Electronic Variable Volume Wall Bulkhead Diffuser (WBD1)
The Rickard Wall Bulkhead Diffuser offers all the advantages that you would come to expect from a Rickard VAV diffuser, in a package to suit applications where there are restricted ceiling voids or where fully-covered ceilings are not available. As the name suggests WBDs discharge supply air into the conditioned space from either a sidewall or bulkhead.
Rickard WBDs control Room Temperature by adjusting the volume of air at the diffuser outlet. By changing the diffusers exit geometry, Coanda, Air Velocity and Throw is maintained at minimum and maximum volume. This technology prevents cold air from dumping at minimum, ensures excellent ventilation, air mixing, Air Change Effectiveness (ACE) and therefore thermal comfort (ADPI). Rickard VAV diffusers reduce pressure loss in the system due to their aerodynamic design and the absence of restrictions in the duct work.
Rickards WBD’s have an excellent ability to distribute air across deep rooms
Rickard VAV Diffusers control Room Temperature by adjusting the volume of air at the diffuser outlet.
By changing the diffusers exit geometry, Coanda, Air Velocity and Throw is maintained at minimum and maximum volume.
This technology prevents cold air from dumping at minimum, ensures excellent ventilation, air mixing, Air Change Effectiveness (ACE) and therefore thermal comfort (ADPI).
Rickard VAV diffusers reduce pressure loss in the system due to their aerodynamic design and the absence of restrictions in the duct work.
Green Building Benefits. Receive Management, Indoor Environmental Quality and Energy Efficiency Credits by using Rickard VAV Diffusers.
Rickard MLM controls use energy efficiently. Rickard MLM Diffusers use - 2.4 VA (24VDC 100mA) only when the motor is running. MLM24 Power Supply Units use – 40VA (220VAC .2A) or (115VAC .35A) max and can supply up to 15 diffusers. MLM Master Communications Units (MCU2) use – 10VA (24VAC .4A) max and can connect to 60 diffusers.
Master/Slave changes are achieved by installing a wall thermostat controller and are activated using Rickards Free Software.
Electronically adjustable maximum and minimum damper limits allow designed airflow volumes to be achieved.
Global manual commands (all diffusers can be driven open) reduce commissioning costs.
Cost effective standalone, LonWorks and BACnet BMS integration.
Automatic heating and cooling change-over
CAPITAL & OPERATING COST
WBD’s are used in areas where restricted ceiling voids exist or where fully-covered ceilings are not available
No regular maintenance is required.
The cartridge design allows easy removal if required.
Diffuser life cycle testing gives peace of mind far beyond our two year warranty period (Electronic diffuser range). Life cycle testing is based on 3000 operating hours and 4000 control cycles per year and is the equivalent of 30 years of service.
When installed, the only visible portion of the WBD is the Rickard linear bar grille. The grille is available as natural anodized or epoxy powder coated in a wide range colours to suit architectural requirements.
Rickard offers a 2 year manufacturer’s warranty on its Electronic VAV diffusers. Please see Terms and Conditions for a full description of our warranty.
Working plastic components are moulded in glass reinforced Makrolon – Makrolon is flame retardant and chlorine and bromine free when burnt. The Rickard Thermo-Disc and Electronic actuators are moulded in Makrolon and are UL Certified.
The Rickard Variable Volume Wall Bulkhead Diffuser (WBD) is normally used in areas where restricted ceiling voids exist or where fully-covered ceilings are not available. The WBD, as the name implies, is intended to discharge supply air into the conditioned space from either a sidewall or bulkhead. Frequently building areas have dividing passage ways with ceiling heights lower than those within the areas requiring air conditioning. In this situation the supply air ducting may be run in void between the passage ceiling and the slab above, with the WBD terminals regulating the supply air from the ducting. In many instances these ceiling voids may also serve as return air plenums.
The Rickard WBD has an excellent ability to distribute air across deep rooms as reflected by the throw data indicated in the selection tables. There are, however, instances where these throws are too great for a specific area & in which case, the rear horizontal deflection vanes will need to be adjusted.
When installed, the only visible portion of the WBD is the aesthetically pleasing Rickard linear bar grille. This grille may be supplied with a natural anodized finish or epoxy powder coated in a wide range of colours to suit architectural requirements.
Room temperature is intelligently controlled by varying the supply air volume in accordance with demand. The diffuser controller uses a proportional/integral response to achieve this. Volume control is achieved by opening or closing a set of aerodynamic damper blades using our patented electric stepper motor, so as to vary the aperture through which the supply air passes. This provides true “VARIABLE GEOMETRY VAV” which effectively maintains air discharge velocity throughout the range of volume control from 100% down to as little as 25%. By using our MLM Controls, maximum and minimum supply air volumes may be adjusted to suit the particular design conditions.
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 7.5m/s (650 and 1500ft/min).
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 with the diffusers damper in the fully open position. A downward moving layer of air 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. Throw remains at acceptable levels throughout the range of air flows, a feature of the variable geometry VAV diffuser concept.
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 know or measured is duct STATIC pressure.
Best results are obtained when diffusers are selected at pressures of 30-40Pa (0.12-0.16ins Wg). Bear in mind that all diffusers served by a common duct will all operate at the same static pressure as controlled by the pressure control damper. Therefore diffusers which are able to supply more air than is necessary will be driven partially closed by the temperature controller and hence the system becomes self-balancing.
NOTE: Avoid upstream restrictions such as manually adjusted dampers. The reason being that at maximum flow any restrictions will result in a significant static pressure loss (which for some cases may be desirable) whereas at minimum flow conditions offer virtually no restriction, which will result in the static pressure at the diffuser being too high at minimum flow causing over-cooling/heating.
The Rickard Wall Bulkhead Diffuser are available in the following standard sizes:
Depending on the installation, WBD's are available with top or back entry cable connections. Top entry is used when there is access between the wall and the duct. Back entry is used when there is only access through the duct. NOTE: Top Entry and Back Entry connections are separate options.