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Prius Inverter Coolant "Thermos"

Discussion in 'Gen 2 Prius Technical Discussion' started by MakeLimeade, Jan 11, 2022.

  1. MakeLimeade

    MakeLimeade New Member

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    I'm working on a heating system that needs to store hot coolant for later heat transfer to water. It's a hydronic system if you're curious.

    A friend with a Prius said there's an inverter coolant reservoir that works like a thermos in the 2nd gen Prius. I can't find the capacity, do you know? (There's also a plastic overflow tank, that's not what I'm asking about.)
     
  2. jerrymildred

    jerrymildred Senior Member

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    Why would anyone want to keep the inverter warm? Your friend is confused. The Gen 2 Prius has an engine coolant "thermos." It's part of the coolant heat recovery system (CHRS).

    I can't find a number for the capacity, but it's not a whole lot. This thread might get you started. Can only get 2.9 qts when draining engine coolant? | PriusChat
     
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  3. ChapmanF

    ChapmanF Senior Member

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    In the 2004 New Car Features manual (more info), page EG-24, it says "The coolant heat storage tank is a heat insulation container made of stainless steel, and has a dual vacuum construction. It can store approximately 3 liters of engine coolant and keep it warm. The basic construction of this tank is the same as the household Thermos bottle."

    Nine pages follow with details on the ways the car uses it.
     
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  4. Another

    Another Senior Member

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    What volume do you need
     
  5. MakeLimeade

    MakeLimeade New Member

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    Was hoping for at least a gallon, but seems like it's not enough.
     
  6. MakeLimeade

    MakeLimeade New Member

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    Thanks, thought it was larger than that. I was hoping for 1-2 gallons. It would get used as an overflow for hydronic "coolant" which is basically glycol heated to 180F and used to transfer heat efficiently without drying the air.
     
  7. ChapmanF

    ChapmanF Senior Member

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    Yup, that glycol heated to 180F does seem to serve that purpose pretty well. :)
     
  8. Another

    Another Senior Member

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    Hook two in parallel