Daylighting
• Fisika Bangunan Terapan
DAYLIGHT vs SUNLIGHT
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DAYLIGHT vs SUNLIGHT
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DAYLIGHT vs SUNLIGHT
DAYLIGHT vs SUNLIGHTSunlight • The sunlight offers a moving directional light source. • the sunlight intensity always change; 5 to 10 x more intense
than daylight• the orientations always changing periodically (use sun path
or protractor) • the sunlight brings heat penetration into the room, etc.
Manage sunlight for• creating decorative Focal Points of room, such as stained
glass windows,or• illuminate and emphasize objects or surfaces, such as
fountain or ornamental walls
DAYLIGHT vs SUNLIGHT
Daylight• the daylight intensity always change, but has a
mean intensity (90%). E.g: Indonesia use 10000 lux as Langit Perencanaan.
• the daylight don’t have direction, so that need to be directed.
• the daylight don’t bring heat into the room.
Manage daylight for lighting the room (at day).
DIAGRAM
daylight
About 1/5 of sunlight illuminance
overcast
Direct 80%
sunlight
clear
horizon
zenith
DAYLIGHT dipengaruhi oleh
• Kondisi Awan (overcast sky, partly cloudy, clear sky)
• Posisi matahari (azimuth dan altitude)• Musim• Kandungan uap air di udara
Lθ = Lz (1 + sin θ) , shg luminasi daylight pd zenith adl 3x luminasi pd horizon (overcast sky)
3
Moon & Spencer, 1942
DAYLIGHT di Indonesia
Mengikuti hasil pengukuran Suryawinata 1974, • Utk ketinggian matahari mulai 60°, distribusi luminasi
untuk overcast sky, akan mendekati persamaan di atas. Sedang utk ketinggian matahari kurang dari 60°, posisi matahari akan sangat mempengaruhi distribusi luminasi terutama pada azimuth.
Mengikuti penelitian Adhiwiyogo 1969, Suryawinata 1974,• Langit perencanaan di Bandung, nilai stabil 90% adalah
overcast sky dengan luminasi ≥ 10.000 lux (hanya dari cahaya langit)
• Angka ini dipakai untuk seluruh Indonesia, sebelum ada penelitian yang valid untuk wilayah tertentu.
DAYLIGHT FACTOR (DF)
• Berhubung besarnya cahaya langit yang selalu berubah-ubah, maka untuk menyatakan tingkat pencahayaan dari langit di dalam bangunan digunakan suatu ratio yang disebut Faktor Pencahayaan siang hari (FP) atau Daylight Factor (DF) yaitu
“Perbandingan tingkat pencahayaan pada suatu titik pada bidang tertentu dalam suatu ruangan yang ditimbulkan oleh cahaya langit dengan suatu distribusi luminasi tertentu, terhadap tingkat pencahayaan pada bidang horisontal dari cahaya langit di tempat terbuka, pada saat yang sama” dimana kedua tingkat pencahayaan tsb tidak memperhitungkan cahaya matahari.
DAYLIGHT FACTOR (DF)
DF biasanya dinyatakan dalam persen sbb :
DF = Ei x 100 %
Eo• Ei = level pencahayaan dari langit pada suatu
titik pada suatu bidang di dalam ruangan (lux)• Eo = level pencahayaan dari cahaya langit pada
bidang horisontal di tempat terbuka (lux)
Besarnya DF ditentukan olehKomponen Langit(FL), Komponen Rg Dlm, Komponen Rg Luar
DF untuk aktivitas ruang
Task fc (lux) 10-20Lat. 30 Lat. 50 Lat.Lobby, offices general
10-20 (108-215) 0.5 – 1 1 – 1.5 2 – 3.5
Hotel rooms,
Conference,
Library stacks
20-50 (215-538) 1.5 – 3 1.5 – 4 3.5 – 9
Reading,
Drafting, Sewing, Sports-indoor
Science lab
50-100 (538-1076)
3 – 6.5 4 – 8 9 – 17.5
Principle of Overhang to Daylight Distribution
no overhang
• The curves indicate light levels. Overhangs reduce light and glare near the window, creating a softer gradient in the rooms
1
2
21
1
louvers
3
3
1
• Break up the overhang for better distribution
Sidelighting (areas to be served by daylight) --overcast sky
d
1.5 d
d
1.5 - 2 d
daylighted zone
daylighted zone
Light-shelf
Side lighting (areas to be served by daylight) -- overcast sky
core
Less effective area
Effective areas within daylight 1.5 d
1.5 d
d
Daylight Rule of Thumb (DF-overcast sky)
Side lighting (areas to be served by daylight)
For spaces with sidelighting :
• DF av = 0.2 window area
• DF min = 0.1 window area
floor area
floor area
DF = daylight factorWindow area = total window areaFloor area = total areas to be served by 1.5d
Mechanical and Electrical Equipment for Building 7th ed. p.161
Soal• Lobby kantor dg ukuran 5 m x 6 m memiliki sisi dinding yang berjendela seluas
12 m2 di satu sisi-nya seperti pada gambar. Berapakah jarak dari jendela, yang masih memungkinkan aktivitas penglihatan di ruang tsb?
(DF lobby = 0.5 -1)
6.00
Denah
5.00
1.5 d
Side lighting
DF ave. = (0.2 x window area) / floor areaFloor area = 1.5 d x 5 = 4.5 x 5 = 22.5m2DF ave. = (0.2 x 12) / 22.5 =0 .1067
0.5 = (0.2 x 12) / floor area; Floor area = 4.8; maka jarak dari jendela= 4.8 / 5 = 0.96 m
DF ave. = (0.2 x window area) / floor areaPotongan
d=3.00
Clerestory / vertical monitors (areas to be served by daylight)
For spaces with toplighting / vertical monitors :
DF av = 0.2 skylight glazing area
floor areaDF = daylight factor
Skylight glazing area = total windows
Floor area = total area to be served by daylight
Daylight Rule of Thumb (DF-overcast sky)
Skylight (area to be served by daylight)
Horizontal skylight
DF av. = 0.5 skylight glazing area floor area
DF = daylight factorSkylight glazing = total windowsFloor area = total area to be served by daylight
Daylight Rule of Thumb (DF-overcast sky)
Net Glazing Areas• Required Net Glazing Areas=
2 x DF ave Total area ofInterior surfaces
x 1 - Area weightedave.reflectance of all interior surfaces
x
Visible Transmittance Vertical angle of sky visiblefrom center of window
1 23
54
x
1 Average Daylight Factor• If low-light spaces are desired ; DF = 1• If average spaces are desired ; DF = 2• If bright spaces are desired ; DF = 4
Daylight Planning
Total Area of Interior Surfaces
Add up total surface area of walls, ceiling and floor
2
Daylight Planning
Area Weighted Average Reflectance of all Interior Surfaces
Between 0 and 1. Add up total surface area of walls, ceiling, floor, windows, partitions, furniture and calculate weighted average reflectance (see equation)
3
Area weightedave. reflectance
Wall area x wall reflectance
Total surface area Total surface area= +
Ceiling area x ceiling reflectance
+ …etc.
Use 0.5 as default
Visible Transmittance ( VT)Daylight Planning
4
Generic glazing types(1/4 “panes) Typical VTDouble pane clear 0.8Double pane tint-green or blue green 0.65Double pane tint – blue 0.51Double pane tint – bronze 0.47Double pane tint – gray 0.39Double pane low reflective 0.30Double pane medium reflective 0.20Double pane high reflective 0.10Double pane low-e clear 0.70Double pane low-e tint-green or blue-green 0.63Double pane low-e tint-blue 0.49Double pane low-e tint-bronze 0.45Double pane low-e tint-gray 0.37Suspended low-e film products 0.27 – 0.6
Or use 0.7 for small windows, 0.5 for medium windows, 0.3 for large windows
Vertical Angle of SkyDaylight Planning
5
• Estimate the angle as shown, from center of window.• Value between 0 and 90. • If no obstruction, vertical angle is 90.
horizon
Source : A sequence for daylighting design – J.Lynes, Lighting research and technology,1979
sistem di dalam bangunan
• Structural s
• Envelope / selubung e
• Mechanical m
• Interior i
Dalam bangunan, sistem-sistem tsb saling
berhubungan/terkait sehingga tercapai
efektivitas, efisiensi, serta estetika.
hubungan antar sistem
• Remote
• Touching
• Connected
• Meshed
• Unified
tetrahedron
Remote (berjauhan)• Level yang paling rendah, sistem-sistem
secara fisik berjauhan, tapi terkoordinasi dalam fungsinya.
Touched (bersentuhan) Salah satu sistem menumpang di atas yang
lain, terutama oleh karena gravitasi.
Connected (terhubung) Sistem yang satu terhubung pada yang lain
dengan paku, baut, terjepit, penggantung, perekat, dsb..
Meshed (bertautan)• Sistem-sistem menempati tempat yang sama
Unified (menyatu)• Sistem-sistem berbagi bentuk fisik yang sama
dan tidak lagi bisa dibedakan.
Kimbell Art Museum FortWorth, Texas
a bc
de
fg
hi j
k
a=sheet lead roof b=acrylic skylightsc=post-tensioned concrete shelld=reflectors e=supply ductworkf=incandescent track g=wood floringh=return air ducts i=exposed concrete masonryj=waffle slab k=travertine infill
Kimbell art museum – Fort worth, Texas
Exhibition Hall Turin
Railway Platform, Rotterdam
Kualalumpur International Airport
a=hypar shell roof b= triangular skylight trusses c=steel plate ceilingd=TL lighting track e=RC columnf=aluminium & glazing wall