Windfire, you are adding in more variables and I think inferring/assuming that things will play out the same way as with a standard radiator based loop. Water out-Air in delta has it's place, but your assumption of a 10C delta is based on a standard radiator loop. As temps reach ambient that delta will decrease. Once temps start below ambient the delta will again start to increase, but energy will be flowing into the system, not out. However, equilibrium will be reached much sooner, because of rapidly diminishing returns.

I've been simply trying to keep things simple for the OP and others to understand that things don't actually work the way new folks assume. The 1.5C and 0.75C were established quite some time ago....by Martin, I believe. And the truth is the figures are usually more accurate at: ~1.0C and 0.5-0.75C at equilibrium. Water in-water out is all that's really needed to get the point across.

And, there's really too many variables for you to assume a 3.5C drop. But all that aside, a 3.5C drop

I've been simply trying to keep things simple for the OP and others to understand that things don't actually work the way new folks assume. The 1.5C and 0.75C were established quite some time ago....by Martin, I believe. And the truth is the figures are usually more accurate at: ~1.0C and 0.5-0.75C at equilibrium. Water in-water out is all that's really needed to get the point across.

And, there's really too many variables for you to assume a 3.5C drop. But all that aside, a 3.5C drop

*That's what I'm trying to get the OP (and others) to understand--this stuff doesn't happen instantaneously...it takes time. It doesn't happen first-pass and continue that way. It's just a little bit at a time.....and that's why it takes time.*__in what amount of time?__