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Hypothesis. Under the most rigorouslycontrolled conditions of pressure,temperature,volume,humidity,and other variables air will do exactlyas it pleases.. Concept. Trading Floor. Trading Floor. 440 traders.3 to 4 monitors per desk.Up to 3 PCU's per desk.. Trading Floor. Smoke test on existing floor supply system showed very limited air distribution..
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1. SEMINAR 27:THERMAL COMFORT vs. UNDERFLOOR AIRDisplacement and Underfloor Concepts Peter Simmonds, Ph.D.
IBE Consulting Engineers, Sherman Oaks, CA.
2. Hypothesis Under the most rigorously
controlled conditions of pressure,
temperature,
volume,
humidity,
and other variables air will do exactly
as it pleases.
3. Concept
4. Trading Floor
5. Trading Floor 440 traders.
3 to 4 monitors per desk.
Up to 3 PCU’s per desk.
6. Trading Floor
7. Trading Floor Problems with temperature control.
200 complaints per month regarding warm/hot spots on the floor.
No complaints of draft ‘sensations’
8. Comfort criteria The thermal comfort is influenced by two main components:
local vertical air temperature difference
local air velocity
There is a European CEN -Report relating to comfort criteria: CR 1752. The recommendations of this are as follows.
9. Vertical air temperature difference A large vertical air temperature-difference between head and ankles causes discomfort. Figure 1 shows the percentage of dissatisfied as a function of the vertical air temperature difference between head and ankle.
10. Vertical air temperature difference
11. Air velocity
12. Trading Floor
13. Trading Floor
14. Trading Floor
15. Trading Floor
16. Trading Floor
17. Trading Floor
18. Trading Floor
19. Trading Floor
20. Trading Floor
21. Old and New
22. Trading Floor
23. Trading Floor
24. Trading Floor
25. Trading Floor
26. Museum Displacement
27. Museum Displacement
28. Museum Displacement
29. Theoretical Application Face Velocity
Induction Velocity
Throw
Dtl
Dtz
Diffuser Coefficient
Induction Rate
30. Airport Displacement
31. Airport Displacement
32. Airport Displacement
33. Airport Displacement
34. Airport Displacement
35. Airport Displacement
36. Airport Displacement
37. Airport Displacement
38. Conclusions The diffuser tested performed in accordance to the required design criteria. Full and part load conditions for the main terminal diffusers were tested and the results compared against the original diffuser design. The tested diffuser performed slightly better than the previously tested diffuser and would perform as originally designed.
Temperatures
The temperature gradients of the test diffuser showed that the supply air from the diffuser quickly induces space air which is the cooling function of the displacement diffuser. The temperature profiles also show that there are no uncomfortable spots as a result of incorrect mixing in the areas measured..
Velocities
The velocities of the supply air provide sufficient momentum to the supply air to produce the required throw and spread and at the same time these velocities do not exceed comfort requirements.
Smoke Tests
The visualization of the smoke test showed that the spread of the supply under full and part load condition met the design expectancy of the diffuser.
39. Airport Displacement
40. Airport Displacement
41. Cheung Kong Center
42. Courtroom Conditioning System
43. Courtroom Space Temperatures
44. Courtroom Comfort Conditions expressed as PPD (percentage of persons dissatisfied)
45. Trading Floor