Civil Engineering Reference
In-Depth Information
discussed under the chiller, cooling systems, boiler and heating systems sections
would be part of the overall system power consumers of the following airside
systems where they are applicable.
8.12.2
Constant Air Volume System with Bypass Variable
Air Volume Terminal Units with Reheat
This system (Fig.
8.5
) is consisted of a central constant volume supply fan that
supplies conditioned air to all the local variable air volume terminal boxes through
a network of ducts. Quantity and temperature of the mixture of the air which is
delivered to each room is designed based on the room sensible load, the quantity
and temperature of the outdoor air in the mixture, and space thermostat setting.
Additional part of the air that is not needed for conditioning each space is bypassed
into a common return air path and after getting mixed with the return air from all the
other spaces goes back to the air handling unit as return air stream usually with the
help of a return/exhaust fan. Terminal units are also equipped with hot water reheat
coils or electrical strips that are designed for either heating or dehumidifi cation of
the discharged air to each space.
The sources of energy consumption in this type of systems are air handling unit
supply fan motor input power, return/exhaust fan motor input power, hot water
Fig. 8.5
Constant air volume system with bypass variable air volume terminal units with reheat
