Cold Smoker With Working Mini Refrigerator

Discussion in 'Info and Practices' started by bopplayer, Jun 15, 2012.

  1. Question, would it work to use a small bar fridge that is working and set the Amaze-n pellet maze on the bottom on a stainless tray, drill a vent in the top and have a year round cold smoker? anyone done it???? thanks
  2. pops6927

    pops6927 Smoking Guru Staff Member Moderator Group Lead OTBS Member SMF Premier Member

  3. pops6927

    pops6927 Smoking Guru Staff Member Moderator Group Lead OTBS Member SMF Premier Member

    BTW, if you would kindly go to Roll Call and introduce yourself so we may welcome you properly, and also put your location in your profile, it would be much appreciated!  Thank you!
  4. Thanks Pops just introduced myself. Looks like yours wasn't working I'm thinking about using a working mini fridge. So then I wouldn't need an intake vent right? just up top? thanks
  5. tjohnson

    tjohnson Smoking Guru Staff Member Moderator Insider OTBS Member SMF Premier Member

    Hey Bob,

    I think it's a great idea!

    Some guys convert a non working fridge, but a working fridge sounds interesting........

    I bet I know a guy who could make you a deal on a smoke generator for your fridge [​IMG]

    bgosnell151 likes this.
  6. jsdspif

    jsdspif Meat Mopper

    I think that would work excellent . I'm thinking especially for something like cold smoking pork belly for regular bacon . Cheese comes to mind also . Price is good too , even if you started with a new one (???) Maybe I'm stretching that . I just bought one but it was around $200 but it fits 2 corny kegs side by side and then has more room behind them but not as much height because of the shelf from the compressor . If you already have one though I'd say go for it . I suppose you could still use it as a refrigerator when it's not being used as a smoker ?
  7. I would thing the evaporator would get all gummed up with smoke residue after a while.
  8. mr t 59874

    mr t 59874 Master of the Pit SMF Premier Member

    Last edited: Jun 26, 2012
  9. sigmo

    sigmo Smoking Fanatic

    I know I'm resurrecting an old thread, but I was just thinking of doing the exact same thing.

    Using a WORKING mini-fridge for a cold smoker so the fridge would actively keep its contents cool while smoking cheese in particular, but anything that needs to be kept cold or cool while smoking.

    If you're using an AMNPS, you'd need to provide a heat-proof pan and maybe something to prop it up on to keep the heat from the AMNPS from melting/burning the plastic interior of the fridge, of course.

    And you'd need a bottom vent as well as a top vent because the AMNPS needs air flow to keep the pellets burning. 

    I'd need to figure out if the fridge had enough heat pumping capacity to overcome the heat generated by the AMNPS as well as keep up with the heat in the air that's flowing through the smoker, too.

    That may be a tall order for a mini-fridge's little compressor system.

    Also, you WOULD need to keep the fridge's evaporator clean to maintain its efficiency.

    I wonder if anyone has any more thoughts on this idea.
  10. mr t 59874

    mr t 59874 Master of the Pit SMF Premier Member

    Use an external enclosure to put your smoke generator in and pipe the smoke to the refrigerator.  This will produce a much cooler and cleaner smoke.

  11. webowabo

    webowabo Master of the Pit SMF Premier Member

    I would think it would create a lot of condensation inside the fridge with the heat of the smoke. drippings from top would reek havoc on the meats and the pellets that route... an outside box would almost be mandatory .. and some long piping to help cool the smoke before hitting the Cold cook chamber. There will be some evap coil issues with the residue sticking to the fins, and over time... blocking airflow, freezing up, constant strain on the compressor.. etc 
  12. mr t 59874

    mr t 59874 Master of the Pit SMF Premier Member

    webowabo makes some good points, but all can be overcome.  The drippings can be overcome by placing some absorbent material such as toweling above your product. A convex lid above will help also.  The smoke in my "cold" cold smoker does not come in contact with any coils as the interior walls are cooled to produce internal refrigeration.  You may want to consider putting a separate container (example a Little Chief smoker) inside your refrigerator and pipe the smoke in and out of it.

  13. webowabo

    webowabo Master of the Pit SMF Premier Member

    Tom, thats an good idea putting a separate container inside! Ive been thinking about this the past few hours, and that way seems alot easier.. 
  14. dcarch

    dcarch Smoking Fanatic

    Here is one I made. 4.5 cubic feet working fridge/smoker.

    I boiled some interior plastic parts, it did not deform, so I used the original plastic interior.

    The gaskets are sealing very well as magnetic gaskets can, So I am able to operate the smoker indoors, just venting the smoke thru a small hole in the wall.

    The fridge is so well insulated, I am using a halogen light bulb ($1.50 300 watts) as the heat source. Plenty good.

    The smoke generator is a cold generator, variable speed motor driven. It can generate TBS or blast of white smoke. I have had the generator running as long as 24 hours without any need of monitoring.

    The entire system is PID temperature controlled.

    It has been a fun smoker and a very flexible smoker for cold and hot smoke, winter or summer, rain or shine.


  15. dcarch

    dcarch Smoking Fanatic

    Here is a view of the interior.

    No coils. Evaporator coils are in the walls.

    Notice: The halogen light for heat source, a convection fan, and an ultrasonic humidifier (The bottom clear plastic tray).


  16. webowabo

    webowabo Master of the Pit SMF Premier Member

    wow.. very cool set up.. the fact that its inside is greatness!!!! wish I was that smart to put something together like that.[​IMG]
  17. sigmo

    sigmo Smoking Fanatic

    That really is great, DCARCH!

    Now I've got to try building something similar for my cold smoking!

    Lots and lots of great ideas there.

    Edit to add:

    I'd like to know what some of the various valves and gadgets are that seem to feed into and out of your system.

    I went out and looked at a few inexpensive "mini fridges" today.  What I wonder, as I look at them, is if they'll have enough heat pumping capacity to maintain a cool temperature while having some air moved through them constantly (as a smoker must).  Add to that the heat from whatever is used to generate smoke, and it may be that the little compressors in these things would struggle.

    The advantage, though, is that it wouldn't be much of an investment to just experiment with.  Brand new mini-fridges seem to go from between $64 for a tiny one up to about $130 for a larger one.

    One thing that occurs to me is that depending on how the evaporator coils are arranged, you may need to actively circulate the air inside the fridge to make sure that the evaporator comes into contact with the air well enough to cool the thing. In normal operation, the door is closed and the compartment sealed.  In this application, the normal tendency would be to inject the smoke at the bottom and then have an opening at the top for it to escape.

    But many of these tiny fridges have the evaporator up at the top, expecting that natural convection will cause the cooled air to fall, displacing and pushing the lower-density warmer air back up to the top where the evaporator can again cool it.  If we're constantly letting new, warm, smoky air into the bottom, and exhausting it up out of the top, then the cooling may not be very effective.  So a circulating fan would likely be very helpful.  Not a problem, just something to consider.

    As I looked at all of these fridges, I also saw a small chest freezer that wasn't too much more money than the fridges.  It occurred to me that as long as I'd need to actively circulate the air anyhow, maybe the chest freezer would have greater heat-pumping capacity than the fridges, and be a better layout.  I could feed the smoke from the smoke generator in pretty much anywhere, and exhaust it pretty much anywhere, and just use a small fan to keep the air uniformly smokey and cool.  The thermostat that comes with the unit would likely not go as high as I'd want, but I've done a lot of control system work, including designing controllers to run refrigerators and freezers, so that could be modified or replaced with whatever was needed.

    What I need to do is examine the insides of some of these units to see how things are laid out and get a better handle on what might be the most convenient.  None of the fridges had enough racks positioned where I'd want them, anyhow.  So regardless of what I got, I imagine needing to buy or build different racks to accommodate the cheese or whatever.  So the chest freezer wouldn't be a problem.  I'd just make a rack that I could set down into the unit from above, then lift out.

    Thinking about the points folks have brought up concerning condensation, that could be an issue.  Normally, the air is very dry around here, and letting some flow through a refrigerator or freezer wouldn't generate too much condensation on the evaporator coils.  BUT, in the last few years, we've had more humidity than normal in the summer.  Add to that any moisture that comes out of cheese (hopefully not really that much) or meat that's being smoked, and I can see how some water may condense on the evaporator.  Also, the concern of needing to keep the evaporator surfaces clean, and it means that the form and design of the unit's evaporator will be important.  I'll want to be able to deal with any liquid water that forms on the evaporator surfaces AND I'll want to be able to clean those surfaces, too.

    I've seen store-bought freezers used as BOD incubators in laboratories.  And something that happens to some of them is that the water that condenses on the evaporator coils seems to corrode through the tubing, causing loss of coolant and failure.  This has happened to units with the new aluminum evaporator tubing.  I've never seen it happen to the old units with copper tubing.  It's all worth considering, I think.

    Gotta ponder some more.  :)
    Last edited: Aug 27, 2013
  18. webowabo

    webowabo Master of the Pit SMF Premier Member

    excellent points.. thoughts.. and concerns..... You for sure think Outside.. or welll, in this case, "inside the box"....

    Ill have to ask around at work and see what could be the serious problems inside the fridge. SPecailly on the coils... and on the compressor, etc) I work in the HVAC biz, but Im a mechanical lead for commercial builds. I can fix your home/commecial ac/heat units..but I dont understand how they work..specially refridgeration... my company doesnt even mess with hvac"R" part...  if that makes since (hands on guy.. its broke, and I know whats broke.. I can fix.. if not I call the techs .) 
  19. dcarch

    dcarch Smoking Fanatic

    I bought my fridge on Craigslist for $39.00, brand new unit because it had a not very noticeable dent on the side. 

    It has all the coils, condenser and evaporative inside the walls. No visible coils inside or outside. So be very careful if you have to drill openings. Really not a work to build if you see all the incredible cutting and welding and insulating and gasketing with other builds. Many of the parts are just Home Depot plumbing parts.

    There has been no condensation problem with all my cold smoking.

    Temperature is very even with a little fan inside.

    I will explain more of some of the components later in my next post.

  20. dcarch

    dcarch Smoking Fanatic

    The picture shows the concept of my indoor hot/cold smoker.

    First, in the previous picture, the smoke form the generator goes thru a long brass flex stove gas pipe. The reason is the accordion fold and brass cools down the smoke and the pipe is very bendable to allow easy installation.

    The smoke gets drawn in by a small DC blower "B" and gets blown into the smoker thru by-pass valve "D"

    The smoke gets cold and a lot of creosol is condensed into collector "A" before it coats the food.

    "E" is a clear viewing window which has a little LED light in it, The condition of smoke, TBS or white smoke, is clearly visible before it enters the smoker. I can adjust the blower speed and vent opening on the smoker to get exactly the quality of smoke I want by viewing the view window. There is no need to open the smoker to check. I highly recommend this feature for any smoke generator.

    "C" is a DC blower. By turning the by-pass valve "D" and turning on the blower "C", all the smoke inside the smoker will be evacuated to outside of the house in about one minute, so when you open the smoker, you will not be smoking up the house.



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