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Ed,
It looks like you and I were coming to similar conclusions.
My present plan for my, as yet, unstarted Cozy (unless one counts completion of the shop facilities) is to mount two cores - e.g. the Frigidaire EV6709 - in tandem, with the water flow going first through the rear core and then through the front one. The delta-T won't be *ideal* in either core, but it will be substantial. I just have to work out a plenum that allows no air leakage between the cores.
Still trying to keep the expenses down, without being "cheap".
Dale R.
In essence, they make the statement that thicker radiators with closer fin
spacing provides for more heat dissapation into an airstream. The
refer to the thickness as "L" length of the cooling block (heat exchanger)
and the "D" the hydraulic wetted area spacing (basically related to the fin
area/spacing) . Re is the Reyonlds number which is smaller with lower
velocity.
So a low velocity airflow through a thick radiator (L) with close fin
spacing (D) is the way I interpret their words and equation for the heat
transfer coefficient "k". This would mean you need good pressure recovery
from a diffuser (low velocity out of your diffuser). So long as you have
the dynamic pressure (read that as having adequate airspeed through your
inlet) for the thickness you are using, it appears that you are ahead of the
game using a thicker radiator.
This makes sense (to me) in that a thicker
radiator continues to dump heat into the airstream as long as the air is
passing through it - even thought it becomes less efficient at this transfer
as the air through it heats up (thereby reducing the "Delta T"), it is still
transfering heat to the air.
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