Immersion chiller geometry

Discussion in 'Homebrewing' started by MichaelinFishers, Apr 30, 2012.

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  1. MichaelinFishers

    MichaelinFishers Initiate (0) Mar 10, 2009 Indiana

    So I need to make a new immersion chiller and have been thinking about different geometries. My old one worked adequately, but I found that with one set of coils of uniform diameter (about 9-10"), I ended up with hot zones in the center and around the edge of my 8-gal, 14" diameter kettle very soon after turning the water on for the chiller.

    I'm thinking of either two concentric coils, at maybe 6" and 12", or a setup with three smaller coils in a triangular arrangement, the right size to get within an inch of the walls of my kettle.

    I also plan to make a small coil that would sit in-line with my water line, that I could put in an ice bath to further chill the input water. This would be especially helpful during the summer.

    Has anyone else experimented with alternative chiller shapes? What did you try and what were the results?
     
    #1 MichaelinFishers, Apr 30, 2012
  2. scurvy311

    scurvy311 Savant (1,135) Dec 3, 2005 Louisiana

    If you whirlpool while "chilling", geometry is much less important since you are constantly moving wort. If you have an adequate amount of contact area and you input water is cool enough geometry shouldn't matter.

    If you are not whilpooling, it is recommended that the input water starts in the top of the boil pot. The top wort gets denser and sinks because it cools, then the hotter wort rises from the bottom creating a convective current.

    About 2 years ago I made an attachment for my cordless drill that gets the wort whirlpooling. It cut my chill time from 30 to 12 minutes. And I get the added benefit of clearer wort because the trub gets pulled to the center of the pot. Google: jamil whirlpool chiller

    8gal 14" pot is very close to what I use. I have 50' of 1/2 copper tubing that i coiled around my 5# CO2 tank. I am very happy with the way it works. I bent the input and output so that when I hang it upside down it drains the PBW and rinse water.

    Also there was an article in BYO on chiller geometry/efficiency in the last year or 2.
     
    #2 scurvy311, Apr 30, 2012
  3. MichaelinFishers

    MichaelinFishers Initiate (0) Mar 10, 2009 Indiana

    Thanks. I must have missed that BYO article. If you happen to find which issue, let me know, please.

    I'll check out the drill attachment, too. My biggest difficulty whirlpooling has been that its hard to get going (and keep going) with the chiller in the way. Maybe that will solve it.
     
    #3 MichaelinFishers, Apr 30, 2012
  4. scurvy311

    scurvy311 Savant (1,135) Dec 3, 2005 Louisiana

    Try July/August 2011 of BYO. But im not sure. It was a more in depth (formulas and calculations) than just a comparison of chillers. It talked about tubing length, diameter, and efficiency.

    My drill attachment (welding shop scrap) is 24" of 1/2" or 5/8" solid aluminum rod with 3" of 1"x1"x1/8" aluminum flat bar bolted to the end with SS bolt/nut to form a "T". Works great just start slow or it will pull itself into the chiller.
     
    #4 scurvy311, Apr 30, 2012
  5. leedorham

    leedorham Initiate (0) Apr 27, 2006 Washington

    I have not experimented with mine. It could definitely improve since it is never totally submerged.

    You could do the rib cage design. [​IMG]
     
    #5 leedorham, Apr 30, 2012
  6. maskednegator

    maskednegator Initiate (0) Jan 24, 2009 California

    Changing the geometry of the chiller and whirlpooling the wort both seek to do the same thing - breaking up the temperature gradient in the wort. However, whirlpooling is orders of magnitude more effective at this than changing the geometry of the chiller is.
     
    #6 maskednegator, Apr 30, 2012
  7. MichaelinFishers

    MichaelinFishers Initiate (0) Mar 10, 2009 Indiana

    Thanks for the input. I still may try both, although whirlpooling with the triple-spiral geometry would be much harder that with the concentric spiral design, so I may just go with that. I wonder what I could get my cooling time down to with both of those plus running the input through an ice bath. Time to do some more research and then play. Could take a while, but I'll report back with results when I have them.
     
    #7 MichaelinFishers, May 1, 2012
  8. mikehartigan

    mikehartigan Maven (1,421) Apr 9, 2007 Illinois

    I suspect geometry will give you virtually zero improvement over whirlpooling alone. But go for it.
     
    #8 mikehartigan, May 1, 2012
  9. maskednegator

    maskednegator Initiate (0) Jan 24, 2009 California

    Heat exchangers are well understood in engineering. All you want to do is maximize the difference in temp at all times between the coolant and the wort. Icy water and forced convection/whirlpooling are best. Changing the geometry of the chiller will not do anything for you if you're whirlpooling, as you've already maximized the difference in temp between the chiller and the wort.
     
    #9 maskednegator, May 1, 2012
  10. MichaelinFishers

    MichaelinFishers Initiate (0) Mar 10, 2009 Indiana

    Maximizing surface area for the exchange should help, too. Changes in chiller geometry with a constant amount of tubing shouldn't make much/any difference, but I would expect that a geometry that allowed more tubing to fit into the kettle, increasing the surface area available for heat exchange, would make a difference.
     
    #10 MichaelinFishers, May 1, 2012
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