Water cooling and negative air pressure?

[0d3nnis0]

Hi there,

i am new to this forum and i hope this hasn´t been discussed a hundred times. I am not a native english speaker so please excuse my wording.

I´m wondering if someone has experience with full negative air pressure in a water colled system by using only exhaust fans and no input fans. It really bothers me to buy the newest RGB Fans for 30$ just to mount them upside down and stare at cheap sticker on the back while all this RGB-goodnes lightens the inside of my radiator... I found some tests stating negative pressure is better for overall temps. There is even a test by Linus showing that there is less dust entering the case than in a neutral pressure environment. But all these tests refer to air colled systems as far as i can see, so i wanted to ask if somebody gave it a try or even runs a system like that and would like to share their experience?

For those of you who are interessted, i am running a LianLi O11d with one 360 radiator on the bottom and one in the top so temperatures are no problem its all about the look

.....with all that ARGB-madness going on i wonder why nobody offers fans in Pull-configuration.

cheers
Dennis

 

[0d3nnis0]

Hey doyll,

thanks for your reply. I have a LianLi o11d with two 360 rads, one at the bottom and one in the top. Currently running with 6 LianLi BR lite but I gonna change them for Corsair ml120 pro rgb.
I am pretty familiar with airflow setups but like I said I really wanna try negativ for the aesthetic. I think I just have to give it a try, temps should be good and adiditonal dust filters at the back/pci slots should help ceeping the case clean.

Cheers

 

[0d3nnis0]

Yeah i know but you still see the spider at the back which bothers me and the ml120 just seem to be the better performer. And for the lack of brightness i just install two aditional RGB stripes...

 

[0d3nnis0]

I think you got me wrong. It is not like i musst have negative pressure, I just want all my fans "facing up" (exhaust) for the aesthetic which results in negative pressure. So I am looking for the pros and cons especially regarding that all tests I found so far are claiming its best for temperatures overall. Nonethless nearly everybody goes for neutral/positive pressure and I wonder why...

 

[0d3nnis0]

@Mcnumpty2323 thanks for your thoughts. I am pretty sure I will go with the all exhaust attempt and forget about it when temps are pleasing. Unfortunately there isn´t much space underneath the graphics card so flipping fans is a pain in the ass, time will tell if i am curios enough to compare temps

Negative vs positive pressure case makes no difference in performance as long as pressure differential is the same for both

there is a difference, one can argue how much but there is.

If we have 4 flowing air in then the 2 flowing air out we limit the amount of air flowing to the amount the 2 vents are flowing out

that would only be true for a completly sealed case. In those "open" cases we are dealing with it is nearly impossible to create neutral pressure environment where air volume coming in (through fans) equals the air volume going out (through fans), but that´s beside my point...

 

[0d3nnis0]

Can you give me any data that shows any difference in component temps bases solely on fans pulling air out (negative pressure case) vs fans pushing air in (positive presure case)

sure https://www.youtube.com/watch?v=srhw_mPZkj4&t=271s
https://www.hardwaremax.net/guides/hardware/305-der-perfekte-airflow?showall=1&limitstart=
the basic idea is, that an intake radiator would "feed" warm air to all the components within the case including the exhaust radiator, so only one of the rads gets cool ambient air... makes sense in my opinion.
If you break it down to just one radiator like an AIO setup, pretty much everyone would suggest to mount at exhaust at the top and not as intake in the front!?
I don´t want to offend anybody, I´m just seriously curious. Some times people do things because it´s done that way for ever but what´s proofen for aircooling doesn´t need to be best for watercooling. I hope you get my point here..

Cheers
Dennis

 

[0d3nnis0]

...some fans pushing air in at the front of the cas, if possible

The 011d doesn´t has any front mount possibilities and with my setup I "only" have 3 fan spots in the bottom and 3 in the top left.

You could go really mad and add extra air intake capabilities to the case. Depending on which orientation you have your PSU, remove it's cover (not the PSU shroud ) and flip the PSU fan so it's now sucking air in from the back . Refit the PSU with the fan blowing up into the case not down out of the bottom of the case.

Interessting idea, but the PSU is located in a back chamber so that´s not an option.

I just gonna try it with all fans exhaust when my ml120 arrive....

 

[0d3nnis0]

I assume that you will clean your case out every 3 months to a year?

Yes, since this case has two glas panel I clean it very frequently.

I just gonna observe it for 2-3 month and if dust is getting a problem I instal aditional dust filter. Interestingly there is a video by Linus where he compared possitive, neutral and negativ airpressure over one year in terms of dust and the negativ system collected the least

 

[0d3nnis0]

Fan impeller is designed to spin one direction so even if motor would run in reverse (most won't) it wouldn't move much if any air.

agree!!

Btw, my fans arrived and I am done.... for now....
Temps are looking good, as expected. Let´s see if dust will become a problem.
Thanks to all of you for the input!!!!

 

[0d3nnis0]

I ordered the "bullet proof glas panel for negative pressure build" but the back panel is bend inwards

 

[0d3nnis0]

Still, a nice looking build. Are the temps any different at all?

Thanks! Temp differences are hard to tell since I not only changed direction but also all the fans. GPU and CPU (both overclocked) are sitting at around 50C under load with fans at 1000rpm.