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SEMINAR 27: THERMAL COMFORT vs. UNDERFLOOR AIR Displacement and Underfloor Concepts

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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SEMINAR 27: THERMAL COMFORT vs. UNDERFLOOR AIR Displacement and Underfloor Concepts

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    1. SEMINAR 27: THERMAL COMFORT vs. UNDERFLOOR AIR Displacement 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

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