Passive cooling with a... floor \(o)-(o)/

[g g d h]

Sup... first post. Be gentle 

 

I got into watercooling quite some time ago. Got my first WCed rig (8800GT SLI) way back in uhm... 2006 and ever since i never had any air cooler on my CPUs / GPUs 

Currently sitting on an i7-2600K (quite OK unit >>5GHz @ 4C/8T ezy pzy<<, got it from an overclocker from XtremeSystems who got it to 5.5GHz on LN2) and a GTX780 both sitting on MSI P67a-GD65 with 8GB RAM and bunch of drives. All in a BitFenix Shinobi XL with Thermochill PA360.3 (any old timer still remembers it and how much cooling potential it has?) and an EK 240 thick radiator (don't remember the exact model), XSPC RASA slapped on CPU and FC EK waterblock on a GPU. Oh... and i still have unused and boxed HW Labs BlackIce SR-1 420 radiator that will be waiting patiently for MiniMe to grow up and get hooked on WCing 

 

So to the point: I am about to move in into new house i have build over the last 2 years in Poland. It has floor heating on its 230m2 and has one peculiar extra loop - 35m of a floor heating tube with an inlet and outlet under the to-be-build-desk where my PC in my man-cave will be placed  you know where am i going with this? 

 

1) heat capacity of concrete floor is quite high (thickness in my case varies from 6 to 9cm) and at the same time inertia of heat flow is rather low. In other words: it will heat up slowly and will cool down slowly.

2) floor will never be heated above 28°C so i can assume that's gonna be my max ambient temperature. It is more likely, considering my house is very energy efficient, floor temperature will not pass 25°C. Cooling liquid will always be warmer than that and there will be no situation when loop is being heated by the floor - it will be always other way around.

 

 

So for those who don't know about floor heating it is done like that (perspective of this pic is really distorted as windows on left and right are perpendicular to each other):

 

 

And the additional loop i have placed in a very last literally hour before the floor was poured. And as of now the loop ends look similar like on the pic below (man-cave is already tiled and the walls are finished with plaster and painting):

 

 

As you can see i know exactly what i am doing with this. What i need is some advice on WC gear as i have stopped following the market / trends many years ago (family, work, lack of time for gaming etc.the usual story...):

 

- circulation pump: i doubt regular WC pump will be able to handle such hydraulic resistance (tube has ID=12mm and 35m length). So i will be getting a pump used typically in heating systems. Is it the right route? You have other suggestions? 

 

- i need to figure out quick-disconnects and want to build some sort of a manifold to be able to quickly attach / detach PC without bleeding air into the loop. Preferably at the desk's top close to the PC case. If the loop is not efficient enough i want to be able to quickly add radiators at my will. Any advice how to approach this aspect of a system? 

 

- what sort of reservoir do i need? The volume of liquid in a tube alone gonna be pi*r^2*L = 3.1415*0.006m^2*35m = ca 4L, so really little. But considerably a lot in terms of WC systems (BIG tube reservoir for PC is 0.4L).

 

- since i will not be needing (if it all works at the end... ) radiators i will be on the market for a small case. Not planning on changing my PC dramatically, so ATX MB size, fairly long GPU and at least 2x HDD and few SSD must fit in that case. If it has bulk-head type pass through at the back to run the tubes, that would save me time on modding the case. 

 

 

 

ALL ON BOARD THE CHOO-CHOO TRAIN!

[g g d h]

That's why I want to have an option for connecting the rad ready and waiting at my desk. You know what crossed my mind as much cheaper option compared to x2 D5s? Aquarium pump similar to one I use in my sump. It has 2m+ head pressure, can be run submerged if needed - I can use a bucket as a reservoir and since it will be an open system (evaporation must be under control) the pressure on WCing components won't be an issue.

[W-L]

4 hours ago, g g d h said:

-SNIP-

You will need a pump that is capable of moving that volume of water fairly well, due to the tube there won't be high restriction but high frictional loss from the fluid itself moving through the tubing. 

 

I'd recommend something pretty beefy like the ones Linus used in his whole room cooling loop or something like this below. For the loop it may be best to have a dual loop one portion under the pad and one that is only to the PC with a heat exhanger that way the fluids never mix and issues arising in the PC do not affect the quality of the loop that is unreachable in the concrete. 

https://koolance.com/pump-g-1-4-bsp-pmp-600

[g g d h]

11m head pressure? A circulation pump in a heat pump i use as heat source for my house has 4.8m @ ca 16L/min and runs 1750m of tubing in 26 loops. Who this Koolance pump is actually for? Hard to imagine a cooling system optimal for this pump...

[W-L]

1 minute ago, g g d h said:

11m head pressure? A circulation pump in a heat pump i use as heat source for my house has 4.8m @ ca 16L/min and runs 1750m of tubing in 26 loops. Who this Koolance pump is actually for? Hard to imagine a cooling system optimal for this pump...

I've seen a few builds where they've done the whole room watercooling type idea but to locate the rads from the PC down into the basement of their house going though the floor and having two of theses in series to provide enough pressure for the whole loop up to the PC through all the blocks and back down. Note that pressure is directly proportional to flow so at 11m you essentially have zero flow which mean no actual cooling. This pump would only have 3M of head pressure at approx 16LPM of flow to comparing to your heat pump, if that is not just the absolute max ratings.

 

For the heatpump it doesn't require a lot of pressure being that yours has 26 parallel loops providing very little restriction. In a PC once you start adding blocks and long tubing runs at a decent height that's not just on a single plane like in a slab it can add up.

[g g d h]

I have doubts a PC cooling system is more restrictive them 1.75km of tubing with hundreds of 90° turns and tens of 180° turns. Half of that length is at the upper floor, so it is not a single plane.

And 3x manifolds with 26 rotameters with cut-off valves... 

 

I still think these Koolance pumps are just ridiculous.

 

[W-L]

On 6/11/2019 at 4:22 PM, g g d h said:

-SNIP-

As said it depends on the application and type of pump that one is just a heavy duty D5 design, with 26 parallel loops of 1.75km you still have very little restrictions since there are lots of paths to take. The most restrictive section of a loop will be blocks, for a regular a PC it will be cycling the entire volume of the loop around every 5-10 seconds. The in floor heating doesn't require that kind of flow or pressure for it's application. 

[g g d h]

You are right. 

But I can bet I can go away with low flow because of the volume of liquid in the loop. 35m of tubing will hold ca. 4L on its own. Hardly any WC system gets anywhere near it. 

I will experiment with the pumps I have. In my pc I have this pump known for being modded with solder mod to boost its performance - that was long time ago, will have to refresh my memory. Also have two aquarium pumps to test (planning on getting bigger one for a fish tank anyways).

[W-L]

3 hours ago, g g d h said:

You are right. 

But I can bet I can go away with low flow because of the volume of liquid in the loop. 35m of tubing will hold ca. 4L on its own. Hardly any WC system gets anywhere near it. 

I will experiment with the pumps I have. In my pc I have this pump known for being modded with solder mod to boost its performance - that was long time ago, will have to refresh my memory. Also have two aquarium pumps to test (planning on getting bigger one for a fish tank anyways).

Wouldn't be a bad idea to do a simple test by hooking up the tubing loop with the pumps and a bucket to check the flow and what is needed. I'd also help to flush the loop if there is any dust or debris in it from construction. 

[g g d h]

Slowly but steadily...

 

Got some fittings in plumbing store along with quick disconnects used typically for compressed air systems. Tested already and they work just fine even at much lower pressure typically found in WC systems...

Found at my parents place an old MountainMods MoBo tray, never used, and I am tempted to use it...

 

Now waiting for winter for some more time to spare at my hobbies :) 

[AnonymousGuy]

I have a PMP-600 circulating water with a very good flow rate through 125ft of 5/8" ID tubing, at 24V.  This pump is fairly loud though so it's remote located.  I suspect a D5 Strong (PMP-450S) at 24V would be able to handle it just fine.  I believe there's online calculators that will give you head pressure needed at flow rate through various tubing diameters.  You don't need a massively high flowrate here, just like you don't in a watercooling loop because your actual heat load isn't high (ie you don't have a blowtorch going on the water)

 

Also,  buy a stacked plate heat exchanger.  Never ever try to plumb up your desktop in series with a massive loop.

[g g d h]

I will write up the whole story as i have actually completed the project - now still at the ghetto stage with tubes hanging here and there, but the principle was checked. IT WORKS.

 

And regarding the flow rate and restrictions and couple-hundred € watercooling pumps - it all works with 90L/h flow using 32€ aquarium pump (Eheim Compact 1000 - old version). 

 

 

And just as a teaser please check the thermals after 14 minutes of Furmark GPU and Furmark's CPU burner running simultaneously...

 

[g g d h]

A follow up story... 

 

Upgraded the system to 3700X and a 5700XT, got both watercooled. All packed in CM Silencio S400 case for size and esthetics.

 

When running FurMark with again both CPU and GPU burners running at the same time, the CPU peak temperature flattens around 64C and the GPU does not exceed 43C. This is still with the x2 aquarium pumps running this configuration.

 

Will have to check how good is the CPU block contact with the CPU cause i expected lower temps...

[g g d h]

Not saying that Jake and Linus have read this topic before going ahead with cooling system based on the floor heating pipes embedded in the pool's bottom concrete...

 

but they did LOL 

 

 

Or someone please point them here and see what they think 

 

[NorKris]

ur rly flooring it dude!

[Crittman]

I am actually thinking about doing this in an School bus RV conversion soon. However I was thinking I would dump the heat into a small tank that my tankless(or not in this case) heater would pull from. I was also thinking about adding an aquarium water chiller after the water tank.

[thejackalope]

You could set up a heat exchanger. Have the pump pushing water through a tank with an open top. Then use a regular water cooling set up on the computer but submerge the radiator in the tank