Overclock.net › Forums › Cooling › Water Cooling › Someone clarifies what if one of two pumps in parallel doesn't work?
New Posts  All Forums:Forum Nav:

Someone clarifies what if one of two pumps in parallel doesn't work? - Page 2

post #11 of 19
This is exactly why parallel pumps is a bad idea. I plan to test this in the future, but pumps are very low in restriction when off, so a MAJORITY of the flow would recycle rather than push through the loop. Not all of it, but I would guess you loose a good 90% or more.

Because our loops are generally high in restriction, series pumps is the way to go for performance anyhow. Add to that the fact that if one dies, you still get 100% of one pump working (Redundancy) and series is the clear winner. Also no need for expensive Y fittings in series...just run another pump somewhere in the loop.
    
CPUMotherboardGraphicsRAM
3930K ASrock X79 Ext7 Evga GTX570 CORSAIR Vengeance 16GB 
Hard DriveOptical DriveOSMonitor
Phoenix SSD+2TB Seagate drives ASUS DVD-RW combo Windows 7 28" Hanns-G HZ281 
KeyboardPowerCaseMouse
MS Natural Corsair TX650 Danger Den Torture Rack Logitech MX518 
Mouse Pad
Desk 
  hide details  
Reply
    
CPUMotherboardGraphicsRAM
3930K ASrock X79 Ext7 Evga GTX570 CORSAIR Vengeance 16GB 
Hard DriveOptical DriveOSMonitor
Phoenix SSD+2TB Seagate drives ASUS DVD-RW combo Windows 7 28" Hanns-G HZ281 
KeyboardPowerCaseMouse
MS Natural Corsair TX650 Danger Den Torture Rack Logitech MX518 
Mouse Pad
Desk 
  hide details  
Reply
post #12 of 19
Quote:
Originally Posted by Martinm210 View Post
This is exactly why parallel pumps is a bad idea. I plan to test this in the future, but pumps are very low in restriction when off, so a MAJORITY of the flow would recycle rather than push through the loop. Not all of it, but I would guess you loose a good 90% or more.

Because our loops are generally high in restriction, series pumps is the way to go for performance anyhow. Add to that the fact that if one dies, you still get 100% of one pump working (Redundancy) and series is the clear winner. Also no need for expensive Y fittings in series...just run another pump somewhere in the loop.
However, it is said
Dual D5 should be set in series because of its low headpresure
and dual DDC should be placed in parallel because of its low flow rate
post #13 of 19
Quote:
Originally Posted by c14c13 View Post
However, it is said
Dual D5 should be set in series because of its low headpresure
and dual DDC should be placed in parallel because of its low flow rate
Still doesn't work like that.

As you try to push more flow through the loop it will present more restriction. It is the pressure that overcomes restriction, not the flow rate. Best way I can describe it is graphically:



OK, so this is just a sample, not to any kind of scale and I might be a bit off with the parallel pumps, but you get the idea. Increasing the maximum flow of the pump will not result in much more loop flow rate. Increasing the pressure of the pumps will increase the flow rate.

Parallel doubles the maximum flow rate when there is no restriction. In a loop it will actually not improve things much (theoretically). I look forward to seeing what the results of Martin's testing are.

Edit: So yes, if the loop restriction was really low then parallel would be the way to go. But they tend not to be, as soon as you throw a GPU / CPU block in there the restriction goes up to the point where serial pumps are a better option.

Edited by GingerJohn - 4/25/11 at 5:06pm
Main
(21 items)
 
HTPC
(10 items)
 
 
CPUMotherboardGraphicsRAM
i5 2550k P8P67 Pro Sapphire HD 7950 G.Skill RipJaws X 1600 Cas 9 
Hard DriveHard DriveHard DriveCooling
Corsair Force 120 WD Blue 500GB WD Caviar Green 1TB XSPC RayStorm 
CoolingCoolingCoolingCooling
RX240 MCR 220 EK 7950 Copper Acetal  DDC-1T 
OSMonitorMonitorKeyboard
Windows 7 64-bit Dell U2311H Oculus Rift DK2 Ducky Shine 3 MX Brown 
PowerCaseMouseAudio
Corsair TX 750W CoolerMaster CM690 II G500 Klipsch ProMedia 2.1 
Audio
Asus Xonar DX 
CPUMotherboardRAMHard Drive
A10-6800K Gigabyte GA-F2A85XN-WIFI G Skill 1600 CAS9 Kingston SSD Now 60GB 
Hard DriveOptical DriveCoolingOS
WD Caviar Blue 1TB LG Slim Blu-Ray player Silverstone NT06-PRO  Widows 7 Home Premium 
PowerCase
Silverstone Sfx Series ST45SF 450W Silverstone SG05 
  hide details  
Reply
Main
(21 items)
 
HTPC
(10 items)
 
 
CPUMotherboardGraphicsRAM
i5 2550k P8P67 Pro Sapphire HD 7950 G.Skill RipJaws X 1600 Cas 9 
Hard DriveHard DriveHard DriveCooling
Corsair Force 120 WD Blue 500GB WD Caviar Green 1TB XSPC RayStorm 
CoolingCoolingCoolingCooling
RX240 MCR 220 EK 7950 Copper Acetal  DDC-1T 
OSMonitorMonitorKeyboard
Windows 7 64-bit Dell U2311H Oculus Rift DK2 Ducky Shine 3 MX Brown 
PowerCaseMouseAudio
Corsair TX 750W CoolerMaster CM690 II G500 Klipsch ProMedia 2.1 
Audio
Asus Xonar DX 
CPUMotherboardRAMHard Drive
A10-6800K Gigabyte GA-F2A85XN-WIFI G Skill 1600 CAS9 Kingston SSD Now 60GB 
Hard DriveOptical DriveCoolingOS
WD Caviar Blue 1TB LG Slim Blu-Ray player Silverstone NT06-PRO  Widows 7 Home Premium 
PowerCase
Silverstone Sfx Series ST45SF 450W Silverstone SG05 
  hide details  
Reply
post #14 of 19
GingerJohn, thank you.
"Parallel doubles the maximum flow rate when there is no restriction."
How about
If 2 pumps are in series and there is absolutely no restriction in the loop, what will happen to the flow rate? Same as single pump?
post #15 of 19
Quote:
Originally Posted by c14c13 View Post
GingerJohn, thank you.
"Parallel doubles the maximum flow rate when there is no restriction."
How about
If 2 pumps are in series and there is absolutely no restriction in the loop, what will happen to the flow rate? Same as single pump?
Yup, thats what that image shows.

No restriction series is more or less the same as a single, it'll be a tiny bit more, but neglible (Basically ur X-intercept)

Lots of restriction/little flow (Basically ur Y-intercept) the parallel and the single will flow the same, where as the series will do better.
post #16 of 19
Quote:
Originally Posted by c14c13 View Post
However, it is said
Dual D5 should be set in series because of its low headpresure
and dual DDC should be placed in parallel because of its low flow rate
No, that's not right. There is some validity to the curves being more flow vs head pressure oriented, but you'll still typically see series performing better than parallel. Only in EXTREMELY low restriction conditions will parallel perform better in which case you don't need two pumps anyhow.

Similar to GJs graph, this is one I worked up a while back to show what happens in theory. In actual practice there will be some minor losses with the setups due to fittings and tubing interconnecting the pump, but it will be somewhat like this:



So sure, technically parallel can be better under the EXTREME low restriction condition, but one pump is already providing over 3 GPM...two pumps is a waste in that condition. Two in series under high restriction is where you might consider two pump in which case that will be under the high restriction condition where series is better.
Edited by Martinm210 - 4/25/11 at 5:45pm
    
CPUMotherboardGraphicsRAM
3930K ASrock X79 Ext7 Evga GTX570 CORSAIR Vengeance 16GB 
Hard DriveOptical DriveOSMonitor
Phoenix SSD+2TB Seagate drives ASUS DVD-RW combo Windows 7 28" Hanns-G HZ281 
KeyboardPowerCaseMouse
MS Natural Corsair TX650 Danger Den Torture Rack Logitech MX518 
Mouse Pad
Desk 
  hide details  
Reply
    
CPUMotherboardGraphicsRAM
3930K ASrock X79 Ext7 Evga GTX570 CORSAIR Vengeance 16GB 
Hard DriveOptical DriveOSMonitor
Phoenix SSD+2TB Seagate drives ASUS DVD-RW combo Windows 7 28" Hanns-G HZ281 
KeyboardPowerCaseMouse
MS Natural Corsair TX650 Danger Den Torture Rack Logitech MX518 
Mouse Pad
Desk 
  hide details  
Reply
post #17 of 19
Quote:
Originally Posted by Martinm210 View Post
Similar to GJs graph, this is one I worked up a while back to show what happens in theory.
Similar, but much much better. I just sketched mine quickly, no actual numbers involved, always good to know that someone agrees with me.

I would be really interested in what your testing comes up with though, theory and practice have a nasty habit of disagreeing sometimes.

+rep for an actual graph!
Main
(21 items)
 
HTPC
(10 items)
 
 
CPUMotherboardGraphicsRAM
i5 2550k P8P67 Pro Sapphire HD 7950 G.Skill RipJaws X 1600 Cas 9 
Hard DriveHard DriveHard DriveCooling
Corsair Force 120 WD Blue 500GB WD Caviar Green 1TB XSPC RayStorm 
CoolingCoolingCoolingCooling
RX240 MCR 220 EK 7950 Copper Acetal  DDC-1T 
OSMonitorMonitorKeyboard
Windows 7 64-bit Dell U2311H Oculus Rift DK2 Ducky Shine 3 MX Brown 
PowerCaseMouseAudio
Corsair TX 750W CoolerMaster CM690 II G500 Klipsch ProMedia 2.1 
Audio
Asus Xonar DX 
CPUMotherboardRAMHard Drive
A10-6800K Gigabyte GA-F2A85XN-WIFI G Skill 1600 CAS9 Kingston SSD Now 60GB 
Hard DriveOptical DriveCoolingOS
WD Caviar Blue 1TB LG Slim Blu-Ray player Silverstone NT06-PRO  Widows 7 Home Premium 
PowerCase
Silverstone Sfx Series ST45SF 450W Silverstone SG05 
  hide details  
Reply
Main
(21 items)
 
HTPC
(10 items)
 
 
CPUMotherboardGraphicsRAM
i5 2550k P8P67 Pro Sapphire HD 7950 G.Skill RipJaws X 1600 Cas 9 
Hard DriveHard DriveHard DriveCooling
Corsair Force 120 WD Blue 500GB WD Caviar Green 1TB XSPC RayStorm 
CoolingCoolingCoolingCooling
RX240 MCR 220 EK 7950 Copper Acetal  DDC-1T 
OSMonitorMonitorKeyboard
Windows 7 64-bit Dell U2311H Oculus Rift DK2 Ducky Shine 3 MX Brown 
PowerCaseMouseAudio
Corsair TX 750W CoolerMaster CM690 II G500 Klipsch ProMedia 2.1 
Audio
Asus Xonar DX 
CPUMotherboardRAMHard Drive
A10-6800K Gigabyte GA-F2A85XN-WIFI G Skill 1600 CAS9 Kingston SSD Now 60GB 
Hard DriveOptical DriveCoolingOS
WD Caviar Blue 1TB LG Slim Blu-Ray player Silverstone NT06-PRO  Widows 7 Home Premium 
PowerCase
Silverstone Sfx Series ST45SF 450W Silverstone SG05 
  hide details  
Reply
post #18 of 19
Quote:
Originally Posted by GingerJohn View Post
Similar, but much much better. I just sketched mine quickly, no actual numbers involved, always good to know that someone agrees with me.

I would be really interested in what your testing comes up with though, theory and practice have a nasty habit of disagreeing sometimes.

+rep for an actual graph!
It's next on my list. I was thinking about testing elbow effects on pumps, but this parallel vs series has been a nagging question for a while too.

Will do, should be available by the end of the weekend..
    
CPUMotherboardGraphicsRAM
3930K ASrock X79 Ext7 Evga GTX570 CORSAIR Vengeance 16GB 
Hard DriveOptical DriveOSMonitor
Phoenix SSD+2TB Seagate drives ASUS DVD-RW combo Windows 7 28" Hanns-G HZ281 
KeyboardPowerCaseMouse
MS Natural Corsair TX650 Danger Den Torture Rack Logitech MX518 
Mouse Pad
Desk 
  hide details  
Reply
    
CPUMotherboardGraphicsRAM
3930K ASrock X79 Ext7 Evga GTX570 CORSAIR Vengeance 16GB 
Hard DriveOptical DriveOSMonitor
Phoenix SSD+2TB Seagate drives ASUS DVD-RW combo Windows 7 28" Hanns-G HZ281 
KeyboardPowerCaseMouse
MS Natural Corsair TX650 Danger Den Torture Rack Logitech MX518 
Mouse Pad
Desk 
  hide details  
Reply
post #19 of 19
+10000 rep to Martinm210 and GingerJohn
New Posts  All Forums:Forum Nav:
  Return Home
  Back to Forum: Water Cooling
Overclock.net › Forums › Cooling › Water Cooling › Someone clarifies what if one of two pumps in parallel doesn't work?