Here's a probably dumb question.

[BitGhost]

Fish gills work in a funny way, the water flows from the more oxygenated area to the less oxygenated end. This means that the difference in oxygen between the water and the gill is at a consistent and low gradient instead of a big spike and then a loss of efficiency.

I'm looking into water-cooling my next build, not because I want it to be colder but because I want it to be quieter. To that end I imagine if you had double the rads you could run the fans at half the speeds to make it very quiet under long term load.
I also very much enjoy making compact builds that can sit on my desk and not take up a huge footprint, but water-cooling is very much the antithesis of that, especially with any case that supports more than one rad.

To bring all that together, what if I stacked multiple rads (like 5) together in a chamber not side by side but with the vents end to end, and placed fans in-between them. Running in series with the hot water into the last rad and running the cold water out of the first. This should like a gill let heat transfer consistently through the whole stack at low fan speeds and also be very dense. I could laser cut a case where the pc components are in a compact stack in the top with no fans, and pipe the cpu and gpu coolant into a different chamber with one intake and one exhaust opposite.

My question is would it work or just be a waste of money?

[Fasauceome]

3 minutes ago, BitGhost said:

I'm looking into water-cooling my next build, not because I want it to be colder but because I want it to be quieter

Surface area is the main factor in quiet PCs. With a large surface area, you can get loads of airflow with low fan speeds, hence less noise.

 

4 minutes ago, BitGhost said:

To bring all that together, what if I stacked multiple rads (like 5) together in a chamber not side by side but with the vents end to end, and placed fans in-between them. Running in series with the hot water into the last rad and running the cold water out of the first. This should like a gill let heat transfer consistently through the whole stack at low fan speeds and also be very dense

In a system with 5 radiators, that much surface area alone is gonna get you the quietest setup you can get (assuming you pair the radiators with high end silent fans like noctuas.) The orientation itself would make a pretty tiny difference.

[Subduck]

Your idea of stacking multiple radiators in series sounds interesting, but I’m afraid it might not work as well as you hope. There are a few reasons why:

• The water temperature will increase as it passes through each radiator, reducing the cooling efficiency of the next one. This means that the first radiator will do most of the work, while the last one will barely make a difference. You might end up with a very hot and noisy system.
   
• The water pressure will drop as it passes through each radiator, increasing the load on the pump and reducing the flow rate. This will also affect the cooling performance and the lifespan of the pump. You might need a very powerful and expensive pump to handle such a setup.

[8tg]

With the complexity of doing something like this with so many radiators, you’d be better off just putting a radiator somewhere else outside of the pc where either it can be cooled entirely with passive convection, or just somewhere you can’t hear it.

The idea would work, it would just be needlessly complicated compared to many other solutions to get a quiet system. You could run a passive cooler equipped build with some very low rpm big fans in the chassis to provide airflow and keep something cool while being so quiet it’s effectively inaudible.

A lot will depend on what you’re trying to cool. Because a conventional system wouldn’t require nearly as much radiator surface area to keep cool and quiet.

[BitGhost]

8 minutes ago, Subduck said:

The water temperature will increase as it passes through each radiator, reducing the cooling efficiency of the next one. This means that the first radiator will do most of the work, while the last one will barely make a difference. You might end up with a very hot and noisy system.

I want to reverse the direction of the water to avoid this.

Quote

• The water pressure will drop as it passes through each radiator, increasing the load on the pump and reducing the flow rate. This will also affect the cooling performance and the lifespan of the pump. You might need a very powerful and expensive pump to handle such a setup.

Can I insert a second pump halfway through?

[Subduck]

25 minutes ago, BitGhost said:

I want to reverse the direction of the water to avoid this.

Can I insert a second pump halfway through?

Reversing the direction of the water might help a little, but not enough to overcome the drawbacks I would think.

Inserting a second pump halfway through the radiators will improve the flow rate, but it will also increase the complexity, cost, and noise of your system.
You will also need to make sure that the two pumps are synchronized and compatible, otherwise they might interfere with each other.

The idea is definitely interesting and if you want to, go for it. However at the end of the day, an aftermarket passive heatsink case or using a single, large radiator with a performance/noise focused fan, or to use two or more radiators in parallel instead of in series. This way, you can achieve better heat dissipation and lower noise levels without sacrificing too much space or reliability.

[jaslion]

33 minutes ago, BitGhost said:

I want to reverse the direction of the water to avoid this.

That will still cause for an eventual temperature equilibrium as basically every stage up in the series the air between rads will increase over ambient.

 

Basically eventually resulting in the similar issue of the air eventually being at the temperature of the coolant.

 

Either way its more inneficient than just having them in parralell as in parallel you have colder air on all always

 

Even then like a 360mm rad is enough for even a 13700k and 4090 to run quite quiet togheter. No point in wasting a ton of money on this when you couls juat have 2 360's in a case get fresh air.