FreeLists / opendtv / [opendtv] Re: GM exec: Time to reinvent the automobile

[Jeroen Stessen <jeroen.stessen@xxxxxxxxxxx>]

Hi, 

Barry Wilkins wrote about The Air Car: 
> Furthermore , it would appear that people loose track of the origination 
of the energy source 
> and the losses involved in the storage process. Much heat is generated 
in the compression of 
> air and this is simply waste energy that cannot be extracted by the 
vehicle. 

Not true ! As the air expands in the engine, it cools down. 
It is reheated between cylinders from warm ambient air. 
This extracts energy from the ambient (and provides for free 
air conditioning). Thus the car uses some energy from the 
ambient that it does not have to carry with it. You could 
say that some of the heat from the compressor travels to 
the car through the air and is used by the expander... 

> A vehicle that needs to operate for 4 hours per day at an average 20KW 
work load 

You are completely missing the point. A lot of cars are used 
less than 30 minutes per day. Air would be the perfect solution, 
also because there are no self-discharge losses like in 
batteries and cryogenic hydrogen tanks. You can leave such car 
parked with a full tank for years, and it should still be full. 

> requires double this energy from the electricity supply to compress the 
air in the first place. 

So what ? The alternatives are not that much more efficient ! 

> As a 50KW 3 phase induction motor would be required to operate over at 
least 
> 4 hours to compress this air I do not believe it is a very practical 
solution in general. 

You could connect the air compressor directly to a steam 
turbine and install a compressed air network. But I think that 
in order to fill an empty tank efficiently you need multiple 
sources of compressed air at different pressures. You should 
probably not fully empty the tank in the first place, or the 
power output from the engine would be insufficient. 

Let's also not forget that a simple flame under the heat 
exchanger for this Air Car engine serves as a range extender. 
This flame can be from any source, even burning old newspapers. 

I think I might buy one, if they ever start making them... ! 

Best, 
-- Jeroen

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