Multiple rads

Alan1969 · 29 Jul 2021 at 16:33

Currently I have a slim 360 rad (for cpu) in the roof of my Lian Li 011 dynamic. Currently I have intake fans floor (x3) and side (x3) and exhaust fans (x3) roof.

I would like a gpu block and to put a thicker rad in the roof.

That would leave me with my slim 360 that I may as well put either in the base or side. I have seen this orientation in many systems.

my question is: that surely all the heat which the side or floor rad is taking out of the coolant will then go into the case as warm air and then reheat the top rad = basically all the heat the 2nd rad is taking out will be put back into the system = net effect is zero. ie. with a roof rad there is no point adding a floor or side rad.

[the only way for me to resolve this thought is for me to put the new thicker rad in the floor being fed with fresh cool air and the slim rad to be placed on the side with fresh cool air and to leave the roof empty as an exhaust].

Drumroll · 29 Jul 2021 at 17:56

A single rad for CPU + GPU may work, but generally at higher fan RPM.
I would keep the slim at the top and get a thicker rad for the bottom, or thicker on the top and slim at the bottom.
Dual rad pretty much allows for some good temperatures, depending on which CPU + GPU you're using, but should be fine.
If using a single rad, I would keep it on the top as exhaust. The last thing you want is dump all the heating from the radiator inside the case.
I would keep bottom and side as intake.

LuckyBenski · 29 Jul 2021 at 19:49

To a degree what you're thinking is right, but there are several factors that mean it would still be an improvement.

Only some heat is removed from the liquid via the radiator, so it still has energy to give out if it meets another radiator later.

The air coming out of a radiator is therefore not as warm as the liquid, so can still offer a cooling effect to any other radiators it meets.

Also the case isn't a sealed system so some heat can escape via other routes such as exhaust fans, vents, and also can be conducted along or out of panels, tubing, blocks etc.

For instance if you have 3x intake fans through a radiator and 3x intake fans on a vent, you are effectively making a "50/50" mix of fresh Vs post-radiator air, to feed the second radiator with.

I would say the gains from adding a second radiator will outweigh the inefficiency of some air being "used" twice.

MikeTimbers · 29 Jul 2021 at 21:53

The roof radiator is the one after the cpu and gpu and will remove most of the heat, especially if it's a thick 360

Alan1969 · 30 Jul 2021 at 10:25

LuckyBenski said:
To a degree what you're thinking is right, but there are several factors that mean it would still be an improvement.

Only some heat is removed from the liquid via the radiator, so it still has energy to give out if it meets another radiator later.

The air coming out of a radiator is therefore not as warm as the liquid, so can still offer a cooling effect to any other radiators it meets.

Also the case isn't a sealed system so some heat can escape via other routes such as exhaust fans, vents, and also can be conducted along or out of panels, tubing, blocks etc.

For instance if you have 3x intake fans through a radiator and 3x intake fans on a vent, you are effectively making a "50/50" mix of fresh Vs post-radiator air, to feed the second radiator with.

I would say the gains from adding a second radiator will outweigh the inefficiency of some air being "used" twice.

yes, good point that the air coming out of the rad is not as hot as the coolant. Therefore, if I make the top rad as hot as possible (ie. directly after passing through the GPU and then CPU) then the temperature differential should mean that it will exhaust heat out the system, and then to cool the coolant down further it can then be routed to the floor or side rad before returning to the res/pump.

I know that custom loops pump much quicker (say x10 or 250/hr for my pump) than AIO's. And that the temperature stabilises and is meant to be virtually the same anywhere in the system - but - is there any benefit of sending the hot coolant post GPU to a rad before routing it into the CPU (again common sense is telling me that the GPU is heating the coolant the most and sending warm coolant to the CPU is not as good as sending cool coolant)? ie. i could easily route the tubing from the GPU to the top rad and then to the cpu and then to a side rad and then to the pump/res.

MikeTimbers · 30 Jul 2021 at 12:43

q: rad between gpu and cpu?

while the "temperature stabilisation through the loop" is taken as fact, it does to an extent depend on flowrates. fast enough and the temperature variations through the loop are very minor. no flow and obviously there will be hot spots (!). logically very slow flow must still have hot spots which are reduced as the flow increases.

does putting a radiator immediately after a heat input make a difference? I think it does

Alan1969 · 30 Jul 2021 at 13:17

my cheap EK pump/res combo is quoted at 250 L/hr whereas a quantum 5 is quoted at a max. of 1500 L/hr. therefore I will prob get more temp differences through the loop than a top pump.

Alan1969 · 30 Jul 2021 at 13:31

I have re-found this video from Linus I’ve been water cooling wrong for YEARS - $H!T Manufacturers Say - YouTube

a 240 rad on the roof and on the front worked better than just a 240 rad on the front - despite the heat from the front rad exhaust through the top rad. Problem solved - maybe I just go for a rad on the floor roof and side now.

LuckyBenski · 30 Jul 2021 at 14:13

Alan1969 said:
I have re-found this video from Linus I’ve been water cooling wrong for YEARS - $H!T Manufacturers Say - YouTube

a 240 rad on the roof and on the front worked better than just a 240 rad on the front - despite the heat from the front rad exhaust through the top rad. Problem solved - maybe I just go for a rad on the floor roof and side now.

I think we can definitely agree that more rads = better

Grim5 · 1 Aug 2021 at 05:10

Linus even tested something that few people will do - he stacked radiators and it worked, he showed that even if you stack radiators on top of each other with a fan in between you still get lower temps - as long as the air can move through, the more radiators you stack the better your temps will be

I've thought about doing it in my o11 close (having a 360 ek or rad with 6 fans in push pull and then another 360 rad on top of the fans

Jay85 · 2 Aug 2021 at 11:52

I did regular 30mm Corsair XR5 up top and a Thick XR7 55mm at the bottom in a dual loop system. Temps were good but the bottom rad took up a lot of space.

Grim5 · 2 Aug 2021 at 21:44

Jay85 said:
I did regular 30mm Corsair XR5 up top and a Thick XR7 55mm at the bottom in a dual loop system. Temps were good but the bottom rad took up a lot of space.

YOur fans are also excessively thick and with that thickness you should be doing push+pull, with just pull the bottom radiator is operating no better than a thinner radiator

Jay85 · 3 Aug 2021 at 02:05

Grim5 said:
YOur fans are also excessively thick and with that thickness you should be doing push+pull, with just pull the bottom radiator is operating no better than a thinner radiator

They ran at pretty high rpm so negated the fact that it was only in pull. Temps were okay but nowhere near as good as the setup i have now which is near silent.

Fans were just standard 25mm EK Vadars, not the quietest fans by any means :cry:

Alan1969 · 3 Aug 2021 at 15:06

current set-up:

was thinking of adding a thick 60mm EK rad with single fan in roof or floor.

initially was the top one with clear coolant and a vertical reservoir but couldnt fit the extra floor fan and so changed the reservoir to horizontal to fit the extra floor fan in but now dont have enough room for a side mounted fan on the inside and hence not able to put my slim rad side mounted in the rear compartment.

SpudMaster · 4 Aug 2021 at 10:05

Adding the second rad will definately improve temps, warm air or not. Even warm air flow is better than no air flow. In my system I have two loops in a TJ07. Both my rads are in the lower compartment led on their side with fans blowing through both in push/pull config. So essentially all the heat from my cpu rad is blowing straight into my gpu rad. My Vega56 overclocked doesn't go over 47°C in the current weather so I don't think the warmer air has much of a negative effect

Alan1969 · 4 Aug 2021 at 12:32

OK I am convinced - even blowing warm air through a rad is better than less rads. At the moment I have 6 intake fans and 3 exhaust fans through a slim 360mm rad. If I get a second rad should it be a 40mm with push/pull or a 60mm with a single fan - it would either go in the roof or floor and so I am thinking that a single fan would also have the benefit of convention with the heat just going straight up. I am favouring a thinker rad with a single fan as the amount of cables (I tend to use 3 to 1 fan cable ek splitters) already in my case is off-putting.

MikeTimbers · 5 Aug 2021 at 09:23

Surface area is king. If you can get a thicker rad, do it.

Alan1969 · 9 Aug 2021 at 09:16

Jay85 said:
I did regular 30mm Corsair XR5 up top and a Thick XR7 55mm at the bottom in a dual loop system. Temps were good but the bottom rad took up a lot of space.

how did you secure your graphics card? does the riser screw onto the lower rad fans?

Jay85 · 9 Aug 2021 at 09:45

Alan1969 said:
how did you secure your graphics card? does the riser screw onto the lower rad fans?

I made a custom bracket from frankensteining 2 riser adapters. It allowed me to raise and extend the gpu to a different position so i could fit a thicker radiator at the bottom.

Alan1969 · 9 Aug 2021 at 10:20

some more questions:

I got this soft tubing kit ▷ EK Water Blocks EK-Kit Classic RGB S360 Perfo… | OcUK (overclockers.co.uk)

1. Do I need different fittings if I want to use hard tubing?
2. What diameter hard tubing should I use? although EK do 10/12 and 12/16mm, you would think that you get better flow through the wider tubing? but both must reduce down to a narrower (and the same bore) to go through the fitting and therefore the diameter of the tubing is just aesthetic?
3. I hear that PETG tubing is more forgiving, but that Overclockers use Acrylic - which hard tubing should I use?
4. I currently have the EK SE360 (which uses UNC 6-32 screws) but like the look of the white corsair X5 which uses M4 x P0.7 screws - these presumably are different - do I need to use different screws for the different rads? Would it be easier to use EK stuff thoroughout?
5. If I need to use different fittings for hard tubing and if I stick with EKWB then should I pay more for the quantum fittings?
6. I think that the thick EK XE rad at 60mm is too practically thick for the top or bottom of the Lian Li 011 dynamic case. Would the PE at 38mm thick and a fan 25mm be more sensible? Until I got a GPU block in say 18 months time for the next gen cards (and when supply and prices have normalised somewhat) then at the moment I dont really need any more cooling for my cpu but I may add another rad to try watercooling a bit more and to give me something to do. Hence I am thinking of adding a 2nd rad. I could move my slim SE rad to the bottom and the new PE rad to the roof (graphics card is too long for me to currently house my pump/reservoir on the floor fan and currently being orientated horizontally wont allow me to put a rad fan inside the main compartmant).