Edit: I started this project wanting to use that Rosewell PSU as the basis for a one-fan system. Since it's not currently available, I used a standard PSU which ended up working perfectly. I am even able to use std 3.5" drives without any heat problems....read on. And it's mostly finished now. I've updated the photo album as I went along, so the album shows a few changes as I completed the project.
Here's my latest brain-storm, which may be of interest to you. I am always looking for ways to reduce the number of fans in my computers, at the same time quieting everything, and keeping things cool. It's not easy.......
So far I haven't found a PSU that will run fanless, stay in the case, and at the same time not heat everything up. Scrap that Idea.
The fanless Zen (NCU 1000/2000) requires airflow, a fan, to run at a reasonable temperature with a powerful CPU.
So here's my idea (not completely new for me).......I'm going to use an Aluminum PSU with a bottom 120mm fan, to cool the whole computer, including the CPU. At the same time I won't have to run the fan wide open, and everything will stay cool. Here's how:
First you need a case about 8" wide, giving about an inch clearance on each side of the PSU, this PSU, a Rosewell model.
Then you need a high quality tower-type cpu heatsink, such as an Aero-cool HT101, or an NCU 2000, or something similar from which you can remove it's fan and shroud, pointing up at the PSU fan. I'm also going to move the PSU back into the case about two inches, so the 120mm PSU fan is directly over the heatsink. A short duct may be necessary to force airflow more directly over the heatsink fins.
Now here's the tricky part....may be hard to discribe. I'm going to enclose the PSU in a box (wood to prevent heat transfer back into the case). Only the 120mm fan opening will be visible. The wood box will be as wide as the case......but it won't have a top. Directly above the psu I'll cut a hole in the case, slightly smaller than the top of the PSU.
What this will do is allow airflow out the sides of the PSU (see the photo), without letting the hot air get back into the case. This airflow will go around the sides of the PSU, up to the top of the case, over the top of the PSU (aluminum), then out the vent hole in the top of the case. Since there's no direct opening to the PSU fan from the top......this opening should stay reasonably quiet, at the same time allowing heat to escape out the top. The rear of the PSU will remain stock.....blowing most of the heat out the rear.
With airflow completely around the PSU, it should stay cool, even though it's carrying the load of the CPU heat. You could could use a steel case with this setup because of the Aluminum PSU case....which will transfer quite a bit of the heat. I expect you could run this whole computer on one 120mm fan, at about 1600 rpms. And If you were to use a Laptop hard drive, HD heat problems could be avoided.