First time water cooling - some questions

[turumbar]

I'm getting ready to start my first venture into water cooling, so I'm scoping out some parts for a cooling loop, and I've got a few questions I hope someone can answer.

1. Lots of parts seem to accept/use tubing of different widths. Is there a good reason to use tubes of greater/lesser inner diameter? Does it matter if I mix and match? I.e. Can I use a water black with 1/2" inner diameter tubing with a radiator of 3/8" tubing and a pump with 1/4" tubing?

2. Water becomes hotter for each component that it cools before going to the radiator - is it practical to have multiple radiators in the cooling loop? I.e. pump->cpu->chipset->radiator->videocard->videocard->radiator->reservoir->pump? Or would it be better to just have a second pump/reservoir and make a second loop?

2.5 Does it make enough of a difference that it'd make sense to have an intermediate radiator?

3. Does the length of the tubing make any difference, aside from needing a larger reservoir? I'd like to make the cooler be external, so the tubing would need to be a little longer than normal.


Thanks
Turumbar

 

[javisaman]

I'm getting ready to start my first venture into water cooling, so I'm scoping out some parts for a cooling loop, and I've got a few questions I hope someone can answer.

1. Lots of parts seem to accept/use tubing of different widths. Is there a good reason to use tubes of greater/lesser inner diameter? Does it matter if I mix and match? I.e. Can I use a water black with 1/2" inner diameter tubing with a radiator of 3/8" tubing and a pump with 1/4" tubing?

Larger tubes offer greater flow (i.e. fluid moving faster through components) and better cooling. In addition smaller tubing is more restrictive. A consequence of larger tubes is that they are harder to bend (thus more kinking). I think the most commonly used tubing is Masterkleer 7/16" tubing over 1/2" barbs as it offers the best of both worlds. If you were to mix and match tubing then the flow of the entire system would be the same as the tubing with the smallest diameter; a system with 1/2" and 1/4" tubing would have the flow of an all 1/4" tubing system.

2. Water becomes hotter for each component that it cools before going to the radiator - is it practical to have multiple radiators in the cooling loop? I.e. pump->cpu->chipset->radiator->videocard->videocard->radiator->reservoir->pump? Or would it be better to just have a second pump/reservoir and make a second loop?

Usually the temperature differences between the components are low because water has such a high specific heat, therefore the placement of the radiator(s) has little affect on the overall temperature. Nevertheless, you can have multiple radiators in a loop but I wouldn't recommend it because it adds more restriction to the system (not too much though). If can dual loops would be the best solution.

2.5 Does it make enough of a difference that it'd make sense to have an intermediate reservoir?

Intermediate reservoirs never make sense. Reservoirs add the most resistance and there really is no point to one other than to fill/drain/bleed the system.

3. Does the length of the tubing make any difference, aside from needing a larger reservoir? I'd like to make the cooler be external, so the tubing would need to be a little longer than normal.

Why would you need a larger reservior?

More tubing adds more resistriction to the system. A good loop is usually has at most 2ft-3ft of tubing. You can have loops with 6-7 ft of tubing and still be okay. Adding *significantly* more tubing would require a more powerful pump with a lot of head. The most common types of pumps (Liang DDC/+ and D5) usually offer around 10-20ft of head (but the flow exponentially decreases).

 

[turumbar]

Larger tubes offer greater flow (i.e. fluid moving faster through components) and better cooling. In addition smaller tubing is more restrictive. A consequence of larger tubes is that they are harder to bend (thus more kinking). I think the most commonly used tubing is Masterkleer 7/16" tubing over 1/2" barbs as it offers the best of both worlds. If you were to mix and match tubing then the flow of the entire system would be the same as the tubing with the smallest diameter; a system with 1/2" and 1/4" tubing would have the flow of an all 1/4" tubing system.

So having a component with 3/8" barbs in an otherwise 1/2" system would significantly decrease flow rate?

Intermediate reservoirs never make sense. Reservoirs add the most resistance and there really is no point to one other than to fill/drain/bleed the system.

Yeah, I meant an intermediate radiator... oops

More tubing adds more resistriction to the system. A good loop is usually has at most 2ft-3ft of tubing. You can have loops with 6-7 ft of tubing and still be okay. Adding *significantly* more tubing would require a more powerful pump with a lot of head. The most common types of pumps (Liang DDC/+ and D5) usually offer around 10-20ft of head (but the flow exponentially decreases).

Alright, thanks for the info!

-Josh

 

[javisaman]

So having a component with 3/8" barbs in an otherwise 1/2" system would significantly decrease flow rate?

I wouldn't say "significantly." The flow difference between 3/8" and 1/2" is actually quite small. Nevertheless, having a 3/8" barb makes the loop essentially a 3/8" loop regardless of how many 1/2" components you have. Its better to be consistent with the barb sizes mainly because its easier to replace tubing (you can get tubing in one size). It is also safer because you might accidentally put 1/2" tubing over a 3/8" barb which could fall loose and spill liquid everywhere!

 

[MrE]

I wouldn't say "significantly." The flow difference between 3/8" and 1/2" is actually quite small. Nevertheless, having a 3/8" barb makes the loop essentially a 3/8" loop regardless of how many 1/2" components you have. Its better to be consistent with the barb sizes mainly because its easier to replace tubing (you can get tubing in one size). It is also safer because you might accidentally put 1/2" tubing over a 3/8" barb which could fall loose and spill liquid everywhere!

Agreed. All very valid points. The pressure drop isn't that great, but when you start adding adapters to take your tubing from 1/2" down to 3/8" you are adding resistance your pump will need to overcome. Its always best to pick a size and stick with it for your entire loop.