HVAC Equipment Supplement
AIR-HANDLING UNIT (AHU)
AHU DAMPERS COORDINATED FOR AIRSIDE ECONOMIZER OPERATION
DUAL DUCT DISTRIBUTION
HOT/COLD DECK AHU
MULTI-ZONE DISTRIBUTION
Earlier Generation of
HVAC – AHU
Types of VAV Box
“VAV boxes are not all created equal”
• VAV Box, Un-powered
– Direct damper control of air to zone (“2way valve”)
– Diverting damper (to return duct or
plenum) (“3-way valve”)
• Fan-Powered Box
– Series: fan runs continuously, with
damper controlling mix of SA and recirculated room air
– Parallel: fan runs re-circulate room (or
plenum) air as damper throttles SA,
maintaining constant volume to diffusers.