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  1. #1
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    Mar 2019
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    HELP with understanding HVAC

    HI,

    I am here to ask for your assistance on a world I am struggling to make sense of.

    I apologise if I'm posting in the wrong place.

    I am doing an assignment on building technology as part of which I need to identify parts of the climate control system of a local building. I am struggling even with the help of books to make sense of the HVAC system.

    To cut a long story short what am I looking at in these pictures.

    From what I have read it seems like a trunking system feeding VAVs but then the other picture look likes a fan coil and aren't these 2 separate systems. Please feel free to laugh at my ignorance as long as you provide me with some information on what it is and how it works.

    The company make is Biddle but nothing on their current website looks anything like this stuff (from 1998)

    Any help greatly appreciated, from a struggling student

    yours

    Russ
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  2. #2
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    Nov 2006
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    Apparently, this space has more than one type of system.

    The upper pic is a hydronic fan coil, and the lower pic is a diffuser for a duct system.
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  3. #3
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    Jun 2014
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    Dover, DE
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    Your pictures show some ductwork and a hydronic fan coil.
    I havent failed. Ive just found 10,000 ways that wont work. - Thomas Edison

    Its not whether you get knocked down, its whether you get up. - Vince Lombardi

    "In this house we obey the laws of thermodynamics" - Homer Simpson

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  4. #4
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    Mar 2019
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    Thread Starter
    Thanks for your replies they have helped me make a bit more sense of it.

    These hydronic fan coils are everywhere and they are the units that you can feel blowing out the heat. They are not connected to any of the ducting and each unit has its own thermostat.

    My final question, is it possible therefore that all the heating and cooling is being done by these hydronic fan coils and the separate ducting system with its diffusers and grilles is purely for bringing in fresh air and removing stale air and does no heating/cooling. This system is not in basic text books but it seems like it is whats happening???

    Thanks again

    Russ

  5. #5
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    Aug 2002
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    Quote Originally Posted by russcoop View Post
    Thanks for your replies they have helped me make a bit more sense of it.

    These hydronic fan coils are everywhere and they are the units that you can feel blowing out the heat. They are not connected to any of the ducting and each unit has its own thermostat.

    My final question, is it possible therefore that all the heating and cooling is being done by these hydronic fan coils and the separate ducting system with its diffusers and grilles is purely for bringing in fresh air and removing stale air and does no heating/cooling. This system is not in basic text books but it seems like it is whats happening???

    Thanks again

    Russ
    You need to go on the roof and see what you have. Guessing goes nowhere!

  6. #6
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    Apr 2003
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    Maple Grove, MN
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    Quote Originally Posted by russcoop View Post
    Thanks for your replies they have helped me make a bit more sense of it.

    These hydronic fan coils are everywhere and they are the units that you can feel blowing out the heat. They are not connected to any of the ducting and each unit has its own thermostat.

    My final question, is it possible therefore that all the heating and cooling is being done by these hydronic fan coils and the separate ducting system with its diffusers and grilles is purely for bringing in fresh air and removing stale air and does no heating/cooling. This system is not in basic text books but it seems like it is whats happening???

    Thanks again

    Russ
    Since I don't see any condensate drain coming off of the fan coil unit, and since there is only one set of pipes going to it, I would have to say that those are for heating only.

    It could be possible that cooled air is blowing out of those diffusers all of the time (weather cooling is needed or not), while the heating units cycle on and off to add heat to the space as needed. Of course this isn't a very efficient way of doing it, but "re-heat" systems that work this way are actually fairly common.
    If at First You Don't Succeed, Skydiving Is Not for You.

  7. #7
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    Mar 2019
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    Thread Starter
    Ammonladog I think you just nailed it. There are two pipes going to every fan coil (does this constitute one set?).

    If you put your hand to the diffusers/grilles from the ducting you can feel a breeze like air but if it is being blown then it is not very fast.

    So we basically have a separate heating system independent of a fresh air cooling system would this still then be classed as a HVAC

  8. #8
    Join Date
    Aug 2002
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    Southold, NY
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    The main system may maintain a minimum temperature with the fan coils increasing as needed. A few pictures isn't enough to tell.


    What assignment is this?

  9. #9
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    Thread Starter
    Its an assignment for an MSc building surveying. This project examines a rebuilt buildings new structure, envelope, climate control and energy saving technologies compared to the historical original building.

    I just got stumped by the HVAC system as it wasn't following any textbook diagrams, lucky I found this place

  10. #10
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    Mar 2019
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    Thread Starter
    Some more pics from my phone some are upside down.

    To be honest from my uneducated position it doesn't seem like there's much more I can show just fan coil heaters and separate ducting with grilles/diffusers.

    I think that roof is where it supplies/discharges the air as the system is only for the lower 2 floors.

    Anyway I think I have taken up enough of your valuable time and appreciate all the info you have given.

    Sorry I can't really give you anything in return, unless you require advice on bricklaying (my trade for 13 years)

    Yours

    Russ
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