Copyright 2004 dontworryaboutpeakoil
Here's my idea.
Have an air car with two air tanks, and on board air compressor, and an electric generator at the brakes.
Use one air tank while driving and refuel the other air tank using the air compressor powered by the electricity gained from the brakes.
Having an onboard air compressor will extend the range of the Air Car to limitless miles.
What do you guys think?
PeakOil is You
My dumb idea: The Electric Air Car Copyright 2004 by dontwor
My dumb idea: The Electric Air Car Copyright 2004 by dontwor
by dontworryaboutpeakoil » Mon 01 Nov 2004, 11:10:54
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dontworryaboutpeakoil - Peat
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by dontworryaboutpeakoil » Mon 01 Nov 2004, 14:49:57
$this->bbcode_second_pass_quote('Licho', 'W')ell, umm, this syustem (regaining energy by braking) is already implemented in standard air car design, but even with this, it can onyl drive 100km at very low speed
Why only 100km? If you refill the air tank with the energy from braking, shouldn't the air tank be full and your range is extended?
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dontworryaboutpeakoil - Peat
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by Licho » Mon 01 Nov 2004, 15:33:33
No 
) Not at all.. You cannot "refill it" you can only recover part of energy lost by brakling. But you cannot gain energy that was used to actually move a car..
See other thread about electricity made from turning wheels
http://www.peakoil.com/fortopic2636.html
) Not at all.. You cannot "refill it" you can only recover part of energy lost by brakling. But you cannot gain energy that was used to actually move a car..
See other thread about electricity made from turning wheels
http://www.peakoil.com/fortopic2636.html
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Licho - Tar Sands
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by Kingcoal » Mon 01 Nov 2004, 15:43:36
Go ahead and build it, but you are correct in calling it a dumb idea. You might want to read up on some things first:
http://www.fact-index.com/t/th/thermodynamics.html#The%20Laws%20of%20Thermodynamics
The problem is very simple and explainable with high school physics. You have to go up a hill to use the brakes coming down the other side (unless this is a one way vehicle.) Supposing you use 50% of your air pressure to get up a hill, how much will you recover braking your way down the other side? Less than 50%. Friction and therefore heat, the enemy of any closed system is produced and radiated into the air increasing entropy. The heat loss is produced while coaxing the vehicle up the hill and also coming down the other side.
Thermal Dynamics is the much hated science that explains why perpetual motion, these days called free energy devices don't work.
http://www.fact-index.com/t/th/thermodynamics.html#The%20Laws%20of%20Thermodynamics
The problem is very simple and explainable with high school physics. You have to go up a hill to use the brakes coming down the other side (unless this is a one way vehicle.) Supposing you use 50% of your air pressure to get up a hill, how much will you recover braking your way down the other side? Less than 50%. Friction and therefore heat, the enemy of any closed system is produced and radiated into the air increasing entropy. The heat loss is produced while coaxing the vehicle up the hill and also coming down the other side.
Thermal Dynamics is the much hated science that explains why perpetual motion, these days called free energy devices don't work.
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Kingcoal - Expert
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by dontworryaboutpeakoil » Tue 02 Nov 2004, 10:23:05
$this->bbcode_second_pass_quote('Kingcoal', 'G')o ahead and build it, but you are correct in calling it a dumb idea. You might want to read up on some things first:
http://www.fact-index.com/t/th/thermodynamics.html#The%20Laws%20of%20Thermodynamics
The problem is very simple and explainable with high school physics. You have to go up a hill to use the brakes coming down the other side (unless this is a one way vehicle.) Supposing you use 50% of your air pressure to get up a hill, how much will you recover braking your way down the other side? Less than 50%. Friction and therefore heat, the enemy of any closed system is produced and radiated into the air increasing entropy. The heat loss is produced while coaxing the vehicle up the hill and also coming down the other side.
Thermal Dynamics is the much hated science that explains why perpetual motion, these days called free energy devices don't work.
http://www.fact-index.com/t/th/thermodynamics.html#The%20Laws%20of%20Thermodynamics
The problem is very simple and explainable with high school physics. You have to go up a hill to use the brakes coming down the other side (unless this is a one way vehicle.) Supposing you use 50% of your air pressure to get up a hill, how much will you recover braking your way down the other side? Less than 50%. Friction and therefore heat, the enemy of any closed system is produced and radiated into the air increasing entropy. The heat loss is produced while coaxing the vehicle up the hill and also coming down the other side.
Thermal Dynamics is the much hated science that explains why perpetual motion, these days called free energy devices don't work.
Going uphill won't use 50% of the air pressure! Say an air tank can provide 60KM range, and we have 2 air tanks onboard for a total of 120KM range.
Whenever the brakes are used, the air tanks will be continuously refilled by this energy. Since it takes only 2 minutes to refill an airtank, the range of the air car can be continuously extended. The range won't be limitless but my guess is it will be comparable to the range of a conventional car.
When the Air car arrives home, you simply plug it in the wall and recharge both air tanks for tomorrow.
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dontworryaboutpeakoil - Peat
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by dontworryaboutpeakoil » Tue 02 Nov 2004, 10:28:50
I want to get started on this project. Does anyone want to help me develop the subsystems?
I need someone who can design an air tank that can hold enough air for 60Km and is totally safe.
I regenerative brakes powering a Lithium battery much like the ones in today's Hybrids.
I a 2 or 4 piston engine that uses air pressure to generate sufficent torque and horsepower to move 2,000lbs at up to 90MPH.
I need a lightweight electric air pump.
I need someone who can design an air tank that can hold enough air for 60Km and is totally safe.
I regenerative brakes powering a Lithium battery much like the ones in today's Hybrids.
I a 2 or 4 piston engine that uses air pressure to generate sufficent torque and horsepower to move 2,000lbs at up to 90MPH.
I need a lightweight electric air pump.
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dontworryaboutpeakoil - Peat
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by djd » Tue 02 Nov 2004, 12:11:02
$this->bbcode_second_pass_quote('dontworryaboutpeakoil', '.').. an air tank that can hold enough air for 60Km and is totally safe.
Safety is in the eye of the beholder. High pressure tanks are always dangerous when full; then again, so are gasoline tanks. Vehicles carrying high pressure tanks have been on the roads for many years, although very few of them are air cars.
The MDI Air Cars (a group of commercial products) use "90 cubic metres of air compressed to 300 bars" for a range of 200-300 km. They weigh 1650 pounds, can carry (most models) 1100 pounds, and have a top speed of 65 mph. They feature regenerative braking and can refill their air tanks if supplied with electricity. Alternatively they can be directly charged with air at an "air station".
Using regenerative braking does extend the range, but how much is dependent on the fraction of the energy which is lost to rolling "friction" and air resistance, as well as the efficiency of the regnerative braking system. Since air resistance is roughly dependent on speed cubed, regnerative braking will be more effective the slower you go.
Refilling an air tank in "2 minutes" is very difficult. The power required runs to hundreds of horsepower, or hundreds of kilowatts if you prefer. The MDI cars take hours to refill when connected to 240V power.
In summary, building an air car with performance anywhere near that of a more traditional car is as much of an engineering challenge as the traditional car, and is in practice harder as there is less prior work to draw upon.
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djd - Wood
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by djd » Tue 02 Nov 2004, 12:16:16
$this->bbcode_second_pass_quote('dontworryaboutpeakoil', '.').. an air tank that can hold enough air for 60Km and is totally safe.
I should have mentioned that MDI (http://www.theaircar.com/) is using carbon fiber tanks similar to those used for compressed natural gas powered vehicles, so perhaps CNG tanks could be used in a homebuilt air car? Certainly they would be cheaper than a custom-made set of equivalent quality.
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djd - Wood
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