Parallel Radiators: no waterblocks

[Charlie Hanson]

My new build allows for a few different radiator options. I'm hoping somebody here has some legitimate technical advice, or cold hard experience, to help me decide what to do.

I have the space for any of the following combinations:

(A) 4x 120 radiators: EK's SE, HWLab's GTS, or any other radiator less than 32mm;
(B) 4x 140 radiators: only EK SE will fit (140mm wide) as the GTS is too wide (153mm);
(C) 3x 140 radiators: allows for wider radiators such as the GTS
(D) 2x 240 radiators: again, EK's SE and HWL GTS.
(E) 1x 520 radiator: there are some that fit, but not a great deal of details on their performance exist
(F) 1x 480 radiator: plenty will fit, but again their performance is hard to judge

The question is: do I go for a single radiator, multiple in series, or multiple in parallel?

'Parallel vs Series' has been debated forever, with neither side victorious. However, in my situation there is a catch: I won't have any waterblocks in the radiator's loop. My components are on one loop with their own pump, and the radiators will have a separate pump. The two loops will share a reservoir. The logic behind this layout is:
1) so I can blast water round the 'hot' loop at whatever speed gives the most heat removal, i.e. whatever makes the water the hottest the fastest. I expect that to be on the upper scale of speed;
2) so I can nudge water round the 'cold' loop at whatever speed gives the most heat removal, which I expect to be on the lower speed scale;
3) that rather than one D5 doing all the work I can get away with a DDC for the hot loop and an even smaller pump for the cold loop, as the flow rate in the cold loop doesn't need to be very high;
4) this allows for parallel radiators without worrying how it affects the flow in the hot loop and, in my head, parallel radiators will give me greater cooling power.

I have used a popular 2016 Radiator Roundup to choose the HardwareLabs Black Ice GTS series as the best Watt dissipators given their performance against other slim radiators such as the Magicool G2 and Alphacool's offering. Sadly, there is no comprehensive inclusion of what EK has to offer, namely the SE range, which is why the first three combinations above are there. From what I've gleaned from the aforementioned roundup, (A) and (C) will transfer the same heat given a 2-3% error margin. (B) sounds attractive, but I lack the data on EK's SE range to know for definite.

Any advice? Has anybody done or seen a similar hot-cold loop? Has anyone measured the performance of the same radiator in parallel vs series? All thoughts welcome.

 

[Charlie Hanson]

Thanks for the input. To address some points:

Okay, so what your saying, is ...

Yes, that's right.

And what do you mean by a hot loop and a cold loop?

The 'hot' loop is just the loop that contains the waterblocks, i.e. adds heat. The 'cold' loop is the loop with the radiators, i.e. removes heat. Or adds cold, if you want to disregard physics for syntactical symmetry.

The water is going to mix in the reservoir and equalize the temperature across both 'loops'.

Yes, that's the intention. Hot loop takes cold water and brings it back warm, cold loop takes warm water and makes it cold. That said, I'm aware that the temperature difference between any two points on the loop is going to be negligible due to the volume of liquid. The reservoir is not going to be a heat exchanger, it's just a holder for the water and a pressure leveller for the pumps.

More pumps add heat to a loop more pumps = more waste heat.

For EK pumps: D5 = 23W; DDC 3.2 = 18W; SPC-60 = 6W. So yes, two DDCs will be adding heat, but two SPCs will be half that of a D5. Even so, there's only 1W of difference between 1x D5 and DDC+SPC. I'll be using an EK Z270 full block and a 1070, so no massive effort. The real benefit I see of two separate pumps is that I can set them both at optimum values for each purpose.

If your doing it because it's fun or will look cool... That's OK

I don't want to jeopordise cooling for looks and vice versa. I want this system to run as quietly as possible because it's for the living room. I don't think that airflow will be a problem.

Maybe I'll figure out a way of testing both.

 

[Charlie Hanson]

Here's a rubbish teaser for the build. **SPOILER ALERT** Yes, it;s going to be one of those.

 

[Charlie Hanson]

I'm not sure what technical advice you're looking for? As for cold hard experience; what is it that you're trying to achieve?

Technical advice is "your theory is correct" or "your theory is wrong"; cold hard experience is "i did XYZ and it was OK, but then I tried ZYX and it was better". I want to achieve minimal noise, and also to see if it works how I think it will.

If nobody has tried a hot/cold loop before there's no harm in being the first.