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  1. #14
    Join Date
    Aug 2009
    Location
    Prattville, Alabama
    Posts
    3,515
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    Quote Originally Posted by jbhenergy View Post
    This sounds exactly like a WSHP (water source heat pump) system. I have a building I take care of that uses these. Sounds exactly like your describing, been around for a long time. They try to maintain 55* loop in the winter and 75* loop in the summer. Of the 100 units in the building, they can all do their own thing heating and cooling wise.

    But unless your going to change every unit in your building to you WSHP, then the 180 would need to be maintained for the old units.
    Check out the OP's link that he provided in post #9. It looks like a hybrid Fan Coil Unit WITH an integral Heat Pump. The FCU coil is in series with the HP coil supplying the space. It can be used as either a straight FCU, or as a heat pump, or the two can be used simultaneously in extreme weather for "Power Cooling" or "Power Heating".
    In honor of RichardL: "Ain't 'None' of us as smart as 'All' of us".

  2. #15
    Join Date
    Mar 2016
    Location
    Dayton Oh
    Posts
    1,881
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    Quote Originally Posted by Nuclrchiller View Post
    Check out the OP's link that he provided in post #9. It looks like a hybrid Fan Coil Unit WITH an integral Heat Pump. The FCU coil is in series with the HP coil supplying the space. It can be used as either a straight FCU, or as a heat pump, or the two can be used simultaneously in extreme weather for "Power Cooling" or "Power Heating".
    I tried multiple times to get the link to work and never opened for me. Even tried to google it and still wouldnt open.

  3. #16
    Join Date
    Aug 2009
    Location
    Prattville, Alabama
    Posts
    3,515
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    To the OP,
    We have one building with a two-pipe Fan Coil Unit system. The boilers are on a primary loop, with the FCU's on a secondary loop, with a mixing valve. Typically, our secondary loop is at around 100 degrees when in heating. But the primary loop is around 150 degrees. The higher temperature is mandated by the minimum return temperature requirements of the boilers. The secondary loop, to the FCU's is much more flexible. It's only requirement is to keep people comfortable. I mention this to bring to your attention to the possibility of your customer having a similar system. If so, make sure ya'll are talking about the same water temps.
    In honor of RichardL: "Ain't 'None' of us as smart as 'All' of us".

  4. #17
    Join Date
    Aug 2009
    Location
    Prattville, Alabama
    Posts
    3,515
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    Quote Originally Posted by jbhenergy View Post
    I tried multiple times to get the link to work and never opened for me. Even tried to google it and still wouldnt open.
    Works for me. If I had better computer skills I would take a screen shot or something.

    I've never seen anything like this. Looks like a good idea. We could use them here, but being a state building, our budget sucks. People just tough it out sometimes, like when a front comes through.
    In honor of RichardL: "Ain't 'None' of us as smart as 'All' of us".

  5. #18
    Join Date
    Aug 2009
    Location
    Prattville, Alabama
    Posts
    3,515
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    Quote Originally Posted by jbhenergy View Post
    I tried multiple times to get the link to work and never opened for me. Even tried to google it and still wouldnt open.
    Try Googling "PMAC USA".

    Click on first result.

    Then scroll about halfway down.
    In honor of RichardL: "Ain't 'None' of us as smart as 'All' of us".

  6. #19
    Join Date
    Oct 2018
    Location
    Iowa City, IA
    Posts
    23
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    Quote Originally Posted by startupTED View Post
    Hi guys,

    I am trying to get a product specified for a retrofit project at a building that uses a 2 pipe system.
    They supply water at 45F during the summer, 70F during shoulder season and 180 during the winter.

    The product I have has a small compressor in it, so the water temp can not go above 120F in order for it to work.

    I am having a difficult time convincing the owner that you dont need 180F water to provide sufficient heating.
    In general, is there a reason why the building is running 180F?
    Are they able to control the supply temperature? How many units are you looking at doing? At our University we have some control in individual buildings because we use steam converter/heat exchangers to heat our building water. Many of our FCU's are ancient so we often run 180+ to keep up.

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