Air Flow Issue, PSU can't breathe

[akgrwn]

Hi all,

I have an HTPC inside an entertainment center that I'm trying to make quieter and cooler. The main limitation is the cabinet, there's not much ventilation room. The front is open and the back has three air vents at the top and a hole for wires but the computer case takes up most of the front opening so I'm sure it's not ideal. The odd thing is that the PSU fan is actually the loudest of the whole system. It's quiet when out of the cabinet so I believe the issue is that its heating up and cranking up the RPMs, making it loud.

There's not much room between the case and the back of the cabinet so the PSU is blowing right into the back wall. I've tried adding a case fan to the side of the PC case, and I just added another inside the cabinet but that hasn't seemed to help much. I'll link some pictures because its kinda hard to explain.

The obvious answer seems to be to cut holes in the back of the cabinet, but I'm looking for other solutions so please don't suggest that. Any other solutions are welcome!

pics of the situation:
https://imageshack.com/i/nrnv3aj
https://imageshack.com/i/nejq6cvj
https://imageshack.com/i/mruv5aj
https://imageshack.com/i/n6zax6gj

If I don't reply right away, give me a day or two, I'll be around
Build details:
Case- Silverstone ML04
PSU- Antec Green 380W (stock 80mm fan) intake is back of the psu inside the case, not bottom
GPU- Asus HD6450 fanless
CPU- core2duo, stock cooler
Case fan- fractal design ssr2-80mm
cabinet fan- 80mm coolerguys usb fan

MB- MS 7525, tuner card-avermedia duet a188, RAM- 4GB ocz, HDD- WD Green 2TB, optical drive- LG bluray whs140, Windows 8.1 64 bit

 

[bccorrupt]

Build an exhaust pipe, or basically the same idea. Double sided tape to seal a reducer like this

http://www.zoro.com/g/00056361/k-G3191894?utm_source=google_shopping&utm_medium=cpc&utm_campaign=Google_Shopping_Feed&gclid=CjkKEQjwlcSdBRD3wva3-KOAo80BEiQAjNIhiYj9QXEImo--QLgdPlbnj7Id7dEo9E1n0j11ne0bmfbw_wcB

onto the back of the power supply a touch bigger than the power supply fan. Reduce it down to the size of the hole already in the back and put two 90 degree bends in it to run it out the back with some edge trim like this

http://www.customcargrills.com/proddetail.asp?prod=Trim_Neo

around the hole big enough that it fits snug and doesn't move or vibrate. Also seal the joints with pvc glue. I doubt the power supply fan moves enough air for there to be any wind noise even reduced down to 50 or 60 mm so it would most likely be quieter than it is now with no heat staying in the cabinet except for the CPU fan through the top.

Although it would be lots easier to just do the same thing without the reducer or 90 degree bends with a new hole right behind the power supply.

 

[geofelt]

The job of the psu fan is to protect the psu.
I think you are right that the psu is getting hot.
You should have adequate power, so I don't think the heat comes from a high power draw.
Since the psu works quietly when the unit is out of the cabinet, it is a problem of the psu not getting any cooling intake air.
The case has room for 4 80mm fans along the side. I think I would install those as intakes.
That will draw in air from outside the case and force out the heat from inside the case as well as feeding the psu with cooler air.

The extra fan on the cabinet should be an exhaust to send heat out the back. Perhaps you can add three more to help airflow through the three top oval holes. Use bigger 120mm fans which will be quieter and push more air. Ideally, you would cut round holes but I would try those fans even partially obscured anyway.

 

[akgrwn]

good ideas, I think I will start by trying the cabinet fan in exhaust. it is partially blocked because the wires have to go through the hole, but it probably will be better in exhaust.

I was wondering about adding fans on the side, there's not a lot of room on the sides and I wasn't sure if having a cross flow rather than forward to backward would mess things up.

An exhaust pipe would be interesting, I've never done that on a computer before lol. If all else fails that might be an option though

 

[geofelt]

Case ventilation can be either positive pressure or negative pressure.
Either works. If the side fans are intakes, that is positive pressure.
The air drawn in is forced out through all the other openings. That would include the psu and the other case openings. It is especially good when the fans draw in air through a filter which keeps your case cleaner. Your case does not have any forward intakes at all so you must use what you do have.
80mm fans tend to be noisy and not push much air . But, that is all that you have.
Another possibility might be to attach three 100mm fans to the outside of the case instead.

Another thought:
Could you construct a wooden partition with three largish 140mm holes that could fit fans?
Affix that partition between your pc and the rear where the round and oval holes are.
That would give you very good exit airflow.

 

[akgrwn]

Case ventilation can be either positive pressure or negative pressure.
Either works. If the side fans are intakes, that is positive pressure.
The air drawn in is forced out through all the other openings. That would include the psu and the other case openings. It is especially good when the fans draw in air through a filter which keeps your case cleaner. Your case does not have any forward intakes at all so you must use what you do have.
80mm fans tend to be noisy and not push much air . But, that is all that you have.
Another possibility might be to attach three 100mm fans to the outside of the case instead.

Another thought:
Could you construct a wooden partition with three largish 140mm holes that could fit fans?
Affix that partition between your pc and the rear where the round and oval holes are.
That would give you very good exit airflow.

Very true, without forward intake fans I guess the side fans are my best option.
As far as larger exit fans on the back, the three slots in the back of the cabinet are only ~80mmx20mm so a larger fan would mostly be blocked unless I cut the back of the cabinet. I'm trying to avoid that though, maybe I'll look for a fan that lays flat and just pushes air out the back like on some graphics cards.