Chapter hvac engineering Fundamentals: Part 1 Introduction

11.6.2
Unit ventilators
A
unit ventilator
is a larger fan-coil unit—1000 to 2000 ft
3
/ min is
typical—with an outside air connection which allows it to provide up
to 100 percent outside air for ventilation and natural cooling (Fig.
11.20). The unit ventilator is used primarily in schoolrooms and sim-
ilar spaces where high ventilation rates are needed. Controls are in-
cluded with the unit. The typical control cycle provides for opening the
outside air damper to minimum position when the fan is started, and
increasing the outside air amount to 100 percent as the room temper-
ature approaches the heating set point. Only minimal outside air is
used when refrigerated cooling is required.
Equipment: Part 3
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