When it comes to HVAC developments, chilled beams may be one of the newest. First created in Norway in 1975, chilled beams have become most popular in Europe. But the technology is slowly emerging in the United States as an alternative to traditional systems.
Three types of chilled beams are currently available for commercial buildings: passive chilled beams, active chilled beams, and multi-service chilled beams.
While all three types include a cooling coil that provides radiant cooling through circulated cool water, the passive beam’s cooling coil is held in an enclosure. It relies on natural convection and buoyancy without any direct air supply. When heat is transferred from the room air to the coil, the air is cooled and falls down into the area below.
Active beams provide ventilation air in addition to cooling. They use air-handlers to supply outside air to condition a space. A cold water piping system circulates water through the active beam’s cooling coils. To function correctly, active beams rely on both buoyancy and powered air movement.
Multi-service child beams can be either active or passive, but they also integrate other building systems: lighting, sprinklers, cabling, etc.
All three types of beams can be installed either into or directly below the ceiling. Chilled beams can also be used for heating as well, as long as heat loss through the building envelope is minimal.
Because less supply air is required in chilled beam systems, they require smaller ductwork and air-handling units; ceiling and mechanical space can be reduced in some cases. Chilled beams also contain no moving parts, which ultimately reduces regular maintenance requirements; there are no fans or filters to clean or replace.
Tenants and occupants often enjoy the benefits that chilled beam systems offer: individual room temperature control capability at a very low cost, reduced overall system noise, and reduction of uncomfortable drafts.
Chilled Beams in Action
During a major renovation a few years ago, the 18-story Byron G. Rogers Federal Building in Denver decided to incorporate several innovative MEP systems as part of a quest to achieve net zero energy by 2030.
Part of this massive overhaul included the installation of an active chilled beam system to replace the building’s inefficient mechanical system. After capturing heat generated in the building by occupants, computers, lighting, and solar heat gain, a thermal tank located in the basement stores and circulates this heat through the building’s chilled beam system as needed.
It’s estimated that the water running through the chilled beams at night can heat the building 10 to 20 times more efficiently than a conventional gas-fired boiler. As a result, the active chilled beam system helps reduce energy use in the office tower by nearly 70 percent.
New in Chilled Beams
In February 2015, AHRI (the Air-Conditioning, Heating, and Refrigeration Institute) announced a new certification program for active chilled beams.
AHRI standards for active chilled beam performance have now been published to serve as rating standards for the certification program. The program will certify water flow rate, water pressure drop, water coil capacity, primary airflow rate, sound generation, and induced airflow rate.
This could be a sign that active chilled beam installation is making progress in the United States.