Water circuit order...
 

In my case since my resovoir is in the top and my radiator is in the top, it is the easiest to go in this order...

Pump-> water blocks -> radiator -> resovoir-> Pump

However would this affect my performance? PS my pump is an inline so should add VIRTUALLY NO heat to the water.

Since it's an inline, i should get close or same results with :

Pump->Radiator->waterblocks->resovoir->Pump

Right?

Thanks.

Best to go pump/blocks so you get the best oerformance out of your blocks. Thoguh by all means try both ways and choose the one that gets you the best temps.

~ Boli

I'd go for the first setup as it'll have a shorter run of tubing, causing less pressure drop. The difference of pump heat isn't likely to be that great anyway.

Anything is good, just make sure the resevior is just before the pump or you will have cavitation and loss of pressure and flow.

What pump are you using? If you have crappy pressure then go for pump to blocks, otherwise it's best to go pump to rad then blocks.

Ignoring heat of the pump and all other variables being constant, does directing the pump into the blocks before the radiator really have any advantage over going through the radiator first and then the blocks?

The system is a closed loop, so changing the order can't get faster flow through the blocks or anything, so where does this often discussed better performance come from? Is it simply from the heat of the pump being sent to the block sinstead of the radiator first?

I've been contemplating the ordering of the loop in the system I'm designing right now, and this still eludes me.

I would think that going through the radiator before the WB's would be benificial, because the water coming from the radiator is the coolest the water will be in the entire loop and you want that on your CPU next. I agree with you that order doesn't matter when determining flow in a series, whatever is most restrictive will hinder the entire loop.

I was considdering something similar for my next system also (please refer to attached pic.), but am concerned about the pump pumping directly to the rad. Will this pose too high a restriction for the pump?

Going to the blocks first does at best nothing for temps, at worst you increase temps with pump heat. As you say, in a closed loop the flow rate is the same in all parts, thus putting the block before or after that radiator makes no difference at all to the flow through the block. The whole weak pumps should pump into the block first theory is a myth.

Well, all of this IS theory anyway. Why not just try it and see what temps you get are best? It's going to be different for all different setups as it is...

I can't recall the exact location, but I have seen stuff from BillA stating that the order of the parts in a loop has no measurable effect on the temps, cooling, flow rates, etc. of the loop if everything else stays the same, and the parts are all in serial sequence (or any parallel pairs aren't changed). This is obvious in terms of flow rates / pressure drops, but is a bit counter intuitive for temps. However it makes a certain amount of sense if one thinks about it. All the heat inputs are the same, and the heat dissipation of the rad doesn't change, so why would the sequence matter?

Thus the best arrangement is that which gives the optimal hose routing, namely short and with minimal bends.

Gooserider

i would thing Pump-block-rad-res-pump is the best, just because the most presure would be going though the blocks.. be that as it may it will have an effect thats probly *not* measurable..
thats just me $.02

Well, I'm using a Swiftech MCP600 and a heater core. The pressure of the pump is huge (compared to other pumps in it's level) and the restriction of the heater core tiny. Therefore there must be some cooling advantage of going pump -> rad -> blocks rather than pump -> blocks -> rad.

As I said, it all depends on your setup/parts.

Eheim 1250, I'm thinking Ill do pump -> blocks, because my dual radiator and resovoir are ALL the way in the top of my high tower case.

Ill use 5/8 thick enforced tubing for the tubing from the resovoir to the pump, so a little vaccuum can't be made.

I've come to the opinion that you should put everything where it restricts flow the least.

Yea, but if you think about it, it should not change much, only affect the flow by less than half tenth of a gallon per minute, since practically you still pass each object in the circuit, but the shorter the tubing the less resistance from the tubing itself... So I'll just stay with the old book from my science class, and keep the circuit as short as possible.

Pump -> water blocks -> radiator -> resovoir -> pump.


Think about it, you will still have the rad somewhere in the system, and the flow should be the same throughout the system, thus why would it matter much? Unless you go into the real small details, but then you might just come out to take the shortest way possible... ;)

Pressure is a factor of block design and flowrate. Flowrate is uniform in a given system regardless of order of components. Thus you get the same pressure regardless of where in the loop you put the block. The pump->rad->block setup is because the water is coolest as it exits the radiator.

But it wouldn't suprise me if the temperature was nearly the same throughout the circuit.

When moving over a gallon of water a minute through the tubes, it actually is nearly the same. You are not likely to get over 1C between either of the barbs on the CPU or on the radiator.

Agreed, all the info that I've ever seen says that in a reasonably good flowing system (over about one quart (Liter) per minute) the temperature difference going around the loop is less than 1*C.

If you read some of BillA's articles, you will note that he makes a big deal of this, as this is one of the factors that makes block testing so very difficult. The temp. differences are very small, which makes them hard to measure, and makes any error highly problematic in terms of it's impact on the test numbers.

BillA also says (and I agree) that there is no real difference in block temps caused by component sequence - IOW,
Pump -> Rad -> Blocks will give the exact same CPU temps as Pump -> Blocks -> Rad. This seems counterintuitive, but if you think about it, the logic makes sense.

1. There are two main heat generators in the loop, the pump and the blocks, and one cooler, the rad.
2. Assume for arguements sake that each generator adds one unit of heat to the loop on each pass. Since the system is at equilibrium, the rad must dump two units of heat per pass. (exact numbers aren't critical here)
For each of the following, I'll add or subtract the heat (H) through a cycle
3. Case one - (pump in already has 1H from blocks) -> Pump +1H = 2H -> Rad -2H = 0 -> Block +1H = 1 -> pump in...
4. Case two - (Pump in H = 0) -> Pump + 1H = 1 -> block + 1H = 2 -> Rad -2H = 0 -> pump in...

So, not much difference either way. We do know that given the same components, more flow = better cooling, so it appears that the best way to get the most cooling is to maximize the flow rate. This appears to suggest that the best bet is to arrange the parts in such a way as to give the straightest and shortest loop possible.

Since per the standard flow resistance charts, bends add considerably more resistance than straight runs of the same size, and the sharper the bend the greater the flow resistance, the inevitable balance that has to be drawn between 'short' and 'straight' should probably be tilted somewhat towards straight, but this is a more debateable issue.

Gooserider