10/16/2003

Waste Heat Recovery

 On to
refrigeration.

Much more research to do, so this is only a sketch.  Normally, we compress the
fluid to a high temperature/pressure liquid state, then run it thru a
condenser so we get a high pressure low temperature coolant.  We then expand
it thru a valve and flood an evaporator with it and absorb heat into the now
low pressure fluid and return it to the pump.

Looking at the Daeco patents where they used a freon based intercooler.
Simplest method would be to use a suburban pump and run two circuits - one to
cool the car and one to intercool the charge.  Not particularly efficient but
a nice starting place.

Now we need to look closely at the condenser.  Large and in front of the
radiator and flooding the engine compartment with wasted heat.  Since every
real car uses a 50 lb triplane wing to add 50 lbs of downforce and road
hugging weight, we might think about putting that area to good use.  For
sailboats, they make a flexible freeze plate - freon tubes on one side, a flat
cold plate on the other.  Just make the wing double sided with the cold plates
outside to the air.  Lots of road hugging downforce and a largish condenser
surface.  The flexible plates look like stainless so could be tweaked into a
supermod look.  And the wave of heat boiling off are sure to impress the tuner
boys!!!

Imagine - a wing that actually does something.

So now the condenser is out of the way of the radiator and exposed full time
to cool air and adds to the ricer look.  Neat.

Now let us look at cooling.  All forms of cooling involve the removal of
energy from a "fluid" by forcing the fluid to perform "work".  Any radiator -
whether for intercooling or cooling water or water takes the fluid, forces it
thru a restriction where work can be extracted, converts the work to friction
and radiates the heat to the air or whatever around it.  The amount of work
extracted determines how much cooler the fluid becomes.  Simple fact of
physics.

All radiators and heat exchanger are passive forms of work extraction or
cooling.  Think active.

To cool a fluid, I need to take work out of the fluid.  Nothing stops me from
extracting work and using it mechanically from a fluid.  If I put an air
conditioning compressor into the loop and drove it as a motor, the amount of
work I used from the motor would be deducted from the heat of the charge and
the charge would be cooler.

Suppose, just for thinking, that instead of a letdown valve and a evaporator
coil to cool the charge/car air, we placed a motor driven off the high
pressure temperature side of condensed Freon, extracted a significant amount
of power from it, and then fed the let down valve at a lower pressure but much
lower temperature.  

The amount of work done by the motor would reduce the cooling temperature
exactly as if feed thru a condensor.

The more heat we add to the fluid, the more energy the fluid will have to
drive the motor.  Sources of heat could be the air, the cooling liquid or even
the exhaust, and its not as if we don't have enough of it.

But, maybe I am the only one that could figure out how to use a nice amount of
power that would have been wasted.  I leave that as an exercise for the
student.