1. Objectives Further discuss the Exam problems
Learn how to design VAV systems
Discuss the final project
Cooling and heating Load calculation

2. VAV Example One system Multiple Spaces/Zones
- VAV box for each space/zone

3. VAV System Terms & Equations (you can find them in ASHRAE Standard 62)
Fraction of minimum outdoor air in space/zone supply air
Xi = VOAi / VSAi
Critical space
Space with maximum Xi , Z=max(Xi)
Fraction of outdoor air in system supply air
X = sum(VOA ) / sum(VSA)
Required Fraction of outdoor air:
Y=X/(1+X-Z)

4. Example Solution
Space1
Space 2
Space 3
Space 4
VSA
VOA Xi X Z Y

5. Other Issues Related to VAV
Fan control
Minimum supply air
Occupancy sensors

6. DOAS System

7. Project
Commercial building
Zone orientation

8. Project Cooling and heating load for each zone and whole building:
Fresh air requirement based on number of occupants:
To provide acceptable IAQ in the building, ventilation
system supply minimal amount of
fresh air is in all spaces (except plenums)
that produce 0.2 ACH.

9. Cooling load calculation
Mostly computer based
Handouts for manual calculation
The most important issues