1. Announcement Course Exam October 11 th (Tuesday) In class: 90 minutes long Examples are posted on the course website

2. Objectives Duct Design and Diffuser Selection Reading assignment: thextbook Chapter 18

3. Duct design (part of the HVAC Design successfully integrated into BIM)

4. Pressures Static pressure Velocity pressure Total pressure – sum of the two above

5. Relationship Between Static and Total Pressure

6. Duct design method (defines the layout) Two design methods: -Equal friction -Static regain

7. System Characteristic

8. Static pressure drop (friction losses) in a duct is proportional to square of velocity or flow Duct Design It is a function of -Dynamic pressure -Length -Pipe diameter -Friction coefficient

9. Frictional Losses (in a staring round duct section)

10. Ductulator

11. Non-circular Ducts Parallel concept to wetted perimeter

12. Dynamic (or local) losses Losses associated with Changes in velocity Obstructions Bends Fittings and transitions Two methods Equivalent length and loss coefficients

13. Dynamics (Local) Loss Coefficients ΔP t = C o P dynamic

14. Conversion Between Methods

16. Example 18.7 Determine total pressure drop from 0 to 4

17. Diffuser selection Defines thermal comfort Air quality

18. Forced driven air flow Diffusers Linear diffusers Grill (side wall) diffusers Horizontal one side Vertical

19. Diffusers types swirl diffusers wall or ceiling floor Valve diffuser ceiling diffuser

20. Diffusers http://www.titus-hvac.com/techzone/ http://www.halton.com/halton/cms.nsf/www/diffusers Perforated ceiling diffuserJet nozzle diffuser Square conical ceiling diffuser Round conical ceiling diffuser Wall diffuser unitSwirl diffuser Floor diffuser Auditorium diffuser DV diffuser External louvre Smoke damper Linear slot diffuser

21. Low mixing Diffusers Displacement ventilation