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Inline or Submerssible pumps.??

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waldaize

Registered
Joined
Feb 28, 2001
I have a feeling that everyone has their personal choice.
But what's the pro's and con's of both.

And what do people feel is best for an internal watercooling system?
 

Big Lar

Senior Member
Joined
Dec 16, 2000
I use and like the Submersible pumps, I believe depending on the setup tho, that the inline is more efficient.
 

surlyjoe

Senior Member
Joined
Dec 27, 2000
Location
far west
inline pums are easier to service and can be used for closed loop systes, but sub's are nice if you have a res cause they save space and are water cooled !
 

Colin

Arctic Silver Senior
Joined
Dec 19, 2000
Retailers like submersible pumps because they are cheap (more profit margin) and easy for the user to install. Run a submersible pump modified for inline use, and you will be amazed how much heat it puts out. That heat goes diminishes the cooling ability of your system if you run it submersed. Design the system right, and an inline pump is the only choice. Why compromise?

Retailers like submersible pumps because they are cheap and easy for the user to install.
 

Richard

Senior Member
Joined
Jan 15, 2001
It's probably not a good idea to use a converted sub pump - inline.

You may very well be shortening the life expectency of the pump by running it hot 24/7. Even inline pumps when used in their intended purpose will be submerged in water. (The water source is just from a "clean" source. Eliminating the need for filters, etc.)

Granted, there are inline pumps that are designed to fulfill a variety of tasks. Eheims ring a bell.

Point is, there isn't a lot of data on watercooling. I may be completely wrong. However, I'd rather not be the guinea pig.

FWIW, the primary reason I'm building a sub rig is for safety purposes. It's my personal opinion that the reservoir solution offers more advantages than the disadvantage of adding a small amount of heat. (2) Rio 180 pumps. Note: These are very low power consumption pumps and combined still put out less heat than many others.

Colin (Mar 04, 2001 09:48 p.m.):
Retailers like submersible pumps because they are cheap (more profit margin) and easy for the user to install. Run a submersible pump modified for inline use, and you will be amazed how much heat it puts out. That heat goes diminishes the cooling ability of your system if you run it submersed. Design the system right, and an inline pump is the only choice. Why compromise?

Retailers like submersible pumps because they are cheap and easy for the user to install.
 

surlyjoe

Senior Member
Joined
Dec 27, 2000
Location
far west
any pump will produce heat ,it's a matter of whether u want it radiating off of an inline pumps housing into your case ,or raiating into the water on the way to the RAD to be cooled down ,personally I use only 1 fan on the rad. so I dont want any extra heat in the case
 

Colin

Arctic Silver Senior
Joined
Dec 19, 2000
My example of a submersible pump being run inline was just to expose the heat output. I have played with Rio submersible pumps running in an inline configuration. They get hot. If I want to cool the CPU, I don’t want that heat going into that closed system. A little extra heat in the case from an inline pump is nowhere near what the CPU with an air cooled HS would generate. Just have some good airflow in the case. It’s a lot easier to cool an inline pump and your case than it is to cool your CPU. Run an inline pump and scrounge up an extra case fan.

As far as 24/7 durability goes, I live in central Kalifornia. It gets really hot here in the summer. The Koi Pond people I deal with for Nursery Pro pumps tell me they run for several years without failure. The Danner, Ehiem and Nursery Pro pumps look the same to me. Koi Country says the Nursery Pro is the best. These guys have been in business a long time and know what they are doing. I believe them on the durability issue. As far as Nursery Pro goes, maybe I just bought their line of BS.
 

Newbie_Doo

Admin Parent
Joined
Jan 6, 2001
Location
Stafford, Virginia USA
I agree that there are two schools on this:

School 1 has an inline pump (with ratings as high as 500GPH!) moving a relatively small amount of coolant through the system. School 1 requires a very efficient radiator, as the thermal capacity is proportional to the amount of transfer medium (coolant) used. So they cycle a little water many more times through the system in a given period. By using greater flow, they compensate for lack of overall system capacity.

School 2 has a submerged pump in a reservoir moving a relatively large amount of coolant through the system. School 2 has an overall thermal capacity that is greater than School 1, but uses some of that capacity to rid itself of heat generated by the pump. By having a larger supply of coolant available, the heat load takes longer to increase base temperature of the coolant, but also takes longer to cool. This provides a measure of temperature stability for the system but at the potential cost of slightly higher temps (0-2C) depending on the radiator's efficiency and dissipation characteristics.

So which is better? If you have the room, I prefer the submerged pump with adequate flow (50 GPH actual, not rated) and a large reservoir. If you have a small case, use an inline pump and be diligent with your leak monitoring. The pump's seals will eventually fail.

BTW, I am using a submerged system with a large radiator and reservoir, so you may consider me biased towards that. In fact, I bought a larger case because I need the room for the cooling system. I designed the system and then shopped for the case. Most people do it the other way around.
 

Colin

Arctic Silver Senior
Joined
Dec 19, 2000
The amount of water in a system does not affect cooling capacity. If it did, our cars would all have reservoirs. At some point the water will reach equilibrium. The system with more coolant will just take a bit longer to get there.

The advantage of a reservoir is to aid in filling and bleeding the system. Personally, I like a reservoir at the top of the case and a bleed-drain valve at the bottom with the inline pump.
 

Richard

Senior Member
Joined
Jan 15, 2001
Cars do have reservoirs.

Not huge ones, but reservoirs nonetheless. The radiator in a car is also pretty large. With a pretty big fan mounted right next to it.

I know what you mean about reaching equilibrium though. I have a digital temp gauge on my bike that never drops below 152 degrees. As soon as I stop it creeps up to 190 degrees. Then the fan kicks in and keeps it there. Soon as I start moving it drops back down to 152 degrees.

Of course, we aren't talking about cooling internal combustion engines. It's already been proven that a big enough supply of water (1 or 2 gallon metal pot) will work just as well as a radiator.


Colin (Mar 05, 2001 05:56 p.m.):
The amount of water in a system does not affect cooling capacity. If it did, our cars would all have reservoirs. At some point the water will reach equilibrium. The system with more coolant will just take a bit longer to get there.

The advantage of a reservoir is to aid in filling and bleeding the system. Personally, I like a reservoir at the top of the case and a bleed-drain valve at the bottom with the inline pump.
 

Colin

Arctic Silver Senior
Joined
Dec 19, 2000
When you consider the scale of the system, a car and a computer cooling system without a reservoir are close in size.