I am not sure what to title this...

[Malpine Walis]

Perhaps it ought to be "How not to answer a question"

Several days ago, I posted three questions regarding heat sources (apart from the parts I will be cooling) in a water cooling set up. I learned a bit of useful information but never really heard answers to the questions which I asked.

I did get quite a bit of fallacious nonsense which was presented as real science. some of the points that (failed to) impress me the most include:

Water flow is the same thing as heat. The faster the water is moving the hotter it is.

Originally posted by BBigJ On the most basic level, heat is just the kinetic energy of molecules, the faster molecules move, the hotter the substance is. But this is exactly what your pump is doing. It is making the water molecules move faster (but it is making them all move in the same direction.) The end result is that [B]a 20 watt submersible pump will heat the water exactly the same amount as a 20 watt heating element placed in the water

Friction does not exist. Since water flow is heat, the reduction of flow when a pump is connected to other componenets in a WC system does not have any bearing on the first law of thermodynamics.

[QUOTE]Originally posted by BBigJ You have asked repeatedly about friction. Friction does not make the water hotter.

All pumps put all of thier energy into the water as heat.

[QUOTE]Originally posted by BBigJ The end result is that [B]a 20 watt submersible pump will heat the water exactly the same amount as a 20 watt heating element placed in the water

All of this not withstanding, I would like to hear something which will help me build my water cooling system.

So the new questions are:

1) Elbows, long runs of hose and other flow restrictions slow the flow of coolant. How might I calculate how much a reduction in coolant flow changes the temperature of the water?

2) A high flow rate generally means better cooling. what can I do to maximize the flow rate through a system? Larger ID hoses? Shorter hoses? Teflon lined tygon?

3) As flow rate increases, will I see diminishing returns in my cooling?

[Mizzery]

Although i've never done a watercooling system, i do know that the shorter the run, the less lift (height the pump must pump the water up), the straighter the piping and the wider the piping the better. There is friction in water. A lot less than your foot on the ground, but deffinately will add up after a distance. The shorter the run and the less curves and the larger the pipe the less friction, the more flow rate.
The more your pump has to fight gravity, the more it has to work. Although technically in a closed loop system the gravity should equal out. So I guess this would only really apply to tall bongs cooling setups which i'm not sure if you're doing. Hope that helped.

[000]

I'm assuming your using a radiator and asking these questions about an ambient system.

1) it would be hard to calculate this because you would need to know exactly how much heat your radiator will remove (which you generally don't know before getting it, and can vary pretty wildly depending on size,fan,materials,volume,etc)

2) Optimally the shortest amount of tubing possible with the least amount of bending, the biggest inner diameter for tubing and fittings you can find, possibly using a 2000 series tygon tubing (because they are non polar, making the water travel through them much easier)

3) Yes, you asymptotically get closer and closer to ambient

[Brant]

Originally posted by BBigJ The end result is that [B]a 20 watt submersible pump will heat the water exactly the same amount as a 20 watt heating element placed in the water

I cant believe someone tried to feed you that nonsence.

If all of the energy from the pump went to heating the water, what makes the water move/accelerate/overcome friction.

1) dont try to calculate that, it is way too complicated and wont tell you anything.

2)yes, better pump.

3)Flow rate shouldnt make that much differnece. But higher flow rate is better

At a slow flow rate the water has more time to pick up heat and give off heat, however as the temp of the water increases it is harder for the water to accept more heat. So if the water has less time to pick up heat with a high slow rate, eash molecule will pick up less but does so easier and more molecules pass buy to pick up heat every second. Higher flow rate is better.

I hope you can understand my babble

[BBigJ]

If you had continued to read the thread, you would have discovered that the "fallacious nonsense" was proven experimentally by two independent sources.

[Spartacus51]

I unfortunately am not an expert in any of the fields related to a question like this, so take any and all conclusions from this with a grain of salt.

I will try to draw from the experts though.

1. To your third question... A while back in Hoot's waterblock showdown he showed that flow in a well designed waterblock is not overly significant. The high and low flow gemini blocks scored very close.

2. Aesik and BillA could certainly answer your question better, and do so using all sorts of terms I can't remember. One thing that is important to remember in cooling though is turbulent flow. I'm almost positive both of them would back me on this, the largest contributer to turbulent flow is velocity. I think somewhere around 130 GPH (again, that could be miles from the truth) you're almost gauranteed turbulent flow. (as would be supported by #1)

3. Calculating flow is difficult. There's a variety of contributing factors, and it seems you already know most of them.
Certainly it can be done mathematically. Assuming you know all the resistances, all the cross sectional areas etc. etc. I believe someone did come up with a way to determine it using a little bit of creative deconstruction and reconstruction of a fan, along with some simple wiring.

4. You picked the right things to increase flow rate... short hoses, high quality, high flow hoses, bigger cross sectional area (larger diameter) and so on. It may cost more, but in the end it may also mean better performance. One other tip, any turns you do have make, make with an elbow rather than bending and possibly kinking the tube.

Finally a bit of suggest reading... if that's not enough follow the link at the bottom of the first article.

http://overclockers.com/articles599/

http://overclockers.com/articles511/

[Brant]

Originally posted by BBigJ
If you had continued to read the thread, you would have discovered that the "fallacious nonsense" was proven experimentally by two independent sources.

You must me misunderstanding the independent sorces results. Impossible for all the energy to be heat.

[adamtekh]

but energy is heat , thats basic yo

[Brant]

Originally posted by adamtekh
but energy is heat , thats basic yo


Energy isnt heat, heat is a form of energy.

[adamtekh]

pssssssssss............ with out heat u have absolout zero :argue:

[Brant]

yep

[CharlesHF]

Originally posted by adamtekh
pssssssssss............ with out heat u have absolout zero :argue:

That's entirely right, but I believe that you need to check out some info before making these statements.
Like Brant said, heat is one of many forms of energy. (mechanical, electrical, etc)



And, I'm agreeing with Brant about the heat energy statement. It's completely impossibly---the electrical energy is mostly converted into mechanical energy that turns the impellor. The friction of the moving parts and the heat from some of the electricty is what is transferred into heat energy.

[Christensen]

Malpine Walis--try to remember that this forum is made up of a lot of knowledgable people, but very few experts. To find out an answer to a question, usually you have to take a concensus of what everyone posts and find out what the most common answer is--usually this will be the correct one. We're all learning here --that's what makes this forum fun!

[tcl]

Here is a reply i made some time ago answering why pump heats water. Perhaps it might clear things up a bit here. The whole thread can be found here:
http://forum.oc-forums.com/vb/showthread.php?s=&threadid=75856

I think that most of the heat you are seeing added to the system from an inline pump is not really from the pump, per se. It is from the pump, but not how you would think: So, a 20 watt pump (about what the mj1200 is, i think) loses some energy to resistance in the wiring of the pump (the coils, etc) and this will make the pump a bit wrm to the touch. I imagine it is wasting only a couple watts this way. SO, ask yourself where the other 18 watts or so are going. Well, they are of course being used to move the water. Now, for simplicity, pretend your pump is just pumping water from a bucket through your water block, into another bucket. If there is no hose on the system, the mj1200 will pump 1200 liters/hr. However, if there is twenty feet of hose between bucket A and bucket B, the water "rubbing" the side of the tube for the twenty feet will logically slow it down considerably. Nothing suprising here. So, the water entering the hose at bucket A has an energy eqivalent to its velocity of 1200 liters/hr and the water exiting the tube has a velocity of, let's say 120 liters/ hr and consequently a tenth the energy. the rest of the energy was turned to heat by friction and is now in the water and hose. OK, so the pump adds energy to the water by accelerating it, then this velocity is turned to heat as friction slows the water. The above is simplified of course.