Of course, I'm not suggesting that we all change the way we refer to
our car parts. I was responding to and correcting the guy who said
that heat exchangers and radiators are different not only in name but
in how they work.
He made a statement that was incorrect based on a misconception of the
physics of how radiators work so I had to respond in the same vein.
As far as the issues of this thread are concerned here is my take:

The reason we don't see radiators on boats is that air is an
inefficient cooling fluid. It is a very poor conductor of heat and
has low heat capacity. On the other hand, water is an excellent
conductor of heat and has huge heat capacity. So if a huge supply of
cold water is available near the engine, it is an easy decision. As
an engineer, I'd dump all of that heat in the water rather than try to
force it into the air.

One way to understand the heat conducting properties of water is to
think about how comfortable 72 degree air is vs. 72 degree water. 72
degree water feels alot colder simply because it is carrying your body
heat away very quickly. The lake does the same thing with your engine
heat. Carries it away very quickly.

I'm new to boating and as such have never even seen a heat exchanger
on a boat (my cooling system is open) but I'd bet that they are alot
smaller than radiators in cars. This is further illustration of how
efficent water is as a cooling fluid.

Chris



(Gould 0738) wrote in message ...
A heat exchanger, as the term is commonly applied, transfers heat between
liquids.



Technically, a "radiator" is not a radiator. A real radiator is what
you see on the floor of an old apartment building with no forced air
flow through it.

"As the term is commonly applied........"

Walk into your nearest auto shop this fall and ask to have your heat exchanger
serviced. You'll get more than a few strange looks.

Send a marine mechaninc down to your boat to change the zincs on your
"radiator"
and the wrench might sense this is a perfect time (and you're the perfect
client)
to recommend servicing the framus and the diogenator as long as he's aboard- it
will only run an extra $200.

If it takes a physics lecture to shore up a theory that "radiators and heat
exchangers are really the same thing" it doesn't, in the real world, address
the issues of this thread.

Those seem to have been:

1. Why don't we see radiators in boats?

schools of thought in response

a. Of course we do. I can show you hundreds of inboards with radiators

b. boats use a liquid to liquid heat exchanger rather than an automotive type
radiator to cool the engine.

c. There is no difference between an automobile radiator and a heat exchanger
on a boat.


If this were a multiple choice exam, I'd go with B. Thanks anyway, though.