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  1. #1
    Join Date
    Mar 2005
    Posts
    665

    controlling chilled beams

    Hi controls guys , I`m intrigued in how chilled beams are able to avoid condensation issues/dripping, I do get the basis that MUA units dehumidify as much as possible all incoming air , but what about buildings with functioning windows , or extreme humid climates/loads? building controls monitoring dew temps? rh? resetting chilled beam temps? any humidity type sensors on beams themselves? Or as simple as keeping chw temp range high enough? Just basic answers will suffice to give me food for thought, as I dont design them , just working on chillers with these terminals. and curious, thank you for any replys stan
    Keep it simple to keep it cool!

  2. #2
    Join Date
    Nov 2012
    Location
    Sydney, Australia
    Posts
    8
    I've installed a system which regulates the CHW to the correct temp so it does not condensate via the use of a heat exchanger.
    It also had the condensate sensing tape along the underside of it incase it did get too cold as it was used in a computer room.

  3. #3
    Join Date
    Jan 2008
    Location
    Dallas ,Texas
    Posts
    3,725
    Just get some chilled beams with condensate pans.
    UA 100

    It takes three people to do anything around here. Two do the work, one explains to the crowd of people who showed up when they seen smoke and flames.

  4. #4
    Join Date
    Mar 2005
    Posts
    665
    thanks for replys , I also found this online 5.1 How is condensation avoided in high humidity environments?

    Outdoor air is pre-conditioned and dehumidified in the primary air handling unit, along with any return air needed to make up the primary air total. The building is maintained at a slight positive pressure with respect to the outside to control infiltration of humid air. Once the dehumidified air is in the space, the dew point is monitored and the temperature of the primary air will be controlled maintain the room design humidity level in order to avoid condensation at the beam. If the system can not maintain the room design humidity level then the last resort would be to increase the temperature of the secondary chilled water.
    Dallas , I`m guessing it comes down to cosmetics, I would do the same and be safe , regards , stan
    Keep it simple to keep it cool!

  5. #5
    Join Date
    Oct 2005
    Posts
    327
    Honeywell makes a dew point sensors and an alarm to notify before the chilled beam starts to condense.
    https://customer.honeywell.com/resou...0s/63-2660.pdf
    http://products.ecc.emea.honeywell.c...-ge51r0710.pdf

  6. #6
    Join Date
    Jan 2003
    Location
    USA
    Posts
    1,767
    We have a large building that uses radiant floor for cooling. Outside of keeping the CW temp to the floor a few degrees above dew point we have not have any issues with it. This building is 100% OA from a DOAS unit. It keeps the space humidity in check which is really the key to the whole system. Because all the floors have radiant cooling, it’s enough surface area that we do not need floor temps below 60F to keep the spaces comfortable. Most of the time the dew point limit on the CW temp never comes into play.
    Propagating the formula. http://www.noagendashow.com/

  7. #7
    Join Date
    Oct 2005
    Posts
    327
    Aren't people's feet cold with a radiant floor?

  8. #8
    Join Date
    Mar 2005
    Posts
    665
    Hi tlp261 are you using these control/sensors as digital inputs to BMS? or controlling actuators? stan
    Keep it simple to keep it cool!

  9. #9
    Join Date
    Oct 2005
    Posts
    327
    Stan,

    Sorry, I hadn't seen your post. I haven't done a chilled beam, just had seen these sensors were available.

  10. #10
    Join Date
    Jan 2003
    Location
    USA
    Posts
    1,767
    Quote Originally Posted by tlp261 View Post
    Aren't people's feet cold with a radiant floor?
    You don't even notice it. Most of the floors are carpet, and again they rarely get down to 60F.

    I guess if you lay on the floor or walk around barefoot maybe.
    Propagating the formula. http://www.noagendashow.com/

  11. #11
    Join Date
    Jan 2002
    Location
    Fort Worth\Dallas, Texas
    Posts
    1,708
    The last ones I did I measured the dewpoint in the space and reset the chw water setpoint through the beams 2-3 deg above the space dewpoint. I also had some strap on moisture sensors on the pipes that would close the valve if they sensed moisture.
    Go Rangers!

  12. #12
    Join Date
    Mar 2005
    Posts
    665
    great, Ive learned alot from this
    Keep it simple to keep it cool!

  13. #13
    Join Date
    Sep 2007
    Location
    Australia
    Posts
    162
    We have had some problems down here in oz with regard to insufficient primary airflow (via swirl diffusers) when humidity is high. Once it gets into the building, it can be difficult to get a handle on as you loose cooling ability as the dew point rises
    The DDC system... guilty until proven innocent

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