Using waste heat in an autombile to power a Stirling Engine

[teakstone]

I just discovered Stirling engines last week. What an amazing
technology. I have always been one that wants to use free energy
(waste heat coming from an air conditioning unit, expelled hot gases
from an internal combustion engine, or perhaps from the radiator of
a car, heat from a frige to heat ceramic tile floors, etc)

The question.
Is there enough wasted heat energy in a motor vehicle such as from
the exhaust system or from the cooling system to perhaps power some
accessories perhaps to charge the battery rather than using hp to
turn the alternator to charge the battery?

My question is more theoretical rather than economical. The
economics will come if the scale of production is large enough I
would imagine.

Also, there tends to be alot of trapped heat in attics during the
warm season. Can that heat be used to power the Stirling Engine to
do some sort of useful work?

Thanx

Walter from Toronto

[stan.hornbaker]

This question has been asked before in different terms. There are two hurdles to overcome in utilizing waste heat from any source and that is the high temperature itself and the temperature of the cold sink to which the waste heat of the Stirling engine must necessarily flow into. The amount of useful mechanical energy to run a generator is a function of the absolute value of these two temperatures. This is known as the Carnot efficiency and NO heat engine can produce more power that Carnot will permit.

Secondly there are no small, Stirling enginge-generators being manufactured due to the low demand and high cost of such specialty engines.

To learn more about Stirling engines go to the "Site Map" and explore the links there. Also there is a good Tutorial on