Watercooling Planning - radiator thickness vs. surface area

[Bianks84]

Hi all, as title says, planning a new watercooled build.

Currently have a 3800XT and a 3080 12GB (FTW3 Ultra to be overclocked) cooled by a single 30mm thick 360 rad.

 

Definitely not buying another GPU for a while, may upgrade CPU in 6 months to a year.

 

Planning to use the Hyte Y60 for this, with the following rad config:

• Side intake (60mm thick 240 rad or 45mm thick 280 rad)
• top exhaust (currently used 360 rad)
• rear 120mm intake/exhaust.

My main question is to do with the side intake. Is it worth it to use a 60mm thick 240mm rad instead of the 45mm thick 280? Not sure if the extra thickness at this point would be worth the extra space. Would push & pull fans make the thicker rad more effective? Dealing with ambient temps around 25C max.

 

Curious to hear thoughts on whether this kind of rad config would be enough for the GPU overclocked and PBO on the CPU.

 

Thanks in advance!

[RONOTHAN##]

Thick rads are weird. Most of the time the performance of a thick 240mm and a slim 240mm are actually about the same, since usually as you go thicker the fins per inch goes down and they have effectively the same surface area as the slimmer rads, just with less back pressure so you can have lower speed fans for the same performance. That's not always true, I do have a 60mm thick rad that's just as dense as my slim rads, but it's definitely more in the minority and something you need to check before making your final decision. 

 

I'd stand to guess that the 280mm rad will be the better option, given what I know about them that will be the better performance radiator, though looking at that case it might be a bit tight to squeeze both a 360mm and a 280 in there, I don't have any experience with that case, it might be OK, but I would lean towards the 240mm rad unless you can confirm with other people's builds that a 360 and a 280 fit in there.

[Hairless Monkey Boy]

I might go with the 240 just so I can use all the same size fan.

[Bianks84]

5 minutes ago, RONOTHAN## said:

I do have a 60mm thick rad that's just as thick as my slim rads, but it's definitely more in the minority and something you need to check before making your final decision. 

Lol sorry could you clarify that? If you have a 60mm thick rad that's just as thick as the slim rads... are they slim rads?

 

7 minutes ago, RONOTHAN## said:

might be a bit tight to squeeze both a 360mm and a 280 in there

Still haven't bought the case yet but I didn't think of this.

 

Appreciate the suggestions!

[RONOTHAN##]

Just now, Bianks84 said:

Lol sorry could you clarify that? If you have a 60mm thick rad that's just as thick as the slim rads... are they slim rads?

 

edited it right before you replied lol. I meant to say dense. 

[Zomeguy]

Thicker rads show better results when you do a push pull setup. I don't think the Hyte has the room for that so I would avoid the thick 60mm rad for your setup.

[Bianks84]

1 minute ago, Zomeguy said:

Thicker rads show better results when you do a push pull setup. I don't think the Hyte has the room for that so I would avoid the thick 60mm rad for your setup.

The total side clearance on the Hyte is 150 mm. With fans on each side (60mm+[30mm*2]=120).

Could have room for just the rad, but I would rather use that rad to mount a reservoir so I may go with the 45mm thick.

Also not sure how much room the GPU length will allow on that side as well. Will go through all that once I get the case.

 

Still a good point!

[fonzz1e]

from hyte website, you can also use a 280mm rad on the side

[Cavalry Canuck]

Greater surface area should be the first goal, then thickness.

 

Most manufacturers drop the fins per inch as thickness increases to reduce air resistance. Less fins means less heat dissipation for a given unit of thickness (btus/inch, watts/mm, etc). In this way, a 60mm radiator will not be twice as effective as a 30mm radiator. Maybe 25%.
 

The other issue, regardless of fin density, is the efficiency of the thermal transfer and how it relates to the temperature difference between the water and the air. The higher the temperature difference, the greater amount of heat can be transferred between the water and the air over a fixed area and period of time. The thicker the rad, the more the air is heated as it passes through, the less efficient overall the radiator is.

For example, again, 60mm might be twice as thick as a 30mm. But if the temp delta for the first 30mm is 20c, and the temp delta for the second 30mm is only 5c, the thermal transfer for the second half will only be 25% as efficient as the first half, and the 60mm radiator overall will end up being only 25% more effective than a 30mm radiator would. Faster airflow would mitigate this, but then we get back into the issue of air resistance, needing to reduce fin count so we don’t need 3000rpm fans, etc.