What temperature is the water in a wc system?

@Jay Bee - passive watercooling breaks the rules of some of the water cooling data out there. So actually both you and Monkey Puzzle are right.
For what I can find and personal experance

Active cooling you should be aiming at optermal MIN .9-1gpm.
Flow rate is slightly more important that head (unless useing turbulance blocks)
Copper Rads work best (with force air flow)
High fin count = high fan rmp (performance)
Low fin count = low fan rmp (quiet)
Heat removed mostly by convection

Passive cooling you should be aiming for a optermal MAX of .9-1
head is more important that flow rate (low restriction block are slightly better)
Only low fin count 'standard' rads should be used.
Radient aluminum systems possable (but need large non-fin surface area)

Which Zalman system are you using Jay Bee, and have you tweeked it, as 40c for a quad is very impressive (I get that on my E6600 but it is a 5 block full loop)

Edit: thanks ecat - did it for the quiet, but fanless is a blessing and a curse
 
Last edited:
shadowscotland said:
@Jay Bee - passive watercooling breaks the rules of some of the water cooling data out there. So actually both you and Monkey Puzzle are right.
For what I can find and personal experance

Active cooling you should be aiming at optermal MIN .9-1gpm.
Flow rate is slightly more important that head (unless useing turbulance blocks)
Copper Rads work best (with force air flow)
High fin count = high fan rmp (performance)
Low fin count = low fan rmp (quiet)
Heat removed mostly by convection

Passive cooling you should be aiming for a optermal MAX of .9-1
head is more important that flow rate (low restriction block are slightly better)
Only low fin count 'standard' rads should be used.
Radient aluminum systems possable (but need large non-fin surface area)

Which Zalman system are you using Jay Bee, and have you tweeked it, as 40c for a quad is very impressive (I get that on my E6600 but it is a 5 block full loop)

Edit: thanks ecat - did it for the quiet, but fanless is a blessing and a curse
Click to expand...

Shadow - what's the reason for the lower optimal flowrate in a passive system? Very interested in any useful info you have links to as I'm in the process of designing and building a (hopefully) fully passive system with a silly amount of copper (60m of 6mm OD/4.8mm ID copper microbore pipe and copper sheet, around 60,000-100,000cm^2 total surface area (a TRUE is around 7500cm^2, a cape cora/konvekt-o-matik tube around 2500), around 25kg copper in total - build log to follow) and trying to get the design as efficient as possible....
 
Last edited:
I think it all comes down to air being the limiting factor.
With active system the volume of air over the rads is significantly higher so the benefits of higher flow rates/impingement blocks has real world advantages (abet with diminishing returns)
Passive systems don’t have that luxury - unless your rad is outside (wind) in a wc cistern (flush cycle) or on a window sill (down draft)
But the size and design of passive rads means they act in convection and radiant sources. Also as the flow rate drops and the coolant become warmer more energy is released radiantly (upping the efficiency curve).
If you’re going to use microbore pipe, you may struggle if using water as a coolant. I’m sure that Cathar’s flow graphs showed major performance drop below 8mm ID – something like water wetter may help if you can stand the smell. But at those diameter’s you’re into air conditioning flow data.
I’ve just ordered an 800x400mm radiant heater and a more powerful pump for my next build and I’m concerned it’s all a waste of time... Oh well it will all be in my log if my family can stay well for a at least one weekend this season
 
shadowscotland said:
I think it all comes down to air being the limiting factor.
With active system the volume of air over the rads is significantly higher so the benefits of higher flow rates/impingement blocks has real world advantages (abet with diminishing returns)
Passive systems don’t have that luxury - unless your rad is outside (wind) in a wc cistern (flush cycle) or on a window sill (down draft)
But the size and design of passive rads means they act in convection and radiant sources. Also as the flow rate drops and the coolant become warmer more energy is released radiantly (upping the efficiency curve).
If you’re going to use microbore pipe, you may struggle if using water as a coolant. I’m sure that Cathar’s flow graphs showed major performance drop below 8mm ID – something like water wetter may help if you can stand the smell. But at those diameter’s you’re into air conditioning flow data.
I’ve just ordered an 800x400mm radiant heater and a more powerful pump for my next build and I’m concerned it’s all a waste of time... Oh well it will all be in my log if my family can stay well for a at least one weekend this season
Click to expand...

Should have mentioned - the microbore tubing is running parallel in 48 tubes, it's optimised for 7/16 to 1/2" tubing (total flow resistance for 49 x 4.8mm ID in parallel is equal to 1/2" ID), so pressure drop shouldn't be too much of an issue.

Any idea of firm figures what importance/proportion of heat is transferred by radiation by passive fins - can't find anything definite, and want to know whether to bother treating/painting the copper afterwards, or even sanding/sandblasting to increase surface area (good for increasing radiative loss, not so much for convective loss as far as I understand) if radiation is going to be significant compared to convective loss....
 
Last edited:
shadowscotland said:
I think it all comes down to air being the limiting factor.
With active system the volume of air over the rads is significantly higher so the benefits of higher flow rates/impingement blocks has real world advantages (abet with diminishing returns)
Passive systems don’t have that luxury - unless your rad is outside (wind) in a wc cistern (flush cycle) or on a window sill (down draft)
But the size and design of passive rads means they act in convection and radiant sources. Also as the flow rate drops and the coolant become warmer more energy is released radiantly (upping the efficiency curve).
If you’re going to use microbore pipe, you may struggle if using water as a coolant. I’m sure that Cathar’s flow graphs showed major performance drop below 8mm ID – something like water wetter may help if you can stand the smell. But at those diameter’s you’re into air conditioning flow data.
I’ve just ordered an 800x400mm radiant heater and a more powerful pump for my next build and I’m concerned it’s all a waste of time... Oh well it will all be in my log if my family can stay well for a at least one weekend this season
Click to expand...

edit: Is the 800x400 heater a baseboard type thing? Sounds interesting...
 
shadowscotland thanks for the comment using the V2 system with their additive has run faultless since it went in, holds the 9550 at stock at top 20c into the early 30c if ambient comes up, the overclock holdsat 40ish with ambient at mid 20c in the room so works well considering, very short pipe length res to box nomore than 12-14inchs stock water block but good case which I think helps a lot.
Long live passive!!!!!!!!!!!!!!
Have a second rig with somewhat modified Asetec pumped system that ended near silent but you still need the fans even at 750rpm you can hear them hense the existing setup.
 
We're going off topic here I know but...
@ MP The 800x400 is 6 lenghts of heatprofile skirting stacked in parrallel / series (will test which is better / neater).

@ JB - nice low output quad - might get myself one of them - never run just a single block loop. What keep the rest of the hardware cool, as never managed to keep my case/hhd temps below 50c without either water or a single fan.
 
shadowscotland the case as sig has 2 exhust at low and 1 exhust in the lower compatment all at slowest speed, it sits alongside me on the desk and you can just hear it, the case temp at this moment in time is exactly 26.7c and it has been b!!!!! hot down here today.
Have 4 sticks Domi ram with coolers on top with two sensers , one on stick one and other on stick three and they are at 34.5 and 31.2 so there don't seem to be to much heat in there anywhere you look.
 
Monkey Puzzle said:
Should have mentioned - the microbore tubing is running parallel in 48 tubes, it's optimised for 7/16 to 1/2" tubing (total flow resistance for 49 x 4.8mm ID in parallel is equal to 1/2" ID), so pressure drop shouldn't be too much of an issue.

Any idea of firm figures what importance/proportion of heat is transferred by radiation by passive fins - can't find anything definite, and want to know whether to bother treating/painting the copper afterwards, or even sanding/sandblasting to increase surface area (good for increasing radiative loss, not so much for convective loss as far as I understand) if radiation is going to be significant compared to convective loss....
Click to expand...

From what I consider to be one of the best sites on the web you may find this and the associated links useful, sections 15 and 17:
http://sound.westhost.com/heatsinks.htm

In ideal world 100,000cm2 surface area would give a thermal resistance of about 0.158C/W, not a bad start :)

Edit:
I suspect the trouble with microbore even when run in parallel lengths will be friction, the ratio of internal wall area vs water volume is relatively large ?
 
Last edited:
That's a really useful link - thanks very much ecat. :) Going off topic again, but I've been reading some very dry books on heatsink design, Reynolds and Nusselt numbers, how to decrease the boundary layer etc and umming and ahhing about whether to go to the hassle of creating louvers in the (100+) fins or not.

But it looks like the fins should be painted very thinly I guess. I wonder whether that's possible with powder coating; all powder coating I've seen has been thick and it needs to be sprayed, which isn't easy as it'll need to be done after the soldering/welding of the fins in place... and I imagine electrolytically apllied paint would cost a fortune :(. Pity I'm going to have to cover the copper really, as polished copper is an absolutely beautiful light salmon colour.
 
Polished copper = 0.07, oxidised copper = 0.7 :eek: Maybe it's like mama always told me and pretty isn't always best ?

Oxidised copper (kinda, sorta like anodising) is passably effective, but rarely used due to its cost
Click to expand...

What colour does copper go when you blast it with a blow torch ? Dark enough to increase the emissivity without using an insulating layer of paint ?

Much easier on the eye would be black nickel plating but I have no idea of the thermal consequences.
 
Last edited:
ecat said:
Polished copper = 0.07, oxidised copper = 0.7 :eek: Maybe it's like mama always told me and pretty isn't always best ?



What colour does copper go when you blast it with a blow torch ? Dark enough to increase the emissivity without using an insulating layer of paint ?

Much easier on the eye would be black nickel plating but I have no idea of the thermal consequences.
Click to expand...

Yeah, I've looked into that as well, but haven't found much on it. Plus would no doubt be pretty expensive as well... I've already spent over £100 on copper and don't really want to have to send another £50+ (rough guess) on plating...

It depends really on how important radiation is compared to passive conduction/convection as to whether it's worth it - I'm using a ridiculously large amount of surface area so might just plump for prettiness and less cost if it's not going to make much difference anyhow... Hmmm, maybe I'll email random heat exchanger academics and get their opinions/suggestions; from my dissertation I found professors were surprisingly receptive to random emails!
 
Last edited:
Ill input only to say that copper will go very very black when heated enough. Its a good idea to check the thermal conductivity and solubility of copper II oxide, as I'm pretty sure the former will be low and the latter high.

The black coating which forms will also flake off if you let it thicken too much. Producing an even coating with a blowtorch won't happen easily, I want to suggest heating it electrically but this will do nasty things to that months electricity bill. If done nicely this would be beautiful
 
Indeed, electroplating or electro-anything is the ideal way of doing surface treatment. My personal feeling is do not do anything that reduces the potential for convective cooling. But that's boring, especially when it precludes you from playing with chemicals with names like 'Liver of Sulphur', just thinking the name I can feel base metals start to blush ;)

Some links I've picked up on my travels:
http://www.modelmakingsupplies.co.uk/taps---dies.htm
http://www.how-to-make-jewelry.com/liver-of-sulphur.html
 
Last edited:
You must log in or register to reply here.
Back
Top Bottom