I think you meant flow rate instead of surface area because if you meant surface then your option #3 would be null
because option and 1 and 3 are the same increasing surface area.
Just asking here if
@cadaveca works with HVAC what type of engineer are you
@lilhasselhoffer? Just curious.
Yes and no. I did word the explanation poorly. Fluid flow rate, assuming laminar flow, is a good approximation of the amount of the surface of the liquid coming into contact with the heat source. As a constantly flowing fluid generally is assumed to heat evenly, despite the fact that the fluid conducts heat only on the surface that it touches, we assume that fluid flow rate is a functionally the same as direct conductive heating.
That was probably an even more convoluted explanation. For the sake of simplicity, you are correct.
I've had the opportunity to work with an HVAC specialist on a few occasions. The beauty, or maybe tragedy, is that rarely do they have the ability to transition their knowledge into other fields. This isn't a knock, only an observation that "specialist" is their title. They know a lot about one field, in a rather limited range of situations. You'll note that an HVAC specialist wasn't consulted for the space station, engineers designed it because the insane conditions meant that regular HVAC was functionally worthless (you can't be ball parking when dealing with ammonia). A huge depth of knowledge, with no girth, doesn't transition anywhere well. HVAC specialists, in my experience, knows their coolant specifications and rules of thumb extremely well. Thing is, once you leave those coolants their ingrained knowledge is often difficult to apply. The HVAC people I knew could estimate a building's floor space by observing the building's vents. They could tell me how long it would take for the AC to drop to a given temperature (and how much power would be consumed). The second I asked about the impact a gigantic fish tank would have on the system, and what we needed to keep it heated, they knew nothing. That's water, a liquid and its thermal impact was unknown. This could have just been a string of incompetent people, but if so they were idiot savants. I respected their skills (and honestly admired the ability to be so accurate without ever picking up a calculator), and they understood when something was beyond their depth and they needed backup.
As far as my engineering, I chose the bastard versions (or jack of all trades if you're being realistic). I'm a mechanical engineer. That means I've had 1.5 years of thermo (which is a rough estimate, because my school did a 4 term year with summer being a fourth term). I've had 1 whole year of just state equations (and if anybody tries to model a double pendulum for you begin drinking immediately). Fluid dynamics was relatively brief at 1 year, but had overlap into thermo. I've modeled heat transfer from a rectangular surface into ambient air (if the description doesn't give it away, exactly the same situation as a processor) and into a crude finned heat sink. I've even had the opportunity to model a radiator which would drop the temperature of a fluid by 100 C in a space no bigger than a shoebox (83 simulated runs to get the damn thing right). The only topic that we were brief on was electronics, only getting up to crude 8 bit processors during labs (with primary focus on much higher voltage systems. generally motors). I've had my ass reamed more times than I'd care to count because I missed a single unit somewhere. You'll find that this is why I'm so keen to point it out. Most of the time people calling you incompetent either missed a variable and are getting the wrong answer because they don't understand the units, or don't understand how to apply equations. I've learned that whenever I come to an odd conclusion I need to prove my steps, and that the best thing you can do is ask someone about their units whenever they seem to not have a grasp on the subject.
I've got one request, if anyone believes I'm full of crap. Beat me at the game. I'm a certified engineer, which means I passed a test. Once you've taken that 8+ hour torture and passed it I'll gladly believe you're qualified to talk about theory. Until then, you've got as much right to believe in your superiority of knowledge as I do in my understanding of programming. To put that in perspective, I'm outclassed unless my competition can't understand a batch file and introductory C++.