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Are chilled beam systems going to replace VAV systems?

A few years ago I had the opportunity to work on the installation of an Active Chilled Beam system at the N.Y. Genome Lab in NYC. At that time I did not know the first thing about chilled beams, so I Googled the manufacturer (Dadanco) and learned a bit about how these system work. Although I installed the units and piped the chilled water to them, I didn't have much access to the MER or the prints on the job.

It appears that the engineering borrows from the old induction units of the 1960's and improves on it by placing the units overhead and throughout the space being heated or cooled, instead of the previous perimeter system that has them on the floor and in front of the windows. The new challenge is to keep them from condensing and causing "internal rain" due to the fact that they do not have drain pans under them. The heating portion is not nearly efficient, but the A/C claims to save energy by cutting back on the size and amount of ductwork and fans, as well as, working on the principle that water is a lot more efficient in transferring heat than air. Two systems are built into one, in regards to the air distribution network.

One provides conditioning by removing the humidity (latent heat) and lowering the temp somewhat, while the other removes the remaining sensible heat (chilled beams) to achieve the desired temp of comfort. There is a lot more to this as I am continuing to study this system through available literature from different manufacturers and articles in trade magazines. Recently I read an article from Trane which did more to knock the technology than explain it.

Has anyone had the experience of what they call "internal rain?" I would imagine this potential problem to be the most concerning. Water damage and mold issues can be extremely costly. I am also curious if anyone has had experiences where this system completely replaced and existing VAV system or induction A/C system. There was a job at Harvard University which claimed very reasonable energy and costs savings.


  • SWEI
    SWEI Member Posts: 7,356
    Chilled beams are amazing when done right.

    The system should be set up to monitor dewpoint in at least one indoor location (more is better, usually) and manage the cooling SWT accordingly. What kind of controls are on it?