Common Pump Flow vs Pressure vs Heat vs Price Comparison

[Cathar]

Been working on a little graph of late to better help me to select the pumps that I want to target, and thought that this sort of information would be quite useful for the forum as a bit of a guideline.

Here's the graph:




Some notes:

*) The Danner Mag 3 line is my personal interpretation of a best fit line given the data presented at their website. Their data produces a line that is not even remotely smooth, so I look the liberty to smooth it out somewhat. If anything, I may have overestimated slightly. The in-line heat figure is another approximation drawn from reading about people's experiences. I believe it to be somewhat close.

*) The Swiftech MCP600 in-line heat is another approximation, based on motive pumping power which must be ultimately converted as frictional heat into the water, and some heat from the motor itself.

*) The Johnson pump may be obtained for the price stated from www.depcopump.com. The in-line heat value is an approximation based on my experiences with the Davies-Craig EBP, with both pumps sharings a similar design.

*) The Davies-Craig price quoted is an over-the-counter cash price direct from Davies-Craig. The on-line order price is $201.

*) The Eheim pumps voltages/frequency is not given as Eheim release correctly spec'ed models for whatever country they are targetted for. This means that so long as you buy the Eheim pump that is correct for your country, you should see the performance stated. The Eheim PQ curves on the literature did not have uniformally placed graph lines. The PQ curves given are based on an interpretation of the graphs using the global min-max scale of the graphs presented, and then following the points on the curve. I believe that this actually eliminates some of the discrepencies with the visual interpretation of the Eheim PQ curves that people have occasionally reported on.

*) The block flow/pressure resistance curves presented are for the blocks themselves only. They do not include additional resistances that may be introduced by a radiator or other heat-transfer device.

[pauldenton]

*) The Swiftech MCP600 line is for the original closed impeller model, which presently is not shipping. I am unaware of the PQ curve for the presently shipping interim model.

Cathar, according to BillA they are now shipping the final version, which has the same performance as the original impeller ....


see overclockers forum thread

are there no 240v danner's? - seems fantastic bang for the $....

[Cathar]

Originally posted by pauldenton
Cathar, according to BillA they are now shipping the final version, which has the same performance as the original impeller ....
<snip>
are there no 240v danner's? - seems fantastic bang for the $....

Thanks for the update. Corrected the opening post.

Yes, the Danner Mag 3's are an amazing price/performance mix. I am not aware of any 240V/50Hz models, only 115V/60Hz.

[l00b3r]

Very useful guide. could you do one up for Ba's/LA's and whatever else?

would be good for aproximations..

-Matt

[Goose AU]

very useful guide. Cheers.

just a little hard to read. Damn colour blindness.

[Cathar]

Originally posted by Goose AU
just a little hard to read. Damn colour blindness.

The top two boxes on the right are colored for the two block curves that curve up from the bottom left.

The rest of the boxes start with the highest pressures on the left and go down from there. That way you can match the box/pump position to the curve starting from the left hand side.

[Cathar]

A further aspect to the data to consider is the nominal in-line heat that each pump adds to the cooling loop when running.

This is fairly important. Just because one pump gives higher flow rates doesn't necessarily make it better.

For example, let's compare the Eheim 1048 to the Danner Mag 3.

The Danner Mag 3 is, on average, going to add 16W more heat to the cooling loop.

Let's say we were using a DTek Pro core with a decent fan running at a quiet 7V, and this corresponding radiator setup has an inherent C/W of 0.06, meaning for every watt of heat that enters the water, the water will heat up by 0.06C.

Now with the Mag Drive 3, the water will be 16 x 0.06 = 0.96C warmer than with the Eheim 1048.

With the Mag 3 & the WW, we would expect about an 8.3LPM flow rate (not accounting the radiator). With the Eheim 1048, about a 5.6LPM flow rate.

Now let's look at the White Water flow vs performance chart here:



At 5.6LPM, we see a C/W of around 0.183, and at 8.3LPM, a C/W of around 0.173.

i.e. a 0.01C/W difference. Now if the CPU were emitting a real 100W of power, then the extra flow rate of the Danner Mag 3 would mean that it would be 0.01 x 100 = 1C cooler. However, the water is 0.96C warmer due to the extra heat of the Mag 3, therefore all that has really been gain is 0.04C, or basically nothing.

If the CPU was dumping an unrealistic 150W, then it would be about 0.5C cooler with the Mag3.

If the CPU were dumping 100W, but we had a better radiator setup giving a C/W of 0.02, then the CPU would be 0.7C cooler with the Mag 3 over the 1048.

This is why it is quite important to match the radiator setup with a pump.

[l00b3r]

Originally posted by Cathar
A further aspect to the data to consider is the nominal in-line heat that each pump adds to the cooling loop when running.

This is fairly important. Just because one pump gives higher flow rates doesn't necessarily make it better.

For example, let's compare the Eheim 1048 to the Danner Mag 3.

The Danner Mag 3 is, on average, going to add 16W more heat to the cooling loop.

Let's say we were using a DTek Pro core with a decent fan running at a quiet 7V, and this corresponding radiator setup has an inherent C/W of 0.06, meaning for every watt of heat that enters the water, the water will heat up by 0.06C.

Now with the Mag Drive 3, the water will be 16 x 0.06 = 0.96C warmer than with the Eheim 1048.

With the Mag 3 & the WW, we would expect about an 8.3LPM flow rate (not accounting the radiator). With the Eheim 1048, about a 5.6LPM flow rate.

Now let's look at the White Water flow vs performance chart here:



At 5.6LPM, we see a C/W of around 0.183, and at 8.3LPM, a C/W of around 0.173.

i.e. a 0.01C/W difference. Now if the CPU were emitting a real 100W of power, then the extra flow rate of the Danner Mag 3 would mean that it would be 0.01 x 100 = 1C cooler. However, the water is 0.96C warmer due to the extra heat of the Mag 3, therefore all that has really been gain is 0.04C, or basically nothing.

If the CPU was dumping an unrealistic 150W, then it would be about 0.5C cooler with the Mag3.

If the CPU were dumping 100W, but we had a better radiator setup giving a C/W of 0.02, then the CPU would be 0.7C cooler with the Mag 3 over the 1048.

This is why it is quite important to match the radiator setup with a pump.

Cathar, i see your maths all equals up, but my question to you is, i mean those figures dont account for the radiator so they cant be entirely accurate, i mean you compensated for and all, but would if you got people to collect Data on various Heatercores/Radiators with pumps you would be able to attempt a more accurate version. Im open for the testing of it. I have my LRWW clone arriving tomorrow . after about 1 year of waiting and will dump it on the system and test it. for Data collection of people figures, a generalised rounding would work to a point would be more then sufficiant enough yes? I could flow test my setup as is and report back with my specs.

could be worth it.

-Matt

[Remote Man]

ok unfortunately for me i'm confused.

so what relation do the blocks have to the pumps?

and let me see if i can decipher this.
at 1m worth of pressure the cascade has 4.5lpm flowing through it?

And at 3m worth of pressure the johnson CM30p7-1 moves 10.5 lpm?

SSoooo... to get the cascade flowing at 7lpm withour anything else a danner mag drive 3 would do it?

Is any of that right or do i need to do some research?

[Stoodoo]

Can't see your graph for looking Cathar

[Cathar]

Originally posted by Stoodoo
Can't see your graph for looking Cathar

My web host must be temporarily down.

[Cathar]

Originally posted by l00b3r
Cathar, i see your maths all equals up, but my question to you is, i mean those figures dont account for the radiator so they cant be entirely accurate, i mean you compensated for and all, but would if you got people to collect Data on various Heatercores/Radiators with pumps you would be able to attempt a more accurate version.

Well the BA radiator with 1/2" copper tube fittings has a pressure drop of around 0.7mH2O at 10LPM.

So the trick here would be to plot a curve of Pressure = 0.7 x (Flow / 10)² for the BA radiator.

You then add that curve to the curve for the block and the resulting line is what you'd use.

We can guess at it though. For example, with the Cascade, a BA, and an Eheim 1048, the Cascade intersects the 1048 line at 4.7LPM/1.15mH2O. The pressure drop for the BA at 4.7LPM is 0.7 x (4.7/10)² = 0.15mH2O

Adding the two together we get 1.3mH2O at 4.7LPM

Let's predict 4.5LPM => 1.3 x (4.5 / 4.7)² = 1.2mH2O

We look at the graph and see that the Eheim 1048 does indeed supply pretty close to 4.5LPM at 1.2mH2O, so that would be the predicted flow rate.

[Cathar]

Originally posted by Remote Man
ok unfortunately for me i'm confused.

so what relation do the blocks have to the pumps?

and let me see if i can decipher this.
at 1m worth of pressure the cascade has 4.5lpm flowing through it?

And at 3m worth of pressure the johnson CM30p7-1 moves 10.5 lpm?

SSoooo... to get the cascade flowing at 7lpm withour anything else a danner mag drive 3 would do it?

Is any of that right or do i need to do some research?

Yep, you pretty much understood exactly what it's telling you.

With a BA rad + the Cascade + the Danner Mag 3. Expanding from the post above.

At 7LPM the BA rad has 0.7 x (7/10)² = 0.34mH2O PD
The Cascade has 2.3mH2O PD at 7LPM
The total PD at 7LPM for the Cascade + BA = 2.64mH2O

That's more than the Mag 3 provides, so let's predict something less than 7LPM. Let's try for 6.7LPM

PD at 6.7LPM = 2.64 x (6.7/7)² = 2.42mH2O

Looking at the PQ curve for the Mag 3 again, we see pretty much bang on 2.42mH2O for 6.7LPM for it. So we'd predict 6.7LPM with the Mag 3 + Cascade + BA rad.

[nikhsub1]

Cathar, not to nitpick, but it seems your nominal in-line heat rating may be a bit off on the Mag 3 and/or the MD-15R. The Mag 3 consumes 35W, the 15R 31W. You have the nominal in-line heat rating for the Mag 3 at 20W and the 15R at 21W. Another oddity is the 1250 with it's 28W consumption, yet you only rate it at 11W for the nominal heat rating? Confused is all.

[Cathar]

Originally posted by nikhsub1
Cathar, not to nitpick, but it seems your nominal in-line heat rating may be a bit off on the Mag 3 and/or the MD-15R. The Mag 3 consumes 35W, the 15R 31W. You have the nominal in-line heat rating for the Mag 3 at 20W and the 15R at 21W. Another oddity is the 1250 with it's 28W consumption, yet you only rate it at 11W for the nominal heat rating? Confused is all.

Each pump dumps heat differently.

The Eheim is a measured value.

The Mag-Drive is a guess based on people's experiences. The Iwaki MD15 value is an extrapolation of the MD30.