Constant Volume Radial Diffuser - RCD
The RICKARD Constant Volume Fixed Vane Radial Diffuser (Type RCD) is primarily intended for buildings where good air mixing is required. They are ideal for installations with ceiling voids in excess of 3.0m and where improved occupant comfort is called for in cooling modes.
Due to their ability to achieve a rapidly spreading swirl throw pattern with fast velocity decay and high induction rates, these diffusers are best suited to provide high air volume flow rates without drafts at occupant levels. They create a conical swirl flow pattern for excellent mixing in cooling.
High induction rates for loarge volume applications.
No regular maintenance is required.
The focus of the design was to offer high comfort levels by offering the required diffuser performance with the lowest pressure drop possible.
AESTHETICS AND CONSTRUCTION
Designed with simplicity and functionality in mind the Rickard range of RCD's compliments most of today's large modern spaces.
The RCD is constructed of sheet steel. Each RCD is degreased, primed and finished in our standard semi-matt white chip resistant baked epoxy powder coating. A wide range of colour requirements can be met with our epoxy coating or wet spray options.
Rickard warrants it's RCD's for a period of 10 years.
AREAS WITH CEILING VOID HEIGHTS GREATER THAN 3.0m.
Cools the space with a conical swirl flow pattern of cold or isothermal air.
Heats the space with a conical swirl flow pattern of air that has a temperature differential between room and supply of no more than 10°C.
INTERNAL ZONES WITH A CONSTANT LOAD.
BUILDINGS THAT NEED EXCELLENT AIR MIXING.
WHERE HIGH AIR VOLUME FLOW RATES AND THE ABSENCE OF DRAFTS AT OCCUPANT LEVELS IS REQUIRED.
The most important practical factors to consider in internal zones are noise levels and uniform air distribution without "dumping" effects. "Dumping" is the tendency for cold, dense air to leave the diffuser 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 RCD selected is not too low, dumping of conditioned cold air will not take place. The RCD is designed to avoid the tendency to dump.
A rapidly descending flow pattern similar to dumping can occur when two air streams travelling in opposite directions meet. This tendency is substantially reduced with the use of radial diffusers, but it can be avoided completely by ensuring that RCD’s are placed far enough apart to eliminate drafts in the conditioned spaces. The Rickard RCD’s flow pattern is horizontal. The swirl effect creates a rapid decay in velocity with high induction rates. Using this information, RCD’s should be situated in the ceiling such that two adjacent diffusers are separated by slightly less than the sum of their diameter. Exactly how much less depends largely on the amount of air movement desired in the conditioned space.
Rickard's range of RCD's comes in 2 sizes, namely a 315 and a 400mm diameter unit.
Top entry round and side entry square plenums are availabe as an optional extra.
Entry plenums constructed from coated or uncoated mill galvanized sheet steel are also available.
The Rickard Radial Diffuser Range supports a wide range of mounting methods.