Fan config

Dogfood09 · 2 May 2019 at 08:35

Hey guys,

Building a new rig in the lian li pc011 dynamic, I have a hydro h100i aoi cooler and 3 ll120 fans, my dilemma is I have the fans on the cooler as intake and the 3 ll120 as exhaust, is it ok to have the cooler fans as exhaust and the 3 other fans as intake? I only ask as the ll120 fans have all their beauty facing backwards and not taking full advantage of the rgb goodness... would my cooling be heavily effected as I've read the cooler fans need to be pushing air through the radiator and exhausting it out somewhere else, apologies for noob question

Zeeflyboy · 2 May 2019 at 10:17

If I understand what you are saying correctly, the downside is that you are pulling warm air from inside the case through the radiator, instead of ambient air from the room.

That will reduce your temperature delta between air and loop, and thus reduce the efficiency of the cooling. If you are looking to minimise your temperatures then it is a poor way to set it up... however chances are that as long as you don't mind the loop running a few degrees hotter it will have little if any impact on the actual system performance. If you are running up against CPU temperatures as a limiting factor on your overclocking then you might want to rethink it.

doyll · 2 May 2019 at 11:14

I dissagree with Zeeflyboy. In a system with only water cooling on one component (CPU) I want cool air entering case not pre-heated air. Reason is rather obvious in that every degree warmer the air going to air cooled components is translates into same degree hotter component will be. Combine this with the fact thst your CLC (hate them) likely has more cooling ability than needed and it makes much more sense to have CLC radiator mount as top exhaust. This is also the best orientation to keep any air in CLC from moving out of radiator and down into pump where it can damage / distroy it.

Zeeflyboy · 2 May 2019 at 14:36

You aren't disagreeing, I didn't given opinion on which way was best. I simply stated the unequivocal fact that the downside of that setup IS pulling warmer air through the radiator thus reducing the delta T, and hence also the cooling efficiency of the radiator... That does mean that, as I qualified it, if the lowest temperature is your goal it is a poor way to set it up. That doesn't mean there aren't other upsides to either configuration, and the significance of it will also vary depending on how much airflow you have going through the case in the first place.

We even agree that it likely wouldn't have much impact on system performance since as you say the cooling capacity is probably more than sufficient in either orientation, as I mentioned. I run radiators on both intake and exhaust in my own build.

No need to find disagreement where there is none

Meddling-Monk · 2 May 2019 at 14:47

Yes, it's perfectly fine to have the H100i fans as exhaust (I did something similar myself a few months back after some testing during rejigging of the rig it was in).

If you only have 1 AIO unit that cools only 1 item (CPU or GPU), then it is better to have that AIO unit in an Exhaust configuration and draw the rest of the warm air out of the case through the AIO rad instead. Like what the others have said however, this only applies if your AIO is able to handle the temperatures that are being generated from the item you are cooling (CPU or GPU), and if it is in a suitable location to do so.

Looking at the case you have designated, it looks like there's three mounting points for AIO's, and the top still looks like the best option to place the H100i with its fans in an Exhaust (blowing air out of the case) orientation. This is because the bottom and side placement for the AIO appear to be less optimal if you have them blowing external cooler air into the case through the H100i, which will create more warm air inside the main section.

The bottom location in Exhaust will try and blow warm air out, and I think everyone can see where that's going to go wrong (since warm air will generally rise back again anyway). And if placed into Intake (bringing in external cooler air into the case), the H100i will warm up that air enough that it will then blow this air into the main section and onto some hot GPU or other discrete cards as well. So this location is undesirable and not recommended.

As for the side location for the H100i I would say is a grey area. In theory, having the fans at the bottom or top as Intake (blowing external cooler air into the case) and then having the H100i pull that warmer air through to the side section on the other side, should make it cooler, but possibly may have some heat buildup if the small section on the other side of the case can't release that trapped warm air quickly enough, which may be an issue if that is the case. If we have the H100i as an Intake instead, and the fans elsewhere Exhausting, this would seem like a bad idea, as the H100i will be warming the main section up, which will be heated up by other components, and because the of the distance between the AIO side location and the other possible Exhaust fan placements, it might create a rather large hot spot inside the case as it struggles with warm air being trapped and heating up components before the fans can exhaust it out. The only real way to know is testing this, so unfortunately unless someone has this case and time to test it out, you'll be out guinnea pig in this area as to whether its a good idea or not.

So looking at that, I would suggest the three fans on the side blowing cool air from the small section on the side towards the middle of the case. The H100i at the top will then Exhaust (blow warm air out), keeping everything inside overall cooler. Assuming you're not trying to cool something the H100i can't handle.

doyll · 2 May 2019 at 15:20

Zeeflyboy said:
You aren't disagreeing, I didn't given opinion on which way was best. I simply stated the unequivocal fact that the downside of that setup IS pulling warmer air through the radiator thus reducing the delta T, and hence also the cooling efficiency of the radiator... That does mean that, as I qualified it, if the lowest temperature is your goal it is a poor way to set it up. That doesn't mean there aren't other upsides to either configuration, and the significance of it will also vary depending on how much airflow you have going through the case in the first place.

We even agree that it likely wouldn't have much impact on system performance since as you say the cooling capacity is probably more than sufficient in either orientation, as I mentioned. I run radiators on both intake and exhaust in my own build.

No need to find disagreement where there is none

Maybe you need to re-read what you wrote.
Your opening sentence says ".... the downside is that you are pulling warm air from inside the case through the radiator, instead of ambient air from the room."

That is what I dissagree with, specifically "The downside" part.

I believe havng a CLC radiator as exhaust in a case with everything else being air cooled is cooler airflow goes to all other components is definitely 'an upside' for aircooled compoent cooling.

Zeeflyboy · 2 May 2019 at 15:24

Well it is simply staying the downside of the configuration he wants to do... warmer air going through the radiator. Not sure how you can disagree with that, seems a fairly immutable fact. You can argue how significant of a downside it is, and how it weighs against other advantages, but fact is that is the negative aspect of that configuration. One should be aware of the pros and cons of any given setup so that you can choose the most appropriate for your needs.

Anyway, I don’t really see the point in arguing about it - you may disagree with me but I don’t really disagree with you and you can’t make me

doyll · 2 May 2019 at 15:47

Upside is not the opposite of downside.
I say it's 'upside' and you disagree saying it's 'downside'.
Our disagreement is just that simple, mate.

It's probably not a big deal in this case (no pun) but in some it is.

Zeeflyboy · 2 May 2019 at 15:56

Alright fine, you win. We disagree. Having the air going through a radiator be warmer when it enters is never an upside/positive/advantage/whatever you want to call it. That is simple physics.

I do agree that avoiding warm radiator blown air in the case could definitely be an upside if only cooling a single component with the rad, but it is never an “upside” to have the air be warmer when entering the radiator and it requires a strange twisting of logic to imply that it is. It is simply that avoiding that rad blown air in the case may in some instances be a better trade off than getting the maximum delta, or in other words the pros may outweigh the cons. Doesn’t remove the fact that the cons exist, and I was simply pointing out the main con.