Since87,

LOLOL. Anyone, and I mean ANYONE that works with real centrifugal pumps would tell you that power goes up with flow rate. This is true despite the lower head that you get at higher flow. All ya gotta do is look at a pump curve that includes power and it'll be obvious.

What I can't quite get is safemode's insistance otherwise. I don't frequent OC that often, but generally thought the guy was OK with heat transfer and thermo. Obviously pumps aren't one of the guy's strengths.

Fact of the matter is that the lowest energy consumption you'll ever get is when you dead-head a centrifugal pump. The highest you'll ever see is when TDH is zero. Peak efficiency is the funky one, as it peaks at different flow values for different pumps. Rarely will it exceed 90% in the best industrial pump. Aquarium-style pumps would be hard pressed to exceed 50%. Given the setups people tend to favor, I figure most water cooling pumps are in the 30%-40% range.

BillA,

Sorry to hear about your recent banning. Obviously you've been out spouting lies and half-truths and got in trouble for it. ;)

How did you get 2GPM through the rad alone? I guess I must be missing something, but that doesn't make sense to me. Please fill me in on what I'm not seeing.

ok fellows, what's the deal ?

is this a thread hijacking ?

myv65 ?

I do wish to get right into heat balance and energy balance
we going to do it here or in the new thread here

??

Simple. I matched the pressure drop and flow rates, from the pump and the rad.

If you could draw both curves on the same graph, you'd find that both lines cross each other at one point. That point is 2gpm, 14 feet headloss.

This assumes that there are no other restrictions, but there would be. You're going to have to keep the tubing short, straight, and very smooth.

Better idea. How about the Gen-X Mk4 pump. It runs 70W, $125, is pressure rated, and here is a chart:

12 GPM @ 15ft. Will that be enough toughness for the rad? I like this better anyway since it runs on less electricity and produces less heat. I don't think it is mag-drive, though.

edit: farkin'-A, it IS mag drive!!! And it appears that the front casing is all plastic w/ 3/4" threads. Rawk.

Not bad!

Here's a link to the same pump:
http://www.aquadirect.com/catalog/pumps/genx.htm

Let me calculate the rad flow. brb.

I'm showing 5PSI loss at 2GPM ... I have no idea how to convert that into head loss. Help me help myself, brutha-man! Howdja do that?

UPS just dropped off my radiator. I must say that I am in LUV! *drools*

Try this:
http://www.convert-me.com/

That pump deadheads at 21 feet (i.e. zero flow). That's almost 10 psi. Max flow is about 20 gpm.

At 7 psi, the rad will accept 3 gpm. That's 4.9 meters @ 11.35 L/m, which the pump can handle, and then some.

I'd estimate that you'd get around 3.3 or 3.4 gpm, with a pressure drop of about 9 psi (6.3 meter head).

Still smiling?

So what I'm hearing is that, assuming I only want 2GPM through the rad (anything more is a waste), that eats 5PSI, which converts to 3.5M head loss. Add in the 2M head loss from height, and I am at 5.5M loss, or about 30LPM or 8.5 GPM. After the blocks, lines, joints, etc, I could easily achieve the 6GPM I desire, if I keep a bypass in place, if I use the Mk4 pump.

This is wery wery interesting. I like. As an added bonus, that uses less E than the last pump, putting less into the water supply, and is supposedly ultra-quiet.

I'm going to do a flow test of that rad tonight. I'm going to hook up my football res and 350 GPH Supreme to the res and hose it into my puter and see what happens. I won't have any fans blowing across the rad at this point ... it'll be interesting to see where it peaks ... if necessary, I'll duct tape my 120mm fans to it.

Added test: I'm going to strap the 350 GPM bugger to it in an open flow configuration (submerged pump, rad draining into a bucket) and see what flow rate I get. I know it's not scientific at all and doesn't represent a closed loop application very well, but I have a feeling I may get that 2GPM out of my little Supreme. Call it a hunch. I'll probably post the results to all this in my project page (and here for those that are to lazy to view my insanity in action).

Not quite. If you target 6 GPM, then you must keep the pressure drop, or headloss to 8.5 psi, or 6 meters.

The head in the column has no relevance whatsoever. You're running a closed loop. Your column might as well be 50 feet tall, it would only increase the relative pressure: no effect on the pump (well, some additional restriction in flow, but negligeable).

What you need to figure out is what the pressure drop will be across all the components, then add that to make up the total pressure drop. Then, you convert the pressure drop into head, and lookup the flow rate on the pump chart.

Do try the little pump though. I estimate the flow to be in the fractions of a gpm. You could pee faster than that!

Watch for leaks: 3.5M, aka 5 psi will leak through a weak joint. Teflon tape is your friend!

I hear you on the joints. I didn't use teflon tape on my current setup, and ended up having to PVC glue some of the seals of the hose barbs on my pump. Pissed me off royally. As for now, though, I don't have anything to worry about, and that rad is rated for some crazy pressure.

That rad was "pressure tested to 150 psi". I don't think you have anything to worry about.

For some reason, I had the hardest time finding 3/4" teflon tape here in Houston. I had to overlap 1/2" tape, THAT pissed me off!

I finally found some, last weekend.

Bah, just use JB Weld, it'll do it!

That's too permanent for me. No room for error, or refit.

This is my 22nd post today, so I'm taking a break!

/off topic

sorry for interrupt, but if this would give you any comfort, this is the first time I hear that teflon tape comes in various dimensions. Here we have one-size-fits-all 10 mm tape.:cool:

again, I learned something!

/end

Cheers!

JB Weld isn't permanent! If you need to make a change, just throw the old stuff away and get new stuff. See? Not so permanent after all! Nooge!

*sigh*...

you're brain is too big and your test equipment is too elite

Sorry to hear that m8! State-side, 1/2" (12.7 mm) is standard, and (I always believe) 3/4" (19 mm) is common. There are other sizes, but I don't remember seeing them on a store shelf.

If you're in need, PM me, we might be able to arrange something.

Thanx bbb2k, I'll first look for it in my neighbour countries before I start bugging around!

Thx for the friendly offer!:)

I've never seen PTFE tape wider than 10mm either, in the UK. perhaps it depends where you shop?, Trade~supply I mean...

The test is going to have to be tonight. The radiator uses special fittings, and there is only one place in the palouse that carries them. I had a parts store tell me last night they would order them ... for $10 a piece. Pretty penny for frickin' hose barbs! I should get them at lunch for about a buck a piece.