water pump and lift height

[john3850]

At present I use a D5 pump mounted on the bottom of the case so the pump outlet lifts the water to a top radiator or 18 inches of lift.
Would I gain more pressure if the pump was even or inline with the radiator.

 

[Paperdoc]

An 18" head of water pressure is very small. Atosmpheric pressure is about 15 psi or about 33 FEET of water head (about 400"), so 18" is less than 1 PSI. It is not significant in flow performance of your pump. I'm sure the other parts of your liquid loop provide more flow resistance.

 

[Kenmitch]

I wouldn't worry about it if it was me. Water flows faster downhill anyways so it's probably a wash or very little penalty anyways.

 

[john3850]

thanks for the info people

 

[aigomorla]

18 inches is nothing as others have stated.
The D5 is raited at 3.5m for head pressure, which translates to ~11ft.

Also head pressure isn't as important as flow. Sure there is a relationship between the two, but 18 inches wont impact it very much, unless were talking about 18 inches using 1/8ID tubing, then your going to have flow problems, which is a lot greater then head pressure issues.

 

[john3850]

I had the pump running less then full to prime it when I when back to full speed the water dropped slightly on the intake and that is why I asked the question on pressure I tried 1/2 tubing and went back to 7/16 for a tighter fit.
11ft is quite the height for that small pump to push.

 

[Greenman]

Does it really matter at all? No matter the flow rate, any given molecule of water spends exactly the same amount of time at any given location in the loop no mater what speed it's moving at.

 

[aigomorla]

Does it really matter at all? No matter the flow rate, any given molecule of water spends exactly the same amount of time at any given location in the loop no mater what speed it's moving at.

this false..

increase flow rate, and that molecule will have more passes at the same given time then a less flow rate.

True that it will still pick up X regardless of flow, but it will also dump X.
More flow rate = more passes (both hot and cold), which means more heat is being picked up and dumped at the same X time.

Of course you will reach a bottleneck, where you get diminished returns as you hit a apex in flow, in relationship to heat, but for conventional watercooling in PC's, you always want to maintain that flowrate of 1.5-2 gpm as ideal because that is where you net your most gains in efficiency.