Pump wattage into loop

Output · 12-03-2004, 06:22 AM

I've read some threads about how much wattage different pumps put into the loop. I would think that since nearly all pumps are inside the case that the problem would instead be how much watts they disapate into the air, since that will warm up the air inside, heat all components and finally warm the rad? So my question is, is it not better for a pump to add all its heat into the water, and not into the air? Water will heat less for a given wattage than air also

Bugsmasher · 12-03-2004, 07:32 AM

Just guessing here but...

For the heat radiated into the surrounding its fairly simple with a few decent case fans to move that heat out of the case. If you think about it most cases are sub 2 cubic feet of air. A standard 80mm fan moves nearly 15 times that volume of air in a single minute. Throw in a 120mm fan and you are moving anywhere between 20-50 times that volume of air every single minute. I understand those flow rates are determined under optimal testing situations but the radiated heat from a pump gets moved out rather fast.

The heat that goes into the loop however is different. Obviously the warmer your loop is the warmer your CPU/GPU will be. Stacked on top of this is the fact the warmer your loop is the less efficient your loop will become. As the temperature of the coolant rises less heat will be transfered to each volume of coolant as it passes through the waterblock. While the amount of heat released by the coolant will also be somewhat higher when it passes through the radiator/heater core it will require more airflow through the radiator/heater core to achieve the cooling of a lower over all temped loop.

Watercooling is used because it can pull more heat off of the CPU faster than most air cooling options. With this in mind avoiding heat buildup in the loop is extremely important. Its also the reason that balancing a loop is very important. Someone can go out and get a monster MD20RZ but if they dont have a radiator/heater core or fans that can remove the heat from the loop that monster pump is a waste. Ditto on getting a monster rad and fans that could power a 747 if your pump isnt capable of pushing the optimal amount of water through your waterblocks.

You can see the benefits of low pump-to-loop heat transfer in Cathar's post about pumps. There is a very good reason the very low wattage MCP600 performs so well. By adding the least amount of heat to the loop better overall cooling can be achieved assuming you have a radiator/heatercore and fans that are in balance with your system. The net result is the lowest temps by using a pump that adds the least heat to the system while maintaining a fairly impressive flow.

Output · 12-03-2004, 07:46 AM

Cathars post does not mention that the rest of the heat from the pump is added to the air in the case. for me, as I have 2 rads and a psu as the only way out for air, this will most likly pass my rads(since way more air is passed there than from the psu), therefor "readding" the heat to my loop.
I would see that your point is correct if the pump is outside of the case, or that you have extra fans removing heat from the pump.

Since at least my pump is not near a "output" fan, all the air inside the case will be heated, thus heating all system components by about 12w(ehiem 1250)

Bugsmasher · 12-03-2004, 08:04 AM

Ahhh, gotcha.

I have my heater core at the top of my case pulling air in. Its a dual 120 b-ville core with two 120 exhaust fans very close to it so most of my loop heat gets exhausted out of the case fairly rapidly. My pump is at the bottom of the case directly between an intake and exhaust fan setup as well so most of that heat gets exhausted as well.

Hadnt thought of it but what you are saying does make sense.

Output · 12-03-2004, 08:17 AM

Quote:

Originally Posted by Bugsmasher

Ahhh, gotcha.

I have my heater core at the top of my case pulling air in. Its a dual 120 b-ville core with two 120 exhaust fans very close to it so most of my loop heat gets exhausted out of the case fairly rapidly. My pump is at the bottom of the case directly between an intake and exhaust fan setup as well so most of that heat gets exhausted as well.

Hadnt thought of it but what you are saying does make sense.

Guess that when choosing a pump you really need to consider where its placed, and where your rads are.

I would really like to have the pump outside, on the side of the case, but its so large and I do believe that it would make more noise (hum) mounted that way.

12-03-2004, 06:22 AM	#1
Output Cooling Neophyte Join Date: Oct 2001 Location: Sweden Posts: 31	Pump wattage into loop I've read some threads about how much wattage different pumps put into the loop. I would think that since nearly all pumps are inside the case that the problem would instead be how much watts they disapate into the air, since that will warm up the air inside, heat all components and finally warm the rad? So my question is, is it not better for a pump to add all its heat into the water, and not into the air? Water will heat less for a given wattage than air also __________________ parallel rads is the only way to go!

12-03-2004, 07:46 AM	#3
Output Cooling Neophyte Join Date: Oct 2001 Location: Sweden Posts: 31	Cathars post does not mention that the rest of the heat from the pump is added to the air in the case. for me, as I have 2 rads and a psu as the only way out for air, this will most likly pass my rads(since way more air is passed there than from the psu), therefor "readding" the heat to my loop. I would see that your point is correct if the pump is outside of the case, or that you have extra fans removing heat from the pump. Since at least my pump is not near a "output" fan, all the air inside the case will be heated, thus heating all system components by about 12w(ehiem 1250) __________________ parallel rads is the only way to go!

12-03-2004, 07:32 AM	#2
Bugsmasher Cooling Neophyte Join Date: Sep 2004 Location: Oklahoma Posts: 43	Just guessing here but... For the heat radiated into the surrounding its fairly simple with a few decent case fans to move that heat out of the case. If you think about it most cases are sub 2 cubic feet of air. A standard 80mm fan moves nearly 15 times that volume of air in a single minute. Throw in a 120mm fan and you are moving anywhere between 20-50 times that volume of air every single minute. I understand those flow rates are determined under optimal testing situations but the radiated heat from a pump gets moved out rather fast. The heat that goes into the loop however is different. Obviously the warmer your loop is the warmer your CPU/GPU will be. Stacked on top of this is the fact the warmer your loop is the less efficient your loop will become. As the temperature of the coolant rises less heat will be transfered to each volume of coolant as it passes through the waterblock. While the amount of heat released by the coolant will also be somewhat higher when it passes through the radiator/heater core it will require more airflow through the radiator/heater core to achieve the cooling of a lower over all temped loop. Watercooling is used because it can pull more heat off of the CPU faster than most air cooling options. With this in mind avoiding heat buildup in the loop is extremely important. Its also the reason that balancing a loop is very important. Someone can go out and get a monster MD20RZ but if they dont have a radiator/heater core or fans that can remove the heat from the loop that monster pump is a waste. Ditto on getting a monster rad and fans that could power a 747 if your pump isnt capable of pushing the optimal amount of water through your waterblocks. You can see the benefits of low pump-to-loop heat transfer in Cathar's post about pumps. There is a very good reason the very low wattage MCP600 performs so well. By adding the least amount of heat to the loop better overall cooling can be achieved assuming you have a radiator/heatercore and fans that are in balance with your system. The net result is the lowest temps by using a pump that adds the least heat to the system while maintaining a fairly impressive flow.

12-03-2004, 08:04 AM	#4
Bugsmasher Cooling Neophyte Join Date: Sep 2004 Location: Oklahoma Posts: 43	Ahhh, gotcha. I have my heater core at the top of my case pulling air in. Its a dual 120 b-ville core with two 120 exhaust fans very close to it so most of my loop heat gets exhausted out of the case fairly rapidly. My pump is at the bottom of the case directly between an intake and exhaust fan setup as well so most of that heat gets exhausted as well. Hadnt thought of it but what you are saying does make sense.

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