Variable Air Volume (VAV) Is A Type of Heating, Ventilating, And/or Air

Chilled Beams What are they?
They are a cooling device

They are different from chilled ceilings These rely solely on radiant
cooling (Output 50 to 55 watts per square metre)
(A radiant cooling system refers to a temperature-controlled surface that
cools indoor temperatures by removing sensible heat and where more than
half of heat transfer occurs through thermal radiation. Heat will flow from
objects, occupants, equipment and lights in a space to a cooled surface as
long as their temperatures are warmer than that of the cooled surface and
they are within the line of sight of the cooled surface )
They are an alternative to both Fan Coil Units and VAV systems
Variable Air Volume (VAV) is a type of heating, ventilating, and/or airconditioning (HVAC) system. VAV systems vary the airflow at a constant
temperature.
A fan coil unit (FCU) is a simple device consisting of a heating or cooling
coil and fan. Typically a fan coil unit is not connected to ductwork, and is
used to control the temperature in the space where it is installed, or serve
multiple spaces. It is controlled either by a manual on/off switch or by
thermostat.
There are three kinds of chilled beams
Passive No reliance on primary air supply. They work entirely on radiant

convection. (Output 130 to 170 watts per linear metre)
Active These rely on primary air supply to provide the induction
required for performance. (Output 850 to 1400 watts per linear metre)
Multi Service These are active beams with the additional components
(smoke detectors, lighting, sprinklers etc.) (Output 850 to 1050 watts per
linear metre)
Active Chilled Beams can also be used for heating
The difference between passive and active beams focuses on the way airflow and
fresh air are brought into the space. Chilled beams are room air recirculation
devices, which are used to cool and ventilate spaces wherein user comfort and good
indoor air quality is desired and valued, typically in commercial office spaces,
hospital patient rooms, hotel rooms, classrooms and laboratories. Chilled beams
also supplement the flexible use of available space and are used where the primary
air is dehumidified.
With a passive chilled beam system (suitable for cooling only), outdoor air is
supplied into the airspace through a separate diffuser or grille.
With active chilled beam systems (suitable for both heating and cooling), outdoor
air is supplied into the airspace through the beam itself.
Multi service chilled beams can be of bespoke design and incorporate light, sound,
fire and cable pathway services required for the building. These types of chilled
beams are widely used throughout Europe.
Benefits of chilled beams
Eliminates the fan for room air circulation thereby reducing the lan power
requirements
Chilled beams use water as energy carrier, making it efficient in terms of
system energy use and space requirement of building services in a
building.
Indoor air quality improves since the outdoor air is required to cater the
internal latent load
Chilled Beam system has limited maintenance requirements.
cheaper to buy
Only require simple controls
Variable self limiting output
No condensate drainage required
Source:https://www.bsria.co.uk/download/asset/chilled-beams-event-.pdf
A key advantage is that a chilled beam system requires very little ceiling space and
height, thus enabling shorter commercial buildings but offering the same floor
space for tenancy.
Another advantage is the high energy carrying capacity of water via the copper
pipes.
A forced air system is significantly less efficient because of the low density of air,
necessitating large ducts and taller, less efficient and costly buildings to deliver the
same conditioning of the indoor air.
The amount of outside air required to operate a typical chilled beam system is much
less than that needed for a forced air system.
A chilled beam system typically needs only one air change per hour, using outside
air to pressurize the space.
With a forced air system, that need grows to eight to 10 air changes of recirculated
and fresh air into the space.
With active chilled beam systems, energy to operate fans is reduced dramatically
because of the low pressure and the relatively small amount of primary air being
circulated by the central system.
A chilled beam system can reduce electrical energy demand by almost 25 per cent.
Installed within modern radiant systems such as Chilled Beams (active or passive),
only two chilled water pipes are needed compared to the conventional four pipe
system.
Water flow rates are reduced since there are no control valves, balancing valves, or
piping losses to overcome. The small, reliable circulators take the place of all of
these components.

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Chilled Beams What are they?

They are a cooling device

Passive No reliance on primary air supply. They work entirely on radiant

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