Civil Engineering Reference
In-Depth Information
Fig. 8.15
Displacement ventilation VAV
for control valves and dampers, and the power input to the variable frequency drives
for supply and return fans that can be factored in supply and return fan consumption
itself are the other sources of energy consumption.
8.13.7
Displacement Ventilation w/ Passive Chilled Beams
In cooling mode, supply air through large side wall devices will be introduced to the
room with a higher temperature (usually around 63 °F instead of normally 55 °F in
regular systems). Air is introduced to the room as the space temperature sensor calls
for cooling. If still there is need for further cooling, passive chilled beams in the
ceiling will pick up the rest of the load. A return air bypass arrangement helps to
provide dehumidifi cation without the need for reheat.
The sources of energy consumption in this type of systems are the air handling
unit supply fan motor input power, return fan motor input power, electric preheat
strip (if it is used for freeze protection instead of hot water coil) in air handling unit
and electric baseboard reheat unit (if it is used for dehumidifi cation or heating
instead of hot water coil). Duct air leakage, heat transfer from ducts connecting air
handling unit to the sidewall diffuser, and effi ciency loss in water coils are other
