Dehumidifier glycol chiller

[milldoggy]

I have a 4 tap remote bar with 25 ft 1/4" id lines. I have been using a corny full of glycol in a mini fridge. It has worked OK, but the temps range between 47-49. Won't go any colder.

Had a dehumidifier that was undersized for my basement. Finally decided to convert it.

Here it is disassembled and bent into a cooler. Was pretty easy. Had to drill out of the screws holding the evaporator to the radiator.

I cut out the humistat and wired in a stc1000 I had laying around. Wiring diagram made this easy.

Using a 28 qt Coleman cooler. Notched at the corner. Ordered 3 gallons of glycol from dudadeisel today.

More pics to come.

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[njs170]

I used an old Air Conditioner and did the same thing. I would recommend having a circulation pump in your cooler to help your coil from freezing up. Looks good! Good Luck!

 

[milldoggy]

My line pump will run 24/7. Will that be enough?

 

[njs170]

My line pump will run 24/7. Will that be enough?

In my experience one pump wasn't enough. Try it it might work for you.

 

[milldoggy]

Modified the case today and added some insulation. Was planning on using the location where the humistat was, but the stc was too long. Found a nice spot on the side. Had to slice out the side to fit plumbing, added some aluminum just to dress it up.

 

[milldoggy]

Forgot pic

 

[milldoggy]

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[Mirilis]

i was going to do something similar but use an AC.. i actually have an old dehumidifier lying around.. perhaps ill use that instead.

 

[milldoggy]

Got some inline fuses and completed reassembly tonight. Added a 15 amp ceramic slow burn fuse on the main power in, my outlets are 20 amp where it will be. Added a 3 amp to protect the fan.

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[Mirilis]

have you tested it with water yet? Im curious to see how this performs.

 

[milldoggy]

Solid layer of ice around the chiller in a short time. Worked great

 

[Stealthcruiser]

Solid layer of ice around the chiller in a short time. Worked great

Is that good?
I'm asking seriously, 'cause I thought you would get the best efficiency if it wasn't a "solid layer" of ice.

 

[milldoggy]

I just used water as a test. It frooze the water, so the mechanics of the system are working, so yes good. Once I install it, I will use a 50/50 mix of inhibited glycol, which freeze point is below 0 F. There are charts out that list the freeze point depending on the mix of distilled water and glycol. I also will be running a pump 24/7 to agitate and stir the water. so I should not have any freezing issues, I hope!

 

[milldoggy]

http://www.prochiller.com/reGlycolChart.html

 

[milldoggy]

Have not had time to install it yet, 3 month and a 2 year do not give me a lot of free time. I did make a thermowell though. Used some 3/8 of soft copper I had lying around. Fluxed and crimped an end, dropped in some solder and sweated it closed. Flared the other end to prevent it pulling through. Figured this is safer than leaving the probe dangling in the solution with a pump in there.

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[milldoggy]

Finally got around to setting it up. My freezer died, since I had to replace it, might as well do the glycol. I went with an upright freezer this time, 50$ from CL. I can fit 12 kegs in it. Still need to install the stc and co2, but it is back running. For the chiller, I used 3.5 gallons of distilled water and 3 gallons of inhibited glycol. My 13$ 7m head is struggling a bit. I am only running 9volts and the pump performs best at 24v, so I ordered a new power supply.

 

[milldoggy]

Pics

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[milldoggy]

Also, it only runs for about 3 mins every hour. So 5% of the days.

 

[RonPaul]

I'm building something similar right now. One thing I'm unsure of, however, is that there seems to be a temperature probe and 2 ground wires attached to the coils. Did your dehumidifier have this? And does anyone have any ideas on what to do about it?

 

[milldoggy]

Without seeing a wiring diagram, can't comment much about the ground, but I would stay trace them or splice them.

For the probe, I cut out my humistat, so I just removed it

 

[RonPaul]

Thanks for your response. I tried removing my humistat but then the compressor would never turn on. Instead I was thinking of putting the humistat in the cooler assuming the humidity would always be really high in there.

I was able to disconnect the fan and the compressor still works fine. By the way, did you disconnect the fan on yours?

Here's the wiring diagram in case you're interested:

 

[RonPaul]

Well, so much for my attempt to build this... I had everything apart and I put the cooler in place... it was looking great and I was so excited. Then just as I was making some final adjustments to the position of the coils I heard a hissing sound. Apparently the copper pipe cracked right where it enters the area with the aluminum fins.

Ruined dehumidifier and wasted time.

 

[milldoggy]

Sucks, sorry to hear. It worried me when I was building mine

 

[Mark_tries_brewing]

Any ideas on causing rust to accelerate and break down metal? I pulled the coils out successfully, however the bracket that had held it in the dehumidifier is very rusty. I don't think I could remove it all so I was hoping to get to it rust to the point it would just flake off. I was thinking of starsan or something else? I was also wondering if it would be okay to add bleach to star San or if that would release chlorine gas?

 

[grrickar]

I would not add bleach to anything personally. I don't know if Star San and bleach would create chlorine gas or not, but I would not chance it. If you do decide to do this, I would suggest doing it outdoors and wear something so you don't inhale anything. I'd wear heavy rubber gloves also.

 

[RonPaul]

I don't know of a way to rust off the metal, but my coils also have a metal part attached to it, so let us know if you end up finding a way to get it off. For the time being mine is in the cooler w/ the glycol.

By the way, I originally tried using a dehumidifier, but ended up accidentally cracking the copper coil. I ended up finding an old a/c unit and using that... it worked out quite well. The only issue I have is I don't have an easy way to disconnect the 1/4" ID tubing from the conical when fermentation is done. Right now I have to unscrew the connection which is messy and difficult.

 

[SanPancho]

Solid layer of ice around the chiller in a short time. Worked great

not sure exactly how you finished the setup, so forgive me if i've got the details wrong here-

most glycol systems in breweries run a ~30% mix of glycol. there are some crazy things that happen with the efficiency of heat transfer when you increase glycol % but the explanation is beyond me. just something to note as i dont know the science behind it well.

also- you really do want a recirc pump in the glycol bath. ice around your HX is not good. not sure if the glycol mix solved that problem, but in either case, you're going to get some serious temp gradients in there, effectively shrinking the size of your thermal mass. there's always a recirc pump in a glycol setup. if you really dont want to put one in, or cant find one rated for cold temps, then at minimum i'd set the inlet/outlet lines in opposing corners, i.e. outlet at the bottom left, and inlet at the top right. that way you're at least getting some movement of warm glycol across the whole HX on its way to the outlet.

at this small size its probly not a huge deal if you're not super efficient, but just thought i'd throw that out there.

 

[ajdelange]

I would not add bleach to anything personally. I don't know if Star San and bleach would create chlorine gas or not, but I would not chance it. If you do decide to do this, I would suggest doing it outdoors and wear something so you don't inhale anything. I'd wear heavy rubber gloves also.

I believe Star San is phosphoric acid with some DDBSA (detergent) added. In this case it very probably would result in the release of chlorine gas from bleach (as hypochlorite disproportionates at low pH). But why would you want the bleach in there anyway? The phosphoric acid by itself should clear the rust away. There are products sold at hardware stores specifically for removing rust. One of the most popular of these is Naval Jelly which is phosphoric acid combined with a thickener (so it can be applied to vertical and over head surfaces).

 

[milldoggy]

See

not sure exactly how you finished the setup, so forgive me if i've got the details wrong here-

most glycol systems in breweries run a ~30% mix of glycol. there are some crazy things that happen with the efficiency of heat transfer when you increase glycol % but the explanation is beyond me. just something to note as i dont know the science behind it well.

also- you really do want a recirc pump in the glycol bath. ice around your HX is not good. not sure if the glycol mix solved that problem, but in either case, you're going to get some serious temp gradients in there, effectively shrinking the size of your thermal mass. there's always a recirc pump in a glycol setup. if you really dont want to put one in, or cant find one rated for cold temps, then at minimum i'd set the inlet/outlet lines in opposing corners, i.e. outlet at the bottom left, and inlet at the top right. that way you're at least getting some movement of warm glycol across the whole HX on its way to the outlet.

at this small size its probly not a huge deal if you're not super efficient, but just thought i'd throw that out there.

Been running great for a while. Went with around a 45% mix. Only the one pump. I set my temp control to shut off at 4c, which ends up with a 2c mix after stired up.

Edit, that pump is running 24/7. I had one die, but that ran 4+ years. Not bad for 13$. I went with a little thick mix to ensure no icing and I get none.