Active Chilled Beam Heating and Cooling
Cooling Systems: Chilled Beams vs. Conventional VAV Air Distribution System
A heating and cooling system that draws room air past hot or cold water heat exchangers and provides conditioned air and necessary ventilation air into the space.
Chilled beams are not structural building elements. A chilled beam is a hydronic convection HVAC component designed to heat or cool large buildings. Pipes of water pass through a "beam" (a casing with heat exchanger similar to a radiator or baseboard heater) that is either integrated into standard suspended ceiling systems or suspended a short distance from the ceiling of a room. As the beam chills the air around it, the air becomes denser and falls to the floor. It is replaced by warmer air that moves up from below, causing a constant flow of convection and cooling the room.
Chilled beam systems can be passive or active. Active systems use supplemental ventilation air to distribute the cool air away from the beam. Active chilled beams use circulating fans to move room air to the beam’s heat exchange surface and provide fresh air for ventilation with small ducts. When compared to variable air volume (VAV) HVAC, these systems provide several benefits in medium to large commercial and public buildings, including energy savings.
Chilled beam systems have been installed in office buildings, hospitals and laboratories, K-12 schools, colleges and universities, and government buildings. Because water is a more efficient medium for heat transfer than air, HVAC energy savings up to 20% are possible. Chilled beam systems do not require conditioned air delivery to building spaces, eliminating the need for large supply and return air fans. Low-capacity pumps use less energy than large-capacity supply and return air fans, and duct losses are eliminated. Also, the chilled water for cooling has a higher temperature than conventional chilled air, extending the “free-cooling season.” A higher design chilled water temperature (58°F) may allow chiller efficiencies to increase by as much as 35%.
Chilled beams are popular in Europe and the UK, in areas with climates similar to those found in the Northwest. Condensation on the chilled beam can be an issue that can be mitigated with dehumidification. Chilled beam systems require some provision for ventilation air and may also require supplemental heating and cooling – such as perimeter heating – in less moderate climates. Resolving these issues can incur additional costs (Navigant Consulting, 2012).
Energy Savings: 20%
Energy Savings Rating:
Extensive Assessment What's this?
|1||Concept not validated||Claims of energy savings may not be credible due to lack of documentation or validation by unbiased experts.|
|2||Concept validated:||An unbiased expert has validated efficiency concepts through technical review and calculations based on engineering principles.|
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|4||Extensive assessment||Additional testing in relevant applications and environments has increased knowledge of performance across a broad range of products, applications, and system conditions. |
|5||Comprehensive analysis||Results of lab and field tests have been used to develop methods for reliable prediction of performance across the range of intended applications.|
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