HW Labs' X-Flow?

[Xylo]

Anyone got any info. on the upcoming HW Labs' X-Flow radiators beyond the very vague reference on the front page of the HW Labs website?

Specifically, when are they going to be available, how much, and what are the improvements/differences from the BIP and BIX?

hmmmm....

 

[Hard911]

maybe X-Flow is single pass radiator just like Radiical has their single pass triple fans radiator

 

[Xylo]

maybe X-Flow is single pass radiator just like Radiical has their single pass triple fans radiator

hmmm...I dunno, the info. on the site doesn't sound like that....but maybe...

 

[Top Nurse]

hmmm...I dunno, the info. on the site doesn't sound like that....but maybe...

I believe these are the single pass rads they are coming out with. Sharka told me that they ordered in a mess of them with BSPP threads on them. DD only uses NPT threads on their radiators, but HWL makes a number of different thread specs depending on customer criteria.

 

[Erasmus354]

some people need to learn to read

In this regard, HWLabs introduces the Black Ice PC Radiator® X-Flow series. These 1-pass radiators are designed for use in low-flow and low noise applications.

The Black Ice Pro® and Black Ice Xtreme® radiator platforms will now be available in the X-flow configuration allowing the power users to tune their systems for high performance and low noise.
The Black Ice X-flow radiators will be available in the US thru Danger Den (www.dangerden.com).

So there you have it, right on the front page. The X-flow are a new single pass design. Single pass designs are desireable because you can get good performance with low noise as they dont require as much pressure to get good airflow through them. The PA160 from thermochill is a single pass design as well.

 

[Cathar]

Single-pass has its drawbacks. It's not appropriate in all situations. The PA160.1 was single pass because it is also single-row. The issue with single pass is the per-tubing velocity which affects water-metal convectional efficiency. If you take what was a dual-pass radiator and blindly make it single pass it can result in a performance loss at low-moderate flow rates especially if the radiator is multiple row.

It will be interesting to see some results of these radiators in comparison to their older rads.

 

[Xylo]

some people need to learn to read

You are absolutely correct...I was looking too intently, um, "elsewhere"...
My bad.

 

[Top Nurse]

some people need to learn to read

So there you have it, right on the front page. The X-flow are a new single pass design. Single pass designs are desireable because you can get good performance with low noise as they dont require as much pressure to get good airflow through them. The PA160 from thermochill is a single pass design as well.

So does this mean that the Evo rads were really good all along? BTW, that little sentence on the HWL website about the X-Flow wasn't there the day this thread started. If you check they updated their site today.

 

[Top Nurse]

Single-pass has its drawbacks. It's not appropriate in all situations. The PA160.1 was single pass because it is also single-row. The issue with single pass is the per-tubing velocity which affects water-metal convectional efficiency. If you take what was a dual-pass radiator and blindly make it single pass it can result in a performance loss at low-moderate flow rates especially if the radiator is multiple row.

It will be interesting to see some results of these radiators in comparison to their older rads.

Glad to see you back So what you are saying is that the BI dual pass rads should be better as one pass designs as they use multiple flat tubes as opposed to what kind of radiator that uses mutiple rows? Or are you calling a BI series rad a multiple row? How would you get less of a water to tube ratio? In a dual pass the water makes a "U" shaped path, correct? So if you go to a single pass then you should have approximately the same amount of tube because the total length of travel is halved, but you have twice as many tubes. So why would their be a difference?

 

[BillA]

Single-pass has its drawbacks. It's not appropriate in all situations. The PA160.1 was single pass because it is also single-row. The issue with single pass is the per-tubing velocity which affects water-metal convectional efficiency. If you take what was a dual-pass radiator and blindly make it single pass it can result in a performance loss at low-moderate flow rates especially if the radiator is multiple row.

It will be interesting to see some results of these radiators in comparison to their older rads.

ain't gonna be good; been there, done that
more interesting will be the marketing
I'm reminded of the 'high flow' wb craze where high flow itself became the goal (rather than the reduced convection coefficient)
- apparently your post was not understood either
lol

 

[Cathar]

Glad to see you back So what you are saying is that the BI dual pass rads should be better as one pass designs as they use multiple flat tubes as opposed to what kind of radiator that uses mutiple rows? Or are you calling a BI series rad a multiple row? How would you get less of a water to tube ratio? In a dual pass the water makes a "U" shaped path, correct? So if you go to a single pass then you should have approximately the same amount of tube because the total length of travel is halved, but you have twice as many tubes. So why would their be a difference?

Okay, a row of tubes, being a parallel row of tubes from one side of the radiator to the other. Imagine it as being like a slice of bread, with tubes running from one end to the other. A single-row radiator is like a single slice of bread. A dual-row radiator is like two slices of bread together.

In a single-pass (cross-flow) radiator the water flows from the inlet at one end, once straight through all the tubes, in all the slices, and to the outlet in the diagonally opposite corner to the inlet.

In a dual-pass radiator the water flows down one half-side of all slices, U-turns, and back up the other half-side of all the slices.

Single-pass benefits because it presents all the tubes with the highest possible water temperature at once, whereas a two-pass radiator will only the highest temperature inlet water on one side, and then cool slightly cooler water up the other side. This doesn't make a huge difference though. Generally it provides a 1-15% performance benefit from this effect alone.

Where single pass falls down though is the tubing velocity. Because the water is presented to all the tubes at once, the water velocity through the tubes is half of what it is through a dual-pass radiator. Increased water-velocity increases water turbulence, which in turn increases the ability of the water to pass the heat that's stored within it into the metal walls of the tubes that its flowing through.

If you now suddenly halve the water velocity by mading a dual-pass radiator into a single pass radiator, you will lose the heat transfer benefit being provided by the higher water velocity through the tubes.

This effect can be seen in terms of radiator heat dissipation based upon changing just the water flow rate alone. eg.

As the flow rate (and hence water velocity in the tubes) goes down, so does the radiator performance start to fall away. With a single-pass you've gone and halved the water velocity in one hit. This is offset somewhat by the temperature delta benefit of single-pass, but it is by no means a sure thing that single pass will be better.

Looking at that graph, if we made the HE120.1 into a single pass radiator and our flow rate was 5LPM, then by halving the water velocity with some moderate fans we can see that we'll lose up to 20% convectional efficiency performance. Sure, we gained a bit by going single pass, but we lost a lot due to the per-tube velocity drop.

If our flow rate was 12lpm though, then we only lose ~10%, and maybe (just maybe) single pass might be a better option. Don't know too many people with 12lpm running through their loops though. The HE120.1 is a dual-core radiator too, so this example highlights how turning the HE120.1 into a single pass radiator would quite likely be a bad idea.

Now that is just a single (simplistic) example to express what I mean. Ideally such graphs need to be generated for each radiator to make predictions on what's going to happen by going single-pass, but as you can see, it's not a "sure thing". Blindly going single-pass is much like BillA said, people who blindly go high-flow without understanding what they're really trying to achieve. A misguided marketing goal here will drive radiator performance backwards.

 

[Top Nurse]

Okay so say a car radiator is a typical multi tube single pass radiator. This is because there are usually two to three tubes per slice correct? So a BI series rad is a typical dual pass radiator correct? And the Aqua Computer Evo rads are what you would call single pass radiators because the water comes in one end travels back and forth in one tube or is it called something else? Since the Evo rad has a high velocity or pressure of water relative to the flow, due to it's design, why do people say that it isn't very efficient?

So if someone wants to redesign their radiator from a dual pass to a single pass they would have to reduce the size of the tubes and make more of them correct? This would be so that they keep the water velocity and turbulence up while still maintaining the same flow?

 

[Xylo]

BTW, that little sentence on the HWL website about the X-Flow wasn't there the day this thread started. If you check they updated their site today.

You maybe I wasn't quite as incompetent?...heh.

 

[Top Nurse]

You maybe I wasn't quite as incompetent?...heh.

Absolutely, because the day this thread started I went to the HWL site and it wasn't there.

 

[Cathar]

Okay so say a car radiator is a typical multi tube single pass radiator. This is because there are usually two to three tubes per slice correct? So a BI series rad is a typical dual pass radiator correct? And the Aqua Computer Evo rads are what you would call single pass radiators because the water comes in one end travels back and forth in one tube or is it called something else? Since the Evo rad has a high velocity or pressure of water relative to the flow, due to it's design, why do people say that it isn't very efficient?

The Aqua Computer Evo radiators are coiled copper tubing designs. They are used most frequently in conditions that require high pressures, such as refrigeration condensors. While the coiled tube is great for operating well under low-flow conditions, it is bulky and consumes up a lot of the body of the finned area in comparison to a heater-core style radiator. Additionally, the spacing between the tubes and the fins in the coiled tube radiators makes for a less than optimal setup with respect to the conduction distance.

I suppose a good analogy is that while the looping tube style radiators are good for liquid-metal heat transfer, they are generally far less efficient at metal-air heat transfer when given the same space and size constraints. Heater-core style radiators come close to as good as it gets for metal-air efficiency, and provided you give them sufficient flow rate for their internal design (single pass, multi-pass, whatever) the liquid-metal efficiency can be as good as the looping tube style radiators. Heater-cores fall down though more quickly at lower flow rates than the looping tube style radiators. Given the historically low flow rates that occur in Teutonic systems, the looping tube style radiators make a fair degree of sense.

It's a case of horses for courses. Looping tube can work better at very-low-flow rates, while heater-cores tend to work better at low-moderate flow rates and higher.

So if someone wants to redesign their radiator from a dual pass to a single pass they would have to reduce the size of the tubes and make more of them correct? This would be so that they keep the water velocity and turbulence up while still maintaining the same flow?

The problem here is costs. Heater-core radiators are cheap because they leverage off commonly available components from the car industry. Once you start doing things like custom tube sizes and other custom tweaks that move away from what's commonly available, costs will go up quite quickly, and to be honest, there's probably not a lot to gain in terms of performance. Heater-core style radiators are very efficient items when working well. It tends to more be a case of trying not to lose performance while you're mucking about with building custom ones.

Have to remember that the water-cooling market, in terms of radiators, enjoys its privilege almost solely to the car market. The water-cooling market would be totally different if there were not as much commonality between cars and computers for heat transfer.

 

[BillA]

very nice posts Cathar, your patience is incredible

TN
I have some comparative rad data of different types, Gabe may post it in a week or two as a white paper
- continous tube are the 'worst' as compared to flat tube and corrugated plate (heater core)