Refrigerants, Wide range EGO and other thoughts.

[steve ravet]

Thor Johnson wrote:
> 
> > Refrigerants
> >
> > Sounds like someone is trying to adapt the ammonia  absorption
> cycle
> > refrigeration system to use as an intercooler.  What is
> interesting is that
> > although this cycle is less "efficient" at cooling  than a
> compressed gas
> > cycle, it gets it's pumping energy from heat - in the  case of
> a propane RV
> > refrigerator from a small propane flame, or in this  case from
> the waste heat
> > of the exhaust.  The problem is probably the exhaust
> temperatures raise the
> > ammonia/water solution past the efficient working  range and
> the gentleman is
> > looking for another absorption cycle fluid that will work in
> this range.
> 
> You have any good sources of info on the ammonia cycle?  I'm a
> nuts&bolts guy who would like to build one for the heck of it....
> (An EE that likes to play with the ME's toys ;).

Get on Deja News, and do a search on ammonia refrigerators.  You'll come
up with a lot of posts in rec.boating of all places, including one that
explains ammonia fridges in detail.  The author's name is Rod McInnis. 
A mixture of water and ammonia is heated in a column.  Because of
different boiling points, one end of the column is mostly ammonia, the
other end is mostly water.  The two are separated, and pumped into the
fridge.  When water and ammonia mix, the temperature of the mix goes way
down.  It's a physical process, not a chemical one, that I cannot
remember the name of right now.  The mixture never changes pressure, so
there is no compresor.  The only energy input is a flame or electric
heat to boil the mixture.  In an RV, there isn't even a pump, the system
is cleverly designed so that the gravity causes the mixture to 
circulate.  That won't work in a car with lateral G forces, but there's
no reason why you couldn't add a small pump to circulate the mixture. 
It's been mentioned before here, it seems like it would be a good way to
use exhaust heat to cool the incoming mixture.  The only thing is that
the ammonia mixture is very stong (poisonous), much stronger than
cleaning products.

--steve

> 
> TIA,
> -Thor Johnson
> thormj at iname.com

--
Steve Ravet
International Meta Systems
http://www.imes.com
steve at imes.com