Radiator in front and back of the case

[Zaskar]

Lets say I have a triple rad in the front of the case and an additional single in the back, will the addition of that smaller one in the back potentially raise temps as it will be sucking in slightly warmer air if the thermal dissipation limits of the primary triple rad haven't been reached yet? (MountainMods case, so it has 2-3 triple rad spots in the front blowing in)

[twwen2]

Good question. I don't really know. My gut feeling is that it shouldn't make temps any worse, but won't be nearly as efficient as it would pulling fresh air.

[Zaskar]

Your question is not clear... Would the proposed rear single rad be in same loop as front triple rad???

Ahh yes my bad.

It would be in the same loop. I currently have what may be a spare single rad Im thinking of adding to either the GPU or CPU loop, but it would be in the back of the case. The front with have 3 triple rads, in either case as of now both loops aren't meeting the thermal dissipation limits of the rads already, but I have the extra rad and I though it couldn't hurt to add it and thats when i though "what if it might" since it would be getting the air from the other rads and whatever heat was in the case.

If it was a situation where the current rads in the loop weren't enough for the heat load then it would hands down help, but thats not the case here so I wanted to see if it could actually negatively impact temps at all (or simply not really help)

This may even apply to your rig man, since your using I think a rad in the front and back of your MM case for one of the loops, and just the rad in the front alone probably isnt having its thermal dissipation limits exceeded yet (though normally it could still help, just not as much) so if it could make it worse, Id like to know before :D

[Kibbler]

Same loop: Possible lower temps, at worst no improvement. Depends on your loop order. A rad cannot generate energy by it's presence alone, unless you count other negligible factors that indirectly raise temps ie. friction, restricting flow, etc.

Separate loop: Highly highly unlikely to raise temps, unless you have something incredibly imbalanced like quad core + 2xGPU + NB + SB on the front rad and mosfets on the rear rad.

[Zaskar]

Don't really know if it will help or not... IMO, it shouldn't hurt...

I'm setting up rads as follows:

FRONT:
(2) PA120.3 - CPU
(1) PA120.3 - GPU

REAR:
(1)PA120.3 - NB/SB/MOSTET 1 & 2

The rear rad will be pulling air from inside the case, but it will be fine for the chipset blocks, actually it's overkill....
Oh yea man, The singe rad in the back was actually what I was planning to use for the NB/Mosfets and that was even a bit overkill :P, but after some thought im considering the idea of not watercooling those now (for reasons of access to the CPU and ability to remount after all loops are filled) and if I dont do that 3rd loop, I have this additional rad to add to one of the other 2.

[cobra_kai]

Don't really know if it will help or not... IMO, it shouldn't hurt...

I'm setting up rads as follows:

FRONT:
(2) PA120.3 - CPU
(1) PA120.3 - GPU

REAR:
(1)PA120.3 - NB/SB/MOSTET 1 & 2

The rear rad will be pulling air from inside the case, but it will be fine for the chipset blocks, actually it's overkill....

you have 2 120.3 rads on your CPU loop??? isn't that insane overkill?

[Zaskar]

you have 2 12-.3 rads on your CPU loop??? isn't that insane overkill?

Ehh, the case has space for it :P And I think he is using 2 pumps which will add a bit more heat load. Additional rads always help, but if the first rad hasn't reach its thermal dissipation limits yet then the improvement could be considered negligible, but its still there.

[Kibbler]

you have 2 120.3 rads on your CPU loop??? isn't that insane overkill?
way overkill short of skulltrail quads imho

[MomijiTMO]

Make a hole in the top or bottom of your case and have that rear rad draw air in.

[Soulwind]

On my setup (another MM case here), I've got a PA120.3 in the front and a PA120.2 in the back.

The 120.3 has the CPU, NB, SB and the 120.2 has the GPU and Mosfets.

Both are set to be pulling air into the case from the outside (along with another 120mm in the back pulling air in over the motherboard),
then I've got 4 80mm fans set at the top of the case to vent the air out.

So I've got all my fresh air coming in at the bottom to middle of the case (through the rad's) and then passing up and out of the top.

Keeps things nice and cool (and, so far at least, relatively dust-free).

[Zaskar]

I know its best to have air coming in from the outside, just wanted to know if the addition of a rad sucking air from the inside of the case, to a loop that had one sucking air from the outside, could potentially make temps worse (sucking in air from the first rad, and rads from the other loop which may or may not have hotter air, any any additional head from the Mobo's components/PSU)

Or am I totally off base here and it would still help temps? (even if the first rads heat dissipation limit hasn't been reached)

[Kibbler]

I'm repeating myself...

Thermodynamics. Adding another rad does not add any energy (in the form of heat) to your computer. Therefore, for your computer as a whole, total wattage output would not increase, and therefore total heat would not increase.

It can only increase temps in very specific cases, and even then only for certain component, and only if you have the rads in separate loops.

For example, if your front rad is cooling CPU + GPU + NB + SB, and your rear rad is cooling mosfets in a separate loop. Then it is likely that the air coming from your front rad is hotter than the water in your mosfet loop. In that case, your mosfet temps would probably increase. But there is no effect on the rest of your components.

If both rads are in one loop, then your temps can only be EQUAL or BETTER than before for all components.

Caveat:
The 2nd rad can indirectly affect your temps due to restricting flow. But I think that effect is not the core of your question.

EDIT: RRR, very nice pics but you're not really constructively answering his question.

[IanY]

Zaskar,

Regardless of fan orientation, it makes very little difference either way. I highly recommend a PA160 for the single. Its a wonderful radiator, and I think it would fit between the two PSU openings. The PA120.1 isn't bad at all either and my son has one of them.

[Kibbler]

Another way to think about this:

In a normal (not sub-ambient) watercooling system, the air is NEVER NEVER hotter than the water. Imagine this loop (let's ignore the pump for simplicity):

front rad -> cpu -> gpu -> nb -> front rad

If you replace the bolded arrow with a 2nd rad, your loop would look like this:

front rad -> cpu -> gpu -> rear rad -> nb -> front rad

And in that loop, the water in the rear rad CANNOT be hotter than the water in the bolded arrow section of the original loop. There's just no way.

[Kibbler]

The OP was asking if the temps would rise due to the fact the air that would be cooling the (second rear) rad would be warm case air as opposed to the front rad (in same loop) being cooled by cool outside air...

NOONE HERE WAS MAKING THE CLAIM THAT JUST BY ADDING A SECOND RADIATOR YOUR TEMPS WOULD INCREASE.....

@Kibbler....neither are you....
...really? :confused: That seems like a such a braindead question...of course it would be warm air...:shrug:

Zasker, sorry, do you mind clarifying your question? Are you asking if your component temps would increase, or if your 2nd rad would be getting warm air?

[Zaskar]

Sorry :D

Ok I have 3 triple rads in front, 1 CPU, 2x GPU loop.

If I wanted to add a smaller single rad in the back (sucking air from inside the case) to the CPU loop, I was just wondering if it could Hurt temps, due to air in the case being hotter, potentially adding heat to that loop due to air from the second loops rads "potentially" being hotter then the first, combined with heat from the inside of the computer given off from components and PSU (combined with air from the first rad in the CPU loop. which couldn't make temps worse, but doesn't help in making them better)

I know radiators if sucking in hotter air then the water could hurt temps, so just making sure.

[IanY]

Zaskar,

It doesn't hurt temps. It improves temps. The "hot" air from inside the case does nothing to raise temps. Been doing regular case super hot ambient Lian Lis forever.

[Waterlogged]

If the amount of CFM in and out of the case is equal or biased towards output, the air temp inside the case will equal ambient. It won't really matter if the air has passed through a rad as air has a crappy thermal transfer rate. It also helps to have as much of the air as possible travel in a straight line (over the MoBo if possible) so as not to deposit dust.

[skinnee]

Zaskar,
I agree with IanY and Waterlogged, adding a back rad exhausting from the case will not hurt other temps within the case. Now, I don't have test data to back this up (temp sensors for my loops will be ordered soon)...but, water temp from the back rad would be slightly higher because of the "ambient" or case air passing through it.