Best water temp for in floor radiant heat

Discussion in 'General Discussions' started by ellisaac, Jan 16, 2010.

  1. ellisaac

    ellisaac New Member

    A tech came out to look at our basement concrete floor radiant heat and said the delta T was too great returning from the floor loop. He thought the unit may be having a hard time keeping up. As a result he increased the temp from 120 deg to 130 deg on the tank. He decrease the pump speed for the floor and increase the pump speed between our GSHP and the tank. Does that make sense? It seems to me that if the delta T was too great that you would want a higher pump speed to the floor.
     
  2. Guest

    Guest Guest

    This does not make sense. You are correct.

    Increased flow across the radiant loops will decrease DeltaT. Pushing your geo system temps up will increase your energy cost geometrically (or maybe exponentially, I should have paid better attention in algebra class) and decrease capacity.

    The biggest problems I see with radiant floors-
    -Not enough pump, not enough flow, to much delta t
    -Supply temps to high

    The biggest problems I see with w-w geo-
    -Not enough pump, not enough flow, to much delta t
    -Supply temps to high

    The pumping and flow requirements have to be calculated for a given system. Just throwing different pumps at it costs alot of money.

    I rarely see a properly piped and insulated concrete floor that needs more than 90*F.
     
  3. ellisaac

    ellisaac New Member

    Thank you for your response. That leads to another question though. I had planned on using that water to water unit for the floor and to feed a fan coil for a bonus room. Those seem to be at odds with each other with respect to ideal temperature for the water. Can this be done efficiently?
     
  4. Guest

    Guest Guest

    Yes, if you use an oversized aircoil (in the order of 2 to 3 times rated capacity) with right sized fan/cfm (not typically found mated together in a factory box).
     

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