Mid range pumps VS high volume pumps

[Kosmic]

I've beend doing a lot of forum searching and reading, and haven't been able to find a thread about this. I know that a powerful pump is needed to overcome head pressure and that no pump will actually move water as fast as it is rated to do in a closed system.

As I think about water flowing through my eventual water cooling system, when the water goes through the radiator it gets to go through a fun little cooling ride to strip out the heat and I'm thinking that if it goes through the radiator TOO fast that it might not have all the heat possible removed from it.

I think a 230 GPH pump (I'm eying a maxi jet 900) would really be a strong enough pump, even given that it won't actually move the water that fast.

So let's hear some debate...mid range pumps VS the HUGE volume pumps. Which do YOU prefer, and why?

K1

 

[ToTalXS]

certainly

I agree that the water will only move as fast as the system will let it reguardless of the pump.....you cant force 500gph through a system that allows 200...........

 

[SaT985]

actualy there are a couple of threads that cover this, you have to sift through alot to find em though. been reading these last few days, gettin ready for my watercooling. I think a 300gph pump would be about right. that is if you plan on doing chipset/vid card along with it. 1/2" tubing would be a givin. you've got say 2' of tubing for res-block then 18" from block-radiator, then another 2' back to the res. so you'd be looking at about 5-6' that the water would have to move for a complete cycle.

http://www.marinedepot.com/a_ph_danner.asp?CartId=

^ got that from another thread that i found while searching. Its a chart of the danner mag pumps and how much water they move at certain distances. very useful.

at 5-6ft your gonna be moving 180-210gph. so if you cool chipset, cpu, and gpu then that'd be about 65gph each, if you used same diamete tubing for all of em. I'd say a gallon a minute is about right, wouldn't you.

 

[Pepsi]

There is a good guide to this for free. It has all the math to figure things like flow velocity and friction loss, head loss via lift. It's mainly geared for pvc, but the math is still the same. Go to www.harvel.com and order their product bulletin part #L3. Like I said though it's geared for pvc, but it might help you out.
Stay Cool
Pepsi

 

[Barryng]

http://forum.oc-forums.com/vb/showthread.php?s=&threadid=78055

This topic was discussed extensively in the recent thread above.

Bottom Line: More Flow through a heat exchanger gives better cooling without exception. The idea that slowing down the flow will allow the water to get slighty colder or hotter is true but this is done at the expensive of a reduced flow rate. The mass flow rate dominates so the total heat transfered will be less.

Put another way, low flow rates cause the average temperature of the water to get closer to the temperature of either the heat source (water block) or air (radiator). This means the average Delta T between the two sides of the heat exchanger is smaller. The bigger the Delta T, the faster heat/energy is exchanged. It is the Delta T that is the "driving head" for heat transfer. It is better to have a larger Delta T for faster energy transfer and a lot mass of flow to continue to bring new water into the heat exchanger.

BTW, bigger pumps add to the heat load on the system. Therefore, if a high flow is achieved via a huge pump, the pump heat might negate the efficiency gained by the increased flow rate.

I hope the moderators will consider making the thread referenced above a sticky because this topic continues to surface.

 

[Kosmic]

Thanks for the link to the thread I was wanting to find, RhoXS! And thanks for the other very useful links, Pepsi and SaT985. I knew it had to already be discussed extensively on the board, I was just not finding it.

K1