Coolermaster Dual Storm

[Xtian]

The purpose of the design of Colermaster Dual Storm
is to center the airflow to the hotspot on the CPU
heatsink.
In a traditional heatsing (withouth heatpipes) the
base of the heatsink (usually copper) spread the
heat from the very small spot on the processor that
generate the heat, to a larger area which then is
cooled by numerous fins.
A traditional fan have very little airflow at its
center, meaning its cooling power is worst at the
center of the heatsink where the heat dissapation
is the greatest - not on optimal solution of course.

So now comes Colermaster Dual storm that by the use
of two fans compresses and center the airflow to the
center - GREAT !!

THG decided to test this new invention but in a, imo,
very wierd way.
Instead of useing the fan with a traditional heatsink
that would most likely take the biggest advantage of
the new technology, they use a heatpipe heatsink.
The great thing with heatpipe heatsinks is that the
heat from the hotspot is distributed much more evenly
to the heatsink fins. A heatpipe heatsink design does
not really get much advantage having the airflow
concentrated at the center, they could in fact
perform worse than with a traditional fan.

Why on earth didn't THG test this with a variety of
heatsinks, including the traditional simple copper
plate based heatsink with many colling fins ?
That should definitely be where this technology
would gain most.

Can someone at THG point explain who the only tested
this new fan technology where it logically would
perform worst?

Ignorance?

I'm no expert, just a happy amateur with countless
hours of testing heatsinks and fans efficiency.

Is the rewiever at THG incompetent or am I just having
a bad brain day?

What does the rest of you HSF freaks out there think?

//Xtian

I woke up one morning, and then that day was ruined.

 

[haggy]

Ja, I had similar thoughts regarding the review.

 

[Raider73]

Mostly same thoughts about the article, but i have doubts about this "compression". If you read the article you will notice that the cooler works better when running at low speed. Consider this you push less cool air through the heatsink and the cooler works better. In my Opinion this can only be explained by the disturbance in the airflow, caused by the two fan working in different directions. If there was some point in this new "technology of air compression" one would this that if you increase the speed of the fans you would also increase the "compression" and thous the cooling efficency. But no you only get a lot of noise from the disturbance of the airflow and get inferior cooling result. In my opinion this cooler wants to bait the customer to buy it becaue it has this "new" technology. Imo THG wasnt critical enough in this review.

 

[fishmahn]

I agree, I don't think it's the compression.

I'm not an airflow specialist (but a little basic physics application led me here)... but I think the reason it worked so well at low speed is because of air deflection.

Basically, in a single stage fan, the blade strikes an air molecule and that molecule wants to move in a straight line based on the angle of deflection and speed of the blade. That means it will move down (in the case of a cpu fan) and off to the side - tangentially to the axis of rotation.

Now it's more complex than that because you have to take into account the other molecules that impede it and the tunnel effect of the shroud, but keeping it simple...

This means that the airflow is down and at an angle aiming slightly outward from the fan (angled in the direction of the fan's rotation. That means that some of the air is not going to hit the bottom of the HS because it moved outside the area of the fan. (making another assumption - the hs is the same diameter as the fan)

Add a second, counterrotating fan just below the first, and the airflow is deflected to be more centered straight down. If the second fan blades are shaped properly, it can also reduce the dead zone just below the fan hub by deflecting the air towards the center (slightly).

Did that make sense without pictures?

Mike.

 

[Crashman]

I have news for you: A one-piece heatsink with fins running all the way to the baseplate does NOT benefit from a heat pipe. And if you disaggree, it proves you're not thinking.

The purpose of a heatpipe is to move heat from a hot place to a cool place. The fluid condenses at the cool place and flows back to the hot place. In order for a heatpipe to work, there has to be a large enough temperature difference between the cold part and hot part to allow the phase change to occur.

If the fins go all the way to the base, you have a traditional sink. The heat pipe is moving heat less efficiently than the solid conductor (the fins). But because the fins are so large, the heat pipe doesn't have a negative impact NOR a positive impact, rather it's just there for looks.

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[poindexter]

I agree that the review was limited and uninformative. They should have used a conventional heat sink with fins and not a heat pipe style. I also don't know of any heat pipe systems that contain a liquid that changes states. The OEM touted "compression" between the two fans: this was never tested. Are we needing an upgrade in lab equipment at THG? Perhaps a trip to the local HVAC supply store for a water manometer is in order. This gauge measures extremely low pressures [approximating here: 1psi=2"Hg=7"H2O]. It seems the basic design of the fan is lacking: there's a stator section missing between the two rotating fans. There isn't enough room here to explain the complex physics of how air flows through stacked rotating fans but the results clearly point to a flow problem. Also, fans are not supposed to cool off the center of the sink, this is what the fins are for. The sink is responsible for giving the heat generated by the cpu somewhere to go that's not as hot-this being the thick metal base of the sink. The fan is there to aid in removing the heat from the fins, not the base. It's important to remember that heat will move to a cooler area so by cooling the fins with airflow the heat entering the sink at the base has somewhere to go. Heat can be transferred by three methods; conduction, convection and radiation. Conduction requires direct contact for heat transfer, convection is via airflow and radiation is through infrared light emissions.

 

[Crashman]

d00d, that's how a heatpipe is supposed to work, phase change cooling. You know those giant cooling towers at nuclear plants? Same concept, the evaporate rizes, condenses, settles to the bottom. That's exactly the way those heatpipes in SFF boxes worked, but then again, those were REAL, functional heatpipes, put there to work, not just look good.

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[poindexter]

What you are implying is that a heat pipe is partially filled with some liquid and that the liquid boils from the heat of the cpu and that this liquid changes to a vapor that condenses back into a liquid, so can you tell me what fluid is used? What are it's physical properties? Boiling point? Heat of vaporization? Specific gravity? Or is this some secret?

 

[Crashman]

The last guy I saw build one used R134A. As you know, boiling point depends on pressure, pressure changes with heat, and AC technicians go by weight. He determined the volume of coolant he wanted and had that weight added to his heat pipe, after having it evacuated, then sealed it under that pressure with the fluid inside. Due to the volume of the pipes, it operated with a very small change in temperature for a moderate change in heat output, within the range the thing was designed for.

Heat pipe designers have to know the amount of heat a processor will output and design the unit for a certain range, to get optimal results. In his case, the base of the heatpipe would heat rapidly to 38C, then slowly progress towards 45C as heat output was increased.

And you know how heat output is increased, by increasing the voltage/frequency/stress on the CPU.

Basically the nature of heat pipes allows them to act like a water cooler, but using evaporation/condensation rather than a pump. Some companies add a wick to the heat pipe so it can be laid on it's side, and the wick draws the fluid up to the evaporator. IMO this is far less efficient than purely gravity fed pipes.

You also know that the choice of coolant can be made by the manufacturer, while this home builder used R134A because of it's availability, there are many other coolants used in industry.

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[Crashman]

BTW, you asked about boilding point, the guy I described must have (either by design or coincidence) designed his to boil at base pressure at 38C. Of course increasing heat increases pressure, hence it climbed anyway, but likely on a curve.

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