Chilled beam

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Image:Active chilled beam diagram.gif
Active Chilled Beam: Primary/ventilation air (1) is introduced into the active chilled beam through a series of nozzles (2). This induces room air (3) up into the active chilled beam and in turn through a secondary water coil (4). Induced room air is cooled and/or heated by the water coil to the extent needed to control the room temperature. Induced room air is then mixed with the primary/ventilation air and the mixed air (5) is discharged into the room.

A passive chilled beam is a building cooling device that circulates air using the principles of natural heat convection. A recent innovation[1], the major advantage of a passive chilled beam over more common forced air systems is that it circulates building air without the noise and expense of ductwork and air handlers. Typically mounted overhead near or within a ceiling, the beam is a type of radiator, chilled by an external source such as recirculated water. It cools the space below it by acting as a heat sink for the naturally rising warm air of the space. Once cooled, the air naturally drops back to the floor where the cycle begins again. With passive chilled beam systems the ventilation air required must be delivered to the occupied spaces by a separate air handling system.

There is another type of chilled beam - active chilled beam[2]. The chief difference is the ventilation air required is delivered to the active chilled beams.

With active chilled beam systems[3] the building's primary/ventilation air is continuously supplied to the active chilled beam terminal units by the central air handling system. This primary/ventilation air is cooled or heated to partially handle the temperature-driven sensible loads, while in the summer being cooled/dehumidified enough to handle all of the internal moisture-driven latent loads. Secondary air is induced up into the active chilled beam and is cooled or heated by the heat exchanger within the beam. The primary air and the induced air is then combined in the mixing chamber and then supplied into the room via linear slots on the edge of the active chilled beam. Active chilled beam generally have much higher sensible cooling capacities than passive chilled beams.

Both passive and active chilled beams typically provide only sensible cooling but can be used for heating with the correct design parameters. The latent moisture-driven cooling capacity required is provided by the cooled and dehumidified ventilation air.

[edit] References

  1. ^ Laboratory Design, "Chill the ceilings for cool energy savings, accessed 2007-04-18.
  2. ^ Affiliated Engineers, Inc., Chilled Beams, accessed 2007-04-18.
  3. ^ Dadanco Active Chilled Beams, What is an Active Chilled Beam?, accessed 2008-03-10.
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