Rad Exhaust Temperatures?

[RabidRedRabbit]

I am planning a compact uATX or mini-ITX, water cooled system based around having a massive single fan and radiator to cool the entire system inside a custom built case. The Cooling system in question is a Silverstone AP182 and an Alphacool NexXxos Monsta 180mm single rad. Currently I have planned the rad and fan the inlet of the case,blowing over the internal components, and out the I/O and (fanless)PSU.  

 

I have never done a custom watercooling loop, and I don't know what kind of temperatures I will be seeing under load from the 180x180x85mm rad with a CPU AND GPU in the loop. Since the air will be passing through the rad first BEFORE cooling the other components, I definitely need to know what to expect before I start buying parts. Ideally I would be running the fan at 700rpm, 80CFM, so I assume the cooling would be similar to a 240mm rad with fans typical 120mm fans on high, though there is significantly more volume inside the 180mm rad for heat transfer. If a typical rad is 45mm thick, then a 240 mm rad has a functional cooling volume of 1.30 L, and the Monsta 180mm rad has a volume of 2.75 L; more than twice the volume allowing more efficient transfer of heat out of the system to operate the system as a whole at a lower temperature. However, I am still concerned that the air will be too warm to properly cool the other components, primarily the power supply since they are most often rated at an operating temperature of 40 degC but do not mention a maximum operating temp. The absolute last thing that I want to do is invest in a beautiful, multi-thousand dollar system that shuts itself down when it is tasked to utilize its power.

[Faceman]

Thats not a good idea for a few reasons.

 

#1 180mm, even a 85mm thick 180mm radiator is not enough for both CPU and GPU, especially if you plan to overclock at that fan speed.  Because it is so thick, you will likely need push/pull at a medium to high RPM just to be adequate.

#2 The air coming out of the radiator is going to be HOT.  That is not enough surface area to dissipate heat.  I personally own a GTX 780 cooled with a G10 and a single 120mmx30mm radiator, and the air coming out of it is hot.  I have it set to exhaust because I don't want that hot air going into my case.

[airdeano]

the issue i have always run into on using the 80+thick radiators is the effort to

shove air through them and still keep the rig quite. the fan choice looks pretty

good on specs, but to use them at 700 rpm (1.1mm/h2o) is too weak to make

the effectiveness to pass the air through that thickness and usually you'd

need two fans (push/pull) to get the air in and finish getting the air out and keep

the temperatures comfortable.

 

your 180x 180x 80 (2592) is equal to a 360x 120x 60 (2592) which support a

moderate voltage overclock CPU and stock clocked GPU to maintain temps

and noise. but the caveat is the fan selection is near zilch to make adequate

choices of temps and sound. your 182 are great till 1200 rpm and then thats

SP120L loud.

 

and as described, above, the heat gen'd at full tilt would be a bit off-putting for

the internals.

[RabidRedRabbit]

the issue i have always run into on using the 80+thick radiators is the effort to

shove air through them and still keep the rig quite. the fan choice looks pretty

good on specs, but to use them at 700 rpm (1.1mm/h2o) is too weak to make

the effectiveness to pass the air through that thickness and usually you'd

need two fans (push/pull) to get the air in and finish getting the air out and keep

the temperatures comfortable.

 

The radiator has a low fin density specifically to make it easier for a fan to move air through, but do you still think it would be too much resistance for the one fan? Also, since I am not necessarily trying to achieve an overclock, just build a rig with some power and the absolute least fans possible, what about going down to a 45mm thick rad?  The rule of thumb that I have heard is that a 120mm rad is sufficient for each component, so the 180x180x45mm rad is of comparable size to a dual 120mm rad using the same logic as above for comparing radiators

[airdeano]

The radiator has a low fin density specifically to make it easier for a fan to move air through, but do you still think it would be too much resistance for the one fan? Also, since I am not necessarily trying to achieve an overclock, just build a rig with some power and the absolute least fans possible, what about going down to a 45mm thick rad?  The rule of thumb that I have heard is that a 120mm rad is sufficient for each component, so the 180x180x45mm rad is of comparable size to a dual 120mm rad using the same logic as above for comparing radiators

 

from what i experienced, the monsta and the UT60 have similar if not the same

thermal performance with less worries on airflow management.

 

running fans low speed for the UT60 is not an issue, same fan speed for the

monsta isn't enough and the speed usually has to be increased to get the full

airflow benefit or push/pull.

 

the 180x 180x 45 (1450) is comparable to the 240x 120x 45 (1296) which

is not close to cooling a CPU and GPU in the same loop. minimum with

no overclocking would be 280x 140x 45 (1764) to keep it quiet and cool.

 

you can run it on a XT45 180, but the fan speed would be 1200 rpm+ and

any overclocking would make it even louder.

 

the rule of thumb that i go by is 240 start (CPU) and 120 per device

afterwards to keep a low noise level and thermal capabilities even

overclocking under load.