Are there any threads here of building a refrigerated air dryer using a mini fridge/freezer?
I have a fridge. Sam’s Club has a freezer for few hundred.
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Little dorm fridge, the cooling happes in the little freezer portion at the top, lines run up the back.
40’ of 1/2 copper turbing coiled inside the fridge. Drill two holes in the side of the fridge, one for air in, the other for air out - air in is a higher hole, out is lower. Install drip leg on the output with a drain valve.
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I just googled “mini fridge air dryer”……piles of Youtube videos of people who have done just that……
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I made one from a mini fridge. Toughest part was trying to find where NOT to drill holes that would go through the cooling lines. I put about 20 feet of copper tube coiled inside the fridge. Really takes any remaining water out of the compressed air… after the transmission cooler on the compressor. I haven’t changed silicon drying beads in a year or more. I run the fridge at about medium cooling on the dial… and only start it up about an hour before cutting… in the warmer weather. $30 for the used fridge. Great investment.
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Thanks for the feedback.
I’ll have to cost it out compared with the HF unit.
I was planning on using one for a plunge pool chiller… Now maybe it could be dual purpose, lol.
The big crux of the mini fridge / freezer idea comes with what happens if you get a condensate clog inside the coil because your water vapor freezes? How do you monitor and control temp to keep this from happening? You’d need a thermocouple at the outlet of the fridge somehow set to adjust duty cycle such that it doesn’t ever get to 0°C.
Now you also need to ensure the coil of copper in the unit is only spiraling down, such that you won’t get trapped water as well, so that it all gets caught in the post chiller water collector.
All that being said, I just went with the HF unit. A lot of work just to potentially break even, with no warranty.
Yeah, that’s what I’m finding. Here in CA, the Central Pnu air dryer from harbor salvage goes for 650.00. The fridge and copper are almost that much.
As far as freezing, with a fridge as opposed to a freezer, and keep the coil submerged in water (assuming the seal doesn’t leak)…
I must have gotten lucky with mine. 40’ (2 20’ coils) inside on the top shelf. Has not froze up yet, and it’s in NE, where every morning we usually start out at 99% humidity during the summer, and lucky to get below 40% by the evening.
As @apynckel stated, have the coils going downhill, inlet on the top, outlet on the bottom as best I could.
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Also fill the excess space with cans of beer. They need to be aluminum cans to maximize heat transfer. 
Water bottles. I always have cold drinks when it’s 105 and 90%h
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For that to work it’d have to be Miller 64 or Bud Light
Are those beers? 
Miller 64 less alcohol i drink twice as many and pee 3 times more often. I am getting old 
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