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Environmental Controls I/IG

Environmental Controls I/IG. Lecture 13 Solar Geometry Shading Strategies. Sun Position. Can be described by two angles : Altitude Azimuth. S: p. 1514, T.C.12. Solar Angles. Describe the sun position relative to a vertical surface. Solar Altitude: β (beta).

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Environmental Controls I/IG

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  1. Environmental Controls I/IG Lecture 13 Solar Geometry Shading Strategies

  2. Sun Position Can be described by two angles: Altitude Azimuth S: p. 1514, T.C.12

  3. Solar Angles Describe the sun position relative to a vertical surface

  4. Solar Altitude: β (beta) Vertical angle to sun position

  5. Solar Azimuth: Φ (phi) Horizontal bearing angle from south

  6. Surface Azimuth: Ψ (psi) Surface horizontal bearing angle from south

  7. Surface Solar Azimuth: γ (gamma) Angle between solar and surface azimuths γ = Φ - Ψ

  8. Sign Conventions Angles east of south are negative Angles west of south are positive 90º -90º + - S 45º -45º 0º

  9. 30º -45º Calculating Surface Solar Azimuth γ = Φ – Ψ For example: Building façade is oriented south east (Ψ =-45º) Solar azimuth (ϕ) is 30º west of south γ = 30º – (-45º) = 75º Note: |γ|≥ 90º, façade in shade

  10. Profile Angle: Ω (omega) Defines limits of shade conditions For horizontal projections: TAN(Ω)=TAN(β) / COS(Y)

  11. Profile Angle: Ω (omega) For horizontal projections: SH=PH TAN(Ω) where, PH: width of enclosing side of horizontal projection SH: height of shadow below horizontal projection

  12. Profile Angle: Ω (omega) Defines limits of shade conditions For vertical projections: TAN(Ω)=TAN(Y)

  13. Profile Angle: Ω (omega) For vertical projections: Sw=Pv TAN(Y) where, Pv: width of enclosing side of vertical projection Sw: width of shadow beyond vertical projection

  14. Sizing Horizontal Projections Establish fenestration pattern and determine size of openings

  15. Sizing Horizontal Projections Determine cut off date and time for solar penetration Mar 21 @10 AM solar time Determine surface azimuth Due south, Ψ=0º Determine required shadow height SH=6’ ?

  16. Sizing Horizontal Projections Establish profile (Ω) angles for the solstices at solar noon using surface solar azimuth (Y = Φ –Ψ). At solar noon (Φ=0º) and for L=40º, Ψ=0º: 12/21β=90-23.5-L=26.5º TAN(Ωw)=TAN(β)/COS(Y) Ωw=26.5º 6/21β=90+23.5-L=73.5º TAN(Ωs)=TAN(β)/COS(Y) Ωs=73.5º

  17. Sizing Horizontal Projections Establish profile (Ω) angles for cut off date and time using surface solar azimuth (Y = Φ –Ψ). At 10 AM solar time and for L=40º, Ψ=0º:

  18. Sizing Horizontal Projections Mar 21 @10 AM Solar Time β= 41.6º Φ= -41.9º Y=Φ-Ψ Y=-41.9º-0º=-41.9º S: p. 1514, T.C.12

  19. Sizing Horizontal Projections Establish profile (Ω) angles for cut off date and time using surface solar azimuth (Y = Φ –Ψ). At 10 AM solar time and for L=40º, Ψ=0º: 3/21 β=41.6º Y=-41.9º TAN(Ω)=TAN(β)/COS(Y) TAN(Ω)= 0.888/0.744= 1.19 Ω=50º

  20. Sizing Horizontal Projections Given SH = 6’ and SH=PH Tan(Ω) Solve for PH PH=SH/TAN(Ω) PH=6/1.19=5.04’ ~ 5’-0 ½” say 5’-0”

  21. Louver Spacing Sh Ω Ph Solar Envelope Reduce horizontal projections by adding horizontal louvers in a vertical screen

  22. S H ΩS Sizing Horizontal Projections Use the summer solstice profile angle (ΩS) to determine spacing of vertical louvers Spacing (S)= H/TAN(ΩS) If H=12’’, then S=12/TAN(ΩS)=3.55” say 3½” Note: method does not include louver thickness

  23. Sizing Horizontal Projections Use the summer solstice profile angle (ΩS) to determine spacing of reverse inclined louvers H ΩS 2S S Spacing (S)= H/TAN(ΩS) If H=12’’, then S=12/TAN(ΩS)=3.55” say 3½” Note: method does not include louver thickness

  24. Lateral Penetration Mar 21 at 10 AM solar time β When Y≠0º, lateral penetration occurs at an angle = β

  25. Lateral Penetration Solutions Extend projection bilaterally β

  26. Lateral Penetration Solutions Install vertical component bilaterally

  27. Critical Angle Analysis Critical angles define solar aperture height (SAH) ΩW SAH Ω ΩS

  28. Sizing Vertical Projections SW =|PVTAN(Y)| or PV=|SW/TAN(Y)|

  29. Sizing Vertical Projections On Mar 21 @ 10 AM (Y=-41.9º), if SW=6’ what should PV be to shade window PV=|SW/TAN(Y)| PV=|6/-1.115|=5.4’ ~5’-5”

  30. Shading Strategies

  31. Shading Devices – Overview South Façade: Horizontal overhang or Brise-soleil San Cristobal Stables The Capital (Chandigarh)

  32. Shading Devices –Overview East/West Façade: Vertical fins angled to the north and/or Brise-soleil Keio University Graduate School Research Center Monastery of Ste Marie de La Tourette

  33. Shading Devices –Overview North Façade: Vertical fins (used in hot climates only) Phoenix Central Library L: p. 559 fig. 17.10b

  34. Shading Devices – Tectonics • Vertical Louvers or Screens Jewett Art Center, Wellesley, MA John Deere Headquarters, Moline IL

  35. Shading Devices – Tectonics • Horizontal Solid and louvered planes, projections or recesses Paimio Sanatorium, Finland Getty Center Los Angeles, CA

  36. Shading Devices –Tectonics • Sculptural Form Thickness Projections Screens Reynolds Aluminum Building, Detroit, MI Unity Temple, Oak Park, IL Beach House, Lido Shores, FL Obayashi Tokyo Design Center

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