SPCR

Under the current ATX standard, a power supply has its largest pair of faces oriented vertically. This means that using that face for the largest fan a power supply can fit, as done on the 120-140mm fan models, means that the fan flow is not oriented with the exhaust, and must be used in to push the air, rather than pull it.

Would it be possible, then, to change the standard so that PSUs were put into the case with their largest pair of faces oriented towards the back? Currently, this would be like rotating the cord-end of the PSU upward from how they're used today, so that there would be a straight path through the fan to the outside, and the fan could be moved back and used to pull the air through the PSU. Obviously, PSUs would have to be changed to have the switches and cords on the correct faces for this orientation. Also, my preference would then be to have the PSU completely isolated from the main chamber, and have hard drives in the front, so the PSU pulls outside air over the hard drives, then into itself, then exhausts it.

Any thoughts? Sorry my artistry skills aren't enough to really illustrate what I want to do here.

I like the idea, but you're forgetting one very important aspect - the circuit board inside the power supply. In order for your idea to work, it could only be the size of the second-largest face, giving much lower total capacity. Additionally, as the height of the board is pretty much limited, there'd be a lot of wasted space. Manufacturers would want to shrink the largest dimension to remove the waste, and grow in the next-largest dimension to increase circuit size. The result would be the same shape we have now.

If I understand Scrooge correctly the PSU itself wouldn't need to change much. Just move the AC input, flip the 120mm fan and tweak the intake holes a bit.
The big change would be to the computer case, it would need to be taller. Not a good thing today when mATX is getting more popular.

I like the idea, but I don't really see a need for change in the near future. Except for power hungry graphics cards the power consumption of the components seems to go in the right direction.

Scrooge wrote:Also, my preference would then be to have the PSU completely isolated from the main chamber, and have hard drives in the front, so the PSU pulls outside air over the hard drives, then into itself, then exhausts it.

Is this any different from the bottom-mount styles of cases like the P180/182?

tehcrazybob has a good point about the PCB size, but more importantly when you have an "exhaust" fan, or negative airflow, without an airguide, you will be exhausting air from everywhere in the vicinity and it will be the airflow with the least resistance (not the air around the heatsinks and components). With an intake fan or positive airflow you can direct the air where you want it, knowing that as long as there is ample venting, it will be exhausted properly. It's kind of a weird dichotomy with the negative airflow that the ATX standard works with, but...there it is.