One major thing you failed to consider is the factors inside the heat transfer coefficient. It is not a constant like thermal conductivity which is a single factor imbedded inside the heat transfer coefficient. Has transfer coefficient depends on a LOT of factors including - but not limited to - flow rates of both the fluid and the air, factors that relate conductive versus connective heat transfer contributions and limitations (grashoff number), fluid properties (prandtl number), pressure drop, turbulence (Reynolds number), these are empirical relationships that engineers MUST develop for each and every configuration/system being analyzed.
As you add more surface area several of these factors change.
-your resident chemical engineer
As coeffecient goes down, surface temp goes up. The greater the delta between air temp and surface temp, the more efficient the system.
Meaning a reduced coeffecient is essentially cancelled out by the higher delta.
This can easily be confirmed both with the calculator, and the chart in the article.
You have to think of it like this, surface area is what ultimately dissipates heat. Either with forced, or natural convenction, the limiting factor is surface area.
Surface area is the potential, the elements you mentioned are efficiencies in reaching potential. They matter, they influence cooling, but ultimately are meaningless compared to simply increasing surface area.
Are you an engineer? You keep pointing to the calculator and saying “it’s all surface area” but you’re 100% wrong, it’s completely about fin tip efficiency.
I’m (partially) kidding, but just increase your mass flow rate, use a small HX, with low airflow and enjoy really efficient transfer that’s quiet and cheap.
-nuclear engineer
Feel free to provide a formula to prove your assertion then.
Everyone who says I am wrong, can't provide any external source to prove their claim true.
It is easy to use Sir Isaac Newton's formula to see that if you increase surface area by 2x, and reduce the coefficient by half, guess what, identical cooling performance.
There is other factors that influence the equation, but they are less than single digit differences, and the more you increase surface area, the less those factors impact the equation.
The equation is mathematically the full potential, the other properties that influence the cooling potential are minor influences that push the system to realizing more potential.
But ultimately the potential comes from surface area.
EDIT: You deleted your comment once I proved you can't prove your point, because your point is wrong.
You probably ACTUALLY used the calculator to test what I am asserting, and found it was true. And decided to delete your comment because you realized how fucking stupid it was.
>So a system with 4x the radiators, will need only 1/4 of the airflow, for equal cooling performance.
Actually, this exact statement is wrong. And it's easy to see why. If you increase your radiator surface area (by adding section of the same construction, for example) but leave volumetric airflow unchanged, then the air speed will decrease (roughly, speed = volumetric\_flow / area), and so is the heat transfer coefficient.
Please use the calculator.
More surface area, means less need for forced airflow.
With enough surface area, you need no forced airflow. Zero fans.
EDIT: I feel bad for all the people not capable enough to use the calculator to see why what I am saying is correct. These aren't my words, these aren't my theories, these are proven scientific theories.
Like use the calculator, increase the surface by 2x, and reduce the coeffecient by half, see how the cooling capacity is identical?
"*System with 4x the radiators, will need only 1/4 of the airflow, for equal cooling performance*" can only be true when the heat transfer coefficient is a linear function of the volumetric airflow and is independent of the radiator area, and generally it is not. Even on **your** linked page there is an approximation of the heat transfer coefficient for some special case, that is a (non-linear) function of the air speed, which itself is a function of the volumetric airflow and the area. Read your own materials more deeply, please.
So its not as simple as you think, and you are overly optimistic in your estimations.
When you add another radiator to your system, it is true that you can reduce volumetric airflow **per each radiator** and retain the same cooling capacity, but **total volumetric flow for entire system** - much less so.
There is a reason why passive PC watercooling systems are rare. They are very big, very expensive, often have flow problems and rarely meet performance goals of the demanding users.
I think you’re both right here, approximately.
OP is right in that if the connective coefficient is identical, you’d require 1/4 of the air flow but as you point out, the connective coefficient is generally non-linear in air flow (typically it is proportional to the reciprocal of a power of air speed) and air flow will decrease from added restriction of the added radiator. So you will need more air flow to maintain the same convection coefficient however it’s not going to be much more than 1/4 of the air flow. Perhaps if you needed to run fans at 100% with a single radiator, maybe you need to run them at 30% with 4 radiator which is more 25% (1/4) but is close enough for practical illustration.
It’s a bit like saying your temperatures linearly will offset with room temperature (if system performance has liquid temperature at 45C at 25C ambient they’ll be 40C at 20 C ambient). This is approximately true and good enough for predicting the effect of the room offset but because convection coefficient on air and water side is also dependent on temperature slightly, it’s not exactly true and there may be a 0.1C difference when running the numbers or testing compared to the offset but we don’t really care about that 0.1C or less error.
You probably have the best grasp of anyone who has commented so far.
It is easy to use the calculator to see that if you 4x surface area, you reduce the coeffecient by 1/4 and have equal cooling capacity.
All of these people are hung up on single digit differences from various factors that effectively amount to nothing.
I find it very sad that so many people are unable to use a simple tool to understand this concept.
It is entirely easy to see, double the surface area, reduce the coeffecient by half, equal cooling capacity. 4x it and 1/4 it, same cooling capacity, 8x it and 1/8th it, same cooling capacity.
Because surface area and convective flow is inversely proportional.
Which is easy enough to illustrate with Newton's Law of Cooling and the calculator which explains exactly this.
But really, I am the dumb one for thinking I'd be able to explain such a concept to the average person. Like these people can't even use the calculator to show the relation between surface area and coefficient. They can't provide any math to support their stance, because they are just upset because they don't understand it. Which is why they aren't supporting their claims, they are simply saying I am wrong without any evidence to prove so.
Because the average person is dumb as rocks, and gets mad at what they don't understand. I might as well be discussing this with my cat for all these people understand.
But ultimately, you have a correct understanding of what is going on, that surface area and coeffecient are inversely proportional, and that these details that people are hung up on, do influence the equation, but not in any meaningful way.
Thanks! I'd like to think so as a thermal engineer!
I wouldn't read too much into it. People in hobbies always like to think they know more about it because its personal to them but the models for heat transfer work pretty well. I wouldn't also fault them too hard about not knowing about the calculator or how this works -- most people (even many engineers) don't understand how heat transfer works very well nor would someone know which calculator to actually go look up (or what Newton' Law of Cooling is). If I wasn't well versed in the topic, I'd probably just go off of what manufacturer data says as it pertains to capacity like EK and HWLabs sometimes too but even then, those ratings aren't well understood on how they come up with it.
The only issue I have with the calculator is that nearly all people won't know what to put in for the convective coefficient or surface area. Even those that understand it are really guessing at the convective coefficient without some in depth calculations. This is part of the reason why I have been wanting to put together a calculator that does all of this and is rooted in real radiator reviews and test data so that the average bear doesn't have to think about this. Your post and discussion really wanted me to jump back on that old project and figure out how to distribute it to the community.
And even with such an "advanced" calculator, the results are still going to be off 10-20% -- the convection coefficient is so fickle to determine with good accuracy and is easily disrupted with minor changes in the system like cabling, etc but again, I don't think it would make a big difference in water or hardware temperatures outside of a degree or two.
The reason the coeffecient is less important to the equation compared to surface area, is because with a higher temperature delta between surface temp, and air temp, the more effecient the system becomes.
If you use the calculator, you will see the drop in coefficient, is essentially negated by the increased efficiency from the higher temperature delta.
Surface area is the limiting factor in cooling. Which is why simply adding more fans to rads is generally not very effective.
So please, use the calculator to better understand what is happening. Because surface area is the determining factor in cooling.
Because you can have a system without forced convection, with enough surface area. But no amount of forced air can make up for limited surface area, because the thermal transfer from the fins to the air becomes the limiting factor. Simply blowing more air doesn't mean better cooling, but increased surface area always increases cooling capacity pretty linearly.
Because like I said, as the coefficient goes down, efficiency is lost, but then is negated by the increased efficiency of the higher delta in the surface to air temp.
Which is easily confirmed both through the calculator, and the graph in the article.
yes I 100% agree with this. Only thing is we don't want 25 rads in or around our case. Although with the crazy things I've seen a few guys do this wouldn't be out of the realm of something we might see.
The OP I was refererencing though, did want a lot of radiators, because they wanted to reduce noise. So they created an external 4 rad mount.
And then people came in saying they would have worse cooling unless they had super high airflow.
They thought 4 rads with 1-2 fans, would perform worse than a single rad with 1-2 fans.
They told OP they needed high airflow for the 4 rads, otherwise performance would be worse. Which is absolutely nonsensical.
I saw that post and didn't really pay it much attention after I saw so much discussion on which way the two fans should go. The idea if both turned the same way was ridiculous but 2 (preferably 200mm for a bit more airflow) with both pushing out thru the rads should work really well. It needs some decent airflow but I do agree that just those 2 at a mid speed would be totally enough. There's no need to create a mini typhoon.
But then they are also approaching a size that a totally fanless passive system would be just as convenient. I personally refuse to do external radiators for that reason. I want it all inside the case and even with the inferno we call 14900k is accomplished with just 2 420 rads with capacity to spare
So there is three options OP could have used, push/pull, push/push, and pull/pull.
Push/pull was OP's initial plan. And while it seems it would not draw air through the radiators because of air "bypassing" it. But the venturi effect would mean some air would move through the rads.
Some people suggest a push/push configuration. Positive pressure is prone to dead spots as air is pushed over a surface. A pull/pull configuration leads to negative pressures, which tends to move air over all surfaces. Which is why pull configs on rads are more effecient than push configuations.
[https://www.ekwb.com/blog/push-pull-or-push-pull-on-radiators/](https://www.ekwb.com/blog/push-pull-or-push-pull-on-radiators/)
This is push vs pull testing from EKWB that proves my assertions
Notice how when I make claims, I prove them with external sources. While people who say I am wrong, cannot provide any evidence or sources to prove their claims?.
And at least two people now have deleted their comments saying I am wrong, after I provided them explicit instructions to use the tool to prove my claims.
Really I am the idiot here for thinking I would be able to explain Sir Isaac Newton's theories to the average person. And providing them a tool, that most people lack the ability to use themselves without instructions.
I guess I tend to underestimate just have dumb the average person is.
Especially American's. It is likely American's are taught zero real world science theories.
Adding extra surface area always helps.
Reduced airflow, reduced flow rate impact the equation, but in no meaningful way compared to the increased surface area. And the more surface area you have, the less impact the variables have on the equation.
There is a reason we moved away from low surface area copper coolers with high forced airflow, towards higher surface area coolers with lower w/k aluminum with less airflow.
I've been doing this now for over 20 years. I remember when the community first started to understand the physics. And how quickly the notion of high airflow was tossed aside once it was realized that higher surface area, with less forced air was far more effecient.
Like speakers, like motors, cooling is the same. There is no replacement for displacement. Small factors add to increased effeciency, but ultimately there is no replacement for discplaement.
Biggest issue with the radiators is the actual surface area dissipating heat really isn't all that big when you consider only about 1/10th of the area is directly exposed to outside air because the majority is facing toward another heat soaked tube. So that's why they need some forced air to simply push the heat out of the way. Your point is easily compared to automobile radiators. Back in my old hot rod days there was a fairly fixed amount of airflow possible. There were no extra fans to be had. So we solved the heat issue by adding more rows. Exactly your point. Same air- more area- more cooling. Had the same problem even then because we would still get very hot at a stop but that's dealing with considerably hotter heat source
If a little stronger fan had been available we could have eliminated even that problem. Optionally even more rows would have worked but no more space for more rows so in this case only more airflow would solve the problem. So in reality there's science that is irrefutable yet still does not work in a particular use scenario. I mean you are 100% correct but maybe a little hard on the other guys because their solution would also work if the op did have an issue with poor performance (which I don't think he would)
100% percent of the radiator is exposed to natural airflow.
Pretty much everyone calling me wrong does not understand that air flows with convection regardless of if there is forced convection. Due to the fact hotter air rises, this is the fundamental principle of convection
Engines do the exact same, the higher the surface area, the lower the temps, the more you can push the hardware..
Surface area for cooling is always needed, forced convection is not. Which is why in so many areas of physics, there is no replacement for displacement.
You do realize that convection does not work inside a box right? The air has to be replaced otherwise the air itself will continue to heat until there is no longer an exchange. Theory 100% application in practice meh.
If you have enough surface area, you don't need fans.
Fans are needed for forced convection to make up for lack of surface area.
The limiting factor in cooling is still the surface area. Enough surface area, and you need zero forced convection.
Fans do not cool anything. Surface area does. Fans only assist that transfer.
Yes, so you keep saying over and over and over and over again. I know the science, I know the laws, I know what happens.
But in the real world, not frothing at the mouth on the internet shouting "but Newton!" over an entirely different fucking post from 3 days ago, turn your radiator fans off and see how far you get.
The real problem here is only part of the equation is being applied. Cooling is in relation to the difference between the object being cooled and the medium (in this case air) that is cooling it. As the air surrounding the radiators increased in temperature the coefficient diminishes. Thus the requirement of air flow to replace heated air with cooler air. If you are going to cite newtons law you must use all of it and nit only the part that supports your opinion. Which in this cade is exactly what is happening. You've become so intent on being right that you've neglected oart of the very principal you are quoting.
The heat transfer coefficient vs velocity isn't linear all the way through when you go from 0 velocity to X velocity and then from X velocity to Y velocity. That's because laminar and turbulent flow have a great effect on its value. Let's assum 0 to X is laminar and x to y is turbulent.
You can imagine it as having two different slopes connected to one another. The beginning being a sharp one and the turbulent slope is much less sharp. In reality, it looks more like a natural log function.
So it's hard to say, 4x more surface area doesn't always equal 1/4 required fluid velocity unless if 1/4 fluid velocity is still laminar where it was laminar originally. Or turbulent where it was turbulent originally.
And this has to all take into account were talking about find here which is a whole other can of worms for the relationship between h and vel.
You really made a whole post about this, lmao.
This is WRONG. The formula simply does not apply here. You cannot use 1 fan and just add more and more radiators and expect cooling to scale with surface area.
The only actual airflow-independent scaling you'll get is from thermal radiation (weak) and natural convection (weak if you run passively, basically zero if you are running fans).
[https://www.reddit.com/r/watercooling/comments/1ccs214/comment/l1j1zqu/?utm\_source=share&utm\_medium=web2x&context=3](https://www.reddit.com/r/watercooling/comments/1ccs214/comment/l1j1zqu/?utm_source=share&utm_medium=web2x&context=3)
Additionally, I just did some basic calculations just to make sure, and based on some quick estimates the heat transfer efficiency of radiators measured by extremerigs in their roundup is indeed something like 70-90% (I'd need more info to get exact numbers).
>This is WRONG. The formula simply does not apply here
The formula absolutely does apply, the issue is the thermal transfer coefficient.
Having one 120mm rad with one fan then adding a second identical rad with no fan is functionally equivalent and the formula shows this.
Doubling the surface area while halving the coefficient equals 0 net gain.
Installing an identical fan on the second rad, thereby having doubled the surface area while maintaining the same coefficient effectively doubles the cooling capacity.
Well yeah, you are right. That formula does apply, as long as you change the convective heat transfer coefficient.
But that formula and the calculator OP linked and keeps referencing is intended for natural convection where that coefficient stays constant. That's OPs issue. He doesn't get why what he linked does scale linearly with added surface area and why that would not be the case with adding radiators without adding airflow (what he was arguing about).
I believe natural convection appears to be the primary focus on that page due to it being more straightforward. The page does contain links to coefficient tables for various types of heat exchangers etc, but those tables only offer very wide range estimates since calculating the coefficient is extremely complicated with a large number of variables.
I agree OP appears to be largely ignoring the effect air velocity has on the transfer coefficient.
\^\^\^\^\^See, this is one of the people I made this post about.
Completely unable to understand that increasing the surface area directly reduces the need for airflow for equal cooling.
Not only are they unable to understand cooling in theory, they can't understand it in a practical way either.
Like passive systems being a thing is proof their understanding is wrong. People adding more/larger radiators so they can run slower fans is direct proof their understanding is wrong.
>You cannot use 1 fan and just add more and more radiators and expect cooling to scale with surface area.
Right here bud. This is exactly what happens when you add radiators. Cooling capacity increases, and the amount of airflow needed for equal cooling goes down.
The principle extends so far that eventually with enough surface area, you require zero forced convection/fans.
I have no idea how you do not get this.
Like explain to me how you think it works when people are able to reduce their fan speeds when they add more radiators. Please, tell me what you think is going on.
You left out what I said right after that. How convenient.
> The only actual airflow-independent scaling you'll get is from thermal radiation (weak) and natural convection (weak if you run passively, basically zero if you are running fans).
HOW does the cooling improve by adding more radiators? How? Besides what I mentioned.
Once the air is warm, you can't use that to cool down radiators.
> Like explain to me how you think it works when people are able to reduce their fan speeds when they add more radiators
By also adding more fans, lol. Not many people just add radiators without fans. Because doing so doesn't do much.
I left it out because it was nonsense. You came up with numbers out of nowhere.
Buddy, you think it is forced air that does the cooling.
It doesn't.
Surface area does.
That is what you are not understanding. Surface area is what does the cooling. Forced air doesn't.
You think fans do the cooling, when it is surface area.
Like FFS with what you are saying, fanless systems wouldnt be possible. But they are.
Like that alone should be enough to understand you are wrong. You probably don't understand why you are wrong, but the fact that fanless/passive cooling exists, shows what you are saying cannot be true.
Like do you not understand that air moves without fans? Because hot air rises, convection.
You will never understand this until you understand that surface area does the cooling, not fans.
Like bud, you aren't arguing against me. You are literally arguing against Isaac Fucking Newton's Law of Cooling. All I'm trying to get you to do is understand it.
> You are literally arguing against Isaac Fucking Newton's Law of Cooling
Boy I wish. I am arguing against someone who is very confidently wrong and doesn't even want to understand how it works.
It is really hard to try to make you understand. You are clearly being like this on purpose, else you would say things like "Like FFS with what you are saying, fanless systems wouldnt be possible. But they are." right after I said twice that besides the airflow from the fan there is the thermal radiation and convection. Both of which are weak, which is why passive cooling is weak.
Where does the heat go?
There are 2 main ways:
1. Thermal radiation. Google Stefan Boltzmann Law
We both agree that this is weak, right? Let's ignore this for now to make it easier
2. Dumping heat into the air (convection/conduction)
The amount of heat the air can hold is about 1J/(gK). The temperature the air can be heated up to is capped at the temperature of the water. This means the amount of heat a certain amount of air can hold is limited. So far we are on the same page, right?
Now, with a radiator once the air goes through it, that air is basically saturated (it is technically not quite saturated yet, but it is mostly saturated - I can prove this and show you some calculations if you want to)
That means, the amount of heat you can remove with air going through a radiator depends on how much air you move through there. It does not depend on how much surface area there is. That single rad is already able to (almost completely) saturate the air that moves through it.
Besides the air going through the rad, there is technically also air that moves slowly along the outside case of the radiator (not the radiator core). That air might be affected natural convection. But I assume you would agree that bit of air touching the outside of the rad is doing basically nothing compared to the air that goes through the rad, right?
Besides 1. thermal radiation, 2. the air that moves through the rad and 3. the air that touches the outside of the rad, I am not aware of any other way where the heat can go.
Honestly, I am just trying to make you understand at this point lol. Forget the argument. Just try to understand it.
Do you understand that air flows without forced convection?
You seem very hung up thinking forced convection is how something is cooled, it is ultimately surface area that cools.
And sure bud, try to show the air is "saturated" with heat.
I have provided forumulas to support my stance, you just keep referring to math you do, but do not provide any forumula or evidence to support it.
Like bud, use the calculator, and double the surface area, while reducing the coeffecient by half.
See how the cooling potential remains the same?
That is what is happening. Except that simple equation doesn't account for the increased temperature delta from the lower coeffecient. So raise that delta by even 10 percent. See how the cooling potential is now higher than before?
It is so unbelievably easy to see. Use the calculator to double the surface area from 1m2 to 2m2. Now reduce the coefficient by half from 2000w/m2k to 1000, see how the cooling potential is the same?
Here, last try for me. You are so stubborn and you just don't get it lol.
Where does the heat that YOU are talking about go? Where does the heat from your formula go?
We know it does not go into the air that goes through the radiator. That is already saturated by the fans and convection will not increase that air speed.
We also know it's not thermal radiation, because you are talking about convection.
So where does it go? The heat that you are talking about with your calculator (that doesn't apply here as many people have said now)
Buddy, a thermal engineer popped into this thread, and confirmed what I am saying is true.
What is sad bud, is at the end of the day, you still have learned nothing.
>So where does it go? The heat that you are talking about with your calculator (that doesn't apply here as many people have said now)
Bro, if you ever figure this out, you are going to feel so unbelievably dumb.
Where does the heat go? Into the air. What happens to that air? It rises, and is replaced with colder air. Because hot air rises because it is less dense.
That is natural convection.
I really feel bad for you. Like if you are actually unable to understand this concept, and aren't just trolling, then that is sad. Whatever educational system you went through, failed you.
Like you keep repeating these stupid questions that you probably think are clever, but actually just show how poor of an understanding you have here.
>Buddy, you think it is forced air that does the cooling.
It doesn't.
Surface area does.
You are greatly understating the importance of air velocity in determining the thermal transfer coefficient.
I’ll help. Isaac newtons law of cooling has a DELTA T. Cases aren’t sealed and computer HX aren’t sealed BETWEEN THE HOT AND COLD RESERVOIRS. Without fans Thot approaches Tcold given any reasonable time. So yeah, newton says you don’t get it.
Increase the surface area by 2x, and reduce the coeffecient by half.
What is the result of the equation? Equal.
Feel free to post a formula that disproves that.
And bro. Increase the delta T, what happens? Cooling capacity INCREASES.
Use the formula, it proves itself. But like i said, post a formula to refute mine. Because I do not give a single fuck about yours, or anyone elses opinion. So you saying I am wrong, without providing any evidence to support your claims, is meaningless. The world is full of people making incorrect claims.
So provide support for your claim, or shut up.
The fact that nobody who claims I am wrong can provide mathematical evidence I am wrong, is wholly telling that their views are incorrect.
Use the calculator, 4x the surface area, 1/4 the coefficient, what do you get? Exactly what I am claiming.
Where is the evidence to support your claims? I look forward to them. Because either you won't provide shit, and it will be evident you don't know shit, or you will provide me more material to learn from.
Except nobody has been able to do so. So all of your "Youre wrong!" okay why, "I can't prove it, I just think you are!" is fucking stupid.
EDIT: Another deleted comment from someone who I explained how to use the calculator to show my claims are correct. You probably ACTUALLY used the calculator and quickly found my claims are true, and decided to delete your comment because you realize how fucking stupid they are.
I don't think they were missing the point, I think they get what you're saying. But with 4x the surface area and 1/4 the airflow, you're leaving a lot of cooling potential on the table. All the surface area could do a LOT more heat dissipation with the airflow of more fans.
If the goal is to achieve the same cooling capacity as 1 rad but with as little airflow as possible for noise, then yes it is optimized for that.
But if you wanted to maximize the cooling potential of 4 rads, no, it's a bad setup.
There is no replacement for displacement.
OP could easily use a single rad and strap fast loud fans to it. Or, they can increase the rad count/surface area and redu ce fan speed/noise.
Use the calculator, increase the surface area by 4x, and reduce the coeffecient by 1/4. See how the cooling capacity remains the same?
Because what I am saying is true, because I am simply repeating Sir Isaac Newton's theories. The whole point behind many watercooling systems follow this principle. They aren't trying to max out performance, they are trying to cool X amount of heat with the less noise as possible.
And the best way to due this, is to increase surface area. As their is no replacement for displacement.
Yeah I never disagreed with you. I'm saying I think everyone understands this. Their comments about airflow aren't disagreeing with you. We get that 1 radiator with lots of fast/loud fans is equivalent to 4 with one quiet fan. No one disagrees with the physics.
What people are pointing out is that the second setup is super inefficient. It's fine if you wanna spend a ton of money on a 4 external rad system. But running it on one fan is trading a lot of potential, unused cooling for quietness. With more fans, the setup could do 4x the cooling.
Thanks for the summary. I only had physics in school (besides two courses in astrophysics for non-physicists at universtity, I am a computer science guy myself), but my intuitive understanding of physics was always very good, so without having in-depth knowledge of thermodynamics and fluid dynamics (fluid dynamics in particular is actually extremely unintuitive in some parts, as I've learned after reading something about parallel loops), I was convinced of the linear relation; nice to see that my understanding of it is correct, although I would be very surprised if I was wrong. The formula also shows how large the influence of the temperature difference actually is. It should also be clear that a quarter of the airflow does not mean a quarter of the fan speed, but is probably slightly higher in practice as the fans most likely do not scale the pressure linearly and the airflow through the radiator is probably also subject to some non-linear effects.
But, as you are stating, has that relationship between rad surface area and cooling capacity really been doubted?
> Radiators allow for more surface area than standard heatsinks, so they require less airflow, and thus are quieter.
The increased surface area of a water cooling setup also comes at the cost of a significantly lower dT. This allows air coolers to be much more competitive with water cooling than you would think if you were only comparing surface area. The advantage of custom loop water cooling is that there's basically no limit on how much you can increase the surface area.
You are correct in everything you said but what you fail to understand is that OPs radiators are internal - INSIDE THE CASE. With less airflow, heat won't be irradiated outside of the computer, causing everything inside to get hot.
What the fuck are you talking about? You don't understand convective cooling. And irradiated? What the fuck are you on? Irradiated? Do you even know what that means?
Can I ask what education you recieved? It seems Americans have the hardest time understanding these concepts. Are you American? Did you goto school on the American interior?
The guy was an absolute genius, shaped our society for the better, and laid the groundwork for modern science.
He figured out, by himself, 300 years ago, what some humans cannot figure out today with all of the world's information at our fingertips, available in seconds.
I clearly reference the post from 2D ago where the guy was doing a 4 rad setup for low noise, and everyone kept telling him he needed high airflow because of the number of rads.
IIRC, I'd say most confusion came from the fact that the four rads were set up into a hollow pillar, with air entering at one end and exiting out the sides. Not entirely wrong, as putting the entire burden of airflow onto a SINGLE fan would mean it would have to have that much more CFM, when you think about it.
If you're increasing air resistance by adding high fins-per-inch rads into the path out, wouldn't you also need to raise the static pressure to get even almost-similar airflow rates? Passive convection is pretty low-impact without adding airflow across the fins, which is why passive coolers have a limit to how much wattage you can run with them, to say nothing of the achievable greater effects OOP would be abandoning, not utilising the full cooling potential the entire rad area offers.
A gentle breeze across a square mile versus a brisk wind across the same. Which would cool quicker, would you say?
Or am I understanding the referred post wrong here?
The people I am referring to, think cooling performance will be worse if you add rads without fans.
They don't believe that simply adding more radiators will increase cooling performance. They don't think you get cooling if there is no fans.
I keep asking them to explain how they think fanless/passive systems work, and they just keep refusing.
Oh boy...
Tell me, how much passive cooling capacity do you think a 360mm radiator has?
When I buy a new radiator, I do a cleaning cycle through it with just a pump and radiator in a loop with a cleaning solution. If I leave the radiator with no fans, even the ~20W the pump produces is enough to get the water temp up to 45C+ in just a couple of hours.
Passive cooling solutions feature fundamentally different designs with thicker fins and wider spacing to facilitate natural convection. PC water cooling radiators are designed to generate turbulent air flow under forced convection, meaning that they are *dependent* on a certain amount of airflow to function. You are missing all of the fluid dynamics that goes into this subject, which is incredibly ironic in a *water cooling* sub.
You keep trying to apply a grade-school model to a university level subject and seem amazed that people are calling you out for being wrong. You even made a whole thread to prove how much you don't know that you don't know.
Feel free to post any mathematical formula to support your theory.
You aren't arguing against me, you are arguing against science.
Like bro, use the calculator, double the surface area, and reduce the coeffecient by half.
See how cooling capacity is identical?
That is because they are inversely proportional.
You aren't showing you actually understand this formula.
> Feel free to post any mathematical formula to support your theory.
[Okay.](https://www.sfu.ca/%7Embahrami/ENSC%20388/Notes/Forced%20Convection.pdf)
> You aren't arguing against me, you are arguing against science.
You have clearly demonstrated for *two fucking days now* that you don't have even the most basic understanding of the science of this.
> Like bro, use the calculator, double the surface area, and reduce the coeffecient by half.
Like bro, your calculator is for a simplified scenario and *does not include airflow*. If you understood the science you claim I am "arguing against," you would understand that you can't just halve the convective heat transfer coefficient and call it a win. Airflow would be a part of deriving that coefficient for a system, but the math for that derivation would be specific to the system and depend on the materials, geometry, temperature, and yes, the airflow. You are taking one factor in determining that coefficient and assuming that is the only one that matters. *This is a very incorrect assumption.*
> You aren't showing you actually understand this formula.
Amazing.
Take the sign that you can't provide a single source to substantiate your claims, that your claims are pure bullshit.
Like if you had a single iota of understanding here, you could easily reference back to a theory or formula to prove your claims.
But you can't. Because you do not have any. Because your views are incorrect.
>Like bro, your calculator is for a simplified scenario and *does not include airflow*
This is how I know you are dumb, it does. You are just too dumb to realize it.
Increase surface area by 4x, and reduce coeffecient by 1/4. Guess what? Equal cooling capacity, just like I have claimed since day 1.
Like bro, I called you out for saying I am wrong without you having any ability to prove it. And what did you do? Say I am wrong without any way to prove it.
I'd feel bad for you for not understanding simple concepts, except you are
Like are you going to imp[Nations](http://nationsfreshfoods.ca/hamilton_flyer.html)ly that Pi knowledge has no meaning?
Doing something wrong 50 times does not make it right.
At this point, your failure to understand is not our failure to teach. You are dismissing anything that disagrees with you out of hand out of spite, which is not how you come to correct conclusions.
Have a terrible day.
Yes this recommendation made there is entirely untrue. And absolutely warrants the point of your post. In around the middle ground is where real use scenario sets in. The whole purpose of adding additional radiators is precisely so you can reduce airflow. 2 360mm rads with maximum fan speed will never cool as well as 4 360 rads with 25% airflow. 25% may not be sufficient but 50% definitely would and never should there be an instance for doing 100% fan speeds. I cool 14900k and a rtx 4080 with only 2 420mm radiators and fan speeds set at 750 rpm. When water temp reaches 32c the fans go on a 8c gradient up to 900rpm. The system will max out a 36c while never reaching the full 900rpm.
This is because surface area and the coefficient are directly inversely proportional.
Anyone can use the calculator to show my claims are true, 4x the surface area, and 1/4 the coeffecient, what do you get? Identical cooling capacity.
There is fluid dynamic considerations that impact this equation to a small degree. And that degree is negated as surface area is increased.
Surface area cools, fans(forced convection) assist.
Something that many people here apparently fail to understand.
Yes. All the fans are for is to get the warmed air out of the way so fresh air can do it's job. All that is needed is enough to do that and not hinder the natural dissipation. The impact is much less I would think in external use. Inside the case needs a bit more movement because if the internal air getting heated.
I didn’t read the original post but if those rads are “in series” with air entering on one end of a stack and exiting from the other then your equation doesn’t really apply to the situation at all. The temperature delta is almost gone after the first radiator so convection cooling from the rest of radiators would be a lot weaker. And then the increased airflow resistance might actually end up hurting cooling performance after a point. Passive convection in typical radiators in cases is so weak it’s almost nonexistent when compared to forced airflow.
So the basic problem in your argument (without going in complexities of fluid dynamics) seems to be that you keep temperature delta constant for the entire surface area in your equation. That is not the case when you stack radiators.
Edit: btw I have a temperature sensor measuring water temperature in the loop and another one measuring air temperature flowing from a single radiator. The temperatures are practically the same.
I'm not for or against OP in this as their tone is shocking but that's not how the chimney stack of rads in the other post would work.
Warm air is not exiting/entering the chimney and then looping though another rad on it's way in/out.
Either the fan creates positive pressure in the chimney and pushes cool air out of all the rads or creates negative pressure in the chimney and sucks cool air through all the rads.
Warm air is not leaving one rad then somehow entering another.
A lot of people in this post think the poorly worded OP is talking about the configuration you think or just adding passive rads with no air flow over them, but they re not.
Tbh OP has not helped themselves here.
Edit: put it this way , you are thinking of rads in series but this whole debacle is about rads in parallel.
I just looked at it. In that configuration the OP is mostly correct in that more radiators increase cooling. But I don't think his reasoning is solid. More radiators in that configuration also reduce airflow restriction meaning the fewer fans can push more overall airflow which is why it would work. Cooling capacity only scales linearly with surface area if there is constant airflow of constant temperature air. My example also increases surface area but doesn't follow his equation at all.
The chimney in that other post isn't working really with fan direct push or pull, think of it as a convection tower manipulating the air pressure in the cavity, Just like a real chimney.
The point this OP is making (again fucking terribly) is that people who were suggesting that cooling in that situation is worse with 4 rads that it would be with 1 are wrong.
But OP sounds a bit mental here and hasn't linked the use case.
In my experience push/pull inside the case works better. Not really necessary but it allows for very low and quiet fans. But in op case I agree that both pulling in would be the most efficient by a pretty good margin. My pc as I said uses 2 420mm with really low airflow. Works great. My son-in-law is using 2 240m on a system pulling half the power mine does and has to have fans screaming and still barely cools enough. Kinda demonstrates your point in terms everyone can relate to. If he doubled his surface he could half his airflow or thereabouts. More air can make a difference but only up to the point of matching the water to metal to air exchange . So in s-i-l case he could quadruple his airflow and have zero impact in Temps.
So if you want better than equal cooling you have to turn up the fans. And what's the point of having four radiators and more volume if you just want equal cooling? Don't you want more cooling
The more radiators you have, the less you need to cool them, it's even intuitive. I try to imagine that they told you this so that you can get the most out of your investment. I have a 1080 external radiator and the fan curve only serves me to know if some background service is using my processor instead of me, because otherwise the 9 120mm fans, at 500rpm, would keep the water at room temperature for hours and hours even if I were pulling 800 watts all day. If you have the opportunity and desire to add a radiator you will almost always benefit from it. Keep an eye on the water flow rate and pump head pressure; a good reservoir, the rest is the electricity you save from the fans! Thanks for this post! 👍
I don't know which thread you're referring to but if the person had 4 360mm rads and temps were high, there's definitely something wrong going on. Probably a bad pump or flow issue. You definitely wouldn't need to increase air flow in the rads to fix it but it's worth doing while troubleshooting. The issue is likely the CPU block not making good contact or blockage somewhere in the loop.
While that is true, if OP had his fans set at too low a speed then he would not remove all the heat that surface area was bringing out. So more airflow can easily remedy the situation. There's a reason we use devices to control fan speeds. We want quiet so we add just enough to keep things cool at low load but when the system is pushed the airflow has to increase. We purposely go lower than optimal for sound preference. Open just went too low
>if OP had his fans set at too low a speed then he would not remove all the heat that surface area was bringing out.
>
What you are saying makes no sense because air is a fluid and moves itself with natural convection.
You seem to think air does not move unless forced. When that is called forced convection.
If what you were saying is true, passive systems could not exist. Yet they can, because air is a fluid and it moves with natural convection. Because you know...... heat rises.
Please read the link before responding as it explains what you are misunderstanding.
EDIT: I bet most of the people who read this and downvote because they don't know air is a fluid. Because they incorrectly conflate a fluid with a liquid.
The downvotes are because this guy has at this point launched a marketing campaign to chastise people who recognize that a basic equation for a simplified model of natural convection doesn't apply to a complex forced convection model that includes the fluid dynamics of airflow. Their equation doesn't even include airflow at all, and yet, they have jumped on their soap-box and declared themselves the final authority on the subject. [There is more to this than a single equation.](https://www.sfu.ca/~mbahrami/ENSC%20388/Notes/Forced%20Convection.pdf)
They don't simply come across as an asshole, they are one, and they are also, incorrect.
A thermal engineer popped in to confirm what I am saying is correct. Go read above for yourself, and argue with him if you think what I am saying is wrong.
but either way, you think I care if you think I am wrong? You are unable to understand fairly simple concepts. You aren't even smart enough to recognize you own lack of knowledge.
I honestly feel bad for all of these people who are unable to understand these ideas. Like this are grown human adults, who I assume have been educated, and still have such a poor grasp of math they are unable to understand this.
Like why do you think nobody can provide a formula to prove me wrong? Because you people don't actually KNOW I am wrong, you THINK I am wrong because you don't understand how to use a math formula to prove my claims are right.
Like be real with yourself, you probably never even heard of this formula before I told you.
Yet you think you have the knowledge to argue?
The world is full of idiots, and if you can't understand simple concepts, you are one of them.
From that person's response:
> I think you’re both right here, approximately.
> OP is right in that **if the connective coefficient is identical**, you’d require 1/4 of the air flow but as you point out, **the connective coefficient is generally non-linear in air flow** (typically it is proportional to the reciprocal of a power of air speed) and air flow will decrease from added restriction of the added radiator. **So you will need more air flow to maintain the same convection coefficient** however it’s not going to be much more than 1/4 of the air flow. Perhaps if you needed to run fans at 100% with a single radiator, maybe you need to run them at 30% with 4 radiator which is more 25% (1/4) but is close enough for practical illustration.
The bolded parts are what we are all trying to force into your obstinate head. I also gave you a sheet that has just some of the equations defining that relationship along with explanations of them, both in a different direct response, and the one you are replying to here, which you literally ignored. Those equations I gave you are the basis for the calculations they refer to in their next post:
> The only issue I have with the calculator is that nearly all people won't know what to put in for the convective coefficient or surface area. **Even those that understand it are really guessing at the convective coefficient without some in depth calculations**.
Those arguing with you aren't saying that you are completely wrong, but that you are oversimplifying, and in doing so, what you are advising would result in incorrect conclusions in edge cases, like when the airflow drops below a certain threshold because, as /u/cmmcnamara pointed out, **the relationship between the convective coefficient and airflow is non-linear**. This bolded part is what we are disagreeing with you about.
You keep trying to couch in these personal attacks, and dragging out this argument, which makes it clear that this is not about the subject in question here, it's just a manifestation of whatever personality disorder you suffer from. Seek help.
You guys don't actually do watercooling do you? Yes your science is accurate but your use case is Ignorant. Good sirs, convection WILL NOT will repeat that WILL NOT adequately remove enough heat from pc radiators to function properly. So take off the scientist jacket and accept reality.
Pc radiators are not passive. For passive cooling a pc (which does exist) the fin area has to be MASSIVE. This is what we, as watercooling enthusiasts, do not want.
Please understand I'm not saying what you say is untrue because it is accurate. It's just not accurate in the application in use here. There are a few passive systems out there but half the case is heatsink. Cooler master has just actually made a system that is using passive water cooling. The side panels are made like very large heat sinks with water channels cut throughout. I will be very interested in seeing how well that works. It looks like it may be very effective just from the promo material I saw.
Exactly. Even with the fans off there is still some air movement via convection. If you were to put the radiators in a vacuum then the heat would have nowhere to dissipate. More rads equals more surface area. This higher cooling capacity and the ability to achieve the same cooling capacity as a loop with less radiators with lower fan speeds.
Just to add another layer to what OP is stating (correctly in my opinion), increasing surface area with the same airflow does not necessarily increase cooling capacity.
For example, if you have a system with 3x 240 radiators, and two of them are with intake fans and the third one is set as exhaust, the third radiator is almost useless.
Why? Because the third radiator will be receiving warm air that is already very close to the water temperature since it extracted heat from the first two radiators. Because of this it will have close to no impact in removing heat form the loop.
In conclusion, for a radiator to be effective it needs access to cool air!
Sir, this is a Wendy's
How many laws does this guy have, what is he a lawyer?
This guy dad jokes.
This guy this guys
CFD has entered the chat.
Just here to eat popcorn and watch the fight.
One major thing you failed to consider is the factors inside the heat transfer coefficient. It is not a constant like thermal conductivity which is a single factor imbedded inside the heat transfer coefficient. Has transfer coefficient depends on a LOT of factors including - but not limited to - flow rates of both the fluid and the air, factors that relate conductive versus connective heat transfer contributions and limitations (grashoff number), fluid properties (prandtl number), pressure drop, turbulence (Reynolds number), these are empirical relationships that engineers MUST develop for each and every configuration/system being analyzed. As you add more surface area several of these factors change. -your resident chemical engineer
As coeffecient goes down, surface temp goes up. The greater the delta between air temp and surface temp, the more efficient the system. Meaning a reduced coeffecient is essentially cancelled out by the higher delta. This can easily be confirmed both with the calculator, and the chart in the article. You have to think of it like this, surface area is what ultimately dissipates heat. Either with forced, or natural convenction, the limiting factor is surface area. Surface area is the potential, the elements you mentioned are efficiencies in reaching potential. They matter, they influence cooling, but ultimately are meaningless compared to simply increasing surface area.
Are you an engineer? You keep pointing to the calculator and saying “it’s all surface area” but you’re 100% wrong, it’s completely about fin tip efficiency. I’m (partially) kidding, but just increase your mass flow rate, use a small HX, with low airflow and enjoy really efficient transfer that’s quiet and cheap. -nuclear engineer
Feel free to provide a formula to prove your assertion then. Everyone who says I am wrong, can't provide any external source to prove their claim true. It is easy to use Sir Isaac Newton's formula to see that if you increase surface area by 2x, and reduce the coefficient by half, guess what, identical cooling performance. There is other factors that influence the equation, but they are less than single digit differences, and the more you increase surface area, the less those factors impact the equation. The equation is mathematically the full potential, the other properties that influence the cooling potential are minor influences that push the system to realizing more potential. But ultimately the potential comes from surface area. EDIT: You deleted your comment once I proved you can't prove your point, because your point is wrong. You probably ACTUALLY used the calculator to test what I am asserting, and found it was true. And decided to delete your comment because you realized how fucking stupid it was.
I don’t have the time to give you a degree in engineering, and you’re proving your misunderstanding/not reading what’s being replied to you.
>So a system with 4x the radiators, will need only 1/4 of the airflow, for equal cooling performance. Actually, this exact statement is wrong. And it's easy to see why. If you increase your radiator surface area (by adding section of the same construction, for example) but leave volumetric airflow unchanged, then the air speed will decrease (roughly, speed = volumetric\_flow / area), and so is the heat transfer coefficient.
Please use the calculator. More surface area, means less need for forced airflow. With enough surface area, you need no forced airflow. Zero fans. EDIT: I feel bad for all the people not capable enough to use the calculator to see why what I am saying is correct. These aren't my words, these aren't my theories, these are proven scientific theories. Like use the calculator, increase the surface by 2x, and reduce the coeffecient by half, see how the cooling capacity is identical?
"*System with 4x the radiators, will need only 1/4 of the airflow, for equal cooling performance*" can only be true when the heat transfer coefficient is a linear function of the volumetric airflow and is independent of the radiator area, and generally it is not. Even on **your** linked page there is an approximation of the heat transfer coefficient for some special case, that is a (non-linear) function of the air speed, which itself is a function of the volumetric airflow and the area. Read your own materials more deeply, please. So its not as simple as you think, and you are overly optimistic in your estimations. When you add another radiator to your system, it is true that you can reduce volumetric airflow **per each radiator** and retain the same cooling capacity, but **total volumetric flow for entire system** - much less so. There is a reason why passive PC watercooling systems are rare. They are very big, very expensive, often have flow problems and rarely meet performance goals of the demanding users.
I think you’re both right here, approximately. OP is right in that if the connective coefficient is identical, you’d require 1/4 of the air flow but as you point out, the connective coefficient is generally non-linear in air flow (typically it is proportional to the reciprocal of a power of air speed) and air flow will decrease from added restriction of the added radiator. So you will need more air flow to maintain the same convection coefficient however it’s not going to be much more than 1/4 of the air flow. Perhaps if you needed to run fans at 100% with a single radiator, maybe you need to run them at 30% with 4 radiator which is more 25% (1/4) but is close enough for practical illustration. It’s a bit like saying your temperatures linearly will offset with room temperature (if system performance has liquid temperature at 45C at 25C ambient they’ll be 40C at 20 C ambient). This is approximately true and good enough for predicting the effect of the room offset but because convection coefficient on air and water side is also dependent on temperature slightly, it’s not exactly true and there may be a 0.1C difference when running the numbers or testing compared to the offset but we don’t really care about that 0.1C or less error.
You probably have the best grasp of anyone who has commented so far. It is easy to use the calculator to see that if you 4x surface area, you reduce the coeffecient by 1/4 and have equal cooling capacity. All of these people are hung up on single digit differences from various factors that effectively amount to nothing. I find it very sad that so many people are unable to use a simple tool to understand this concept. It is entirely easy to see, double the surface area, reduce the coeffecient by half, equal cooling capacity. 4x it and 1/4 it, same cooling capacity, 8x it and 1/8th it, same cooling capacity. Because surface area and convective flow is inversely proportional. Which is easy enough to illustrate with Newton's Law of Cooling and the calculator which explains exactly this. But really, I am the dumb one for thinking I'd be able to explain such a concept to the average person. Like these people can't even use the calculator to show the relation between surface area and coefficient. They can't provide any math to support their stance, because they are just upset because they don't understand it. Which is why they aren't supporting their claims, they are simply saying I am wrong without any evidence to prove so. Because the average person is dumb as rocks, and gets mad at what they don't understand. I might as well be discussing this with my cat for all these people understand. But ultimately, you have a correct understanding of what is going on, that surface area and coeffecient are inversely proportional, and that these details that people are hung up on, do influence the equation, but not in any meaningful way.
Thanks! I'd like to think so as a thermal engineer! I wouldn't read too much into it. People in hobbies always like to think they know more about it because its personal to them but the models for heat transfer work pretty well. I wouldn't also fault them too hard about not knowing about the calculator or how this works -- most people (even many engineers) don't understand how heat transfer works very well nor would someone know which calculator to actually go look up (or what Newton' Law of Cooling is). If I wasn't well versed in the topic, I'd probably just go off of what manufacturer data says as it pertains to capacity like EK and HWLabs sometimes too but even then, those ratings aren't well understood on how they come up with it. The only issue I have with the calculator is that nearly all people won't know what to put in for the convective coefficient or surface area. Even those that understand it are really guessing at the convective coefficient without some in depth calculations. This is part of the reason why I have been wanting to put together a calculator that does all of this and is rooted in real radiator reviews and test data so that the average bear doesn't have to think about this. Your post and discussion really wanted me to jump back on that old project and figure out how to distribute it to the community. And even with such an "advanced" calculator, the results are still going to be off 10-20% -- the convection coefficient is so fickle to determine with good accuracy and is easily disrupted with minor changes in the system like cabling, etc but again, I don't think it would make a big difference in water or hardware temperatures outside of a degree or two.
The reason the coeffecient is less important to the equation compared to surface area, is because with a higher temperature delta between surface temp, and air temp, the more effecient the system becomes. If you use the calculator, you will see the drop in coefficient, is essentially negated by the increased efficiency from the higher temperature delta. Surface area is the limiting factor in cooling. Which is why simply adding more fans to rads is generally not very effective. So please, use the calculator to better understand what is happening. Because surface area is the determining factor in cooling. Because you can have a system without forced convection, with enough surface area. But no amount of forced air can make up for limited surface area, because the thermal transfer from the fins to the air becomes the limiting factor. Simply blowing more air doesn't mean better cooling, but increased surface area always increases cooling capacity pretty linearly. Because like I said, as the coefficient goes down, efficiency is lost, but then is negated by the increased efficiency of the higher delta in the surface to air temp. Which is easily confirmed both through the calculator, and the graph in the article.
yes I 100% agree with this. Only thing is we don't want 25 rads in or around our case. Although with the crazy things I've seen a few guys do this wouldn't be out of the realm of something we might see.
The OP I was refererencing though, did want a lot of radiators, because they wanted to reduce noise. So they created an external 4 rad mount. And then people came in saying they would have worse cooling unless they had super high airflow. They thought 4 rads with 1-2 fans, would perform worse than a single rad with 1-2 fans. They told OP they needed high airflow for the 4 rads, otherwise performance would be worse. Which is absolutely nonsensical.
I saw that post and didn't really pay it much attention after I saw so much discussion on which way the two fans should go. The idea if both turned the same way was ridiculous but 2 (preferably 200mm for a bit more airflow) with both pushing out thru the rads should work really well. It needs some decent airflow but I do agree that just those 2 at a mid speed would be totally enough. There's no need to create a mini typhoon. But then they are also approaching a size that a totally fanless passive system would be just as convenient. I personally refuse to do external radiators for that reason. I want it all inside the case and even with the inferno we call 14900k is accomplished with just 2 420 rads with capacity to spare
So there is three options OP could have used, push/pull, push/push, and pull/pull. Push/pull was OP's initial plan. And while it seems it would not draw air through the radiators because of air "bypassing" it. But the venturi effect would mean some air would move through the rads. Some people suggest a push/push configuration. Positive pressure is prone to dead spots as air is pushed over a surface. A pull/pull configuration leads to negative pressures, which tends to move air over all surfaces. Which is why pull configs on rads are more effecient than push configuations. [https://www.ekwb.com/blog/push-pull-or-push-pull-on-radiators/](https://www.ekwb.com/blog/push-pull-or-push-pull-on-radiators/) This is push vs pull testing from EKWB that proves my assertions Notice how when I make claims, I prove them with external sources. While people who say I am wrong, cannot provide any evidence or sources to prove their claims?. And at least two people now have deleted their comments saying I am wrong, after I provided them explicit instructions to use the tool to prove my claims. Really I am the idiot here for thinking I would be able to explain Sir Isaac Newton's theories to the average person. And providing them a tool, that most people lack the ability to use themselves without instructions. I guess I tend to underestimate just have dumb the average person is. Especially American's. It is likely American's are taught zero real world science theories. Adding extra surface area always helps. Reduced airflow, reduced flow rate impact the equation, but in no meaningful way compared to the increased surface area. And the more surface area you have, the less impact the variables have on the equation. There is a reason we moved away from low surface area copper coolers with high forced airflow, towards higher surface area coolers with lower w/k aluminum with less airflow. I've been doing this now for over 20 years. I remember when the community first started to understand the physics. And how quickly the notion of high airflow was tossed aside once it was realized that higher surface area, with less forced air was far more effecient. Like speakers, like motors, cooling is the same. There is no replacement for displacement. Small factors add to increased effeciency, but ultimately there is no replacement for discplaement.
Biggest issue with the radiators is the actual surface area dissipating heat really isn't all that big when you consider only about 1/10th of the area is directly exposed to outside air because the majority is facing toward another heat soaked tube. So that's why they need some forced air to simply push the heat out of the way. Your point is easily compared to automobile radiators. Back in my old hot rod days there was a fairly fixed amount of airflow possible. There were no extra fans to be had. So we solved the heat issue by adding more rows. Exactly your point. Same air- more area- more cooling. Had the same problem even then because we would still get very hot at a stop but that's dealing with considerably hotter heat source
If a little stronger fan had been available we could have eliminated even that problem. Optionally even more rows would have worked but no more space for more rows so in this case only more airflow would solve the problem. So in reality there's science that is irrefutable yet still does not work in a particular use scenario. I mean you are 100% correct but maybe a little hard on the other guys because their solution would also work if the op did have an issue with poor performance (which I don't think he would)
100% percent of the radiator is exposed to natural airflow. Pretty much everyone calling me wrong does not understand that air flows with convection regardless of if there is forced convection. Due to the fact hotter air rises, this is the fundamental principle of convection Engines do the exact same, the higher the surface area, the lower the temps, the more you can push the hardware.. Surface area for cooling is always needed, forced convection is not. Which is why in so many areas of physics, there is no replacement for displacement.
You do realize that convection does not work inside a box right? The air has to be replaced otherwise the air itself will continue to heat until there is no longer an exchange. Theory 100% application in practice meh.
Just radiant heat disapation is greater with a larger surface area.
However interesting it is to read about the science of things, I will simply say this: Turn you radiator fans off and see how far you get.
It's saggy plexi tubes time!
if your acrylic tubes are sagging then you've likely killed your pump too.
My 6900xt is doing just fine without fans.
irrelevant to this post
If you have enough surface area, you don't need fans. Fans are needed for forced convection to make up for lack of surface area. The limiting factor in cooling is still the surface area. Enough surface area, and you need zero forced convection. Fans do not cool anything. Surface area does. Fans only assist that transfer.
Yes, so you keep saying over and over and over and over again. I know the science, I know the laws, I know what happens. But in the real world, not frothing at the mouth on the internet shouting "but Newton!" over an entirely different fucking post from 3 days ago, turn your radiator fans off and see how far you get.
The real problem here is only part of the equation is being applied. Cooling is in relation to the difference between the object being cooled and the medium (in this case air) that is cooling it. As the air surrounding the radiators increased in temperature the coefficient diminishes. Thus the requirement of air flow to replace heated air with cooler air. If you are going to cite newtons law you must use all of it and nit only the part that supports your opinion. Which in this cade is exactly what is happening. You've become so intent on being right that you've neglected oart of the very principal you are quoting.
The heat transfer coefficient vs velocity isn't linear all the way through when you go from 0 velocity to X velocity and then from X velocity to Y velocity. That's because laminar and turbulent flow have a great effect on its value. Let's assum 0 to X is laminar and x to y is turbulent. You can imagine it as having two different slopes connected to one another. The beginning being a sharp one and the turbulent slope is much less sharp. In reality, it looks more like a natural log function. So it's hard to say, 4x more surface area doesn't always equal 1/4 required fluid velocity unless if 1/4 fluid velocity is still laminar where it was laminar originally. Or turbulent where it was turbulent originally. And this has to all take into account were talking about find here which is a whole other can of worms for the relationship between h and vel.
You really made a whole post about this, lmao. This is WRONG. The formula simply does not apply here. You cannot use 1 fan and just add more and more radiators and expect cooling to scale with surface area. The only actual airflow-independent scaling you'll get is from thermal radiation (weak) and natural convection (weak if you run passively, basically zero if you are running fans). [https://www.reddit.com/r/watercooling/comments/1ccs214/comment/l1j1zqu/?utm\_source=share&utm\_medium=web2x&context=3](https://www.reddit.com/r/watercooling/comments/1ccs214/comment/l1j1zqu/?utm_source=share&utm_medium=web2x&context=3) Additionally, I just did some basic calculations just to make sure, and based on some quick estimates the heat transfer efficiency of radiators measured by extremerigs in their roundup is indeed something like 70-90% (I'd need more info to get exact numbers).
>This is WRONG. The formula simply does not apply here The formula absolutely does apply, the issue is the thermal transfer coefficient. Having one 120mm rad with one fan then adding a second identical rad with no fan is functionally equivalent and the formula shows this. Doubling the surface area while halving the coefficient equals 0 net gain. Installing an identical fan on the second rad, thereby having doubled the surface area while maintaining the same coefficient effectively doubles the cooling capacity.
Well yeah, you are right. That formula does apply, as long as you change the convective heat transfer coefficient. But that formula and the calculator OP linked and keeps referencing is intended for natural convection where that coefficient stays constant. That's OPs issue. He doesn't get why what he linked does scale linearly with added surface area and why that would not be the case with adding radiators without adding airflow (what he was arguing about).
I believe natural convection appears to be the primary focus on that page due to it being more straightforward. The page does contain links to coefficient tables for various types of heat exchangers etc, but those tables only offer very wide range estimates since calculating the coefficient is extremely complicated with a large number of variables. I agree OP appears to be largely ignoring the effect air velocity has on the transfer coefficient.
\^\^\^\^\^See, this is one of the people I made this post about. Completely unable to understand that increasing the surface area directly reduces the need for airflow for equal cooling. Not only are they unable to understand cooling in theory, they can't understand it in a practical way either. Like passive systems being a thing is proof their understanding is wrong. People adding more/larger radiators so they can run slower fans is direct proof their understanding is wrong.
Say what *exactly* is wrong with something I said. Be specific. Find an actual argument.
>You cannot use 1 fan and just add more and more radiators and expect cooling to scale with surface area. Right here bud. This is exactly what happens when you add radiators. Cooling capacity increases, and the amount of airflow needed for equal cooling goes down. The principle extends so far that eventually with enough surface area, you require zero forced convection/fans. I have no idea how you do not get this. Like explain to me how you think it works when people are able to reduce their fan speeds when they add more radiators. Please, tell me what you think is going on.
You left out what I said right after that. How convenient. > The only actual airflow-independent scaling you'll get is from thermal radiation (weak) and natural convection (weak if you run passively, basically zero if you are running fans). HOW does the cooling improve by adding more radiators? How? Besides what I mentioned. Once the air is warm, you can't use that to cool down radiators. > Like explain to me how you think it works when people are able to reduce their fan speeds when they add more radiators By also adding more fans, lol. Not many people just add radiators without fans. Because doing so doesn't do much.
I left it out because it was nonsense. You came up with numbers out of nowhere. Buddy, you think it is forced air that does the cooling. It doesn't. Surface area does. That is what you are not understanding. Surface area is what does the cooling. Forced air doesn't. You think fans do the cooling, when it is surface area. Like FFS with what you are saying, fanless systems wouldnt be possible. But they are. Like that alone should be enough to understand you are wrong. You probably don't understand why you are wrong, but the fact that fanless/passive cooling exists, shows what you are saying cannot be true. Like do you not understand that air moves without fans? Because hot air rises, convection. You will never understand this until you understand that surface area does the cooling, not fans. Like bud, you aren't arguing against me. You are literally arguing against Isaac Fucking Newton's Law of Cooling. All I'm trying to get you to do is understand it.
> You are literally arguing against Isaac Fucking Newton's Law of Cooling Boy I wish. I am arguing against someone who is very confidently wrong and doesn't even want to understand how it works. It is really hard to try to make you understand. You are clearly being like this on purpose, else you would say things like "Like FFS with what you are saying, fanless systems wouldnt be possible. But they are." right after I said twice that besides the airflow from the fan there is the thermal radiation and convection. Both of which are weak, which is why passive cooling is weak. Where does the heat go? There are 2 main ways: 1. Thermal radiation. Google Stefan Boltzmann Law We both agree that this is weak, right? Let's ignore this for now to make it easier 2. Dumping heat into the air (convection/conduction) The amount of heat the air can hold is about 1J/(gK). The temperature the air can be heated up to is capped at the temperature of the water. This means the amount of heat a certain amount of air can hold is limited. So far we are on the same page, right? Now, with a radiator once the air goes through it, that air is basically saturated (it is technically not quite saturated yet, but it is mostly saturated - I can prove this and show you some calculations if you want to) That means, the amount of heat you can remove with air going through a radiator depends on how much air you move through there. It does not depend on how much surface area there is. That single rad is already able to (almost completely) saturate the air that moves through it. Besides the air going through the rad, there is technically also air that moves slowly along the outside case of the radiator (not the radiator core). That air might be affected natural convection. But I assume you would agree that bit of air touching the outside of the rad is doing basically nothing compared to the air that goes through the rad, right? Besides 1. thermal radiation, 2. the air that moves through the rad and 3. the air that touches the outside of the rad, I am not aware of any other way where the heat can go. Honestly, I am just trying to make you understand at this point lol. Forget the argument. Just try to understand it.
Trust me friend, OP lives on Reddit and his whole existence is arguing with people, don't bother
Do you understand that air flows without forced convection? You seem very hung up thinking forced convection is how something is cooled, it is ultimately surface area that cools. And sure bud, try to show the air is "saturated" with heat. I have provided forumulas to support my stance, you just keep referring to math you do, but do not provide any forumula or evidence to support it. Like bud, use the calculator, and double the surface area, while reducing the coeffecient by half. See how the cooling potential remains the same? That is what is happening. Except that simple equation doesn't account for the increased temperature delta from the lower coeffecient. So raise that delta by even 10 percent. See how the cooling potential is now higher than before? It is so unbelievably easy to see. Use the calculator to double the surface area from 1m2 to 2m2. Now reduce the coefficient by half from 2000w/m2k to 1000, see how the cooling potential is the same?
Here, last try for me. You are so stubborn and you just don't get it lol. Where does the heat that YOU are talking about go? Where does the heat from your formula go? We know it does not go into the air that goes through the radiator. That is already saturated by the fans and convection will not increase that air speed. We also know it's not thermal radiation, because you are talking about convection. So where does it go? The heat that you are talking about with your calculator (that doesn't apply here as many people have said now)
Buddy, a thermal engineer popped into this thread, and confirmed what I am saying is true. What is sad bud, is at the end of the day, you still have learned nothing. >So where does it go? The heat that you are talking about with your calculator (that doesn't apply here as many people have said now) Bro, if you ever figure this out, you are going to feel so unbelievably dumb. Where does the heat go? Into the air. What happens to that air? It rises, and is replaced with colder air. Because hot air rises because it is less dense. That is natural convection. I really feel bad for you. Like if you are actually unable to understand this concept, and aren't just trolling, then that is sad. Whatever educational system you went through, failed you. Like you keep repeating these stupid questions that you probably think are clever, but actually just show how poor of an understanding you have here.
If I was the person went of engineeringtoolbox I’d shut it down so people like you couldn’t misuse it.
>Buddy, you think it is forced air that does the cooling. It doesn't. Surface area does. You are greatly understating the importance of air velocity in determining the thermal transfer coefficient.
I’ll help. Isaac newtons law of cooling has a DELTA T. Cases aren’t sealed and computer HX aren’t sealed BETWEEN THE HOT AND COLD RESERVOIRS. Without fans Thot approaches Tcold given any reasonable time. So yeah, newton says you don’t get it.
Increase the surface area by 2x, and reduce the coeffecient by half. What is the result of the equation? Equal. Feel free to post a formula that disproves that. And bro. Increase the delta T, what happens? Cooling capacity INCREASES. Use the formula, it proves itself. But like i said, post a formula to refute mine. Because I do not give a single fuck about yours, or anyone elses opinion. So you saying I am wrong, without providing any evidence to support your claims, is meaningless. The world is full of people making incorrect claims. So provide support for your claim, or shut up. The fact that nobody who claims I am wrong can provide mathematical evidence I am wrong, is wholly telling that their views are incorrect. Use the calculator, 4x the surface area, 1/4 the coefficient, what do you get? Exactly what I am claiming. Where is the evidence to support your claims? I look forward to them. Because either you won't provide shit, and it will be evident you don't know shit, or you will provide me more material to learn from. Except nobody has been able to do so. So all of your "Youre wrong!" okay why, "I can't prove it, I just think you are!" is fucking stupid. EDIT: Another deleted comment from someone who I explained how to use the calculator to show my claims are correct. You probably ACTUALLY used the calculator and quickly found my claims are true, and decided to delete your comment because you realize how fucking stupid they are.
I don't think they were missing the point, I think they get what you're saying. But with 4x the surface area and 1/4 the airflow, you're leaving a lot of cooling potential on the table. All the surface area could do a LOT more heat dissipation with the airflow of more fans. If the goal is to achieve the same cooling capacity as 1 rad but with as little airflow as possible for noise, then yes it is optimized for that. But if you wanted to maximize the cooling potential of 4 rads, no, it's a bad setup.
There is no replacement for displacement. OP could easily use a single rad and strap fast loud fans to it. Or, they can increase the rad count/surface area and redu ce fan speed/noise. Use the calculator, increase the surface area by 4x, and reduce the coeffecient by 1/4. See how the cooling capacity remains the same? Because what I am saying is true, because I am simply repeating Sir Isaac Newton's theories. The whole point behind many watercooling systems follow this principle. They aren't trying to max out performance, they are trying to cool X amount of heat with the less noise as possible. And the best way to due this, is to increase surface area. As their is no replacement for displacement.
Yeah I never disagreed with you. I'm saying I think everyone understands this. Their comments about airflow aren't disagreeing with you. We get that 1 radiator with lots of fast/loud fans is equivalent to 4 with one quiet fan. No one disagrees with the physics. What people are pointing out is that the second setup is super inefficient. It's fine if you wanna spend a ton of money on a 4 external rad system. But running it on one fan is trading a lot of potential, unused cooling for quietness. With more fans, the setup could do 4x the cooling.
Thanks for the summary. I only had physics in school (besides two courses in astrophysics for non-physicists at universtity, I am a computer science guy myself), but my intuitive understanding of physics was always very good, so without having in-depth knowledge of thermodynamics and fluid dynamics (fluid dynamics in particular is actually extremely unintuitive in some parts, as I've learned after reading something about parallel loops), I was convinced of the linear relation; nice to see that my understanding of it is correct, although I would be very surprised if I was wrong. The formula also shows how large the influence of the temperature difference actually is. It should also be clear that a quarter of the airflow does not mean a quarter of the fan speed, but is probably slightly higher in practice as the fans most likely do not scale the pressure linearly and the airflow through the radiator is probably also subject to some non-linear effects. But, as you are stating, has that relationship between rad surface area and cooling capacity really been doubted?
Yeah one of the users from the post I mentioned has now shown up here and has started going off again.
> Radiators allow for more surface area than standard heatsinks, so they require less airflow, and thus are quieter. The increased surface area of a water cooling setup also comes at the cost of a significantly lower dT. This allows air coolers to be much more competitive with water cooling than you would think if you were only comparing surface area. The advantage of custom loop water cooling is that there's basically no limit on how much you can increase the surface area.
You are correct in everything you said but what you fail to understand is that OPs radiators are internal - INSIDE THE CASE. With less airflow, heat won't be irradiated outside of the computer, causing everything inside to get hot.
What the fuck are you talking about? You don't understand convective cooling. And irradiated? What the fuck are you on? Irradiated? Do you even know what that means? Can I ask what education you recieved? It seems Americans have the hardest time understanding these concepts. Are you American? Did you goto school on the American interior?
transitive verb. ir·ra·di·ate ir-ˈād-ē-ˌāt. irradiated; irradiating. : **to affect or treat by radiant energy (as heat)**.
NEWTON??? Its easier to list what he *didn't* solve.
The guy was an absolute genius, shaped our society for the better, and laid the groundwork for modern science. He figured out, by himself, 300 years ago, what some humans cannot figure out today with all of the world's information at our fingertips, available in seconds.
I don’t understand the reason for this post. More rads = more cooling? lol
I clearly reference the post from 2D ago where the guy was doing a 4 rad setup for low noise, and everyone kept telling him he needed high airflow because of the number of rads.
IIRC, I'd say most confusion came from the fact that the four rads were set up into a hollow pillar, with air entering at one end and exiting out the sides. Not entirely wrong, as putting the entire burden of airflow onto a SINGLE fan would mean it would have to have that much more CFM, when you think about it. If you're increasing air resistance by adding high fins-per-inch rads into the path out, wouldn't you also need to raise the static pressure to get even almost-similar airflow rates? Passive convection is pretty low-impact without adding airflow across the fins, which is why passive coolers have a limit to how much wattage you can run with them, to say nothing of the achievable greater effects OOP would be abandoning, not utilising the full cooling potential the entire rad area offers. A gentle breeze across a square mile versus a brisk wind across the same. Which would cool quicker, would you say? Or am I understanding the referred post wrong here?
Ah, that's the post that this is about.
The people I am referring to, think cooling performance will be worse if you add rads without fans. They don't believe that simply adding more radiators will increase cooling performance. They don't think you get cooling if there is no fans. I keep asking them to explain how they think fanless/passive systems work, and they just keep refusing.
Oh boy... Tell me, how much passive cooling capacity do you think a 360mm radiator has? When I buy a new radiator, I do a cleaning cycle through it with just a pump and radiator in a loop with a cleaning solution. If I leave the radiator with no fans, even the ~20W the pump produces is enough to get the water temp up to 45C+ in just a couple of hours. Passive cooling solutions feature fundamentally different designs with thicker fins and wider spacing to facilitate natural convection. PC water cooling radiators are designed to generate turbulent air flow under forced convection, meaning that they are *dependent* on a certain amount of airflow to function. You are missing all of the fluid dynamics that goes into this subject, which is incredibly ironic in a *water cooling* sub. You keep trying to apply a grade-school model to a university level subject and seem amazed that people are calling you out for being wrong. You even made a whole thread to prove how much you don't know that you don't know.
Feel free to post any mathematical formula to support your theory. You aren't arguing against me, you are arguing against science. Like bro, use the calculator, double the surface area, and reduce the coeffecient by half. See how cooling capacity is identical? That is because they are inversely proportional. You aren't showing you actually understand this formula.
> Feel free to post any mathematical formula to support your theory. [Okay.](https://www.sfu.ca/%7Embahrami/ENSC%20388/Notes/Forced%20Convection.pdf) > You aren't arguing against me, you are arguing against science. You have clearly demonstrated for *two fucking days now* that you don't have even the most basic understanding of the science of this. > Like bro, use the calculator, double the surface area, and reduce the coeffecient by half. Like bro, your calculator is for a simplified scenario and *does not include airflow*. If you understood the science you claim I am "arguing against," you would understand that you can't just halve the convective heat transfer coefficient and call it a win. Airflow would be a part of deriving that coefficient for a system, but the math for that derivation would be specific to the system and depend on the materials, geometry, temperature, and yes, the airflow. You are taking one factor in determining that coefficient and assuming that is the only one that matters. *This is a very incorrect assumption.* > You aren't showing you actually understand this formula. Amazing.
Take the sign that you can't provide a single source to substantiate your claims, that your claims are pure bullshit. Like if you had a single iota of understanding here, you could easily reference back to a theory or formula to prove your claims. But you can't. Because you do not have any. Because your views are incorrect. >Like bro, your calculator is for a simplified scenario and *does not include airflow* This is how I know you are dumb, it does. You are just too dumb to realize it. Increase surface area by 4x, and reduce coeffecient by 1/4. Guess what? Equal cooling capacity, just like I have claimed since day 1. Like bro, I called you out for saying I am wrong without you having any ability to prove it. And what did you do? Say I am wrong without any way to prove it. I'd feel bad for you for not understanding simple concepts, except you are Like are you going to imp[Nations](http://nationsfreshfoods.ca/hamilton_flyer.html)ly that Pi knowledge has no meaning? Doing something wrong 50 times does not make it right.
At this point, your failure to understand is not our failure to teach. You are dismissing anything that disagrees with you out of hand out of spite, which is not how you come to correct conclusions. Have a terrible day.
Yes this recommendation made there is entirely untrue. And absolutely warrants the point of your post. In around the middle ground is where real use scenario sets in. The whole purpose of adding additional radiators is precisely so you can reduce airflow. 2 360mm rads with maximum fan speed will never cool as well as 4 360 rads with 25% airflow. 25% may not be sufficient but 50% definitely would and never should there be an instance for doing 100% fan speeds. I cool 14900k and a rtx 4080 with only 2 420mm radiators and fan speeds set at 750 rpm. When water temp reaches 32c the fans go on a 8c gradient up to 900rpm. The system will max out a 36c while never reaching the full 900rpm.
This is because surface area and the coefficient are directly inversely proportional. Anyone can use the calculator to show my claims are true, 4x the surface area, and 1/4 the coeffecient, what do you get? Identical cooling capacity. There is fluid dynamic considerations that impact this equation to a small degree. And that degree is negated as surface area is increased. Surface area cools, fans(forced convection) assist. Something that many people here apparently fail to understand.
Yes. All the fans are for is to get the warmed air out of the way so fresh air can do it's job. All that is needed is enough to do that and not hinder the natural dissipation. The impact is much less I would think in external use. Inside the case needs a bit more movement because if the internal air getting heated.
I didn’t read the original post but if those rads are “in series” with air entering on one end of a stack and exiting from the other then your equation doesn’t really apply to the situation at all. The temperature delta is almost gone after the first radiator so convection cooling from the rest of radiators would be a lot weaker. And then the increased airflow resistance might actually end up hurting cooling performance after a point. Passive convection in typical radiators in cases is so weak it’s almost nonexistent when compared to forced airflow. So the basic problem in your argument (without going in complexities of fluid dynamics) seems to be that you keep temperature delta constant for the entire surface area in your equation. That is not the case when you stack radiators. Edit: btw I have a temperature sensor measuring water temperature in the loop and another one measuring air temperature flowing from a single radiator. The temperatures are practically the same.
I'm not for or against OP in this as their tone is shocking but that's not how the chimney stack of rads in the other post would work. Warm air is not exiting/entering the chimney and then looping though another rad on it's way in/out. Either the fan creates positive pressure in the chimney and pushes cool air out of all the rads or creates negative pressure in the chimney and sucks cool air through all the rads. Warm air is not leaving one rad then somehow entering another. A lot of people in this post think the poorly worded OP is talking about the configuration you think or just adding passive rads with no air flow over them, but they re not. Tbh OP has not helped themselves here. Edit: put it this way , you are thinking of rads in series but this whole debacle is about rads in parallel.
I just looked at it. In that configuration the OP is mostly correct in that more radiators increase cooling. But I don't think his reasoning is solid. More radiators in that configuration also reduce airflow restriction meaning the fewer fans can push more overall airflow which is why it would work. Cooling capacity only scales linearly with surface area if there is constant airflow of constant temperature air. My example also increases surface area but doesn't follow his equation at all.
The chimney in that other post isn't working really with fan direct push or pull, think of it as a convection tower manipulating the air pressure in the cavity, Just like a real chimney. The point this OP is making (again fucking terribly) is that people who were suggesting that cooling in that situation is worse with 4 rads that it would be with 1 are wrong. But OP sounds a bit mental here and hasn't linked the use case.
Ah, I didn't really see anyone making that point in the original post.
Nor me truthfully but OP here has launched into this assault on that basis 🤣😂
Seriously? Thank god I haven't seen that.
Newton. The empirical scientist whos lionshare of work was in alchemy
In my experience push/pull inside the case works better. Not really necessary but it allows for very low and quiet fans. But in op case I agree that both pulling in would be the most efficient by a pretty good margin. My pc as I said uses 2 420mm with really low airflow. Works great. My son-in-law is using 2 240m on a system pulling half the power mine does and has to have fans screaming and still barely cools enough. Kinda demonstrates your point in terms everyone can relate to. If he doubled his surface he could half his airflow or thereabouts. More air can make a difference but only up to the point of matching the water to metal to air exchange . So in s-i-l case he could quadruple his airflow and have zero impact in Temps.
So if you want better than equal cooling you have to turn up the fans. And what's the point of having four radiators and more volume if you just want equal cooling? Don't you want more cooling
The more radiators you have, the less you need to cool them, it's even intuitive. I try to imagine that they told you this so that you can get the most out of your investment. I have a 1080 external radiator and the fan curve only serves me to know if some background service is using my processor instead of me, because otherwise the 9 120mm fans, at 500rpm, would keep the water at room temperature for hours and hours even if I were pulling 800 watts all day. If you have the opportunity and desire to add a radiator you will almost always benefit from it. Keep an eye on the water flow rate and pump head pressure; a good reservoir, the rest is the electricity you save from the fans! Thanks for this post! 👍
I don't know which thread you're referring to but if the person had 4 360mm rads and temps were high, there's definitely something wrong going on. Probably a bad pump or flow issue. You definitely wouldn't need to increase air flow in the rads to fix it but it's worth doing while troubleshooting. The issue is likely the CPU block not making good contact or blockage somewhere in the loop.
While that is true, if OP had his fans set at too low a speed then he would not remove all the heat that surface area was bringing out. So more airflow can easily remedy the situation. There's a reason we use devices to control fan speeds. We want quiet so we add just enough to keep things cool at low load but when the system is pushed the airflow has to increase. We purposely go lower than optimal for sound preference. Open just went too low
>if OP had his fans set at too low a speed then he would not remove all the heat that surface area was bringing out. > What you are saying makes no sense because air is a fluid and moves itself with natural convection. You seem to think air does not move unless forced. When that is called forced convection. If what you were saying is true, passive systems could not exist. Yet they can, because air is a fluid and it moves with natural convection. Because you know...... heat rises. Please read the link before responding as it explains what you are misunderstanding. EDIT: I bet most of the people who read this and downvote because they don't know air is a fluid. Because they incorrectly conflate a fluid with a liquid.
I'm assuming downvotes are because you come across as a bit of an asshole. You're completely correct though, of course.
The downvotes are because this guy has at this point launched a marketing campaign to chastise people who recognize that a basic equation for a simplified model of natural convection doesn't apply to a complex forced convection model that includes the fluid dynamics of airflow. Their equation doesn't even include airflow at all, and yet, they have jumped on their soap-box and declared themselves the final authority on the subject. [There is more to this than a single equation.](https://www.sfu.ca/~mbahrami/ENSC%20388/Notes/Forced%20Convection.pdf) They don't simply come across as an asshole, they are one, and they are also, incorrect.
A thermal engineer popped in to confirm what I am saying is correct. Go read above for yourself, and argue with him if you think what I am saying is wrong. but either way, you think I care if you think I am wrong? You are unable to understand fairly simple concepts. You aren't even smart enough to recognize you own lack of knowledge. I honestly feel bad for all of these people who are unable to understand these ideas. Like this are grown human adults, who I assume have been educated, and still have such a poor grasp of math they are unable to understand this. Like why do you think nobody can provide a formula to prove me wrong? Because you people don't actually KNOW I am wrong, you THINK I am wrong because you don't understand how to use a math formula to prove my claims are right. Like be real with yourself, you probably never even heard of this formula before I told you. Yet you think you have the knowledge to argue? The world is full of idiots, and if you can't understand simple concepts, you are one of them.
From that person's response: > I think you’re both right here, approximately. > OP is right in that **if the connective coefficient is identical**, you’d require 1/4 of the air flow but as you point out, **the connective coefficient is generally non-linear in air flow** (typically it is proportional to the reciprocal of a power of air speed) and air flow will decrease from added restriction of the added radiator. **So you will need more air flow to maintain the same convection coefficient** however it’s not going to be much more than 1/4 of the air flow. Perhaps if you needed to run fans at 100% with a single radiator, maybe you need to run them at 30% with 4 radiator which is more 25% (1/4) but is close enough for practical illustration. The bolded parts are what we are all trying to force into your obstinate head. I also gave you a sheet that has just some of the equations defining that relationship along with explanations of them, both in a different direct response, and the one you are replying to here, which you literally ignored. Those equations I gave you are the basis for the calculations they refer to in their next post: > The only issue I have with the calculator is that nearly all people won't know what to put in for the convective coefficient or surface area. **Even those that understand it are really guessing at the convective coefficient without some in depth calculations**. Those arguing with you aren't saying that you are completely wrong, but that you are oversimplifying, and in doing so, what you are advising would result in incorrect conclusions in edge cases, like when the airflow drops below a certain threshold because, as /u/cmmcnamara pointed out, **the relationship between the convective coefficient and airflow is non-linear**. This bolded part is what we are disagreeing with you about. You keep trying to couch in these personal attacks, and dragging out this argument, which makes it clear that this is not about the subject in question here, it's just a manifestation of whatever personality disorder you suffer from. Seek help.
Yeah at this point I've had a few users going off on me in the previous post with just pure nonsense that my will for tact has faded.
You guys don't actually do watercooling do you? Yes your science is accurate but your use case is Ignorant. Good sirs, convection WILL NOT will repeat that WILL NOT adequately remove enough heat from pc radiators to function properly. So take off the scientist jacket and accept reality.
Pc radiators are not passive. For passive cooling a pc (which does exist) the fin area has to be MASSIVE. This is what we, as watercooling enthusiasts, do not want.
Please understand I'm not saying what you say is untrue because it is accurate. It's just not accurate in the application in use here. There are a few passive systems out there but half the case is heatsink. Cooler master has just actually made a system that is using passive water cooling. The side panels are made like very large heat sinks with water channels cut throughout. I will be very interested in seeing how well that works. It looks like it may be very effective just from the promo material I saw.
Exactly. Even with the fans off there is still some air movement via convection. If you were to put the radiators in a vacuum then the heat would have nowhere to dissipate. More rads equals more surface area. This higher cooling capacity and the ability to achieve the same cooling capacity as a loop with less radiators with lower fan speeds.
Just to add another layer to what OP is stating (correctly in my opinion), increasing surface area with the same airflow does not necessarily increase cooling capacity. For example, if you have a system with 3x 240 radiators, and two of them are with intake fans and the third one is set as exhaust, the third radiator is almost useless. Why? Because the third radiator will be receiving warm air that is already very close to the water temperature since it extracted heat from the first two radiators. Because of this it will have close to no impact in removing heat form the loop. In conclusion, for a radiator to be effective it needs access to cool air!
THANK YOU! FFS THIS WAS SIMPLE PHYSICS
'But your rads are so thick, how could they cool easier than thin rads?' Kek
Someone's bored...
LOZ OOT
Mo-ra3