concept. The
        > production has been designed to be extremely simple, allowing factories to
        > be constructed for a minimal $8-million. Such a factory would produce 2
        > 000
        > to 4 000 vehicles a year with a staff of 130. The factory concept is
        > designed to be franchised, and easily transported to developing countries.
        >
        > The local branch of Zero Pollution Motors hopes to establish a production
        > line in Gauteng next year, being in production by 2002.
        >
        > a.. Zero Pollution Motors was not answering calls.
        >
        >
        >
        > -- The Mail&Guardian, October 30, 2000.
        > Here's a link about it
        > http://www.mg.co.za/mg/za/archive/2000oct/features/30oct-aircar.html
        >
      • Autymn D. C.
        From: Bob Dubner, rdubner@compuserve.com ... I guess you should mail the editor? editor@e-mg.co.za
        Message 3 of 4 , Nov 1, 2000
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          From: Bob Dubner, rdubner@...

          >Not bloody likely!
          >
          >You'd be better off sending your banking information to one of those
          >Nigerian fax scam deals.
          I guess you should mail the editor? editor@...
        • Jozef Vrlik
          By my opinion squashed air car, called the Taxi ZerO Pollution (TOP), has remote polution (chimney of remote power plant). Compressed air (gas) as source of
          Message 4 of 4 , Nov 3, 2000
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            By my opinion squashed air car, called the Taxi ZerO Pollution (TOP), has
            remote polution (chimney of remote power plant).

            Compressed air (gas) as source of stored energy is the worst solution,
            acceptable only in the case when energy is for free. (accumulation of energy
            during braking)

            1. Real compression is adiabatic, that means a lot of compression work is
            transfered to heat and compressor will work against higher pressure of
            heated gas. (Adiabatic curve in p-v diagram is much steeper than isotherm
            curve - integral p dv of adiadabatic compression which represent work of
            compression is higher)

            2. After filling pressure vessel, hot gas will be cooled by ambient
            temperature and therefore all heat energy is lost.

            3. During adiabatic expansion temperature of pressurised gas will fall down,
            therefore gas will reduce expandabe volume and revealed energy is very low.
            From technical reason if in compressed air is a humidity, it will be problem
            with icing of valves, pipes ..., therefore air must be dried using heavy
            drier.

            These physical properties of real gas will cause, that such a system is
            highly inefficient.
            - From technical point of view, compression and expansion on high pressure
            differencies is not so simple. Obviously is used multistage compression with
            intercoolers for lowering pressure differencies on each stage. Multistage
            high pressure compressors are much heavier than low pressure compressors.

            - 300 liters of high pressure steel vessels will have approx. 300 kg (from
            Faber company) or 500 kg (standard steel vessels) - it is too much. It means
            only plastic high pressure vessels could be used, their weight is
            approximately 120 kg for 300 liters of water volume. As I know, plastic
            vessels are designed only to pressure 250 bars (3500 Psi).


            I visit their WWW site of TOP car and on my surprise on the picture is
            special combustion engine, similar to one which was developed in Slovakia in
            1950. Characteristic of this engine is follows:
            -Compression is performed by piston in separate small cylinder
            -Separate combustion chamber is filled by compressed air (or fuel mixture)
            from compression cylinder
            -Expansion of hot gas is performed in separate expander cylinder with higher
            volume than compressor cylinder.

            Of course, this kind of internal combustion engine could work, some of his
            advantages are, that fuel burning at constant pressure could be relatively
            long - it could reduce pollutions. Engine could work on pressurised air as
            well (but it is virtualy possible for each internal combustion engine)

            But disadvantages of such a system are follows:
            a/ There are pressure losses during filling combustion chamber by compressed
            gas through narrow passage.
            b/ There are pressure losses during filling expansion chamber by hot gas
            through narrow passage from combustion chamber.
            c/ Timing of valves between compression cylinder and combustion chamber and
            between combustion chamber and expansion cylinder should be extremely
            precise, otherwise opening valves at high pressure differences will cause
            losses.
            d/ fuel consumption of such engine (measured in gram / kwh ) many times
            exceeds consumption of modern internal combustion engines.
            e/ There are temperature differences between compression cylinder and
            expansion cylinder


            Jozef Vrlik
            NEAT - New Energy Alternative s.r.o.
            Kosice
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