no, only temperature sources are allowed.

I make no sense a to control a output flow dependent.

You mean it makes no sense to control a pump based on a flow it controls, in order to hit a target flow rate? Isn't that the entire point of an automatic controller? How is that different from controlling a fan to achieve a target temperature, which is impacted by that fan speed?

@Electrocutor: Please don't get me wrong, I think your loop design is very impressive and I'm sure you would find a coolant flow dependant output as you describe very useful. I would also say though that your setup is far too elaborate for what most people would find necessary to get decent cooling out of their system. It doesn't make much sense from a manufacturing/development cost point of view to add a feature to the Aquaero that 0.1% of users would benefit from. Again, I'm not poo-pooing your system and loop design, but for my tastes it seems an overly complex solution to achieve the purpose it was designed for where something much simpler could probably achieve at least 90% of the cooling performance your loop is capable of. Out of interest, could you post some pics of your system? I'd love to see how you've connected it all

@Traches: Flow is only a measure of the speed of a substance through a particular medium and is expressed in volume/minute (e.g.) The flow rate of the coolant through your loop or the flow rate of air through your fans. You wouldn't be able to control the pump speed via the coolant flow rate measured by the Aquaero because the coolant flow rate is determined by the pump speed in the first place. Similarly, if you could measure the air flow rate through a fan with the Aquaero, you wouldn't be able to control the fan speed by its air flow rate because the air flow is a result of the fan spinning in the first place.
The difference between the two in a PC watercooling setup is that the air flow of fans is able to impact coolant temperature (via thermal dissipation through the radiator) much more than the coolant flow of the pump. The impact of coolant flow rate on coolant temperature is insignificant (less than 1C) compared to the impact of air flow from fans on coolant temperature. An output controller for coolant flow rate would therefore be useless for most Aquaero users. If you want to set a target coolant flow rate you can already do it by adjusting the pump speed with a constant value controller in Aquasuite. If you want the coolant flow rate to go up and down then set the pump to be controlled by a temperature output, but, if we understand that coolant flow rate doesn't greatly impact on coolant temps anyway, why would you want the coolant flow rate to vary?

Zitat von »cc01«

You wouldn't be able to control the pump speed via the coolant flow rate measured by the Aquaero because the coolant flow rate is determined by the pump speed in the first place.

????? That makes no sense. Your car probably has a cruise control system, right? Think of your cruise control as the aquaero. Think of your speedometer as the flow meter. Think of your carburetor as the pump. In your car....the cruise control (the aquero) monitors how fast the car is going (the flow rate), based on the speedometer readings (the flowmeter readings) and adjusts how much gas to give the carburetor (the pump) so that the speed of the car (the flow rate) goes up or down to a desired level. The speed of the car (the flow rate) is determined by the flow of gas to the carburetor (the pump speed)....but we can still use the speed of the car (the flow rate) to adjust how much gas the carburetor is going to get (pump speed)....right? I find the above statement illogical.

Zitat von »cc01«

The difference between the two in a PC watercooling setup is that the air flow of fans is able to impact coolant temperature (via thermal dissipation through the radiator) much more than the coolant flow of the pump. The impact of coolant flow rate on coolant temperature is insignificant (less than 1C) compared to the impact of air flow from fans on coolant temperature. An output controller for coolant flow rate would therefore be useless for most Aquaero users. If you want to set a target coolant flow rate you can already do it by adjusting the pump speed with a constant value controller in Aquasuite. If you want the coolant flow rate to go up and down then set the pump to be controlled by a temperature output, but, if we understand that coolant flow rate doesn't greatly impact on coolant temps anyway, why would you want the coolant flow rate to vary?

I think we should first clarify that impacting your "coolant temps" are not the ultimate goal here. The ultimate goal is to reduce CPU or GPU temps. Your statement that "coolant flow rate doesn't greatly impact coolant temps" is typically correct. But you should be much more concerned with your CPU/GPU temps, than your coolant temps and/or the water/air delta. Radiator fans are not removing ANY heat from the CPU or GPU, or whatever you happen to be cooling. The radiator fans only remove heat that has already been transferred to the coolant in your loop, and then moved to the radiators. So how does the heat get from your CPU or GPU into the loop in the first place? Flow of the coolant. It's the flow of the coolant that removes heat from your CPU or GPU. I think the myth that flow rate doesn't matter comes from the fact that most liquid cooling loops used to consist of a single radiator. Heck...most testers still use just a single radiator. When you don't have a lot of radiator space, its easy for the coolant to heat up enough so that it becomes less effective in removing heat from the CPU/GPU. But it is becoming more and more common to have 3, 4 or even 5 radiators in a box. When you start getting this much radiator space....the heat is spread over a much larger surface, and it doesn't take as much in fan speed to remove that heat from the coolant. The coolant stays cooler. In a system like this, with lots of radiator space, the flow rate can have just as big an impact on CPU/GPU temps as the fan speed. In a recent build on OCN, the user proved that varying the pump speed from 30% to 100%....decreased CPU temps by about 2.5c, when holding fan speed steady. That is a significant decrease for anybody. He achieved about the same impact on CPU temps when adjusting the fans from 30% to 100%, and holding pump speed steady.

I'm not trying to pick on your statements, and apologize if it sounds that way. Just working on correcting what I think is an outdated notion with regards to the flow rate. Flow rate impacts temperatures, and is important....if you have plenty of radiator space. Flow rate is less important if you don't have much radiator space.

I think I did mention that FOR MOST PEOPLE this is not even a consideration. Minimal performance gains for a lot of outlay and extra components etc is not what the average user cares much about. The gain is INSIGNIFICANT compared to what they have to do to their system. Most watercoolers don't have 3 or more radiators and cases the size of a desk to fit them into and as such the sort of feature being proposed for the Aquaero in this thread is esoteric rather than useful, which is all I was trying to point out.

Zitat von »cc01«

I think I did mention that FOR MOST PEOPLE this is not even a consideration. Minimal performance gains for a lot of outlay and extra components etc is not what the average user cares much about. The gain is INSIGNIFICANT compared to what they have to do to their system. Most watercoolers don't have 3 or more radiators and cases the size of a desk to fit them into and as such the sort of feature being proposed for the Aquaero in this thread is esoteric rather than useful, which is all I was trying to point out.

Your "for most people" qualification related to the complexity of the loop design shown by the previous poster. I was not referring to that statement.

I was trying to correct the false idea that if would be impossible to control the speed of a pump or fan....based on the flow rate or air pressure it produces. Of course you could do that. And there would of course also be useful real world examples of why you would want to do this. And the examples do not have to include the complex loop design that the previous poster had shown. I was also trying to correct the outdated notion that flow rate has an insignificant impact on temperatures. It depends on the radiator setup. And 3 or more radiators is becoming much more common than it used to be. Especially for users who are willing to purchase a monitoring system as expensive as the Aquaero. It looks to me like the previous poster was showing 6 radiators in his loop. So for him....I'd say flow rate would be something important to monitor and will have a significant impact on his temperatures.

But again...I'm not trying to argue with you...and will be moving on. Take care.

@cpachris: Monitoring flow rate is different to controlling flow rate. The only way to control flow rate through a pump is by altering the pump speed and the only way to control the pump speed is to regulate the voltage applied to it. Regulating the voltage can be controlled according to a change in temperature in the coolant, for example. By using flow rate as an ouput to control voltage applied to the pump to alter its speed in the same way as temperature, you are essentially trying to say that you are changing the flow rate according to a change in the flow rate. It makes no sense logically or physically. The analogy of acceleration control in a car you have used is confused and confusing. I think we should clarify what the coolant flow rate is.

It is a problem with language and I am just as guilty of it as most people when it comes to describing their PC watercooling systems. People get lazy in describing things, as I have, or they don't bother to find out exactly how a word or an expression relates to the properties of the thing it describes. I am no expert on fluid dynamics and it is my mistake that I used the expression ‘measure of the SPEED of a substance …’ when I should have written it is ‘measure of HOW MUCH of a substance…’, but they are related. Let us go on then a bit more precisely:

*The FLOW is how fast or specifically the velocity of that substance (a fluid) is travelling through the loop at a particular point (metres/second). It is not what the Aquaero or the AC Flowmeters measure.

*The FLOW RATE is the VOLUME or amount of fluid passing through a loop over a given time (metres cubed/second).

*The ‘speed of the pump’ is also one of those vague expressions. This is the FREQUENCY of the pump (Hz) often expressed in REVOLUTIONS per MINUTE (r/min) and is a measure of the rotational speed of the pump or the frequency of rotation.

*The diameter of the tubing at any given point in the loop will affect the properties of FLOW and FLOW RATE at that point, but not the FREQUENCY of the pump. (ie) The pump frequency is only dependent on the amount of VOLTAGE you apply to it through your Aquaero device.

*The amount of coolant in your loop is a constant. You have x litres. If you vary the diameter of the pipe the liquid is travelling through, such as at a waterblock or a radiator, you will also affect the flow at that given point but the TOTAL FLOW RATE for a loop is always the same. You cannot have, for example 100 l/min at the beginning of your loop and only 40 l/min at the end of your loop. This would go against the conservation of energy. Inflow EQUALS outflow.

*The TOTAL FLOW RATE, (ie) the amount of liquid passing through the inlet/outlet of the pump is determined by the speed or FREQUENCY at which the particular pump is operating. In other words, the coolant FLOW RATE for your entire loop is dependent on the speed (Hz) of the pump, not vice versa.

Electrocutor’s dilemma is not about controlling a pump via flow rate but about ensuring the properties of the pumps he uses do not allow the problem of ‘negative flow’. It is not so much as negative flow but ‘zero flow’ and this occurs when the pump is not operating at sufficient speed in order to maintain a minimum pressure at the outlet of the pump. Understanding pump head and pressure characteristics is more important to him than flow rates. Employing some pressure sensors would be of greater use in finding out exactly how fast his pumps need to spin under given circumstances. But we would need to know a lot about his pumps, the individual pump curve characteristics, pump head, pressure inside his loops and so on before we can determine the sweet spot of maximum efficiency of operation.

@Electrocutor: If you removed the two pumps just before the radiators and placed a pump on your recirculator tube instead, controlling it via temperature inside the second reservoir so that it kicks in only when needed, would that help simplify your problems with the loop? You would eliminate the use of one pump (and the heat it generates) and with a bit of fiddling and testing you could determine roughly the minimum your other pumps would need to operate so you don’t get zero flow in the waterblock sections of the loop when the recirculator pump kicks in. If you haven’t already done so and you are really intent, then it might be an idea for you to look up the ‘Affinity Laws’ concerning centrifugal pumps. Again, I’m not saying your setup is wrong or bad. I think it is extremely impressive, however, a complex system where fluid dynamics is concerned generally demands complex solutions and flow rates are not your solution.

@cpachris:
PS: 'air pressure' is not the same physical property as 'air flow rate'.
PPS: 'Heat' is not removed from the CPU or GPU by the flow or movement of coolant across the block. Temperatures on the hardware are lowered by thermal transfer between the materials in contact with each other. The movement of the liquid or air across the material allows you to achieve a higher rate of thermal dissipation (ie) temperatures will be lowered more quickly, but not a higher rate of thermal transfer, which is related to the Specific Heat Capacity of the material.

What we could ultimately learn from this is not who is right or wrong, but the need to learn the language specific to the science it is describing. I am no expert on fluid dynamics or thermodynamics, nor am I a scientist, and it has taken me a while to get my head around the terminology describing pump and fluid behaviour.
It is not useful for most of us to describe what we are seeing to our colleagues online in our cooling loops by using the specific mathematical formulae that describe it because most of us don't have the necessary mathematical skill or understanding. Unfortunately I sound like a smartarse with all of this but ultimately what it all boils down to is science. I have so often seen the terms, flow, flow rate, speed, speed of flow, pressure etc. used interchangeably in online forums as if there were no thought given or difference as to the property they describe, or the relationship between these properties. This is confusing and it propagates misinformation across the ‘net. The best place, even in this digital age, for learning about scientific principles is the old fashioned textbook, not user forums on a product website. Why not learn the specific terms and what they relate to and how they are related to each other and describe the processes and problems we are actually seeing in our cooling loops rather than offering misunderstanding as knowledge or confusing analogies, such as the example with cars above? The solution to any problem might present itself more easily if we learned how to properly describe the problem.
This also applies to the terminology of heat exchange and to oxidation, which are both physical processes that are necessary considerations in the building of a PC cooling loop. Fortunately manufacturers have dealt with most of the science for us and we can take their products and simply ‘put them in’ and expect a good result in ‘performance’.
In one of the worst examples I have seen of recent times that confused an entire physical process and blamed solely the particular branded product for being faulty is the explanation that these particular waterblocks corroded readily because of the quality of the plating alone, not because of the simple fact that the plating is a metal and when in contact with oxygen it will naturally corrode anyway without the use of corrosion inhibitors, irrespective of the brand of waterblock. All metals do this and the assumption and strong assertion by a large number of online contributors that your cooling loop will be fine with only distilled water and a kill coil, without the use of corrosion inhibitors and as long as you don’t use waterblock xxx was false and misleading and in my opinion designed to harm the brand.
Another misleading example which was posted on a leading computer technology review website was that premixed branded coolants keep temperatures lower in a cooling loop than distilled water. No liquid on earth will have a specific heat that competes with water in your PC cooling loop. If you consider that premixed coolants probably contain 90% water it makes no sense of the website to publish such rubbish information unless there is another motive to do so, which is usually in most instances economic and to the benefit of sales for the coolant manufacturers. Personally I prefer the use of premixed as it takes the guesswork out for me but the example illustrates a point in that the use of language can make such a big difference to understanding, which is why we need to be clear about our how we use it in the first place.
I’m sorry that this is so lengthy, but I can’t write it in any less. The problem of Language.

This will definitely be my last post in this thread, because its deteriorating.

Zitat von »cc01«

@cpachris: Monitoring flow rate is different to controlling flow rate. The only way to control flow rate through a pump is by altering the pump speed and the only way to control the pump speed is to regulate the voltage applied to it. Regulating the voltage can be controlled according to a change in temperature in the coolant, for example. By using flow rate as an ouput to control voltage applied to the pump to alter its speed in the same way as temperature, you are essentially trying to say that you are changing the flow rate according to a change in the flow rate. It makes no sense logically or physically. The analogy of acceleration control in a car you have used is confused and confusing.

I'll try one more time, but you clearly are not understanding what I'm saying, or just can't conceptualize it. Yes, monitoring is different than controlling....but you can do both. I'm not saying that I'm "changing flow rate according to a change in flow rate", as you state above. I'm saying that I'm deciding whether or not to change the voltage applied to a pump, based on what the current flow rate is. Assume for minute that I have a flow sensor hooked up, that returns a value of 2.0 gpm as an output to the aquaero. If I know that I don't get any real benefit once the flow rate exceeds 1.5 gpm, then I would set a curve controller that starts to decrease the voltage fed to the pump once the flow rate exceeds 1.5 gpm. The curve controller would probably start at 100% power, and stay there until the flow rate exceeded 1.5 gpm, and then would start a downward slope. So if the flow meter returned a 2.0 value...the aquaero would then start to undervolt the pump. When the pump gets undervolted, the flow rate will start to decrease. So depending on how steep you make the downward slope of the controller curve....the aquero will end up adjusting the flow rate back down somewhere close to the 1.5 gpm where the downward slope of the curve started. And yes...the aquaero CAN CONTROL the flow rate...because it CAN CONTROL how much voltage the pump gets....which CAN CONTROL how fast the pump spins....WHICH DOES impact the flow rate.

And if you'll take some time to absorb the cruise control on a car example, you'll see that it does make sense. The car monitors how fast its going, and then adjusts how much gas its going to give the engine if that speed was different than its target. Its no different with the flow rate and pump voltage. If I monitor the flow rate of the coolant, I can use that value to adjust how much voltage the pump gets....which then impacts the flow rate. I can monitor....and control. It makes sense logically, and physically. It you think about it, I'm sure you'll get it.

Could you accomplish the same thing by just manually adjusting the pump voltage until you reach your desired flow rate? Sure. But then you would have to do that everytime you have a change in your loop (i.e., different block, change in loop design, new fittings, etc. ) If you could use the flow rate to adjust the pump voltage....it would end up adjusting automatically for you after any such changes. And that is really what the idea of computerized control of fans and/or pumps is all about in the first place, ....right?

Zitat von »cc01«

@cpachris:
PPS: 'Heat' is not removed from the CPU or GPU by the flow or movement of coolant across the block. Temperatures on the hardware are lowered by thermal transfer between the materials in contact with each other. The movement of the liquid or air across the material allows you to achieve a higher rate of thermal dissipation (ie) temperatures will be lowered more quickly, but not a higher rate of thermal transfer, which is related to the Specific Heat Capacity of the material.

By "removed", I of course mean moving it away from the component. If you are relying only on thermal transfer...its no better than having a large heat sink. We are talking about water cooling, so the whole point is using the coolant to move the heat to the radiators, so there is a larger surface area with which to dissipate the heat.

I'm going to bow out of this thread, but I'll repeat the main points I tried to make in the first place:

- Yes...you can, both logically and physically, use the monitored flow rate...to adjust and control the flow rate. And I understand Electrocutor's desire to be able to do so.
- The impact of flow rate is not insignificant on temperatures for people who have plenty of radiator space

Yes, I'm getting out of this thread too.