1. Objectives Discuss Exam Finish with Diffuser Selection
Learn about Fan and Pumps

3. Find Characteristic Length (L)

4. Indicator of Air Distribution Quality
ADPI = air distribution performance index
Fraction of locations that meet criteria:
-3 °F < EDT < 2 °F or -1.5 °C < EDT < 1 °C
Where, EDT = effective draft temperature
Function of V and Δt (Eqn 18.1)
EDT=(tlocal-taverage)-M(Vlocal-Vaverage) , M=7 °C/(m/s)
ADPI considers ONLY thermal comfort (not IAQ)

5. Ideal and Reasonable Throws

6. Diffuser testing

7. ADPI

8. Select Register Pick throw, volumetric flow from register catalog
Check noise, pressure drop

9. Fans Driving force to move air in buildings
Raise pressure and produce flow
Two main types:
Centrifugal
Axial

10. Relevant Fan Parameters
Total pressure rise
Static pressure rise
Power requirement
Efficiency
Note ηtot does not account for motor efficiency

11. Balance Point

12. Fan Performance

13. Centrifugal fans

16. Axial Fans

19. Fan Laws “Approximate relationships”
Given two aerodynamically similar fans, can extrapolate performance data
Be very careful

20. Controlling Air Flow

21. Dampers

22. Effect on Fan Curve

23. VAV Operation

24. Dampers

25. Dampers

26. Pumps Driving force to move air water in buildings
Raise pressure and produce flow
One main type
Centrifugal

27. Pump curves
NPSHR = Net Positive Suction Head Required