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Unread 05-19-2007, 07:27 PM   #249
muffy
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Join Date: Jun 2003
Location: Auckland, New Zealand
Posts: 40
Default Re: How much pump is enough? How much is too much?

[quote=

Has anyone tried putting a pump in a sealed chamber and letting it get very hot. A insulated pump is not transferring heat to the air. So heat is forced to travel to the water. Compare insulated and uninsulated cases and you've got some nice numbers to work off. For extra science points put thermocouples on bits of the pump. the bits that get relatively hotter may indicate what is putting heat where.[/QUOTE]

UMM yes .... well close enough

i disbelieved this guys numbers so much that i spent a few days creating this rest rig .. What you can see in this pic is my modded 655 pump which has max 78watts at 12.24 volts and 2 resisters two mounted to a heat sink and other in the water. Three were three needed to get the wattage the same as what the pump would be put into the water. I am basing my numbers on the authors numbers which i believe is 15 watts of heat for 24watts of electricity. The resister is adding 37.4 watts of heat to the loop and with the pump set to minimum speed its adding 5.1watts. So there is a total of 42.5 watts being added to the loop .For the second test i didn't run any power through the resisters i ran the pump at a higher wattage instead, of 68watts of electricity. This should mean it would make 42.5 watts of heat
.
i then ran these two test systems for an hour and measured the water temp

To my surprise after taking ambient air temp into account the temperatures were closes enough to say they were the same of 30 degrees C over ambient..

So I’ll have to take back what I said a few posts ago .. and say even thought the high inefficiency of a pump sounds crazy it seems to be correct
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