PC waterchilling w/ AC

[WhiteSkyMage]

Hey there oc enthusiasts,

 

I know there are some of you out there that manage to run your PC under sub-zero daily using an AC-chilled water.

I am in the process of planning a similar project, but I just need to know a couple of things.

 

First a couple of things to note - I plan on cooling an i9-9900K and a "worst case scenario" - 400-500W GPU (assume some next gen power-hungry Ampere/RDNA GPU).

So the question is - in terms of "BTU" (British Thermal Unit) - what do you think would suffice? I saw a couple of guys on overclock.net do x2 10 000BTUs and 20K. A friend of mine recommended 24K.

I've been looking for 2nd hand ACs but I am really unsure what would suffice.

 

I am not really sure what AC Timmy Joe is using here. I think perhaps a PMP600 from Koolance will be good enough pump for this use. Afterall it's an industrial pump...

 

Now as far as how am I gonna tackle the condensation (since water + electricity = bad)....

Put my PC in a 2nd sealed box, and put Reusable Silica Gel Humidity Moisture Absorber Beads around the MB. And for activating them - 5min in the Microwave is all that's needed.

https://images.app.goo.gl/Je5jYVf6F3UtDsRd9

[VeganJoy]

sounds like a complicated endeavor, best of luck! just gonna mention that some of the fancy asus z390 maximus boards have condensation safeguards, not sure if those are useful or something

[shoutingsteve]

Have you considered submersing it in oil and running the evaporator coil through the oil?  that would completely remove the danger of condensation, plus you will get much better thermal conduction in the oil.

[WhiteSkyMage]

13 minutes ago, shoutingsteve said:

Have you considered submersing it in oil and running the evaporator coil through the oil?  that would completely remove the danger of condensation, plus you will get much better thermal conduction in the oil.

I thought about oil but the issue then is that the maintenance will get very nasty.

I am not going to be OCing that CPU as much as I would the GPU. There are also MB VRM heatsinks that I can use. So I am not sure if that's worth it though. I see a lot more people do chilling than oil cooling or rather they screw around with those Peltiers...

 

Id rather stick to watercooling because I can do it and I do not need to buy that many fittings as I will not have that many components in that case - 2 for CPU, 2 for GPU, passthrough for the box. No need for radiators. So to be honest, so the price may get about as = as the traditional custom WC rigs, but I will be getting way better temps (it won't look as good from the outside though!). 

15 minutes ago, VeganJoy said:

sounds like a complicated endeavor, best of luck! just gonna mention that some of the fancy asus z390 maximus boards have condensation safeguards, not sure if those are useful or something

I have a Z390 Phantom Gaming ITX from Asrock. I don't think condensation will be much of an issue when the beads are around and I am actively measuring temps inside the box. I might just put a camera inside the box so i can tell when they need to be reactivated (that would mostly be my maintenance. Those beads are cheap anyway.....

[Demonic Donut]

1 watt of pure electrical power to heat is 3.41 BTU/Hr.

 

So for the GPU you'd need about 2000 BTU/hr, assume another 2k for the CPU at full load.

 

In theory you'd only need a half ton chiller.

 

Remember that comfort AC is sized and designed to run at comfort cooling temperatures. I don't remember exact Ashrae numbers, but it's something around condenser air 90-100 and evap entering air at 77 or so? The colder you run the evap side, the less capacity you get. Running lower condensing temperature does help, so if you don't mind your Frankenstein AC dumping heat into your already conditioned space, you can assume condensing temps near your house ambient, or with less efficient units, 10 degrees above ambient.

 

There is a lot to consider, but I'd try to aim for a half to one ton unit. (6k-12k BTU/Hr) and have a fairly large water capacity. Cycling kills compressors, try to have compressor off time be a minimum of 1-2 minutes. Aim for a 12k unit or more if you want to bring temps really low.

 

Even better, look for a small water source heatpump. That way you already have a water coil and don't have to hack something together like Linus' old "chiller"

 

[WhiteSkyMage]

7 minutes ago, Demonic Donut said:

1 watt of pure electrical power to heat is 3.41 BTU/Hr.

 

So for the GPU you'd need about 2000 BTU/hr, assume another 2k for the CPU at full load.

 

In theory you'd only need a half ton chiller.

 

Remember that comfort AC is sized and designed to run at comfort cooling temperatures. I don't remember exact Ashrae numbers, but it's something around condenser air 90-100 and evap entering air at 77 or so? The colder you run the evap side, the less capacity you get. Running lower condensing temperature does help, so if you don't mind your Frankenstein AC dumping heat into your already conditioned space, you can assume condensing temps near your house ambient, or with less efficient units, 10 degrees above ambient.

 

There is a lot to consider, but I'd try to aim for a half to one ton unit. (6k-12k BTU/Hr) and have a fairly large water capacity. Cycling kills compressors, try to have compressor off time be a minimum of 1-2 minutes. Aim for a 12k unit or more if you want to bring temps really low.

 

Even better, look for a small water source heatpump. That way you already have a water coil and don't have to hack something together like Linus' old "chiller"

 

Thanks for the info.

The chiller with my PC will probably be somewhere outside. I will just run a cable or 2 inside. So no worries about the air conditioning in my room. Also - it gets pretty cold where I live so I guess winter would be an overclocking heaven with some really chilly temps.

[Demonic Donut]

19 minutes ago, WhiteSkyMage said:

Thanks for the info.

The chiller with my PC will probably be somewhere outside. I will just run a cable or 2 inside. So no worries about the air conditioning in my room. Also - it gets pretty cold where I live so I guess winter would be an overclocking heaven with some really chilly temps.

To an extent. Again, comfort AC is designed for warm ambient. You'll likely need fan cycling for head pressure control, or you will drive your differential pressure too low and lose refrigerant flow. You could also do hot gas bypass, but that will require brazing and not just electrical work. This can start becoming an issue below 60F or so outdoor temps. But again, with lower than design evap pressure/temps, it might not be as big of a deal until it gets very cold out.

[WhiteSkyMage]

28 minutes ago, Demonic Donut said:

To an extent. Again, comfort AC is designed for warm ambient. You'll likely need fan cycling for head pressure control, or you will drive your differential pressure too low and lose refrigerant flow. You could also do hot gas bypass, but that will require brazing and not just electrical work. This can start becoming an issue below 60F or so outdoor temps. But again, with lower than design evap pressure/temps, it might not be as big of a deal until it gets very cold out.

It gets -10C (14F) here in winter. I might as well attach a couple of rads with fans once temps are below 0C because there won't be any need to use the AC in this case. I can just cool my water with outside temps. MORA 3 will do the job....

[Demonic Donut]

1 minute ago, WhiteSkyMage said:

It gets -10C (14F) here in winter. I might as well attach a couple of rads with fans once temps are below 0C because there won't be any need to use the AC in this case. I can just cool my water with outside temps. MORA 3 will do the job....

Just add some glycol and you'll be good to go!

[WhiteSkyMage]

4 minutes ago, Demonic Donut said:

Just add some glycol and you'll be good to go!

you mean inside the antifreeze/antifreeze mixture that I am cooling? I plan to do a 3:1 (water to antifreeze ratio) with some filter which Timmy Joe showed.

 

I am just hoping that those beads will get the dehumidifying job well enough inside my airtight PC box.