Airflow basics
Posted: Sat Dec 21, 2013 3:32 am
I am highly confused by the way current cases and CPU heatsinks are designed wrt airflow.
I think the basic idea of air cooling is to make sure that cold air passes over hot components, so that it receives heat with those components and takes it away, cooling the components.
If that basic idea is right (is it?) all the systems should be designed either to push cold air into hot components or to pull hot air away, hoping that cold air will replace it. But this basic idea seems to contrast with the way systems are actually designed.
Horizontal CPU heatsinks like the Noctua NH-L12 push hot air over the CPU. The top fan of the NH-L12 pulls cold air and pushes through the heatsink, where it is heated and then pushed by the bottom fan to the CPU. Why?
In most tower cases, GPU fans pushes hot air downwards, while hot hair physically goes upwards. This means that the hot air is being pushed against its natural flow. Shouldn't this make the cooling worse because you are pushing down air what will soon came back up? This is made even worse by the fact that some cases have bottom fans that pushes even more air against the GPU. There are cases where the mainboard is rotated so to have the GPU fans point upwards, but the SPCR reviews of these cases say that GPU will be cooler when pointing downwards.
Most current cases like the Fractal Design Defini Mini have the PSU under the GPU, so the GPU pushes hot air toward the PSU. Why aren't the PSU positioned so that there is no hot air going against it?
Most current cases have front fans that pushes air towards the back of the case, but the PSU is in the back and pushes air towards the front. Doesn't this create a turbolence inside the cases, especially cases that are not very deep?
I think the basic idea of air cooling is to make sure that cold air passes over hot components, so that it receives heat with those components and takes it away, cooling the components.
If that basic idea is right (is it?) all the systems should be designed either to push cold air into hot components or to pull hot air away, hoping that cold air will replace it. But this basic idea seems to contrast with the way systems are actually designed.
Horizontal CPU heatsinks like the Noctua NH-L12 push hot air over the CPU. The top fan of the NH-L12 pulls cold air and pushes through the heatsink, where it is heated and then pushed by the bottom fan to the CPU. Why?
In most tower cases, GPU fans pushes hot air downwards, while hot hair physically goes upwards. This means that the hot air is being pushed against its natural flow. Shouldn't this make the cooling worse because you are pushing down air what will soon came back up? This is made even worse by the fact that some cases have bottom fans that pushes even more air against the GPU. There are cases where the mainboard is rotated so to have the GPU fans point upwards, but the SPCR reviews of these cases say that GPU will be cooler when pointing downwards.
Most current cases like the Fractal Design Defini Mini have the PSU under the GPU, so the GPU pushes hot air toward the PSU. Why aren't the PSU positioned so that there is no hot air going against it?
Most current cases have front fans that pushes air towards the back of the case, but the PSU is in the back and pushes air towards the front. Doesn't this create a turbolence inside the cases, especially cases that are not very deep?