Tapping into the Reservoir

[Boostbaron]

Hey all, I'm a long time reader, but here's my first post
I'm probably splitting hairs here, but away I go anyways...
For ease of filling and accessibility, I'm designing my basic WC setup to have the Reservoir at the highest point in the loop. Now what i'm curious about is this: due to the weight of approximately 1L of water sitting in the Reservior, am I better off tapping the "reservior-in" line at the bottom of the tank, or increasing the head height by about 5-6cm, and allowing the water to trickle down from above the reservior water level.

Would the weight of the water even have any noticable effect on the flowrate? And if so, would that flowrate be any better or worse than a system with a slightly higher head height?

Thanks in advance!

[frankgehry]

I've been reading about water cooling lately and many regard reservoirs as a potential trouble or leak point. They recommend a simple t connection to fill the system. There are several guides to water cooling at www.extremeoverclocking.com that mention this as the best strategy. The t connection must be on the sucking side so that water can be added with the pump on and should be at the highest point. I'm just starting so what do I know, but it makes sense and its one less part to find space for. - FG

[darthan]

The water weight will not affect flowrate no matter where you put the reservoir in line. Water pressure varies with depth not with volume therefore in a system with both ends in the same body of water the height from bottom to top is equal and so there is equal pressure down both lines. It doesn't even matter if the reservoir isn't the highest point in the system, pressure due to depth is measured from whatever the highest point in the system is and it will always cancel out (in terms of flow rate) in a closed system.

Having tried a "simple" t connection and a reservoir in watercooling loops before I cannot recommend highly enough using a reservoir. Yes, technically it is another potential point of failure but if you get a well made reservoir it won't be a problem. And the tiny risk is worth the gain in ease of use (especially since most pump manufacturers will tell you not to run their pumps when dry) because a reservoir (and for this purpose it must be at the top of your system or you will spill) makes filling (and the inevitable topping off every so often) much, much easier.

[Happy Hopping]

For ease of filling and accessibility, I'm designing my basic WC setup to have the Reservoir at the highest point in the loop. Now what i'm curious about is this: due to the weight of approximately 1L of water sitting in the Reservior, am I better off tapping the "reservior-in" line at the bottom of the tank, or increasing the head height by about 5-6cm, !

Am I the one who don't understand the question? Are we saying put the reservator several ft. higher than the computer so the water can flow down easier?

[Boostbaron]

Darthan is right on this one...
After thinking about his post, I realized that the base of the reservior will support all the weight of the water, with the exception of the cross-sectional area directly above the tubing.
It's been too long since my Statics & Dynamics class

As far as the Reservior being at the top of the loop, I just mean that the pump, waterblock, and radiator will be closer to the bottom of the case, and the rez will be nearer to the top. That way, when you open/unseal the rez, water doesn't come gushing out from anything you've got mounted above it.

The "5-6cm" is metric (because US imperial is the --> ) which is approximately 2 inches.

[pdf27]

The main benefit I can think of to having the res at the top of the case is that the average static pressure in the water system will be higher. If you've got a pump with a constricted inlet at the bottom of the case, this might just be enough to prevent cavitation (and vice-versa if the res is at the bottom and the pump at the top). It's probably also going to be easier to fill a loop with the res at the highest point, which is the real reason mine is.

[Happy Hopping]

It's been too long since my Statics & Dynamics class
.

I don't have a degree in Mechanical Engg., let me go totally off topic on a quick question:

From this link:

http://www.atdec-it.com/netscape/articu ... ingle.html

In the Articulated Swing Single:

The ball joint is part metal & plastic.

I'm out of my element when it comes to Particle Mechanics, because I always thought "any system is as strong as its weakest link." If so, even for a 19.84 lb. object, at that ball joint, why wouldn't it break at the point when the arm is connected to the black round sphere, presuming the sphere is plastic?

[HaloJones]

Even if the res is at the bottom of the loop, opening the top will not allow water to "gush out" unless there is a way for air to get in somewhere higher up.

This also applies to a T. it does not need to be at the top of the loop or even for the top of the T to be the highest point.

Suppose you have the pump at the bottom of the case and the T connector a couple of inches from the pump inlet. The rest of the loop is air-tight. Suppose the fill part of the T is six inches high. As you pour water into the T (with the pump off) water will replace air in the loop up to 6 inches high. Blip the pump. Water is pushed up the loop and sucked from the T and the non-pump side of the T. air will be pushed around the loop by the water coming up from the pump. As the water is sucked down from the T, add more water using a funnel to make life easier. Once the loop is full and bled, you don't even need to cap the T to keep the water in as it is a closed loop. Even with the pump off, for the water to leave the T, the loop would have to have a hole in it somewhere.

This pic shows my T. It is actually topped up but the water level above the pump has sometimes been lower than the water-block without any impact whatsoever. Having the T like that with gravity helping to fill the system made filling and bleeding this system as easy as with any erservoir.

[cotdt]

it's a closed system so none of this matters. you don't even need a res as mentioned above. however, water can evaporate slowly through the tubing, so a small res is a good thing.