Active Chilled Beam Product

Overview

An active chilled beam is a hidden-in-ceiling HVAC terminal that provides convective cooling and heating to occupied spaces. Unlike traditional all-air systems that deliver large volumes of ductwork, beams decouple cooling from ventilation: a small amount of low-velocity "primary air" (30–50 CFM) is supplied from a central air handler, while the majority of cooling energy comes from chilled water circulating through an aluminum fin-tube Thermal Coil Assembly. Primary air is injected at high velocity through [[active-chilled-beam-induction|nozzles]] that entrain room air (inducing 5–10 times its volume), creating a powerful mixing effect that cools and stratifies the lower space while maintaining low noise and draft-free comfort.

Beams are the centerpiece of "beam and column" HVAC designs popularized in European office buildings and increasingly adopted in North America. They reduce ductwork installation, lower floor-to-floor height requirements, improve acoustics, and enable independent zone control (each beam responds to its own room sensor). Because the primary air is already partly dried by a central dehumidification process, condensation risk is minimal even in humid climates. A Modulating Water Valve modulates water flow in response to [[active-chilled-beam-controls|zone temperature]], allowing the beam to dial capacity up or down without rerouting air streams.

How it works

Primary air arrives at the Primary Air Plenum at low pressure (300–500 Pa) and is distributed evenly across 6–8 [[active-chilled-beam-nozzle|nozzles]]. Each nozzle creates a small, high-velocity jet (~15 m/s) aimed downward and sideways at roughly 45 degrees. These jets strike the [[active-chilled-beam-coil-fins|fins]] of the Thermal Coil Assembly and induce surrounding room air to accelerate and mix. The induced flow expands and accelerates the total air mass, creating a powerful downward plume that spreads across the workspace.

The Thermal Coil Assembly sits in the direct path of both primary and induced air. Chilled water (6–18°C) circulates through [[active-chilled-beam-coil-tubes|copper tubes]], absorbing sensible heat from the mixed air stream. The Modulating Water Valve modulates the water valve open or closed (0–100% position) based on room temperature feedback, maintaining precise setpoint control without any secondary ductwork or reheat loops. Condensate that collects on the coil surface drains through the Condensate Drain Assembly into a [[active-chilled-beam-drain-trap|P-trap]] and then to gravity or indirect drainage.

Advantages and Application Patterns

Chilled beams are ideal for office tenant spaces, hotel rooms, and buildings with high ceilings and exposed structure where dropped soffit ductwork is expensive or impossible. A single 4 m beam can condition 40–60 m² of floor space. Because all cooling (not ventilation) comes from water, zones can have very different supply air volumes without sacrificing comfort—a corner office with high solar load might pull more chilled water, while a core zone pulls less, all using the same primary air supply rate.

The [[active-chilled-beam-mounting|suspension frame]] allows flexible placement above suspended ceilings or in open-ceiling designs, and the beam remains accessible for maintenance. Room-by-room zone control via [[active-chilled-beam-controls|proportional valves]] means no complex damper logic or VAV box tuning.

Condensation and Dehumidification Strategy

Because primary air is dehumidified at the central level before entering the plenum, it arrives dry. Induction of room air mixes moisture, but the overall humidity remains below saturation. In very humid climates (tropical, high-occupancy spaces), additional primary air volume or desiccant dehumidification at the AHU is needed. The Drain Pan design allows for independent humidity sensor monitoring if condensation risk rises.

Standards and Maintenance

ASHRAE 62.1 sets primary air requirements; a typical office space needs 15–25 CFM of outdoor ventilation, provided by the primary air stream. Every 6–12 months, the Thermal Coil Assembly should be cleaned (dry brushing or gentle vacuum) to maintain heat transfer and prevent mold. The water loop is serviced at the plant level; individual beam maintenance is minimal—primarily drain trap flushing and valve stroke checks.