Chilled Beam Technology

Basic Chilled Beam Principles

Chilled beams are predominantly used for cooling and ventilating spaces, where a good indoor environment and individual space control is valued. Chilled beams use water to remove heat energy from a room and are located in the room space. Chilled beams are primarily used in locations where the humidity can be controlled.

Chilled beams provide excellent thermal comfort, energy conservation and efficient use of space due to the specific heat capacity of water being so good when used as heat transfer medium (typically four times better than air). Chilled beam operation is simple and trouble free due to having minimum maintenance requirements. Chilled beams also supplement the flexible use of available space, at the same time as the high temperature cooling and low temperature heating maximizing the opportunity for free cooling and heating. Operation of the chilled beams is used where the internal humidity loads are moderate, the primary air is dehumidified and any infiltration through the building is limited and controlled.

Active Chilled Beams

Active Chilled beams are connected to both the ventilation supply air ductwork and the chilled water supply. If required, low temperature hot water (LTHW) can be used in this system for heating. The main air handling unit supplies primary air into the various rooms through the chilled beam. An active chilled beam uses the primary air supply to induce warm room air into the beams cooling battery (heat exchanger). In order to cool or heat the room either cold or warm water is circulated through the beams battery. Active chilled beams are able to induce and condition 4-5 times as much room air as fresh air supplied. The re-circulated air and the primary air are mixed prior to being reintroduced into the room by nozzles or slots along the beam. Best practice for active chilled beam systems is to have highly efficient chilled beams, that can achieve the sensible cooling requirements on the chilled waterside circuit when the corresponding amount of primary fresh air is selected to only handle the latent gains and meet typical respiratory requirements of 12lts/sec/person. Typically a building with an occupancy density of 1 person in every 8m2 the amount of primary air should equate to around 1.5lts/sec/m2.

Active Chilled Beam Installation
Active Chilled Beam
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Passive Convective Chilled Beams

Passive Chilled beams comprise of a heat exchanger for cooling. Traditional passive chilled beam operation is based on natural convection. As the warm room air comes in contact with the cooled surface of the chilled beam it flows downwards through the beam into the room. Passive beams are not connected to the ventilation system. The primary air is supplied to the space using separate diffusers either in the ceiling or wall, or alternatively through the raised floor. A recommended maximum cooling of up to 200 W/m applies to passive convective chilled beams (Circa 95% convective elements) based upon the comfort criteria recommended with BS EN ISO 7730 (PPD <15 per cent).

Passive Chilled Beam

Passive Radiant/Convective Chilled Beams

Chilled beams have been around for many years however during the last decade, the technology has been further developed and more widely applied in the space conditioning industry.

The latest development in passive chilled beam technology employs both convective and radiant principles which are designed to deliver high cooling duties with minimal air movement within the occupied zone. The radiant quotient now available on the market is typically 40% of the total cooling effect (the other 60% of cooling generated by convection). Therefore, the ability to cool by radiation means that this new technology can provide 40% more cooling at the same air movement velocities when compared to traditional finned coiled batteries. This is ideal for use with offices where there is a requirement to provide the best possible occupancy comfort levels and excellent energy efficiency is required.

Passive Radiant/Convective Chilled Beam
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Radiant/convective passive chilled beams are designed to be installed free-hanging from the soffit, positioned above a perforated metal ceiling system or as Multi Service Chilled Beam (MSCB’s). Furthermore, a passive radiant/convective chilled beam also offers effective cooling when used with a ceiling system or underplate which is perforated to just 30% free area. Therefore, cooling of up to 270-300 W/m applies to the latest passive radiant/convective chilled beams (60% convective 40% Radiant elements) based upon the comfort criteria recommended with BS EN ISO 7730 CAT B (PPD <20 percent).

FTF Group Climate - Chilled Beams
Frenger Systems - Chilled Beams