Chilled beams can offer facility managers energy-efficient alternatives to standard air conditioning systems in retrofits, renovations or new construction.
First developed in Norway in 1975, the technology has been used successfully throughout commercial applications in Europe for at least 20 years, according to ASHRAE. But chilled beams are just starting to see more use in the United States as an alternative to conventional systems.
Chilled beams are hydronic HVAC components that circulate chilled or heated water. Such systems use pumps to move water instead of using fans to move air and they run more quietly than conventional cooling systems, according to the U.S. General Services Administration (GSA).
There are two types of chilled beams: passive and active – each of which has a cooling coil, notes ASHRAE. The passive chilled beam consists of a casing with a cooling coil inside where the chilled water circulates throughout the coil. Warm air in the room rises, passing through the cooling coil. The cooled air, which is less buoyant than the warm air, flows down, resulting in a gentle circulation of the air.
In the active system, rather than using warm air from the room, air from the building’s air handling system introduces warm air into the beam. Chilled beams are either located in the ceiling or exposed just below the ceiling. There are also some in-floor active chilled beams.
ASHRAE claims there is up to a 30% reduction in energy use when chilled beams are used. Chilled beams save space by eliminating the need for ductwork. Such systems have a simple mechanical design so not much mechanical room space is needed.
In most chilled beams systems a one-inch diameter water pipe is able to handle as much cooling energy as an 18-inch air duct on conventional systems. Because chilled beams don’t need most of the components (i.e., filters, moving parts, air-handling units, etc.) that conventional cooling systems need, maintenance costs are purportedly less.
Additionally, chilled beam systems last longer; they require little regular maintenance; and most systems remain dirt and dust free – requiring minimal cleaning.
One drawback to a chilled beam system might be the cost of switching to the system. Installing chilled beams requires a reconfiguration of the mechanical and ceiling systems. That’s why chilled beams are best used in situations where there is new construction or a major retrofit/renovation is already underway.
Another drawback, is that chilled beams don’t handle high internal loads well, and using such a system requires a tighter control of the facility’s humidity, according to the GSA.