n VAV system varies the air quantity rather than temperature to each zone n Single main duct is run from AHU n Branch duct are run from this main through VAV boxes to each zone n VAV box has an adjustable damper or valve n Air quantity delivered to the space can be varied VAV System

GDC or Conventional System? GDC system:Conventional water-cooled system: A smaller Mechanical Plant Room is required since major equipment for the generation of chilled water is not required. Mechanical Plant Room is required for chillers, cooling towers, make-up water tank and main pumps for the generation of chilled water. Building owners are normally charged for the consumption of chilled water, but compensated by lower electricity bills Building owners have to pay high electricity bills due to the large energy consumption of chillers and cooling towers. Practical if the surrounding neighbours require GDC’s chilled water. Otherwise, can be very costly. Practical if the surrounding neighbours do not require GDC’s chilled water. The global operational cost may be lower since the management of equipment is centralised. The global operational cost may be higher since equipment is owned and managed individually.

VAV System

The function of a VAV Box is to modulates the amount of cool air that is delivered to the room to maintain occupant comfort.

A single storey naval office building requires a conventional water-cooled air conditioning system. The main mechanical plant area shall be located outside the building. The floor of the building will be served by two Air Handling Units. Design the layout of the air-conditioning system, with consideration for sustainable operation and maintenance, by sketching the schematic of the proposed piping and main equipment of the building. Example