Quietest in-cupboard cooling options

[TonyArrr]

Hi all

Not sure if this should be here, or in Networking, or General Chat.

I'm putting in a proper networking rack now that I'm running ethernet/fibre through my walls, which is going in the top of a cupboard in my second bedroom. The ISP line comes in there, and it is right by the biggest opening that is happening in my walls/roof (from other works happening at the same time, makes easiest place to be bringing all the cabling together).

I can fit up to a 9U cabinet in there for the tech, which will be made up of:

• Patch Panel
• PDU
• 8 port SFP+ switch (probably the Microtik CRS309-1G-8S+IN)
• VDSL2 modem
• 8 port GbE switch with 4x PoE+
• Something ProjectTinyMiniMicro to run a pf/opnSense VM and a Home Assistant VM

Where I'm stuck is cooling. The two primary needs for cooling the stuff is:

1. Keep the tech at reasonable temps, so they survive
2. Don't have fan noise that annoys the hell out of my roommate, who lives in the room

Number 2 is why I've leaned towards things that don't have fans. Currently in the cupboard is the VDSL2 modem, a wifi router with a fan, and a Pi 4 running Home Assistant and a DNS server. The fan on the Pi 4 only hits maybe 45 db (measured from standing in front of the cupboard with the door closed) at worst, but you can hear it clearly from across the room and even I agree it is a bit annoying (and I work with a R730xd under my desk).

I know small fans like that are worse for being whiney and bigger fans don't need to run as much but circulation only helps when you have somewhere for the hot air to go, or cool air to come from. The cupboard doors are those roof height sliding mirror doors, so I can't add a vent for airflow there, and the back wall of the cupboard backs onto the laundry (European style, so basically a big cupboard of it's own), so I don't really want to have a vent into there (humidity coming in while the dryer is on, noise coming through while the washing machine or dryer is on).

The side wall could have a small vent installed for intake but routing the air into the cabinet would still be tricky. Additionally, this is a pretty central wall in the apartment, so I guess that might be an ascetic issue? Wouldn't bother me but if I'm selling one day, that may or may not be an issue.

The roof space does get warmer than the main room areas in the apartment, and there is only about 30 cm between the roof and the slab above me. The outside edge of the roof space at the balcony is all metal so I can't fit a vent out there without Strata and executive committee approval.

I also remember being told that having an exhaust fan is worse for dust build up than running intake fans, dunno if that's actually true or not but if so I'd prefer to go the path that involves less dust building up on the equipment.

I went looking to see if MIT's thermovoltaic panels had been commercialised yet, but no such luck


Anyone have ideas or suggestions for how I can give some sort of path for warmth to get out? Ultimately, I'm not expecting to super chill the cabinet, I just want to figure out a way to keep the temperatures from getting out of hand while balancing that with minimising fan noise to not annoy my room mate.

Super appreciate any advice, insights, experience that can be shared! Thank you all!

 

[i386]

A few thoughts/questions to get this going

Server/network racks/enclosures can have vents for fans at different locations. This fans locations can have an impact on cooling perforamnce and accoustic/noise. My 24u server rack for example has vents for fans at the bottom and the top and is not optimal for front to back airflow applications like most servers but it's better for the noise. Side to side fans can be great (some network devices have fans pulling air from one side to another), but if they are on head level the "noise" can be perceived as loud.

If your enclosure/rack has intake/outake vents and at least one fan: get dust filters for the intake.
"One piece" dust filters with big holes are suboptimal, they have a big negative impact on the cooling performance/"air throughput" and they let a lot of small dust through. Example for such a filter: https://www.amazon.com/dp/B01N6BFVKO
Dust filters made of nylon and with a frame are better: the airflow is lot better and it catches more and smaller dust. Example: https://www.amazon.com/dp/B08G5D8W6S
No matter what filters you get, you have to clean them regularly.

For the a passively cooled pfsense system I would look at embedded stuff. There are different vendors with xeon or epyc cpus, but also some with arm cpus.

 

[bitslinger]

First the quietest fan is no fan. I don't run a fan on my RPi4 HomeAssistant box. It runs at acceptable temps. Perhaps one of those four or six port passively cooled firewalls. It sounds like you will be around 100 watts. That will not need much cooling at all. Big slow fans are by far the best.

You will need to exhaust the hot air into the room somehow. You can't seal the equipment in the cupboard. A hole in the top perhaps with a single 120mm low speed fan will be nearly silent.

 

[TonyArrr]

This fans locations can have an impact on cooling perforamnce and accoustic/noise

Well I haven't got the enclosure yet, so I'm not locked into anything. A 9U enclosure is the largest I can fit, but a 6U is likely the smallest that will fit all the equipment.
Most of what I have found so far that are short enough for the cupboard shelf are glass front, but tend to have adjustable or removable side panels, so perhaps side to side might be the way to go. The front doors aren't very "sealy" there is always a gap the whole length, and around the top too, so airflow would probably be ok escaping out that way, so long as I can keep the noise down...

With the left wall facing going into the living room, perhaps I could have a short but wide intake vent up there, if I can duct it down the size of a fan intake on the enclosure... assuming regular cleaning, are those framed nylon filters usually quite long lasting/durable? Or does the airflow tend to wear them down?
If I can find one the right shade of white it might not cause a visual problem (though I'll need an "expert" to check me on that )

big negative impact on the cooling performance/"air throughput"

I hadn't even thought of the filter's impact on airflow, just another point in the calculations

embedded stuff. There are different vendors with xeon or epyc cpus

They make passively cooled Xeons and Epycs? I'm so used to thinking of them in multi-CPU monsters that that thought blows my mind! I have some major research to do now...

 

[TonyArrr]

I don't run a fan on my RPi4 HomeAssistant box. It runs at acceptable temps.

I didn't originally, either, when it was out on a shelf open to a room, but when it moved into the cupboard it idled at 65 C in summer and so I put it in a Argon One case. The fan at 15% keeps it at 40 C much more consistently
If there is a way for me to do this without fan or pumps, then I am 100% in. Both noise makers, and both mechanical, so will wear out and fail eventually, so if they are excludable I am down

Big slow fans are by far the best

I had heard as much. I imagine the biggest of that brand that does the brown fans... (Noctura?) ... would be where I should be looking as far as any fans I have to put in...?

hot air into the room somehow

Well the doors are not much in the way of sealing. they are on sliding rails, and one is behind the other. When aligned perfectly to minimise the gap, there is a... 5mm gap between their closest point, top to bottom, and along the top edge. And they are far more often slightly ajar, leaving two points along the top to bottom side with a 1cm gap all the way up.
At 2.3 meters high and 90cm wide, will that be enough physical space for the warm air to get out, if there is at least a little bit of airflow from a (perhaps big and slow) fan, do you think, without making wind noise through the gaps (or making a rattling of the doors)

Eugh, the more I write this, the more and more it seems hard to find info because it is just damn subjective. I miss my nice constrained clearcut case studies, like compute power and network throughput

 

[CyklonDX]

Wow, what a great thread naming. (I love it)

You can put your fan inline somewhere that could be anywhere where you don't mind the noise.

(something like that.) (but going opposite way)


As long you build a pull configuration (where you will do negative pressure) sucking hot air, you can get away of moving fan somewhere where you don't mind the noise. (you can even mount exhaust on the roof.)

(for best effects seal all holes, and leave only single one - you still want some fans to guide air over components .)

Just make sure you have some dust static meshes - as its going to get dusty.

 

[Sean Ho]

How about a fanless 1150 uSFF with dual NIC? Comes with G3320TE but can be swapped for most any desktop Haswell. Weighs a ton because the entire lid is one big heatsink.

Agreed that you still need to exhaust the heat from the cabinet.