Function of HVAC Equipment Installed to the Ductwork
Equipment is as follows:
These are large rectangular steel modules containing a plenum, heating, and air conditioning equipment along with suction/discharge air filters. Some of the more modern ones also house the main centrifugal fans.
These are the main system fans and can be housed in a dedicated HVAC fan room or in the air handling unit. Either way, the suction should be from under the deck, away from prevailing wind and any hazardous drains or wind-blown spray.
Fire dampers are manufactured in stainless steel, and designed with a pneumatically open-fail shut operation. These shut down the airflow on a gas escape or fire situation.
These are manufactured from stainless steel or galvanized steel plate, being used to balance the system.
These are really silencers which cut the noise of the air flowing through the ducting.
In-line fans are used in segregated systems such as the laundry, galley, battery room, and switch-rooms. Fans are usually supplied as two units; one operating and the other on standby.
- Grills, Diffusers and Louvers
Grills are fitted at the outside duct suctions preventing any ingress of large pieces of rubbish being sucked into the system.
Diffusers and louvers are fitted to internal suction and discharge ends of the ductwork.
The different HVAC systems have suction filters between the fan intake grills and the fan, along with discharge filters between the fan discharge and the louvers or diffusers.
These are adjustable to increase/reduce tension and are used to support duct runs, along with the structural duct supports, whilst reducing vibration.
These are fabricated from mild steel channel, being shot-blasted and painted to a high spec. and welded to the structure. The ductwork can be laid directly onto the supports or on top of a rubber anti-vibration strip glued onto the main supports. An insulation material is placed between the duct and main supports on A/C systems to prevent condensation.
Reference Web: ishrae - overview of offshore HVAC systems