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Freezer Mod problem.

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WT

Registered
Joined
Feb 18, 2002
Ok, I have a lil problem with my new PC inside freezer setup.

This is how I worked it up...I have my motherboard/cpu inside the freezer along with a pump and a res full of anti-freeze. The pump sends anti-freeze that's at the temperature inside the freezer directly to the waterblock (no coil or anything). Now im getting pretty stable temps around 0C over a short period of time (30-60 mins) but if I leave the computer working at 100% for long enough (couple of hours) the temp inside the freezer slowly rises raising with it the anti-freeze temperature so the CPU temp goes up. I test this with a LONG test (played Tribes 2 all day) and I was able to really see how this pattern goes.

Now, the real problem is...even if I were to add a coil or something would it really make a difference? Because it's a close system and the heat generated by the CPU would still be the same and would remain inside the freezer, I think im screwed.

Anyone have any ideas?

(PS : Sorry if I dont have any pictures or if this text is barely readable, I haven't had time to take picts yet and I wrote this in 2 mins. ;p)
 

Tiger

Member
Joined
Apr 6, 2001
Location
UK
Just a few observations;
1. The interior of the fridge is likely to be in the order of 0-3C which is normally the lowest setting for a fridge type of setup
2. You say you are using antifreeze and I assume you mean pure antifreeze? If it is pure antifreeze then it is a poor conductor and you would probably get better results from a 40-50% mixture.
3. You don't mention the temp of the coolant in the res but if its in the freezer its likely to be lower than -15C?

Given what I have said above then you need to insulate the pipe carrying the coolant to and from the res because there is quite a big difference in temps. The insulation will help reduce the heating of the coolant other than that from the proc. Secondly you need to pack the rest of the dead space in there to reduce the amount of work the freezer is doing. I assume that the res is just in the freezer and the freezer is not in the res. Because the coolant is actually colder than the fridge you are also now running the risk of condensation in the system.
I tried that route and it is not successful. It is better to go the chiller route and put the freezer in the res and just insulate everything else.
 
OP
W

WT

Registered
Joined
Feb 18, 2002
Actually...

Im not too sure what you mean.

My setup is like this...

-My WHOLE computer is inside the freezer (except CD, HD and PS)
-I am using pure antifreeze
-Its a freezer so a normal temp inside that is 0F (-18C).


Why would I need to insulate my pipes they NEVER go out of the freezer, where would they be heated from?


My main problem is that my computer is producing MORE HEAT than what the freezer can cool. But its a really close fight and the temperatures just go up 1C per hour about.

I want to know if there's anything I can modify to HELP my freezer dissipate that heat.


Any help?
 

JFettig

Hey! I showered! Senior
Joined
Jan 5, 2002
Location
MN
dont use pure antifreeze use the mix tiger suggested, and you should insulate your pipes becaue the water and the air around the pipes iis a little bit warmer and it warms your water a little bit

i wanna see that setup!
but you dont want to open that door much or youll get condensation, just open take a few pix and close it quick, i wanna see this setup, i have been wanting to do this for a wile, but someone else beat me to it,

what are your specs?
 
OP
W

WT

Registered
Joined
Feb 18, 2002
One more thing

just forgot to add that...

since the the temp of the freezer goes up slowly, it takes the water temperature up with it and then, once I let my PC go down to 0% load, it takes a LONG time for the ambiant temp of the freezer to go back down to normal...

id say about the same time it took for it to go up.
 

Tiger

Member
Joined
Apr 6, 2001
Location
UK
The freezer may freeze contents to -18C but it doesn't get the air inside to that temp and that's the problem. The res you are using only has partial contact with the metal wall of the freezer so there is an additional layer of thermal transfer involved. Because you have only a small portion of the evaporator in contact with the coolant you cannot cool the amount of coolant adequately.
Is the freezer a chest type or upright?
 
OP
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WT

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Feb 18, 2002
Yea, I know...I leave that freezer CLOSED all the time because I have used ABSOLUTELY NO CONDENSATION PROTECTION. So opening the freezer door while the PC is working is almost certain blow-up. Only time im gonna open it is if my PC is closed and I have enough time to let it dry.

Ill have pictures in a few days maybe, im gonna open it up soon. But I would like it it someone would give me some tips on how to "overclock" my freezer in order to deal with the heat created by the PC, so I could fix it sooner.
 
OP
W

WT

Registered
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Feb 18, 2002
Before I installed this whole setup I had thought about using a coil type system that would run along the inner walls of the freezer (where it's coldest) before sending it into the CPU. But that required more $$ that I didnt have at the type..I got a bit now but I dont wanna spend a lot.
 

Tiger

Member
Joined
Apr 6, 2001
Location
UK
Here's a possible solution;
The motherboard etc should be placed high in the freezer and the bottom turned into the res. i.e. don't use a res just put the coolant mix in the freezer. That way you are going to get maximum contact with the freezer walls. Don't drop the motherboard in the coolant ;) or make a cover over the top of the coolant and the pack the rest of the freezer with styrofoam blocks to minmise the heating.
 

Shroomer

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Joined
Oct 8, 2001
Location
Ohio
... OR put a copper coil in your coolant loop and submerge it in a container of water (the bigger the better). The ice will act as a buffer for when you are on it for a long time. As long as you don't run 24/7 it would probably be okay.
 

tcl

Member
Joined
Feb 10, 2002
Location
nyc
You mentioned "overclocking" the freezer which might have been in jest but- I think things would be improved considerably if you made sure air circulation withing the freezer was very good and in particular lots of air passed the cooling elements. (how is is cooled, btw?- just through the walls or is cool air ducted into the freezer?) Blowing a fan at the warm side of the system should help too. If you want to go real crazy, you could dismantle the freezer and replace the circulating fan with something more powerful.
Anyway, definately stick a fan in there. I also like the suggestions made about filling the freezer with water or something that will "store" the coldness and slow the warm up.
 
OP
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WT

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Feb 18, 2002
Just a warning to those who suggested "if you arent running 24/7". In this kind of setup (very low temps...in the below -10C range) its imperative that your computer runs 24/7 because otherwise the change of temperature between "on" and "off" would be so great it would be a strain on the metal parts of the motherboards. The motherboards ARE NOT MADE to support this kind of contraction and dilatation, and could eventually cause problems. Wasn't a problem for me because I was already running my PC 24/7.
 

Cougar522

Member
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Jan 8, 2002
Location
USA
yes u should definitly pack the rest of the unused spac with something to insure that the freezer is only concentrating on cooling the the liquid and not the rest of the space. this will help the liquid and your system stay cooler longer.
 

Shroomer

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Oct 8, 2001
Location
Ohio
AND put a fan on the coils of the freezer, like it's been suggested in your other thread. It will make the Freon cooler in that stage of the phaze change.
 
OP
W

WT

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Feb 18, 2002
Anti-freeze plus silicone?

I was thinking about Tiger's setup of putting the antifreeze/water mi directly at the bottom of my freezer in order to get max efficiency, plus a problem arose. The bottom of my chest freezer is not a "one piece mold" it has silicone joints. Now, im pretty sure that the bottom of the freezer is water-tight but will there be a problem with exposing silicone joints to antifreeze (its the non-toxic kind but still wondering), will the silicone eventually melt and cause me some BAD BAD problems?

Just wondering, a quick answer would be terrific because im supposed to go out later to buy the pieces I need to make the modifications.

Thanks.
 

Tiger

Member
Joined
Apr 6, 2001
Location
UK
I have been giving this quite a lot of thought as I had considered this route myself at one stage.
Here's the proposal. Seal those joints with some heavy duty sealant. Ask at the hardware store for advice on the product. Explain that it will be submerged. They use them in fish tanks so I don't see a problem.
The next thing is to build a kind of tank in there. Use plexi or acrylic and make pieces that will fit perfectly along the two sides parallel to each other. They should be about the depth of the freezer. Glue them into the freezer about 75mm (3inches) from the freezer wall on both sides. Then measure the other two sides and make two more walls that will fit perfectly into the gap between the two previous walls. Again glue them in with twin pack epoxy. Before glueing the plexi walls into the freezer on one side make a a connector (a brass barbed hose fittings would be ideal. The one with threads and a backing nut). In the first side put the connector at the bottom. Where that tank connects to the far side at right angles make another hole at the top so that the coolant is forced to flow by by siphon effect from the first chamber. In the second chamber take a pipe from the hole to the bottom of the second tank and second hole at the top of the other end to feed the 3rd side. I hope I am explaining my thoughts clearly???. Each tank is forced to flow by siphon effect and the coolant is exposed to the maximum surface area of each wall. When finished you should have a central area in the freezer that will be completely dry. If you don't get what I mean I'll try and draw a diagram for you.