Reverse Cooling (Front Exhaust) project.

Sqrly · Mar 15, 2024

Hey people,

I'm building new PCs and I have to get a new case for the living room. My 2004 Alienware Area 51 tower was never made to cool todays hardware.

That PC sits under a custom desk and during heavy gaming you get air fried. So, I'm planning on setting up the new case to pull in air from the back and sides and exhaust it out the front.

I going to use a Cooler Master N400 NSE-400-KKN2. It has 8x120mm fan locations. I'm going to seal the top up. That leaves 1 in the back, 1 in the left side, and 2 in the right side pulling in and 2 in the front blowing out. (The lower right side will have have the 120mm radiator inside of it.)

The entire front of the case is mesh so the excess pressure will vent out above the 2 front fans.

I'll let you know how it works out.

Flashorn · Mar 15, 2024

Sqrly said:
under a custom desk

This I never liked to hear. They should not be Under a desk.

Ghot · Mar 15, 2024

Sqrly said:
I'll let you know how it works out.

I think you'll find that it does not work well.
The vid card exhausts out the back. It exhausts a lot of heat.
An intake fan on the rear will just suck all that heat, right back into the case.

As for side fans... I haven't tested recently, but in the past, I found that they "disturb" the normal case airflow, which tends to raise temps.

But let us know what results you get.

The best airflow plan I've found would be this...

Sqrly · Mar 15, 2024

Flashorn said:
This I never liked to hear. They should not be Under a desk.

Agreed but that's were it fits. It's a "Deskertainment" center I built that fills the nook under the wall mounted TV. The top of it is covered in Lego Hogwarts buildings.

Ghot said:
I think you'll find that it does not work well.
The vid card exhausts out the back. It exhausts a lot of heat.
An intake fan on the rear will just suck all that heat, right back into the case.

As for side fans... I haven't tested recently, but in the past, I found that they "disturb" the normal case airflow, which tends to raise temps.

But let us know what results you get.

The best airflow plan I've found would be this...

View attachment 90269

My PC is on the top shelf of my desk, in my bedroom, above my head when seated and it has a similar airflow. There's no bottom fan but a left fan that blows in right under the GPU. That is not the best, it's a negative pressure setup and negative pressure increases dust buildup inside. On top of that, we live in an agricultural area so I have to take my PC out in the garage once a month to blow it out but, it does stay very cool inside. I've actually installed a 100CFM exhaust fan in the ceiling above my PC to keep it from heating up my room.

As for this new living room project the goal is to not heat up the person sitting at the desk.

I'm not only going to be sucking the heat from the GPU back inside I'm also going to be pulling air in through the radiator for the CPU. 6 case fans is serious overkill but I'm hoping brute force will do the trick. The new coolermaster sickleflow fans are pretty nice. They are now PWM and have vibration damping rubber mounts. The new Mobo can fully control the speed of all the case fans so it will be quiet until someone starts playing a demanding game.

Ghot · Mar 15, 2024

The CM Sickleflow fans are nice.

This is the CM case I would get... but that's me.

https://www.coolermaster.com/catalog/cases/mid-tower/masterbox-cm694/#overview

Sqrly · Mar 15, 2024

Ghot said:
The CM Sickleflow fans are nice.

This is the CM case I would get... but that's me.

https://www.coolermaster.com/catalog/cases/mid-tower/masterbox-cm694/#overview

It would be the Masterbox Q500L for me. The left side of the PC is facing me so it would be handy. I bet the vertical airflow works great.

But this project is not for me, it's for a specific location.

hdmi · Mar 15, 2024

Maybe just go for fourteen 140mm case fans in the Thermaltake CTE. Hope it doesn't freeze you to death

Steve C · Mar 16, 2024

Not a great plan due to the GPU air flow as mentioned above. I use fans blowing air from front to back and bottom to top.

abactuon · Mar 16, 2024

It all seems a bit odd to me, but of course you can test how it would work. It's not hard to change it later.

I'm wondering how to connect the fans to the sensors on the motherboard.

Are there any general guidelines?
Or how it is done on gaming computers.

antspants · Mar 16, 2024

Ghot said:
I think you'll find that it does not work well.
The vid card exhausts out the back. It exhausts a lot of heat.
An intake fan on the rear will just suck all that heat, right back into the case.

As for side fans... I haven't tested recently, but in the past, I found that they "disturb" the normal case airflow, which tends to raise temps.

But let us know what results you get.

The best airflow plan I've found would be this...

View attachment 90269

In my opinion, this is the best configuration.

Steve C · Mar 16, 2024

antspants said:
In my opinion, this is the best configuration.

I agree since that's what I do.

antspants · Mar 16, 2024

Steve C said:
I agree since that's what I do.

The way I see it, having more exit points with more exhaust fans is the only logical option (lets say 4). It also fast tracks air in through the front intake (in my opinion) through sucking air in faster regardless of the fan speed, again in my opinion.

Trying to force 4 exhaust fans of air flowing into a computer case, out of one exit point will force the hot air to circulate due to not being able to release it fast enough.

If the case isn’t able to handle it, buy a new case would be my answer. A case should have at least two fan intakes at the front, I believe

TVeblen · Mar 17, 2024

I would suggest leaving the case ventilation alone - leave it exhausting out the back as designed - and work on moving hot air out of the cabinet and into the room.
It's hard to tell what would work/look best without seeing the actual setup, but something like two 140mm fans mounted high in the front of the cabinet opening and sucking from the cabinet and blowing into the room might work OK.
It is also important to have a good 2-4 inches of space between the back of the cabinet and the PC, and 2 inches of space around the sides and top for decent airflow. It would be hard/impossible to change the cabinet now, but that's what you want to achieve.

I've seen people just use a standard room cooling box fan blowing at the case to move the hot air out. Not a good solution for your setup, but that's the idea.

Berton · Mar 17, 2024

Ghot said:
As for side fans... I haven't tested recently, but in the past, I found that they "disturb" the normal case airflow, which tends to raise temps.

I have an older custom Win10 Desktop with a 'funnel' device mounted on the side panel that allows the CPU fan to suck in air, don't know that it's all that effective as I'll get periodic fan noise when they speed up. That device isn't exactly/totally aimed at the CPU but it's difficult to get all cases built to accommodate all motherboards.

Ghot · Mar 17, 2024

Berton said:
I have an older custom Win10 Desktop with a 'funnel' device mounted on the side panel that allows the CPU fan to suck in air, don't know that it's all that effective as I'll get periodic fan noise when they speed up. That device isn't exactly/totally aimed at the CPU but it's difficult to get all cases built to accommodate all motherboards.

I have an old generic case from the early 2000's, and it has a left side fan.
It was a pain to keep that computer cool.

In 2008, I bought the case I have now, with no side fans. It's much easier to keep cool.

Berton · Mar 17, 2024

Ghot said:
I have an old generic case from the early 2000's, and it has a left side fan.
It was a pain to keep that computer cool.

In 2008, I bought the case I have now, with no side fans. It's much easier to keep cool.

I keep that Win10 as it otherwise runs as it should, has an AMD Phenom II X4 CPU and 16GB RAM.

Ghot · Mar 17, 2024

Berton said:
I keep that Win10 as it otherwise runs as it should, has an AMD Phenom II X4 CPU and 16GB RAM.

I had one of those... the AMD Phenom II x4 955. I still have it, it's just disassembled.
Same with my AMD FX-8350

ThrashZone · Mar 17, 2024

Hi,
There is only one fan on the back and no filter
Side no filter either
Top is the only other filtered place besides the front usually.

So if you don't mind dust filling your case with dust bunnies I'm sure it will do that very well even if you remove the filtered front and top panels hehe

Sqrly · Mar 18, 2024

TVeblen said:
I would suggest leaving the case ventilation alone - leave it exhausting out the back as designed - and work on moving hot air out of the cabinet and into the room.
It's hard to tell what would work/look best without seeing the actual setup, but something like two 140mm fans mounted high in the front of the cabinet opening and sucking from the cabinet and blowing into the room might work OK.
It is also important to have a good 2-4 inches of space between the back of the cabinet and the PC, and 2 inches of space around the sides and top for decent airflow. It would be hard/impossible to change the cabinet now, but that's what you want to achieve.

I've seen people just use a standard room cooling box fan blowing at the case to move the hot air out. Not a good solution for your setup, but that's the idea.

If I can't get this to work out and I have to send the heat out the top like normal, I'll probably mount a 240MM on top of the case at the back to blow the air out from unter the desk.