Series and Parallel

bob_folkerts · 09-06-2001, 10:54 PM

I have been looking at the various posts and it seems that cooling blocks are usually connected in parallel so that the flow rates through all blocks will sum to the flow through the pump.

Does anyone run components in series? The 'downstream' components will get water warmed by the previous componnents, but all components will see the full flow rate.

What are the experiences of the readers on this?

In order to understand the trade offs of series and parallel configurations, a knowledge of the the pump's flow rate at different pressures would be helpful. Has anyone found flow-rate vs. pressure curves for the pumps?

Spinoza · 09-07-2001, 12:22 AM

I'm actually about to put two althons under two dangerden blocks. I have them set up in series. If the performance is really bad or something. I might try reworking it to parallel. I have an Ehiem 1250 pump. I am not sure of it's exactly pressure rating, but it's a fairly large pump and move a lot of water. here is a pic of my series setup. Don't mind those super long wires from the NMB power supply.... grrrr

I am figuring that the pump moves the water fast enough as to make much of difference in the temp from one block to the other... I hope I'm right, as I would like to get these chips up to 1.5Ghz or so.

jtroutma · 09-07-2001, 01:19 AM

According to the sources I asked about that very same question; series is mostly better than parrallel. (some exceptions apply)

Reason: resistance differences.

Take my system for example: I have all 3/8" parts (except my radiator which is 1/2") and I am cooling a CPU waterblock and a chipset waterblock using the same pump. IF I were to put the two blocks in parrallel, one block my have a smaller resistance on the waterflow and thus that block would get more volume. (Water is like electricity; it takes the shortest/simplist path).

Again back to my setup; say my CPU waterblock has more resistance than my chipset waterblock (less turns). That would mean (in theory, of course

that the chipset waterblock would get more waterflow than my CPU waterblock. NOW that would not be ideal because my chipset (EVEN with a pelter) gives off no more than 50W where my CPU is currently giving off more like 100+W and my CPU would get MUCH hotter due to less waterflow.

If I remember correctly, you are planing on useing two IDENTICAL waterblocks to cool two IDENTICAL CPUs using the same pump. In that situation IMHO sounds like parrallel would not be such a bad idea since the resistance SHOULD be the same (probably should check that) BUT add any other component (say GPU cooler) put that in series.

Hope that this helps you out.
Good luck.

redleader · 09-07-2001, 03:37 PM

I wanted to have my GPU blobk in series with my CPU. Compared to the CPU, my GeForce is an ice cube so it just made more sense to not dick around with balancing flow rates in a paralelle system.

At least it should have, but today when I got home I saw that DangerDen had shipped me the wrong waterblock

LiquidCool · 09-08-2001, 01:35 AM

If your running a high flow system (300GPH+) with decent flowing blocks and rad then daisy chaining shouldn't hurt much. The water will only heat up 1C-2C at most when leaving the first block which could come out to be 3C-5C Difference in temps. As long as your not trying to get 1.7Ghz out of them it should be ok.

I personally would run them in parralel with a high flow pump.

09-06-2001, 10:54 PM	#1
bob_folkerts Cooling Neophyte Join Date: Aug 2001 Location: Marion, Iowa Posts: 8	Series and Parallel I have been looking at the various posts and it seems that cooling blocks are usually connected in parallel so that the flow rates through all blocks will sum to the flow through the pump. Does anyone run components in series? The 'downstream' components will get water warmed by the previous componnents, but all components will see the full flow rate. What are the experiences of the readers on this? In order to understand the trade offs of series and parallel configurations, a knowledge of the the pump's flow rate at different pressures would be helpful. Has anyone found flow-rate vs. pressure curves for the pumps?

09-07-2001, 12:22 AM	#2
Spinoza Cooling Neophyte Join Date: Jun 2001 Location: Upstate NY Posts: 42	I'm actually about to put two althons under two dangerden blocks. I have them set up in series. If the performance is really bad or something. I might try reworking it to parallel. I have an Ehiem 1250 pump. I am not sure of it's exactly pressure rating, but it's a fairly large pump and move a lot of water. here is a pic of my series setup. Don't mind those super long wires from the NMB power supply.... grrrr I am figuring that the pump moves the water fast enough as to make much of difference in the temp from one block to the other... I hope I'm right, as I would like to get these chips up to 1.5Ghz or so. __________________ Thunder K7 Athlon 1800's Danger Den/Ehiem to cool jig of RAM http://www.cs.oswego.edu/~vito/complete.jpg

09-07-2001, 01:19 AM	#3
jtroutma Cooling Savant Join Date: Aug 2001 Location: SLO, CA Posts: 837	According to the sources I asked about that very same question; series is mostly better than parrallel. (some exceptions apply) Reason: resistance differences. Take my system for example: I have all 3/8" parts (except my radiator which is 1/2") and I am cooling a CPU waterblock and a chipset waterblock using the same pump. IF I were to put the two blocks in parrallel, one block my have a smaller resistance on the waterflow and thus that block would get more volume. (Water is like electricity; it takes the shortest/simplist path). Again back to my setup; say my CPU waterblock has more resistance than my chipset waterblock (less turns). That would mean (in theory, of course that the chipset waterblock would get more waterflow than my CPU waterblock. NOW that would not be ideal because my chipset (EVEN with a pelter) gives off no more than 50W where my CPU is currently giving off more like 100+W and my CPU would get MUCH hotter due to less waterflow. If I remember correctly, you are planing on useing two IDENTICAL waterblocks to cool two IDENTICAL CPUs using the same pump. In that situation IMHO sounds like parrallel would not be such a bad idea since the resistance SHOULD be the same (probably should check that) BUT add any other component (say GPU cooler) put that in series. Hope that this helps you out. Good luck. __________________ Athlon64 X2 4200+ @ 2.5Ghz (250FSB x 10) OCZ VX 1GB 4000 @ 250FSB (6-2-2-2 timmings) DFI LANParty nForce4 Ultra-D SCSI Raid 5 x (3) Cheetah 15K HDDs LSI Express 500 (128MB cache) OCZ PowerStream 520W PSU ATI X850XT PE (Stock) DTEK WhiteWater + DTEK Custom Radiator Eheim 1250

09-07-2001, 03:37 PM	#4
redleader Thermophile Join Date: Jun 2001 Location: The deserts of Tucson, Az Posts: 1,264	I wanted to have my GPU blobk in series with my CPU. Compared to the CPU, my GeForce is an ice cube so it just made more sense to not dick around with balancing flow rates in a paralelle system. At least it should have, but today when I got home I saw that DangerDen had shipped me the wrong waterblock

09-08-2001, 01:35 AM	#5
LiquidCool Cooling Savant Join Date: Apr 2001 Location: Central Florida Posts: 231	If your running a high flow system (300GPH+) with decent flowing blocks and rad then daisy chaining shouldn't hurt much. The water will only heat up 1C-2C at most when leaving the first block which could come out to be 3C-5C Difference in temps. As long as your not trying to get 1.7Ghz out of them it should be ok. I personally would run them in parralel with a high flow pump.

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