Constant Volume Linear Ceiling Diffusers (CLN) | rickardair

Constant Volume Linear Ceiling Diffusers (CLN)

Rickard Constant Volume Linear Diffuser (CLN) can be used to shielded the load transmitted through a buildings windows or as an attractive diffuser alternative in internal zones. Their pattern controllers can be adjusted to create a vertical curtain of conditioned air that acts as a barrier to uniform thermal loads or create a horizontal flow pattern that creates good mixing and limits drafts.

Rickard CLN diffuser tracks are designed to be joined end-to-end to create uninterrupted lengths of attractive linear track.

Rickard 2 Slot Constant Volume Linear Diffuser

PERFORMANCE

Aerodynamically shaped diffuser components reduce noise and improve air flow characteristics.

OPERATION

The airflow pattern is adjustable from below the ceiling, being changeable from one-way blow in either direction or to vertical down blow.

INSTALLATION SAVINGS

Included Jubilee Clamp saves time and material when attaching the flex.

CAPITAL & OPERATING COST

Low diffuser height can reduce a buildings overall cost by reducing the height of the ceiling void.

AESTHETICS

Rickard CLN Diffuser tracks are designed to be joined end-to-end to create uninterrupted lengths of attractive linear track. CLN Tracks are compatible with other Rickard CLN tracks, Dummy tracks (inactive sections of track often used for return air) or VLN tracks (Variable Volume Linear Diffusers).

Tracks are finished in a wide range of high quality epoxy powder coated finishes. Matt White comes as standard.

MAINTENANCE

Surface mount CLN diffuser tracks are accessible from below the ceiling. No skilled labour or special tools are required for fitment or removal.

The CLN’s plenum is constructed form corrosion resistant mill galvanized sheet steel. The diffuser tracks are constructed from aluminium extrusion and are coated with epoxy powder coating.

No regular maintenance is required.

ZONES WITH A CONSTANT LOAD
COOLING AND HEATING
PROPORTIONAL TERMINAL RE-HEAT
HEATING WITH STAND ALONE OR BMS CONTROLS
HEATING WITH REMOTE SETPOINT

RICKARD Constant Volume Linear Diffusers are intended for zones where load fluctuations are limited. The Constant Volume Linear Diffuser, as its name implies, do not automatically regulate the air volume entering the conditioned space - they are constant volume devices. Consequently, room temperatures will vary with room loads (assuming the duct air temperature and pressure remain constant).

Should this method be decided upon, care should be taken in selection of the CLN diffuser to ensure dumping does not take place at minimum air flow status.

The Rickard CLN diffusers can be used to supply spaces that require heating or cooling. To ensure that dumping does not occur in cooling and stratification in heating care must be taken to supply the diffuser with adequate pressure.

Constant Volume Diffusers can be used to supply top up heating when required. This is achieved by fitting them with a Rickard Neck Heater.

A useful feature of the RICKARD CLN is the ease with which the direction of airflow may be adjusted. Although airflow direction is not normally changed once the system is operational, it does simplify the ordering procedure. All linear air diffusion track is identical and the choice of one-way or two-way blow is easily implemented on site by simply flipping the flow directional vane to the preferred side. Single slot CLN’s are only available in horizontal blow.

It is possible to direct air vertically downwards for better room penetration, especially when the CLN is in the heating mode.

The first consideration when designing a system is to calculate the required supply air volume and temperature to satisfy room conditions at maximum heat loads. It is recommended that ducting is sized using static regain design principles. Supply air velocities in branch ducts should be between 3.5 and 7.5/s (650 and 1500ft/min).

THROW

This is the distance from the centre of the diffuser to the point at which the supply air velocity has reduced to 0.25m/s (50ft/min) when measured 25mm (1 inch) below the ceiling. Coning occurs when two airstreams travelling in opposite directions meet and result in a downward moving cone of air (applies to pattern controller in the horizontal position). A similar effect is experienced should a diffuser be positioned at a distance from the wall that is less than its throw. The air will strike the wall and flow in a downward direction such that the point at which the air reaches a velocity of 0.25m/s (50ft/min), the sum of the horizontal and vertical travel of the air is equal to the diffuser throw.

NOISE LEVEL REQUIREMENTS

The published diffuser noise level must be checked to ensure it is within the project specification. Published diffuser noise levels represent only the noise generated by the diffuser and do not take into consideration any duct-borne noise.

DUCT STATIC PRESSURE

Diffuser performance has been established using diffuser neck TOTAL pressure, although that which is normally known or measured is duct STATIC pressure. What happens between the duct and the diffuser depends on the length and type of flexible duct being used.  For simplicity, it can be assumed that the duct STATIC pressure is approximately equal to the diffuser neck total pressure. This is a valid assumption for systems where flexible duct lengths are not excessive and can be explained briefly as follows:

The static pressure loss due to friction in the flexible duct (±10Pa or 0.04ins Wg) would normally be about the same as the velocity pressure in the neck of the diffuser and since total pressure is the sum of static and velocity pressure. Although the tables reflect diffuser performance for neck total pressures ranging from 30-70Pa (0.12-0.28ins Wg), caution should be exercised when selecting diffuser outside the 30-50Pa (0.12-0.20ins Wg). At lower pressures air movement and induction may be insufficient and at higher pressures draughts and excessive noise may result. Best results are obtained when diffusers are selected at pressures of 30-40Pa (0.12-0.16ins Wg).

 

 

TRACK LENGTHS

The standard CLN is available in unit lengths of:
600mm
900mm
1200mm
1500mm

TRACK TYPES

CLN Linear Diffusers are available with 1 - 8 Slot tracks. 2 to 8 slot variants are available with adjustable pattern controllers (vertical to horizontal), single slot tracks are available with a horizontal blow pattern controller as standard.

CLN Linear Tracks are designed to fit Plastered Ceilings (Surface Mount) and most Ceiling Grid (Drop-in) variants.

Rickard CLN Diffuser tracks are designed to be joined end-to-end to create uninterrupted lengths of attractive linear track. CLN Tracks are compatible with other Rickard CLN tracks, Dummy tracks (inactive sections of track often used for return air) or VLN tracks (Variable Volume Linear Diffusers).

Tracks are finished in a wide range of high quality epoxy powder coated finishes. Matt White comes as standard.

1 Slot CLN2 Slot CLN

8 Slot CLN

SPIGOT SIZE AND QUANTITY

CLN Linear Diffusers with multiple slots require larger and/or more spigots. Please see the CLN Spigot Detail table for more detail.

CLN Spigot Detail

CLN Length

HEATING OPTION

CLN’s are also available with built in heaters. Please see Electric Section for more Information on this option.

SENSING OPTIONS

If fitted with Heating, CLN’s can get their signal from another Master Diffuser or by attaching a remote Wall Thermostat. Onboard Sensing is not available on CLN’s.