Constant Volume Ceiling Diffuser (CCD, CRD, CSD3) | rickardair

Constant Volume Ceiling Diffuser (CCD, CRD, CSD3)

The RICKARD Constant Volume Ceiling Diffusers (CCD/CSD/CRD) have been designed to provide a cost effective outlet that provides excellent levels of comfort in an architecturally pleasing package.

PERFORMANCE

Good Coanda, Velocity and Throw at all diffuser damper positions.
Good Air Change Effectiveness.
Good ADPI values.

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

OPERATION

Damper adjustment is easily accessible via a screw driver slot in the diffuser face.

INSTALLATION SAVINGS

Included Jubilee Clamp saves time and material when attaching the flex.
Tile can be installed separately of adjustment sub-assembly.
Included plastic packaging  can be used to protect the Tile once installed.

CAPITAL & OPERATING COST

Low diffuser height (100mm) can reduce a buildings overall cost by reducing the height of the ceiling void.

AESTHETICS

Face Plate Mounting structure not visible from within the air-conditioned space.
Indented diffuser edge detail ensures the face of the diffuser is flush with the underside of the ceiling tee frame.
High Quality Epoxy Powder Coated Finish available in a wide range of colours. Matt White comes as standard.

MAINTENANCE

Merely twist the Trim Plate 5º clockwise to remove all moving parts from below the ceiling.  No skilled labour or special tools are required.

SAFETY

All internal components of non metallic construction are molded in fire retardant glass reinforced Makrolon – Makrolon is used in our Thermo-Disc Actuator that is UL certified.
Stainless steel safety cable ensures that internal components remain attached in the event of building fire.

INTERNAL ZONES AND ZONES WITH A CONSTANT LOAD
COOLING AND HEATING
PROPORTIONAL TERMINAL RE-HEAT
HEATING WITH STAND ALONE OR BMS CONTROLS
HEATING WITH OR WITHOUT REMOTE SETPOINT

RICKARD Constant Volume Ceiling Diffusers are intended for use in internal zones of a building where uniform radial discharge is the most suitable supply air pattern.  Normally these zones are less complex to air-condition as load fluctuations are not as severe as those on the perimeter.  The Constant Volume Ceiling Diffuser, as its name implies, does 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 CCD/CSD/CRD diffusers to ensure dumping does not take place at minimum air flow status.

The Rickard CCD/CSD/CRD 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 diffusers 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.

Although the CCD is a constant volume terminal, the air volume may be adjusted manually to obtain the required design air flow.  This is achieved by adjusting the control disc up or down manually using the screw driver slot located in the face of the trim.

The most important practical factors to consider in internal zones are noise levels and uniform air distribution without "dumping" or "coning" effects.  "Dumping" is the tendency for cold, dense air to leave the diffusers as a vertical column similar to a waterfall.  The effect of dumping is to overcool the person immediately below the diffuser while the person further away will not be cooled enough.  Dumping is eliminated by ensuring that the discharge air energy from the diffuser is adequate to distribute conditioned air evenly throughout the conditioned area and at the same time provide good secondary room air induction rates.  Providing the total pressure in the neck of the RICKARD CCD diffuser selected is not too low, dumping of conditioned cold air will not take place.

In the context of radial discharge ceiling diffusers, 'coning' occurs when two air streams travelling in opposite directions meet.  As a result a downward moving cone of air is produced which will have a similar effect to dumping.  Coning is avoided by ensuring that diffusers are placed far enough apart to eliminate drafts in the conditioned space.   The table CAV Ceiling Diffuser Performance Data shows the distance from the various diffusers at which air velocity has reduced to 0.25 m/s (50 ft/min) (the 'throw' of the diffuser).  Using this information, diffusers  should be situated in the ceiling such that two adjacent diffusers are separated by slightly less than the sum of their throws.  Exactly how much less depends largely on the ceiling height and the amount of air movement desired in the conditioned spaced.  If the CCD is used in conjunction with Variable Linear Diffusers or Side Wall VAV Units, their throws should also be considered.

DETERMINING MAXIMUM CEILING HEIGHT

The drawing below describes how to determine the maximum ceiling height that can be achieved from a diffuser. Please see the diffuser performance data page for airflow, throw, noise and pressure information.