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Thread: External Glycol tanks

  1. #1
    Join Date
    Jun 2005
    Posts
    52

    External Glycol tanks

    Thanks for the replies on running glycol temperatures, but here is another wrinkle. My 5 ton chiller is roof mounted. I can easily get -40 weather and many weeks in the -30C range. The glycol reservoir is external as well. The problem the refrigeration guy outlined was that increasing the glycol concentration, so that it doesn't gel up while outside, makes the solution less effective. What do people do with systems located in very cold areas? Is there any need to supply heat to the reservoir or does flow inside cover that?

  2. #2
    Join Date
    Oct 2003
    Location
    Pittsburgh, PA
    Posts
    407
    Wow, that's cold. And I thought keeping my place at 35 in the winter was chilly - at least yours is outside though.

    One thought I had was that for one, mother nature will probably provide a good deal of the cooling power you need. It's very efficient for your chiller to "dump heat" into such a low ambient temperature at that time of year, so it won't have to work very hard. (Have you thought about installing it inside and using it as a heat source?)

    Regarding freeze-up, "flow inside" will probably cover some of that - plus don't forget that the chiller will be generating a bit of heat in it's own operation in addition to the heat it's pulling off of the process tanks.

    I know these aren't very specific suggestions, just things to keep in mind. The manufacturer will probably be a good resource here... as will others with more specific experiences.
    Scott

  3. #3
    Join Date
    Oct 2003
    Location
    Santa Rosa CA USA
    Posts
    962
    Move your glycol tank into your walkin (and then insulate it) and you will lose no energy on a warm (if ever) day, and it won't freeze. How about just a big fan blowing the outdoors in? With weather like that a sharp refrig man could rig a system without a compressor- cooling by ambient.

  4. #4
    Join Date
    Jun 2005
    Posts
    52

    External Glycol tank

    Thanks, I'll mention the idea of moving the holding tank inside. Space inside is at a great premium though - we are using the 'sardine can' method of brewing. He is planning on wrapping the external lines with heating tape, and he did say that about 8 months a year the compressor won't even kick in.

  5. #5
    Join Date
    Jan 2003
    Location
    Palau
    Posts
    1,622
    I suggest locating the unit indoors. Do not rely on any heat being added by pumping, frictional losses, etc. Your propylene glycol should be ready to take any temperature that mother nature will dish out. As far as efficiency goes, more PG will make for slightly less heat transfer. That being said, you WANT less heat transfer with -40 PG. Such a huge temperature differential between the PG and the cooled product may cause unwanted temperature swings, product icing on the jacket, and require constant monitoring for concentration. Also making the case for an indoor location: The power required for pumping -40 PG will go up significantly as the viscosity is much higher. As you put more energy in to the system by pumping, and pick up more thermal energy from cooling tanks, it seems a waste to discharge to the tundra. This heat could be used indoors. At one brewery I worked for, we had a plywood sheet that directed the chiller air either inside, or outside depending on the season. Study your system a bit more and be certain that you want to locate your chiller outside. Good luck!

  6. #6
    Join Date
    Jun 2005
    Posts
    52

    External Glycol tank

    It seems the roof is the only place it can go. It is really big and heavy, so I don't know how we could put it inside. So the plan now is to enclose it, insulate it, and supply heat with a relay set for about 0C or -5C. We'll also connect our small internal chiller system to it so that during the cold months it will have another source of heat. It does seem crazy that we have to worry about heating the chiller, but that is the Great White North I guess.

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