Re: MDI air car
Posted: Thu Nov 13, 2008 9:03 am
This is true. In a truly integrated system I suppose one could run the hot compressed gas through a heat exchanger to recover the heat. Heat some domestic hot water or some such. More of a problem is the adaibatic cooling when the pressure is let down, as you say. The air must be completely dry and some form of pre-heating would be preferable...I wonder if a reverse radiator might work? I know that the torpedoes used circulating seawater to "heat" the air.solarcooker wrote:Another thing to keep in mind with using compressed air. When you compress a gas, it gets very hot, which raises the pressure. Then when it drops back to room temperature, all that energy is lost, and the pressure drops. There really isn't a good way to reclaim that energy, in most cases. That hurts the argument that you can just hook up to an air compressor and fill the tank. You lose half the pressure as it cools down, unless the tank is insulated, and you take off right away. If you wait until it cools, and then "top off" the tank, then the expanding air quickly freezes any water vapor in the valves and lines, and clogs up the system as it leaves the tank. When you compress air, you add all the water vapor in it also.
If you aren't using solar or wind to power the air compressor, the efficiency is not that good. The car may not pollute, but the power plant does. (Not trying to be negative. I've just worked with compressed air)
