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Chassi airflow might be out of sync cuz new radiator

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September 24, 2014 9:22:34 PM

Hi,

I've had my Corsair Hydro H100i for 2 days now, and its a monster, hehe. But it seems like that the ambient temp has risen pretty much.. The CPU temperature is awesome though, 30C idle and 45C load with 2x radiator fans at 50-60%.

But it still wakes a few thoughts.. E.x when I put my hand on the side panel, front, the side glass etc, its freaking hot in there.. Before liquid cooling, when I touched the chassi, it used to be cold, colder than my hand..

Is the airflow fked up, or is this normal on H2O? I used to have one exhaust fan on the top fins along with one intake front, bottom and 2x 80mm on each side panel. And one exhaust on the rear. But now, the radiator is on the top fins, along with 2 fans outside the chassi, as intake, so the radiator get's fresh, cool air on it. So, now I have only one exhaust fan, located on the rear.

And heat rises ofc, and intake on the bottom, I dont know, my common sense tells me that the airflow is messed up in there..

Any thoughts or advices?

Chassi: Zalman Z11 Plus

More about : chassi airflow sync cuz radiator

September 24, 2014 9:37:27 PM

never, ever, ever, ever, have radiator set up as intake, its pushing all that hot air back into the case. Swap to exhaust. problem will be solved. All top/rear fans should be exhaust, front/lower intake, have more exhaust than intake, negative pressure in my experience always cools better (better to get hot air out than force cool air in. side panel fans can be a hit and miss as to weather they obstruct or help airflow depending on the case.
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September 24, 2014 9:38:01 PM

I have all my case fans blowing into my case except for my H100i. I exhaust the case air out through the H100I. Case is Corsair 650D. Your mileage may vary.

I believe in positive pressure. IE more cool coming into the case than exhausted causing a higher air pressure inside the case.
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September 24, 2014 9:38:51 PM

Fans on the radiator should be taking cool air from outside and blowing it theu the rad and into the case .... just like in custom water cooling rigs and as per Corsair's written instructions. Here's the deal

Ambient Air = 23C
Coolant = 33 C
Interior case air = 28C

The amount of heat removed from the coolant may be expressed as Q = C x Delta T where Q is the quantity of heat removed, C is a constant and Delta T is the temperature difference

Pushing / Pulling Outside Air thru Rad Heat Removed = C x (33 - 23) = 10C
Pushing / Pulling Inutside Air thru Rad Heat Removed = C x (33 - 28) = 5C

Using fresh outside air rather than case air pulls twice the heat out of the coolant.

The laws of Thermodymics are laws.... not options.

Forget that heat rises..... ever seen a ceiling fan ? An electric motor and fan blades literally "blow the hell" outta the heat rises thing. Key is getting the coldest air possible to your coolant.

In an air cooled case, air goes in front , sides and bottom and out the rear and top.

In an water cooled case....Always, cool air into the rad, never hot air. Think about it..... does your car radiator fan blow hot air off the engine thru your rad or does it suck in cool air from the outside ? The reason Corsair and every other radiator manufacturer tells you to pull cool air in is because they know their business. If we're wrong than every car ever built is built wrong and every water cooling manufacturer has no idea what they are doing.


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September 24, 2014 9:46:42 PM

Corsair H100i mounting instructions straight from the manual.

The fan installation can be done in multiple ways, but by default we would recommend having the fans mounted on the bottom of the unit exhausting air up through the radiator towards the outside of the case.

http://www.corsair.com/en-us/blog/2013/february/how-to-...
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September 24, 2014 9:49:09 PM

JackNaylorPE said:
Fans on the radiator should be taking cool air from outside and blowing it theu the rad and into the case .... just like in custom water cooling rigs and as per Corsair's written instructions. Here's the deal

Ambient Air = 23C
Coolant = 33 C
Interior case air = 28C

The amount of heat removed from the coolant may be expressed as Q = C x Delta T where Q is the quantity of heat removed, C is a constant and Delta T is the temperature difference

Pushing / Pulling Outside Air thru Rad Heat Removed = C x (33 - 23) = 10C
Pushing / Pulling Inutside Air thru Rad Heat Removed = C x (33 - 28) = 5C

Using fresh outside air rather than case air pulls twice the heat out of the coolant.

The laws of Thermodymics are laws.... not options.

Forget that heat rises..... ever seen a ceiling fan ? An electric motor and fan blades literally "blow the hell" outta the heat rises thing. Key is getting the coldest air possible to your coolant.

In an air cooled case, air goies in front , sides and bottom and out the rear and top.

In an water cooled case....Always, cool air into the rad, never hot air. Think about it..... does your car radiator fan blow hot air off the engine thru your rad or does it suck in cool air from the outside. The reason Corsair and every other radiator manufacturer tells you to pull cool air in is because they know their business. Visit any serious water cooling site and they will tell ya the same thing.



thats nice that Corsair wants to turn your case into an oven for the sake of their radiator working slightly more efficiently, i can 100% garantee that if he exhausts the hot air from the radiator out of the case his problem with increased case temps will be solved.
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September 24, 2014 9:52:53 PM

LAW of conservation of mass....every CFM in that comes in goes out. There is no heat build up as each fan blowing one cfm into the case is blow out thru the grilles or exhaust fans. The heat you are imagining is gone....it's been exhausted. Think about it..... 4 fans blowing in means say 4 x 45 crm = 180 cfm

A typical case 18 x 20 x 8 = 1.5' x 1.67' x 0.67' = = 1.67 cf.... that means that the entire case volume is flushed and exchanged with cool outside air 108 times a minute .... or once every 0.55 seconds.

Your assumption doesn't hold up in the laboratory or in the field. I speak from experience having taught thermodynamics and fluid mechanic at the college level

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September 24, 2014 9:56:06 PM

jas340 said:
Corsair H100i mounting instructions straight from the manual.

The fan installation can be done in multiple ways, but by default we would recommend having the fans mounted on the bottom of the unit exhausting air up through the radiator towards the outside of the case.

http://www.corsair.com/en-us/blog/2013/february/how-to-...


Corsair H100i Instruction manual

http://www.corsair.com/~/media/Corsair/download-files/m...

Quote:
Step 1 - Install the Fans and Radiator

Attach the radiator to the fans as shown. For the best cooling performance, we recommend mounting the fans as air intake into your PC case

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September 24, 2014 10:10:38 PM

JackNaylorPE said:
LAW of conservation of mass....every CFM in that comes in goes out.

Your assumption doesn't hold up in the laboratory or in the field. I speak from experience having taught thermodynamics and fluid mechanic at the college level



what assumption? that hot air going into a case will heat it up? (seems pretty logical, not an assumption). Now it may increase rad and cpu temps drawing warmer air over the rad, but personally i would like to not have the hot air blowing onto my gpu and motherboard, i'd rather it out of the case regardless of Corsairs instructions. Ideally in a pro watercooling setup, you wouldnt have the radiator in the case at all.

Or the one about the positive and negative pressure? which i have tried in my last 2 cases (current is corsair spec 01), and having more exhaust than intake results in cooler internal temps by 2-3 degrees under load. But hey, different enclosures and putting the temp meter in different positions and different fan locations may change those results.

Your also assuming all fans/fan speed blowing in are identical to blowing out with your statement, and there is 0 pressure or aerodynamic resistance obstructing a fans cfm. Which is never going to be the case. maybe thats why in my setups the negative pressure resulted better temps in real world testing, and why theory is just that....theory.
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September 24, 2014 10:58:42 PM

First...the air isn't "hot" .... your coolant if it is doing it's job is never more than 8 - 10C above the ambient air. That puts their air coming outta the rad at maybe 4C above what it came in at. The object of water cooling is to get components that need it away from their thermal limits .... the CPU, heavily overclocked obviously fits that category....

Now go thru your component literature and try and find me a single component which might be affected negatively by 27-28C air. You MoBo surface at 40C will be slightly less cooled by the 27C air than it would by 23C air .... might raise it's temp by a degree or 2 .... is 42C surface temp dangerous to the MoBo ? Look at the recent GFX card reviews .... GPU temps in the low 60s and thermal limits of 98C ... who cares if they get 1-2C hotter ... unlike the CPU, they are no where near their limits?

And well if ya concerned about GPU temps (few are ....290x owners perhaps) you are water cooling them also.... my water cooled GFX cards are about 39c or 44C id I turn the fans down.... I didn't do it for the heat reduction, I did it cause I don't want to be able to tell if my computer is running using my ears.

But let's remember that "the heat has "left the building".... can you tell me how much heat a case full of air can absorb before it is pushed out just 0.55 seconds later. Your components create 300 watts of heat, whoosh .... 0.55 seconds later its gone .... Ever pass your hand thru a flame ? It needs time to get heated and it's simply not there long enough so your hand isn't burnt.

Pro water cooling setups do not have exterior rads.... pop over to frozencpu.com and see how many you can find..... selection is very limited and very old models. I haven't seen an exterior radiator in years, .... only time it's done is for a budget mod where someone doesn't wanna invest in a proper case....never done on new builds

You are certainly entitled to install your setup any way you like. But that doesn't make Corsair wrong. They pay people with the proper training and experience to design these things, they perform laboratory testing under strict controlled conditions .... and every vendor, every water cooling geek, has come to the same conclusion. Pop over to OCN .... you will see the occasional "heat rises / rad exhaust" post but the user is quickly educated.

Positive / negative pressure is a "red herring" .... makes no difference whatsoever other than dust buildup. What can affect temps however is turbulence and where those fans are in relation to what is being measured is way more influential than positive or negative. That's why "Spot Cool" fans can be so effective.... they don't remove air from the case but they do eliminate dead spots.

One reason peeps see an increase when they go negative is really very simple.... intake fans generally have air filters which restricts flow. When you have more exhaust fans, air comes in not only thru the filtered fan intakes but also thru the open grilles which have much less resistance....less resistance = more cfm....more cfm means more cooling. the temp drop comes from more air not pressure reversal.

For example, I have 15 fans ....10 on rads all blowing in and 5 case fans. I have 6 thermal sensors installed. The case has panel filters which slide out for easy cleaning.... just removing the filters brought my coolant temps down from 12.8C to 8.4C

If ya ever want to do some experimentation, I use a Reeven Six Eyes. It has 6 thermal monitoring points and displays them in a 5.25 bay. I have ambient air, case air, rad 1 in , rad 1 out, rad 2 in, rad 2 out.

Two other things ....

1. if ya have ya top rad blowing out, what does the bottom rad do ? Blow down and out against heat rises ? front rad, blowing out towards you ?

2. Also blowing in is quieter..... quite a major thing with the 100i's vacuum cleaner like noise levels.
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September 24, 2014 11:14:00 PM

top rad/ bottom rad? i only have one rad.....very basic my water setup is.....
Anyways, the OP's problem is since installing the rad the case is warm to touch where before it wasnt. So i suggest despite arguments, that the rad fans be reversed to get the hot air out and see what happens..... It may be the case that he can still have the rad blowing into the case but modifying case flow/layout/exhaust fans etc he could also fix the issue. You seem to be quite an expert JackNaylorPE so maybe you could give him some pointers in that regard.
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September 24, 2014 11:42:47 PM

Sweet lord, so many replyes!.. :o 
First, i gotta make myself clear. I never said I have 2 radiators.. Where did u guys get that from? And no, reversing the fans aint a option for me. My radiator deserves fresh cool air ^^

Though, im thinking of installing the radiator on the front and the rad fans as intake ofcourse. Yes, im aware that I will be pulling hot air into my rig, but atleast then it will follow the airflow and be exhausted at the rear and top. The rig still get's fresh cool air from the bottom, so I think it'll be better than what I have now.. Two negative sides tho with this option.. I will loose the mount for my NXZT Sentry 2 LCD Fancontroller, and I have to modify pretty bigtime in there aswell.. I have already cut off the HDD bay at front bottom to improve cooling, hehe.

The H100i temperature in Corsair LINK is 27C right now. Is that good or bad? CPU socket temp is 33C with the fans on 40%

Btw, I got 5 thermal diodes or whatever its called, came with the fancontroller. Where should I put it to measure the ambient chassi temp? And rad in/out, that cant be accurate... I mean, its a fan... You cant measure the air-temp from a FAN, thats BLOWING the air... Or :p  ??

And ONCE N FOR ALL! Positive air pressure is way better than negative. Then its sure that every component get's fresh cool air.
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September 25, 2014 1:31:21 AM

Alanthor said:

1- "reversing the fans aint a option for me. My radiator deserves fresh cool air ^^"

2- "And ONCE N FOR ALL! Positive air pressure is way better than negative. Then its sure that every component get's fresh cool air. "

1- so you have an issue that happened after you installed that radiator, and you won't try a suggestion that would take 5-10 mins that would very likely solve your hot case issue?

2 - And you have tried this? I have, and in the 2 cases I've tried it in, negative was better than positive. And by better I mean cpu, gpu and motherboard temps were down with negative pressure vs positive. I think the key may not necessarily be weather its positive or negative, but whatever creates the best directional flow to avoid hot air pockets (which seems to be happening in your case) forming. If you have air filters and your aim is to keep dust out with them, then slightly positive pressure is your only option for the filtration to work properly.

Here's some more reading I dug up if your interested:
http://www.tomshardware.com/faq/id-1858957/airflow-101-...
http://www.extremetech.com/computing/128313-extremetech...
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September 25, 2014 5:14:23 AM

1. Yes, because where the radiator is located now, used to be exhaust, and the airflow was perfect. But the radiator kinda ruined it, lol.

2. Okay, to be honest, I dont know which one is best, but my common sense tells me that Positive air pressure should be better than negative, aslong the airflow is synced and good.

Anyways, switching the radiator to the front would be too much job, and im way too tired atm. But I had to do SOMETHING, because it caused hot air pockets aloot.. So, ONE 120mm exhaust rear, dont manage to pull all of the air the two radiator fans takes in. So I mounted a 120mm fan on the front grill, at the top, and another one in the bottom of 5.25'' bay, but as close as possible to the motherboard.

Now I think I have reestablished a good airflow.

Ambient chassi temps = 24C
Exhaust air temp = 26-27C
H100i coolant temp = 25C
CPU Socket temp = 30C
Radiator fans = 890RPM on both.
GPU Temp = 29-30C
SSD = 24C

EDIT!!!
I just got an awesome idea. What about having every fan as intake except the radiator. That way, the left radiator fan gets cool, fresh air from the rear intake, and the right radiator fan gets fresh and cool air from the top front intake. It's a little longer "air-travel" than the rear intake to left radiator fan, but it only passes the RAM modules.
And WOW! Really, the airflow would be perfect, wouldnt it? My bottom intake fan push air up, and the bottom front intake should get pulled diagonally straight to the radiator. Does it sound good?
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September 25, 2014 9:11:33 AM

Most custom water cooling boxes are set up as follows:

Top - here's where the biggest rad usually is (420 or 480) typical fan set up is two fans in push / blowing down into the case.

Bottom - 2nd largest rad usually goes here oir it's empty....fans blowing into case.

Front - sometimes a rad here also but again, fresh air blowing into case not right back out at your face.

Rear - Always exhaust

Windows side - rare as peeps usually want big windows to show off their water cooling

Back side - This is a good lesson. With only 1 or 2 rear exhaust fans, most peeps logic goes, make these exhausts as the intakes greatly outnumber the exhaust (meaningless concept trying to have as many of one as the other). However, this is a bad idea ..... think about it before peeking at spoiler

Spoiler
The two back side fans are usually towards the front .... in my Enthoo Primo, there are two 140mm fans her and two 140mm the front. What happens is however, the fresh air coming in thru the front fans was just making a quick right turn and short circuiting going out the back side fans 4 inches away ..... the cooler air coming in was exhausted right out before passing over anything that it moght cool.


I wasn't suggesting that their were two rads in the build in original post by the way.... just demonstrating concepts ....

If you are using heat rises as a justification for exhausting hot air outta the case on the top, what happens with rads placed on the bottom ?

As for the new idea think about it..... your water cooling system is handling the output from your 84 watt CPU, say 130 watts overclocked. Now your plan is to take the heat output from your HDs (10 watts each), Optical (10 watts) RAM (10 watts) GFX card (250 watts), MoBo (80 watts), PSU (not all will be exhausted by its own fan) and preheat the air going thru the rad with 300+ watts of heat ?
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September 25, 2014 11:54:06 AM

Gosh you know alot about airflow...Hehe, I have learned alot today :) 

Anyways, I tryed my new idea with ALL fans as intake except the rad, and actually, the CPU socket is one degree lower, and it seems that the airflow is synced with eachother (Keeping my ambient chassi temp stable)
Btw, my CPU isnt 84watt, its 125watt stock. (Running 4.5GHz). And my HDD and SSD ALWAYS stay under 30C.

But we'll see how this works out. Im gonna play BF4 abit and check the temps and such :) 

I cannot have the radiator on the bottom. My PSU is there and a 120mm fan.. No space at all.
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September 25, 2014 3:40:25 PM

LGA 2011 socket ?

4790k - 88 watts
4770k - 85 watts
3770k - 77 watts
2700k - 95 watts
3960k - 130 watts
4960k - 130 watts

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September 25, 2014 3:56:14 PM

But who ever said that I have Intel CPU, hehe? I have AMD FX-8320. But I used the intel mounting-plate on the H100i ^^ Couldnt find my stock brackets, so I took the Intel plate and took 2 screws diagonally.
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September 25, 2014 3:59:02 PM

My bad, AMD water cooling is not very common so I jus assumed .... and we all know what Felix said to Oscar about assuming :) 
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September 25, 2014 4:15:26 PM

Hmm, why not? I mean, what's the difference? Isnt it just to get AM3+ cooling blocks? And hey, while im already here. Im pushing to the limits *Baam baam* :p  No but, what is the maximum vcore, like what shouldnt I exceed? The pc is on m,aybe lets say 13-15 hours per day with no energy savers at all in BIOS

Right now, im just at 4.5GHz with 1.392Vcore. 1.404Vcore is the max measured. I really like to continue OC, I was able to maintain a stable 4.7GHz, though, the Vcore was ridicilousy high.. Around 1.47 I think.. Well, what's the max cpu voltage? Cuz I rly rly dont wanna fry my new CPU.
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September 25, 2014 4:49:33 PM

Well my old "separater" budget wise between an AMD and Intel CPU was an $850 build price. Haven't been asked to do an AMD build in 3+ years tho
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September 25, 2014 5:08:11 PM

What?..
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September 25, 2014 5:41:36 PM

$850 is the generally accepted divider budget wise on which way to go.

Budget < $850 ... AMD Build
Budget > $850 ... Intel Build

Seems everyone has lotta money these days ... no one has asked me to do an AMD build in years.
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September 25, 2014 6:44:26 PM

Alanthor said:
What?..


i think wat he's getting at is AMD cpu's are used in budget builds that generally wouldnt have expensive watercooling. If your going to get an 8350/20 and then put $100's in watercooling, well you may as well have got an intel rig thats faster to begin with. Obviously as an upgrade path if you already had the 83xx then it may make sense to water cool it to get more of an OC than air would allow rather than swapping your whole build to an intel build, which would be even more $$$, or if you do use software that can make use of its 8 cores.
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September 26, 2014 6:51:37 PM

Lol, yeah.. Lol, just because AMD is more cheap than Intel, doesnt mean I dont take care of it.. And having a air cooled FX-83xx CPU isnt so good IMO, especially if you're overclocking.
And I rather buy a H2O cooling than a new, expensive Intel motherboard AND CPU, it would be over 400 bucks.
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