Heat Dump Discussion: Power/Heat - Overclock.net

*CyberDruid* · 06-25-07

I find that when I run in my loops for 24 hours that the MCP 655 makes the loop quite warm if no fans are on, just running the loop with a jumpered PSU.

I did not notice this with the DB-1.

As these are the only two I have used to build a number of loops I was wondering does the extra power freally offset the heat dump--I think that theere must be some actual data on this somewhere (XS likely) but just wanted to hear about this from other LCers that have used different pumps.

Are certain pmps notoiously hot? Are some famously cool?

Is the extra power really going to make a better loop if it also dumps a ton of heat?

I am thinking that the lowest restriction loop with a small cool pump would have to be best... Meaning that is mioght be better to run dual Db-1 loops to cool CPU and GFX than a single MCP 655 to cool both...

Any thoughts on this?

DuckieHo · 06-25-07

I believe the D5 dumps something like 12-18w into the loop. I definitely have seen articles about this. Some pumps are more efficient than others. Also, this is why submerged pumps are not recommended for PC cooling.

Sreenath · 06-25-07

Quote:

Originally Posted by DuckieHo

I believe the D5 dumps something like 12-18w into the loop. I definitely have seen articles about this. Some pumps are more efficient than others. Also, this is why submerged pumps are not recommended for PC cooling.

good point. i guess all the heat from the sump-pump would directly transfer to the water.

as for the ~12-18W, does that make a lot of difference with a rad? i mean, i am sure even a sub par 120mm rad with a good fan should be able to handle 12-18W extra heat load with EASE, and minimal temp increase. Even cheap WC kits ~$150 have ratings of ~0.14C/W so extra 12-18W only accounts for a temp increase of 1.68-2.52C

**ira-k** · 06-25-07

You have to take the heat dump into consideration but as has been pointed out its a tiny portion of the heat dump into a loop...Now an RD30 should be run at 18V to curtail some of its heat dump...

The 50Z is one of the coolest running pumps and is supposed to be great with 2 in-line...

...AquaXtreme 50Z-DC12 Mag Drive Inline Pump w/ 1/2" Barbed Fittings: COOLTECHNICA

*CyberDruid* · 06-25-07

Numbers...cool. That helps. So in essence power offsets heat dump in most cases...or at least with the MCP 655.

Here's a hypothetical situation: same loop--PA 160/d-Tek FuZion with two diferent pmps--db-1 and MCP 655--as I could build this loop in these two configs would the MCP 655 definitely provide more cooling than the db-1? Does more flow even in a low restriction loop offset the heat dump?

*CyberDruid* · 06-25-07

Quote:

Originally Posted by ira-k

You have to take the heat dump into consideration but as has been pointed out its a tiny portion of the heat dump into a loop...Now an RD30 should be run at 18V to curtail some of its heat dump...

The 50Z is one of the coolest running pumps and is supposed to be great with 2 in-line...

...AquaXtreme 50Z-DC12 Mag Drive Inline Pump w/ 1/2" Barbed Fittings: COOLTECHNICA

50Z...gonna search that up and take a look--I really like the db-1 ou pointed out earlier...

EDIT: LOL that's the exact pump I have in WaterClocker that I built like two years ago..it's still running perfectly--and it does not seem to get warm. It is basically the D-5 in a metal housing. And it looks great too...

**ira-k** · 06-25-07

Quote:

Originally Posted by CyberDruid

Numbers...cool. That helps. So in essence power offsets heat dump in most cases...or at least with the MCP 655.

Here's a hypothetical situation: same loop--PA 160/d-Tek FuZion with two diferent pmps--db-1 and MCP 655--as I could build this loop in these two configs would the MCP 655 definitely provide more cooling than the db-1? Does more flow even in a low restriction loop offset the heat dump?

I don't know if it would make a big difference in a low restriction loop or not CD...I've never run a low flow before....And I don't know what flow rate the Fuzion is optimized for...I would guess 1-1.5gpm since that is what most guys run....

Throw a loop together with the D-5 and record your temp's then replace it with the db-1 and record the temp's....I'd like to know to...

Martinm210 · 06-25-07

I would think the percentage is too small to record any difference. If something like the PA120.3 can dissipate up to 600 watts of heat and if the db-1 is 6 watts, the difference is only about 6 watts of 600 available that's only 1% of the capacity.

Now look at a small light duty radiator and low speed fans with reduced voltage and say you're running some low speed fans at 5V on an MCR120:

You only have 75 watts of heat dissipations, so now that 6 watts is 10% which is probably of note especially if you were running an efficient CPU or other low heat piece of equipment in a small single loop.

CrazyJoe · 06-25-07

Check out this thread ... http://forums.procooling.com/vbb/showthread.php?t=10825

Some hard numbers given and the whole article is really quite informative.

Quote:

For each of the pumps we see that we'll get the following flow rates, and also the corresponding radiator C/W, and waterblock C/W at that flow rate:

Eheim 1046, 3.2 LPM, 0.045, 0.187
Eheim 1048, 4.2 LPM, 0.044, 0.178
Eheim 1250, 5.2 LPM, 0.043, 0.172
MCP600, 5.7 LPM, 0.042, 0.169
MCP650, 5.8 LPM, 0.042, 0.168
MD-15R, 6.7 LPM, 0.041, 0.165
MD-20RZ, 8.7 LPM, 0.040, 0.159
MD-30RZ, 10.0 LPM, 0.039, 0.157

Okay, so the CPU heats up by the CPU wattage dissipated by the waterblock's C/W at that flow rate. The water temperature rises above ambient by the radiator's C/W at whatever flow rate multiplied by the CPU wattage plus the pump heat wattage being added to the water.

This now gives us a predicted correlation for the relationship between the final CPU temperature as affected by the flow rate, but more importantly also after factoring in the pump heat.

Eheim 1046, WB delta = 100W * 0.187C/W = 18.7C, Water delta = (100 + 1.5)W * 0.045C/W = 4.6C, Total CPU temperature = 23.3C above ambient
Eheim 1048, WB delta = 17.8C, Water delta = 103 * 0.044 = 4.5C, Total CPU Temp = 22.3C above ambient
Eheim 1250, WB delta = 17.2C, Water delta = 109 * 0.043 = 4.7C, Total CPU Temp = 21.9C above ambient
MCP600, WB delta = 16.9C, Water delta = 108 * 0.042 = 4.5C, Total CPU Temp = 21.4C above ambient
MCP650, WB delta = 16.8C, Water delta = 115 * 0.042 = 4.8C, Total CPU Temp = 21.6C above ambient
MD-15R, WB delta = 16.5C, Water delta = 122 * 0.041 = 5.0C, Total CPU Temp = 21.5C above ambient
MD-20RZ, WB delta = 15.9C, Water delta = 131 * 0.040 = 5.2C, Total CPU Temp = 21.1C above ambient
MD-30RZ, WB delta = 15.7C, Water delta = 150 * 0.039 = 5.9C, Total CPU Temp = 21.6C above ambient

*CyberDruid* · 06-25-07

Great find!

		Overclock.net - Overclocking.net > Cooling > Water Cooling
Heat Dump Discussion: Power/Heat

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)