The problem with Radiator Sandwiching?

[TristanDuboisOLG]

I was asking around about radiator sandwiching. The idea of getting more thermal headroom without having to compromise more space sounded pretty good until I started looking into the specifics. Apparently there was a lot of talk on this subject some 4-6 years ago and since then there hasn't been much. Apparently there was someone that did a butload of testing on the subject and he had a few different charts.

Looking at this I was curious, is the reason that this doesn't work basically because the radiator is moving heat from the liquid into the air via rad 1 and by the time the air reaches rad 2 the air is already really saturated and can't absorb the same amount of heat?

So basically the second rad often would end up impeding air flow and thermal soaking in the already hot air?

That would mean that I could possibly still stack radiators in the same area if I found a way to separate the airflows that are feeding them right?

Is my assumption correct or am I grasping at straws here?

 

[Necere]

If one just thinks about it for a minute, sandwiching two radiators is little different from using a single thicker radiator (assuming same fin density). What matters is surface area and airflow - how you get there is less important.

This is also why having rads on both a case's intake and exhaust doesn't necessarily make that much sense, and won't just double the performance (assuming e.g. two 240 rads).