Typical Antifreeze Used in Closed Loop

Discussion in 'Vertical and Horizontal Loops' started by Lah72, Oct 13, 2017.

  1. Lah72

    Lah72 New Member

    What type of antifreeze is typically used in a closed loop system and why is it needed? Also, what level of protection (degrees) should the system be designed for?

    Thanks for the help
  2. waterpirate

    waterpirate Well-Known Member Industry Professional Forum Leader

    Hi and welcome!
    There are two major types of antifreeze used. Glycol based and methanol based. There is also a non toxic glycol used under the brand name environol. antifreeze is used in the loop to protect it and your equipment from freezing if the loop temp dips below 32 degrees after leaving the unit. The amount of antifreeze needed to operate any given loop field is a function of the winter time design temps for the system. 20% is a general catch all, but not to be relied on without more info.
    Hope this helps
  3. geoxne

    geoxne Active Member Forum Leader

    Environol is a ethanol based antifreeze.

    Here is info on selection and use from Waterfurnace.
    Excerpted page 19 from-

    Most current Geo HPs are designed to operate in heating with entering source temperatures as low as 20F. Your antifreeze protection level should at least meet the control board setting for freeze protection safety lockout. In most cases your choice is 30F for water or 20F for antifreeze.
  4. Lah72

    Lah72 New Member

    Thanks for the info! Anyone happen to know where you can buy methanol (generally)? I don't know the first clue how to get my hands on this stuff.
  5. docjenser

    docjenser Well-Known Member Industry Professional Forum Leader

    To add to this a bit, keep in mind that if you have a 20 F EWT, you usually have 15F leaving WATER temperature. For the water to be 15F the medium cooling it down has to be less than that, you need a delta T to transfer heat).
    Thus the inside of the coax is SIGNIFICANTLY colder than 15F, which is why that part always builds up ice first.
  6. mtrentw

    mtrentw Active Member Industry Professional Forum Leader

  7. waterpirate

    waterpirate Well-Known Member Industry Professional Forum Leader

    We send local diy ers to a speed shop for go carts, where they can purchase in 1 gallon increments for around 4.00 a gallon.

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