Final justification of paralell rads

[George M. Dailey]

Gentlemen, I checked a my reference books and could find none that spelled
out one routing is beter than the other.  I will bow in disgrace. There have
been many post by experts in this feild, that confirm the paralell routing
to be the best. I do hate to holster a weapon without firing a few shots:),
so I can still prove I was originally correct, through fundamental heat
transfer logic. I thought I was wrong about something once in the past, but
later found out I was right:) So here it goes. Clik...clank

T=inlet temperature
T1=outlet temp from Rad1
T2=outlet temp from Rad2
Assume that total coolant flow is equal in each option 
Assume that cooling air flow and temp is equal in each option to each rad
Assume that rads are not placed one behind the other in any option
Assume each rad to be identical to the other
H1=heat dissapated from Rad1
H2=heat dissapated from Rad2

series set up

                      H1                        H2
>>>------------/\/\/\/\/\/\/\/\----------/\/\/\/\/\/\/\/\----------->>>
T                    Rad 1          T1         Rad2                  T2

In this setup, the following can said with confidence.

Fact 1: Heat dissapated by any rad will increase as the inlet temperature to
that rad increases or simply put,  H1 & H2 are directly proportional to T1 &
T2. 

Fact 2: Since Fact 1 is true, H1 must allways be greater than H2 because T
is allways greater than T1.   If T=T1, then no heat was dissapated by Rad 1.
If T1=T2, then no heat was dissapated by Rad 2 and it is not needed. If
T2>T, one or both Rads picked up some heat. 

Let's look at the paralell setup.


                              H1
                    ----/\/\/\/\/\/\/\/\---
                    |                     |
       >>>----------|                     |--------->>>
        T           |                     |         T1
                    |                     |
                    ----/\/\/\/\/\/\/\/\---
                              H2

since the total flow must be equal to the series arrangement, we must have
1/2 of the total system flow going to each radiator.

Fact 3: Since only the flow changed (when compared to H1 in the series
setup) H1 in the paralell setup must be greater than the H1 in the series
setup. This is because you are giving it more time to dissapate the heat
than in the series set up. Remember, it stays in the radiator twice as long
because the flow has been reduced by 1/2. The inlet temps (T) in each setup
are identical.

Fact 4: H1 and H2 must be equal in the paralell setup because all other
factors are equal.

Fact 5: since H1 in the paralell set up is dissapating more heat than H1 in
the series set up, and H1 must equal H2 in the paralell set up, we are
forced to draw one conclusion. The paralell set up must be dissapating more
heat than the series arrangement.

summary:

total H paralell=H1+H2
total H series=H1+H2
H1 must allways be greater than H2 when in series
H1 must equal H2 when in paralell
H1 in paralell must allways be greater than H1 in series

If some one can justify a different conslusion, I would love to hear it.
Fire away and excercise extreame predjudice!

Thanks to all who commented and the excellent asci art. 
GMD