Tower 900, 2 Res, 2 pumps, single loop?

[LordCorellon]

Trying to get some opinions here, I have a tower 900 case and it has a lot of space and for aesthetics would like to have two reservoirs to balance each size out. The simple and straight forward approach would be to run dual loops but I don't really see the thermal dump of each loop being equal so that's a lot of "wasted" rad.

I'm aiming for a 5090 with a 9800x3d or the newer 9850x3d with two 560mmx60mm thick rads. Since I anticipate most of the heat dump will be coming from the 5090 and I feel it would be a shame not to use both rads to dump the heat rather then running dual loops. I am planning push/pull for each of the rads, ideally would like to keep it at lower speeds (Fans are Silent Wings 4 Pro 140mm which have some decent static pressure to fight against the thick rad) which is why I'd rather keep both rad's together. I wonder what the effect would be if the rad's were merged together to run parallel then split to feed back to the res, in theory the pressure should be equalized feeding each res. I have to play with direction, the case is pretty "leaky" so running both rads in and creating positive pressure might work so long as it doesn't push too much out into the front chamber (I'm planning some mods to better isolate it from the back airflow wise and make it more like a true dual chamber). I do need the HDD bay in the middle as I still hold on to some mechanical disks for cheap storage that doesn't need to be fast.

That said the initial thought would be to run the loops as an X of sorts with the res serving as a "mixing pot" since they have two inputs and outputs each.....
D5(1)->CPU->________________->Res(1)->D5(1)
________________Rad(1)->Rad(2)
D5(2)->GPU->________________ ->Res(2)->D5(2)

In theory I think this will keep the pressure of each res equalized, but not sure if that will still cause other issues. I'm not too concerned with a pump failure, Aqua computer makes good stuff and these pumps are new and even though D5's rarely die (I've only had one die in the last 18 odd years) I still set them up to shutdown the computer on failure (or if the flow meter detects no flow), I also found some BSPP and G 1/4 check valves (pure copper or nickel platted brass) but I'm sure they would add a ton of restriction to the line. I'm also planning some QDC's that I could bypass a pump/res if it failed if needed while getting a replacement and to make changing out/cleaning a block easier. Used Acrylic for my last build, it's a pain but think I'll be doing that again for the front (visible) tubing and then using EPDM tubing in the rear for ease of routing. An advantage of doing it this way too is that if a pump were to fail I could just swap the QDC to isolate it turning it into a single pump loop.

Open to other suggestions but I am going to insist on two res to balance the aesthetics.

Thanks

 

[Tsumi]

What is your planned airflow? Are both radiators going to be intake or exhaust? Or will it be one each for left-right/right-left airflow? Personally I would do both as exhaust, allowing the top, bottom, and back vents to be the intakes. In this configuration, I would have the radiators be in parallel with Ys.

I would do serial flow. It's possible to do this by going Res1 -> D5 1 -> CPU -> GPU -> Res2 -> D5 2 -> radiators -> Res1. Alternatively, you can do Res1 -> D5 1 -> CPU -> Rad1 -> Res2 -> D5 2 -> GPU -> Rad2 -> Res1. As long as the reservoirs are sealed, the system will act the same as having the pumps next to each other. The only thing to be careful about is during filling. If fill ports are open on both reservoirs, whichever pump has less restriction will push more liquid into the side with more restriction, eventually causing the reservoir to overflow. To make sure that doesn't happen, just fill from one reservoir at a time while making sure the other fill port is closed.

 

[pendragon1]

if its all in a single loop, order doesnt really matter much after heat-soaking....
id' just put it together however looks best to you and make sure the rads are exhaust.

 

[owcraftsman]

 

[LordCorellon]

Lot of great input here thanks!

Tsumi I'm leaning towards both being exhaust or both input depending on what sort of fan speeds I end up needing to run (if it's very low (so that it doesn't spill into the front chamber) I'll do input so as to keep positive pressure) but most likely will be doing both exhaust.

pendragon1 yeah the order itself isn't so much my concern it was the whole parallel vs serial vs hybrid setup.

owcraftsman thanks for the image! That's actually how I was originally considering doing the setup but was told off by others for considering dual res in serial, I didn't like a full parallel system either so why I was thinking of the hybrid of rads in serial but the rest in parallel (Again other advise was that rads in parallel were a no-go).

Very interesting in the difference in the feedback I've received of parallel vs series, I'm glad my original thought process wasn't as out to lunch as I originally thought and it was a viable idea. I've got a lot to think over again now, usually I'd do the res with the ports on the top to make bleeding/draining easier but it makes sense with them on the bottom, generally I'll fill from the res top (multiport top) rather then the rad but as noted that would be a consideration to ensure they don't over spill. Been toying with the idea that if I added a leakshield (standalone) to the system it would be tying the top of the res together like a T with the leakshield being on top (to assist with filling as well) but that's complicating an already comlicated setup.

Once again, really appreciate the feedback and assistance.

 

[Tsumi]

I essentially have a dual reservoir system in my current setup (Koolance RP-452X2). There is absolutely no problem with running two reservoirs in series. The only thing to remember is regardless of where you're filling from, have only one open fillport at a time unless it's at the same height on the same component (i.e. two fill ports on top of the same reservoir, two ports on top of a radiator, etc). Once the system is sealed, the reservoir acts like a giant piece of tubing. Anyone that tells you running two reservoirs in series is problematic doesn't know physics.

 

[LordCorellon]

Yeah I didn't understand it myself because essentially in a closed loop it's not going anywhere unless as you said you open and let the water out. I did have some consideration that one res or the other would run lower but given that they have ~600ml each I'm pretty sure I could spot and top them up before that became a real issue. Funny enough it wasn't just one person saying it but a group. End push was always to just run dual loops instead of a combined loop so perhaps that was just the motivation right there.

Thanks again, think I have an idea of what I'll be doing but will just need to wait for the GPU and CPU blocks to arrive along with some odds and ends to put it all together.

 

[Tsumi]

What would happen is the air in one reservoir would compress and the other would expand until the pressure difference equals the pressure difference of each segment of the loops. The less air you have in the reservoirs, the lower the change in volume to equalize the pressure. Air cannot travel from one reservoir to the other unless it's getting sucked down to the pump.