Frenger
Cooling Effects & Chilled Beams
Thermal Comfort Principles
How we experience the thermal indoor climate
depends primarily on our overall heat exchange with the
surroundings. A person’s thermal comfort is affected by the
following: Air temperature, radiant temperature, relative humidity,
air velocity, activity and clothing.
Thermal comfort is realised when a person feels
in thermal balance, ie. they are neither too hot nor too cold. In
addition, there should be no unwanted heating or cooling of
individual exposed body areas (draughts in the neck or on the
ankles). We primarily exchange heat to our surroundings via
convection and radiation.
These two methods of transferring heat are
approximately equal with normal air movement in a room. Therefore,
we are affected just as much by the room’s surface temperatures as
we are by the air temperature.
If the temperature of the room’s surface is
decreased, fully or in part, the air temperature can be increased by
an amount corresponding to the decrease in the room surface’s mean
temperature. Therefore, when we cool an environment with a radiant
cooling device, the desired operative temperature can be raised
slightly as a result of a perceived lower room temperature. This
effect is in the region of 1-2ºC.
Frenger Passive Beam Features
40% Radiant Effect / 60% Convective
Passive System
Can be concealed behind perforated ceiling system
Requires minimal control
75W/m² - 140W/m² cooling capacity
Frenger Active Beam Features
Fresh air introduced via unit
Room air induced through cooling batteries
High Capacity - upto 1500W/linear metre cooling capacity
Can integrate lighting heating, sprinkler outlet and data cables
Architectural Casing Options
Running Cost / Energy Use - Chilled Beams
There are several aspects of an active chilled
beam system that promoted a more energy efficient operation than air
based systems such as fan coil units and VAV.
Typically the chilled water is distributed to the
chilled beams at 14-17ºC to minimise the risk of condensation,
whereas fan coil units operate typically at 6-12ºC.
Elevated chilled water temperatures offer two
principal benefits in terms of energy efficiency:
- By operating the chiller plant at elevated
temperatures its co-efficient of performance (COP) is increased &
energy consumption reduced. The efficiency of the compressor can be
increased by using a dry cooling system (inlet water 14ºC instead of
7ºC) with a percentage increase in COP of typically 22%.
- Elevated temperatures enable a significant
increase in the opportunity to avail free cooling from sources such
as outdoor air or ground water heat sinks. That is an annual
increase from 800 hours to 2000 hours for a 12 hour day and 2100 to
5200 hours for 24 hour operation.
Fan coil unit and VAV systems rely on a fan
assisted cooling distribution; that is each fan coil unit
incorporates a fan. Chilled beam systems utilise a centralised fan
that delivers just enough air to meet respiratory requirements (or a
little more in the case of some active chilled beam systems); with a
consequent reduction in capital cost, electricity consumption and
maintenance cost.
To deliver 100 W/m² cooling:
(Click on image for larger display)
Maintenance Costs - Chilled Beams Vs. Fan Coil
Units
There are no moving parts in chilled beams and
therefore maintenance requirements are very low. An active chilled
beam will require the cleaning of the batteries - using a vacuum
cleaner and brush attachment - at intervals of 3-4 years by simply
wiping the surfaces with a damp cloth. The chilled beam itself
requires no further maintenance and can be expected to last the life
of the building; however water quality must be appropriate and
associated control valves and flexible hoses will require frequent
inspection/replacement.
The maintenance and replacement cost illustrated
below is taken from REHVA’s Chilled Beam Application Guidebook
issued 2005:
(Click on image for larger display)
Request information:
Frenger radiant panels electric radiant
heating convective heaters
Request information:
Frenger Chilled
beams passive active chilled beams MSCB chilled ceilings
Technical information associated with:
Frenger Radiant
Heating radiant heaters radiant ceiling panel
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