How to cool a room and under desk?

pilsburypie · 2 Jun 2014 at 22:53

I have recently moved computer rooms. I used to have my desk and a single PC in my large spare room with plenty of space around the case, but now my son is older, he has got that room and I am consigned to the "box room". I have also added a second PC and extended the desk to give the family their own machine (more to the point, not using mine!).

Now this room is a little tight, the desk pretty much has the 2 cases next to each other enclosed on the sides by one of the supporting panel legs. There is a 10" gap on top of the cases. I am really limited on where else they could go to enable my legs to get under the desk. This is causing quite a heat build up behind and also make the room feel the warmest in the house.

Short of aircon, what are my options? I have considered mounting a PC fan in the rear corner of the desk top hidden under the printer to draw the warm air from under the desk. Would this be of any benefit to the PC? I just worry the warm air is being recycled by the intake fans instead of fresh air. I have also considered venting the exhaust fan externally kind of like a bathroom extractor vent.

Has anyone else had a similar problem and what were your solutions. Mine all appear a bit daft to me.

pilsburypie · 2 Jun 2014 at 23:18

Yes mightymouse - that is my reasoning behind a fan mounted in a hole cut out of the desktop perhaps under the printer - basically a bit of a helping hand for the rising warm air to be sucked out from behind the cases under the desk.

How to control this fan though? I'm not sure how to do this. Can I connect this desktop mounted fan into my PC so that when the PC is on the fan comes on?

pilsburypie · 3 Jun 2014 at 21:25

Hey doyll - your assumptions are totally correct. I thank you for your suggestion and yes, my CPU fan is PWM and controlled by the Asus AI Suite.

I must admit that your detailed instructions are a little confusing to me - not due to poor description, just a lack of knowledge and a little tech fear on my behalf.

Although your suggestion seems to be a solid and most likely proper solution, my investigations have led to a similar solution, if not quite as effective, but certainly less work for me. All over fleabay, and also in the OCUK store are the usb desk cooling fans. Although these are probably a bit of a gimmick for a hot summers day to cool your face in a frenzied "gaming" session, I kind of thought I could plug 1 or 2 of these fella into the rear usb ports angled up to blow the warm air out the gap of the back of the desk.

What do you think to my easier bit of a bodge solution?

edit - can I run 2 or 3 usb fans from a single usb port via a usb splitter? usb kicks out 5v right? The usb fans are obviously 5v so how would it affect the power running 3 from the single port?

pilsburypie · 3 Jun 2014 at 23:29

A kind offer of help doyll. I'll take the side off tomorrow and have a look at the PWM adapter I have - I assume the PWM splitter just links in and attaches my two current CPU cooler fans up leaving spare connections for the new fans?

This seems like a decent option so the extra extraction fans also shut off when the PC sleeps. I'll consider whether to go with your suggestion of fans mounted at the front of the desk or to do a bit of butchery to the desk at the rear where the heat is originating from.

Thanks again.

pilsburypie · 4 Jun 2014 at 13:50

Doyll - I do like your idea, but it does seem quite involved and possibly expensive. The simple desk fan is also an option, but would require turning on and off when required - a bonus of your more involved method.

Abbotsmike seems to have a cheaper solution which may well be effective enough. The warm air wants to rise so maybe just a little help of the single fan drawing out at the back of the desk might do the trick. One question: When the PC sleeps, will the extractor fan shut off too?

OLDPHART - door and/or window open seems to be the only option short of aircon - out of my budget and also space for air con is an issue. Simple is often best!

pilsburypie · 4 Jun 2014 at 23:30

So if I were to adopt abbotsmike idea and go with doyll's 2 fan suggestion, what connectors would I need? You'll have to forgive my lack of knowledge. I'd appreciate a spec of say 2 quiet 140mm fans and the appropriate molex cable long enough to link the fans. Probably 1m minimum. I've looked at fans and some say 3 pin and some say molex. Would it be molex that comes off my psu?

I do appreciate your knowledge.

pilsburypie · 5 Jun 2014 at 13:26

Cheers mate. I was thinking of this 200mm fan for 2 reasons - firstly in stock! Secondly it is quiet which is important and thirdly it shifts a fair amount of air and can be mounted on the underside of my desktop underneath my amp and therefore hidden. The quietness is important so this is why I seem to have been drawn to the bigger fans, slower speed for quieter operation while still moving air. Now to me, it looks like this fan comes with several connectors, including a 4 pin molex. I have seen on ebay a 90cm Molex extension (don't think I'm allowed to link on here - but OCUK don't sell this). My PSU is in my sig, but should have spare 4 pin molex connectors right? My PC is so intrenched in wires with the 2nd PC next to it, I'm loathed to get it out and disconnect the damn lot until it is fitting time!

http://www.overclockers.co.uk/showproduct.php?prodid=FG-003-NX&groupid=701&catid=2331 or http://www.overclockers.co.uk/showproduct.php?prodid=FG-019-NX&groupid=701&catid=2331

Thoughts appreciated

pilsburypie · 5 Jun 2014 at 14:06

2 x 200mm fans? Wooohaa! My desk would fall to pieces! I shall investigate your concerns.... I have the same case as in my signature just with stock fans and the Phanteks CPU cooler. My second PC is just a stock Dell XPS 420.

pilsburypie · 5 Jun 2014 at 14:22

Right, apparently the stock 120mm fans in the Corsair Obsidian 550d are: 1100 RPM, 37.93 CFM, 21 dBA.

Seeing as there are 2 on the front and only one on the back to keep a bit of positive pressure, I'm not sure what the total output would be - can only guess somewhere in the mid 50's CFM.

The old Dell XPS420 has God Knows what fans in..... but a guess would be pretty crappy with far less than my Obsidian case.

Conclusion: In my limited opinion, I guess the near 90CFM of the 200mm fan specified would be a pretty reasonable bet to get most of the hot air out.......

pilsburypie · 5 Jun 2014 at 19:35

Ok doyll. I think you're suggesting my stock case fans are inadequate? This is another matter to look into but are bringing it up with regards to what might be needed in the future to extract from under the desk?

I will have a butchers at 140mm case fans too.