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Hardware Princess
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Discussion Starter · #1 ·
I had this piece of crap dehumidifier sitting in the basement. It came with the house when I bought it 4 years ago and I never really used it. I figured for its size it wouldn't have much cooling capacity but decided to check it out today. Turn out it can draw 4.8A at 120V which means it's probably a 1/2 HP compressor! It also uses good ole R22 which boils at a nice low -41c. It was made in 2009 and I thought R22 was banned by then? Must be because it's from China lol. I had nothing to lose, so I decided to disassemble the thing to see what I could do with it. It came apart with a lot of screws but not too much difficulty.

In a dehumidifier, the evaporator and condenser are back to back. This way, the evaporator can collect moisture from the air due to condensation and drop it in the tray below, while the condenser heat keeps it from freezing up and also keeps the inlet/outlet temps roughly the same (since the system is basically exchanging heat with itself). Obviously this setup wouldn't work to cool a computer. The screws connecting the two took a drill and several different sizes of philips heads to remove, since they had corroded in place. I also removed the humidity sensor that they had shoved into the evap, lol. The next challenge was to bend the evaporator to where I needed it to be, so I could dunk it in a tank of water. I had to very carefully bend the copper inlet and outlet pipes, lest I break one and lose all my precious R22. The braze joint from the outlet to the evap was particularly concerning. Luckily, I took my time and nothing broke.

I used a storage bin I had laying around as a res. It was what I had that was the right size, though not ideal. I filled it up with tap water and let it rip. It worked great, too well actually, the evaporator turned into an ice block lol. I shut it down soon after as I was worried about the expansion of water into ice damaging the evap. In a way it's good, as it verifies this system will have subzero capability. The whole bin of water stayed at 40f for hours (though it probably was somewhat cold from the tap).

I will need a coolant with a lower freezing point to test further. I'm thinking 60% propylene glycol, 40% water, which freezes at -48c. I'd like to acquire a smaller container for the evaporator (to reduce the amount of glycol I'd have to buy, and make it easier to fill/empty/move). That, and a pump/res, tubing, fittings, insulation and a waterblock that I could actually connect it to a computer with.
 

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That looks like a neat project. I have a phase cooler laying around ( -50 C on 5960x, but too slow to react to load changes) and might want to mod that for some GPU liquid cooling. BTW, check this Linus vid out...he's using some sort of 'RainX' windshield wiper fluid (apparently, there are two types, one of which is ok for a PC loop)
 

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Hardware Princess
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Discussion Starter · #3 ·
That looks like a neat project. I have a phase cooler laying around ( -50 C on 5960x, but too slow to react to load changes) and might want to mod that for some GPU liquid cooling. BTW, check this Linus vid out...he's using some sort of 'RainX' windshield wiper fluid (apparently, there are two types, one of which is ok for a PC loop)
https://www.youtube.com/watch?v=HMtvEbD2MQo
He only uses a 1/10 HP chiller though, mine should be much more capable :) I'm surprised a 1/10 HP could do much of anything with a 2990WX, lol. Of course, he doesn't show much in the way of benchmark results. He sure does love that Rain-X. I found an SDS for it which says its main component is methyl alcohol AKA methanol. Probably mixed with water to achieve the desired freezing point (and save money) since methanol freezes at -96c. It also has a specific heat of 2.51, vs. water at 4.186 and propylene glycol at 2.2. So it would actually work better, but not sure the Rain-X would get cold enough for me without freezing.

According to this, it looks like a 50/50 mix would get me down to -50c:

https://www.engineeringtoolbox.com/methanol-water-d_987.html

It is still pretty cool that I have something with the cooling capacity of a $600 Hailea HC-500A chiller, for free!
 

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Hardware Princess
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Discussion Starter · #4 ·
Bought some GOODIES from Harbor Fright and Lowe's today.

Somehow managed to find a 4 gallon igloo cooler in EXACTLY the perfect size. Also got the laser temp reader, and a nice case thing that could be used to hold CPUs.

Of course, it being Harbor Freight, the temp reader didn't come with the 9V battery it needs to run, lol. I didn't have any laying around, so I just borrowed one from my smoke detector. Don't worry, I put it back when I was done so the house won't burn down.

The tin snips with footlong grips work really well for opening that stupid blister packaging!

I put the evap in the igloo and added 3 gallons of RV coolant (like 50% water, 50% propylene glycol). So far, it hasn't frozen yet. I will see how cold it can go! The RV coolant I put in the freezer flowed fine at 5F, it didn't turn into syrup.
 

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Hardware Princess
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Discussion Starter · #5 ·
UPDATE:

So the propylene glycol / water mix still seems to freeze, or at least slush up. The evaporator forms this snow or frost like layer on it. I think the water separates out from the glycol. But there is still a little glycol in that slush so it turns into a snow-like substance rather than freezing into an ice block that could damage the evaporator. Maybe it will still work? The remaining liquid still flows easily, I think the glycol concentration increases. Still pumpable unless that slush breaks off, could damage a pump? Maybe I will try ethanol/water instead, if I can figure out a reasonable way to buy some.

The good news is that it gets cold. I saw as low as 20F/-7C on the liquid and can probably get it colder. And the igloo cooler insulates fantastically well, zero condensation on the outside. When I looked at it this morning after 9 hours, the liquid was still 25F!
 

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Hardware Princess
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Discussion Starter · #6 ·
Welp... looks like propylene glycol is out. Time to try something more toxic ;)
 

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This is a very cool project. I am glad you posted this. +1 on the rep for this. I am interested in the results when you find something that wont slush up and that I could even make for my chilled test bench. So please keep the updates coming :)
 

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Hardware Princess
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Discussion Starter · #8 ·
This is a very cool project. I am glad you posted this. +1 on the rep for this. I am interested in the results when you find something that wont slush up and that I could even make for my chilled test bench. So please keep the updates coming :)
Thanks :) I tested it with Rain-X de-icer which worked much better, stayed nice and thin even at -20F with no ice on the evaporator. Problem is, it gives off toxic fumes, so can't really use it indoors. Next step is to try ethanol, should be safe to have inside and not too flammable if mixed 50/50 with water. Ethanol has similar chemical properties to methanol.

I think -20F is about as cold as I can go on R22, but still excellent. I mean, this is the cooling capacity of a $600 fishtank chiller, for free!
 

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I think -20F is about as cold as I can go on R22 said:
Yes, I was looking into chiller options for my test bench only and when I seen this I thought that was a very good idea. Have you only tested the cooler to see if it ices? Or have you ran it through any tubes and a waterblock to see if it can actually keep the liquid that cool with constant heat from a waterblock and a 9900k or 7980xe?
I see chillers that say they will cool 6 liters or something like that, and I know a loop is only about a liter depending... But, with constant heat from a CPU block and a GPU waterblock it makes me wonder if it will stay a nice cool at -20c or something that you can actually use for extended periods without going for a $1,000 chiller.
 

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Hardware Princess
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Discussion Starter · #10 ·
Yes, I was looking into chiller options for my test bench only and when I seen this I thought that was a very good idea. Have you only tested the cooler to see if it ices? Or have you ran it through any tubes and a waterblock to see if it can actually keep the liquid that cool with constant heat from a waterblock and a 9900k or 7980xe?
I see chillers that say they will cool 6 liters or something like that, and I know a loop is only about a liter depending... But, with constant heat from a CPU block and a GPU waterblock it makes me wonder if it will stay a nice cool at -20c or something that you can actually use for extended periods without going for a $1,000 chiller.
Not sure yet but I will find out :) At 1/2HP and with a 4 gallon reservoir it should do pretty well. I will probably try it on some old crap hardware first just in case I run into any condensation or chemical degradation issues. (i.e. ethanol eating through plastics or rubber) At some point I'd like to pick up a 9900K for the test bench, but maybe in a few months. Probably going to spend the $ on Titan RTX first lol
 

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Very nice, well when you get around to testing that please pay an update.
 

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Hardware Princess
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Discussion Starter · #12 ·
Finally bought a real tube cutter today, instead of just using scissors which doesn't work well lol. Also some polyethylene tubing which is safe to use with ethanol. It doesn't bend too well, almost like hard tubing. The hose clamps did seem to compress it though, so hopefully it will seal well on barbs. I think I'll use the EK barbs. Just need to find a pump/res that would work.

I also need a new PSU, think I'll buy a used EVGA 1200 P2 off ebay for ~$110. It's amazing how quickly PSUs depreciated, that one's $250+ new. My 10+ year old Silverstone 1200 has like 4.8V on the 5V rail and 3.2V on the 3.3V rail, I think it's shot.
 

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The clamp over a barb should do the trick if the fit is tight, the picture you posted looks like it would be more than enough.
Did you finally settle on isopropyl and water or something else?
 

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Finally bought a real tube cutter today, instead of just using scissors which doesn't work well lol. Also some polyethylene tubing which is safe to use with ethanol. It doesn't bend too well, almost like hard tubing. The hose clamps did seem to compress it though, so hopefully it will seal well on barbs. I think I'll use the EK barbs. Just need to find a pump/res that would work.

I also need a new PSU, think I'll buy a used EVGA 1200 P2 off ebay for ~$110. It's amazing how quickly PSUs depreciated, that one's $250+ new. My 10+ year old Silverstone 1200 has like 4.8V on the 5V rail and 3.2V on the 3.3V rail, I think it's shot.

I've used a heat gun (low setting, safe distance) on polyethylene before to help tighten hose clamps...obviously, first try it out on a separate piece of your polyethylene tubing stock.
 

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Hardware Princess
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Discussion Starter · #15 ·
The clamp over a barb should do the trick if the fit is tight, the picture you posted looks like it would be more than enough.
Did you finally settle on isopropyl and water or something else?
I am looking to use ethanol, just need to find a way to source it at a reasonable cost. The denatured stuff tends to have nasty additives that I don't want to breathe in. I suppose I could use 4 gallons of cheap vodka, for $100 or so lol.

The heat gun is good advice. I need to choose a pump/res so I can do some testing here. Think I'm also gonna get the Bykski full metal waterblock, since it's usable on my ancient LGA 775 parts, then I can test my insulation skills there. Much cheaper if I lose something to condensation.
 

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Hardware Princess
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Discussion Starter · #16 ·
Just ordered the following:

EVGA Z390 Dark
Trident Z 4133 19-19-19-39 1.35V 2x8GB
Dimastech Test Bench (in red!)
XSPC X4 Photon 170 (glass res, the pump is plastic so may disagree with ethanol/cold temps, but pretty much all PC watercooling pumps are plastic too, so I'll see how it does. No reason to spend more on a d5 that might melt just the same lol)
EK Supremacy EVO Full Nickel waterblock
EK Barb fittings 3/8"
EVGA 1300 G2 psu
Some other stuff I'm probably forgetting

I also picked up a HWLabs 360GTX (also in red) and some EK Vardar fans for the test bench, for when I don't feel like insulating stuff. Forgot to buy a hard drive, gonna get a 250GB 970 evo at some point (don't need more space than that) for now the OCZ Vertex is fine. Considering their reliability, I must have the last functioning Vertex on earth lol.
 

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Hardware Princess
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Discussion Starter · #17 ·
Looks like everything will be here Thursday! Well, everything except the motherboard which will show up next week when I'm in Houston lol. I can try the chiller on my ancient Q9550, though. I think the waterblock will fit that far back? Maybe. I'm thinking just put water in the tank this time, and run the temp down to the dew point. It would be a good test.

I'm looking for a way to reduce the volume of the tank so I don't need to buy $75 of Vodka lol. ROCKS maybe?
 

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Discussion Starter · #18 · (Edited)
Got some goodies in today from Frozen central processing unit. The polyethylene tubing wouldn't fit onto the barbs at all at first, until I hit it with the hair dryer. It's on there so tight that it doesn't even need hose clamps to not leak! It also formed into a nice romantic heart shape automatically lol. Pump is the XSPC X4 Photon 170. It has a glass res. Pretty tough to fill since there isn't an easy way for the air to escape. The top lid doesn't come off for filling like an EK D5.

I think I will get some regular PVC tubing instead. This stuff works, but will be a pain everytime I need to change something. The barbs have to be removed with pliers, and the tubing is not very flexible. PVC has an "acceptable" resistance to ethanol which is probably fine for test bench use.

Interestingly the water in the pump has warmed up to 86F just from the friction of being pumped in a loop. A good reason not to bother with two pumps in a system - it adds heat!
 

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Can't you just use something else as the reservoir? Maybe like a modified cooler?
I'm pretty sure you're going to run into problems with any normal water cooling pump but I can't remember the exact sort of pump used for this, I've seen it in the 24/7 chill box thread but I can't find it...it's a pretty big thread to read through.
Either way I'm glad to see it's coming together. :thumb:
 

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Hardware Princess
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Discussion Starter · #20 ·
Can't you just use something else as the reservoir? Maybe like a modified cooler?
I'm pretty sure you're going to run into problems with any normal water cooling pump but I can't remember the exact sort of pump used for this, I've seen it in the 24/7 chill box thread but I can't find it...it's a pretty big thread to read through.
Either way I'm glad to see it's coming together. :thumb:
I have a 4 gallon igloo cooler to house the evaporator. Only wanted a res on the pump so I could use it to prime the pump (i.e. not run it dry), and/or reuse it later in a regular watercooled computer. The glass res should be okay, but there is a risk of the seals in the pump leaking and possibly plastic cracking. Will find out, the pump in this thing is pretty cheap lol :)
 
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