Bo's phase change Q&A

[harleybro]

It semms like some people might be interested in phase change but could be reluctant due to not knowing about it. I spoke with boshuter and suggested a Q&A thread be stickied. Here you can ask questions where the resident expert can help you with anything you might want to know about phase.

[Subsider]

sound like a exelant idea !
I have breifly spoke (pm) with bo and i know ill be havin him build me one in month or so , after i recoup from all the other upgrades . I cant wait to get the tec station and phase slaped around a good mobo and fast cpu just want to wait till i have the cash to go all out bo builds one heck of a sweet unit

[NINaudio]

Can they be used 24/7?

Can one unit cool both a video card and processor?

What exactly is the difference between single and dual stage (cascade)?

[1Day]

Okay my question is quite simple - Benching, what set up will allow me the most flexibility in benching. I want to be able to switch between CPU to GPU and maybe even Crossfire/Sli with my CPU on Dry Ice. I think I am wanting more than the tech can do but hell don't we all want that...?

[boshuter]

Can they be used 24/7?

Can one unit cool both a video card and processor?

What exactly is the difference between single and dual stage (cascade)?

Ok..... I'll just answer these with basic info for now, we can get more detailed with more specific questions.

1. Yes, they can be used 24/7. For 24/7 use a controller is almost mandatory IMO, it provides a way to automatically shut down the phase unit and pc in case of a problem.

2. Yes, one unit can be built to cool both a gpu and cpu, or dual gpu's. A unit like that needs to be fairly powerful and is relatively hard to build/tune. This is something that is more of a "benching only" type system.

3. A single stage uses one compressor with a gas that can be condensed in an air cooled condenser. A cascade uses 2 or more compressors with a gas in the 2nd and succeeding stages of higher pressure that have lower boiling points, but cannot be condensed at air cooled temps; The first stage evaporator is actually a heat exchanger that the second stage gas is run through, the first stage gas cools the second stage gas enough for it to condense. This works the same for the next stage if you have more than 2 stages.
This is a pretty simple explanation of a fairly complex subject. Basiclly it comes down to using using the first stage only to cool the second stage gas enough for it to condense.

[boshuter]

Okay my question is quite simple - Benching, what set up will allow me the most flexibility in benching. I want to be able to switch between CPU to GPU and maybe even Crossfire/Sli with my CPU on Dry Ice. I think I am wanting more than the tech can do but hell don't we all want that...?

Well, that question isn't really all that simple What you want is possible, to a point. For all your goals to be met would require a dual evap unit. Those can be built and can be used as cpu/gpu or gpu/gpu fairly easily; the problem comes when you want to run a pot on the cpu and are not running sli or crossfire. You really need to have both evaps loaded when running a dual evap unit. (I've been tossing around an idea of how to build one with the ability to turn on and off one of the evaps, I'm not sure yet if it's feasible, but hope to try it soon)

You also run into capacity problems with a dual evap, with the wattage put out by todays quad cpu's and even gpus, you need a lot of capacity to cool them, much less 2 at the same time.

Your best bet for all out benching with a single stage is a simple unit with a fairly powerful compressor, that will give you the best temps and can be easily switched from cpu to gpu (single card).

[NINaudio]

so, in dual or more stage condensers, you are really only using the final stage for the purpose of colling your processor or gpu, etc. The stages before the final one allow it to be used, correct? So if the first stage were to break, then the unit itself would no longer function? Would it still function if the last stage were to break? Does this also imply that in general more stages will lead to lower possible temps?

[boshuter]

so, in dual or more stage condensers, you are really only using the final stage for the purpose of colling your processor or gpu, etc. The stages before the final one allow it to be used, correct? So if the first stage were to break, then the unit itself would no longer function? Would it still function if the last stage were to break? Does this also imply that in general more stages will lead to lower possible temps?

Excellent questions NIN This give me a chance to bring up a main concern with cascades..SAFETY:stop:

You are correct, the final stage is the one that is used to cool the cpu/gpu, the stages before that are only used to get the next stage gas cold enough to condense.

The safety aspect comes in with your other question... if the first stage fails a cascade can very quickly turn into a bomb you need to have devices on the system to shut down the second stage if a failure occurs in the first stage, this would include a shut down and also a pressure relief or "blow off" valve to prevent the high pressure gas from getting out of control. The second stage of a cascade should never be started until the first stage has brought the heat exchanger down to operating temps.

If a failure occurs in either stage the unit is not going to work, but the first stage is most critical in a safety standpoint.

[1Day]

Okay thanks boss I think the solution is then to have two units that are separate. One that is geared primarily for CPU and another that is GPU focused. When Dice is being used on the CPU and Crossfire or SLI is being used then both would be needed. If only CPU then only one - Super PI type runs and such. Does that make sense?

[boshuter]

Okay thanks boss I think the solution is then to have two units that are separate. One that is geared primarily for CPU and another that is GPU focused. When Dice is being used on the CPU and Crossfire or SLI is being used then both would be needed. If only CPU then only one - Super PI type runs and such. Does that make sense?

For all out benching, that would be the best setup

[Hardass]

I purchased this evap mount from Ssilencer. The problem as you can see in pic is even without insulation the thumbscrews do not reach the 4 mounting tubes. Not sure if it is a case of thumbscrews too short, tubes too short or mount itself too thick. He is real busy and I have not yet received a reply to my pm,s from him. harleybro suggested I might get help here.

[ol'norton]

It's not meant to mount up the other way is it, so the flange is at the bottom?

[Hardass]

It's not meant to mount up the other way is it, so the flange is at the bottom?

No, I thought the same thing. If you flip it there is no where to put insulation. I had it the other way and sent Ssilencer pics he told me it was upside down. It might be the 2 half moon shaped pieces inside the mount that hold the evap inside the mount are too thick. But I do not know how far the evap is suppose to stick out.

[boshuter]

No, I thought the same thing. If you flip it there is no where to put insulation. I had it the other way and sent Ssilencer pics he told me it was upside down. It might be the 2 half moon shaped pieces inside the mount that hold the evap inside the mount are too thick. But I do not know how far the evap is suppose to stick out.

It's not upside down. The evap should only protrudee a couple of mm or so from the bottom of the mount.

Can I ask what evap you have inside that mount? From the pics it looks like you have a lot of the evap protruding from the bottom, if you are using an evap that is taller than the ones Ssilencer uses, you will have to cut the insulation (the 2 foam pieces) to let the evap move farther up inside the mount.

Hope this helps, feel free to pm me if you need some clarification on this.

[Hardass]

I think it is a Chilly1 evap, atleast Ssilencer guessed it was when I told him it had a slot for a o-ring. It sticks out roughly 1/2" from base of mount. Here are some pics of evap, and plastic pieces.