Lecture 4:

Daylighting
In Passive Design
 • Introduction
• Characteristics and Availability
• Photometric Units
• Daylight Availability
Daylighting in Passive • Performance of Daylighting
Design • Comfort and Health
• Visual Performance
Part 1
• Thermal Comfort and Energy Use
 • Daylight is necessary for the comfort of human beings,
who often occupy buildings for most of their lifetime..

Daylighting in Passive • Its dynamic change is the stimulus for our daily
biorhythms.
Design • it can influence our mood and health..
• contributes to sustainability, if daylighting is
Introduction appropriately integrated into the design process..
 • The nature of light is described as a wave-particle
Daylighting in Passive duality (Albert Einstein), as it has both a particle
nature and a wave nature..

Design • Our practical experience with light is mainly influenced

by our visual perception but the theoretical findings
contribute to a deeper understanding of the observed
Characteristics And Availability phenomena..
Daylighting in Passive
Design
Solar radiation E [kWh/m2] over wavelength [nm]. Dotted line: Extraterrestrial.
Photometric Units Straight line: Terrestrial (on the ground). Spectral colors of light.
 SI Photometry Units

• Luminance is the characteristic for measuring the

image seen of an illuminated surface or room.

Daylighting in Passive • It is used to assess illumination quality by brightness,

darkness and contrast of areas seen.

Design • Illuminance describes the light incident on a surface,

and often is used for standards..

Photometric Units • The luminous efficacy is used to evaluate the energy

demand and sustainability of light sources..
 • The source of daylight is, of course, the sun.
• Its incident light at the earth's surface is influenced by
daily and annual cycles of movement, and the degree
to which the light is diffused by atmospheric
conditions..
• The daylight illuminating a given point in a room may
reach it in the following ways;

Daylighting in Passive • Direct sunlight travelling in a straight line from the sun
through a window to the given point.

Design •
•
Diffused light from overcast sky coming through a window.
Externally reflected light (from the ground or other
buildings) coming through a window.
Daylight Availability • Internally reflected light, travelling from the floor, walls,
ceiling or other internal surfaces.
Daylighting in Passive Daylight entering a building. a: direct sunlight. b: diffused or skylight. c:
externally reflected light. d: internally reflected light.

Design
Daylight Availability
 • The performance of daylighting involves many aspects,
Daylighting in Passive including;

Design •
•
comfort and health,
visual function,
• energy use and
Performance Of Daylighting
• economy
 • Solar radiation and light is necessary for our
Daylighting in Passive physiological and psychological wellbeing,
• As we now spend most of our lifetime in buildings,
Design they have to offer, according to their use, sufficient
daylight quality..

Comfort And Health • Buildings also have to protect our bodies appropriately
from the harmful effects of solar radiation.
 • Circadian Effects - The 24-hour cycle of darkness and
light is a fundamental need, used by the body to
regulate sleep, hunger, body temperature and
alertness in conjunction with hormone production..
• Seasonal Affective Disorder - The lack of sufficient
daylight for long periods, e.g. during winter..
• Vitamin D - Exposure to sunlight is the natural means
by which the human body produces vitamin D..
• View Out - Visual contact with the outside world is
vital for building users..
Daylighting in Passive • Glare - Too much light, which causes glare, should be
avoided in buildings. Direct sunlight is intolerable to
Design our eyes..
• Color - Color rendering of daylight is important for
Comfort And Health many visual tasks and for a realistic contact with the
outside world..
 Daylight factors and impact

Daylighting in Passive
Design
Comfort And Health
 • Visual function depends on the specific task and the
parameters of luminance, contrast and color
rendering..
• visual performance improves with illuminance, and
how well the task in hand is lit. Illuminances of 1,000
to 6,000 lux are recommended for high visual
Daylighting in Passive performance (Lange, 2002)..
• Daylighting design and technology can realize much
Design higher illuminances to promote optimal visual
performance and comfort for many hours of the day,
in economical and sustainable ways.
Visual Performance
 • Windows transmit daylight as well as solar heat gains.
• Therefore windows need light (glare) control as well as
solar (thermal) control, especially for sunny, clear sky
conditions.
• These are defined in many directives by reduction
Daylighting in Passive factors (%) of light transmission and solar heat gain.
• This is an issue of comfort and energy use and a
Design challenge for integrated building design..
• Optimized daylighting and solar control systems will
Thermal Comfort and Energy Use contribute to a significant decrease in energy use, i.e.
running costs and CO2 emissions.
 • Daylighting Design
• Urban Design
• Building and Room Design

Daylighting in Passive
• Window and Skylight Design
• Daylighting Systems and Solar Control
Design •
•
Glazing
Window Design And Visual Comfort
• Systems To Enhance Natural Lighting
Part 2
• Shading
 • The distance and height of neighboring buildings
influences the amount of direct and diffuse daylight
reaching the windows..
• The ratio of building height to the width of the street
canyon is another important design parameter for
Daylighting in Passive daylighting (and thermal heat gain).
• Climate zone, latitude and orientation have to be
Design taken into account, as well as the reflectivity of walls
and ground surfaces.

Daylighting Design : Urban Design.. • Additionally the shadows of trees can influence the
availability of daylight.
Daylighting in Passive
Design
Means of Urban Design (b: Diffused or Skylight, h: Height,
Daylighting Design : Urban Design w: Width)
 • Buildings and their subdivisions (storeys, zones and
rooms) receive daylight through openings in the
building envelope.
• Single storey buildings and roof floors can be
illuminated via windows (vertical openings in the
walls/faҫades) and skylights in the roof and skylights in
the roof..
• Stacked storeys can only be illuminated via vertical
windows..
• There is a rule of thumb that recommends the

Daylighting in Passive following room depth for adequate daylighting

(daylight factor 1–2%) under overcast sky conditions:

Design • Room depth = 2.5 x window height above desktop for one
window wall.
Daylighting Design : Building and Room Design • Room depth = 5 x window height above desktop for
windows in two opposite walls..
Daylighting in Passive
Design
Means of Room and Window Design (h: Window Height
Daylighting Design : Building and Room Design above Desktop)
 • The type of glazing used in a window or skylight
influences the light transmittance considerably.
• A single sheet of glass transmits about 90% of the
incident light, a double glazing with a low-e coating
about 65%, and solar control double glazing from 65%
to 30%.

Daylighting in Passive • In climatic zones with significant heating demand,

double or triple glazing with low-e coatings are used,

Design to achieve low heat transmission coefficients (u-

values).
• In regions with significant cooling demand, double
Systems To Enhance Natural Lighting: glazed units with low-e coating and external shading
devices are very efficient, especially if they are
Glazing adjustable for good daylighting..
Daylighting in Passive
Design
Systems To Enhance Natural Lighting:
Glazing Selection of reflective coatings and U Values of double glazing windows
 • The illuminance of rooms can be influenced by their
size, location, orientation and shape of the openings.
• For vertical windows in walls, the right mix of
orientation to the sun is important.
• The higher windows are located in the wall, the
further into its center will the room be illuminated.
Daylighting in Passive Window openings below desk level do not contribute
to room illumination, but may be important for the
Design view from high rise.
• The window area should be sufficient for daylighting,
Daylighting Design : Window Design And Visual however, fully glazed faҫades are not the optimum –
causing glare and heat gain.
Comfort
 Clerestory windows are placed in the upper part of walls above eye level in

Daylighting in Passive order to improve the illumination of the room's center…

• Clerestory windows are placed in the upper part of

Design walls above eye level in order to improve the
illumination of the room's center…

Daylighting Design : Window Design And Visual • The light transmittance of windows is influenced by
the type of glazing and the area of casement frames..
Comfort
 In a hot-humid climate overhanging roofs help to reduce the glare from the sky

Daylighting in Passive • In hot-humid climates, since the sky and not the
ground is the main source of glare..
Design • However openings should be positioned in such a way
that the sky is not directly seen.
Daylighting Design : Window Design And Visual • Overhanging roofs or large verandas can be used for
Comfort obstructing the direct view of the sky
 • The steps to determine required glass area:
1. Assess how much natural light the space receives, by
calculating the effective sky angle;
2. Assess how much lighting the space needs, by setting
the target mean daylight factor desired (DFm);
3. Calculate the window to wall ratio (WWR) required to
Daylighting in Passive achieve the set daylight factor;
4. Evaluate the dimensional constraints imposed by
Design the target DFm chosen in step 2, by calculating the
appropriate depth of the space and the colour of the
walls;
Daylighting Design : Window Design And Visual
5. Determine required glass area
Comfort
 Evaluation Of The Sky Angle And Room Depth Past

Daylighting in Passive
Design
Daylighting Design : Window Design And Visual
Comfort

Calculation of the maximum depth of room and the surfaces reflectance

 • Checklist of designing with daylight - If minimization of
energy consumption is not a priority;
1. Minimize the glass surfaces in the east, and,
especially, in the west façades.
2. Keep WWR factor around 0.3 - 0.4.
3. If you do not know who will occupy the building, use
ribbon windows.
4. Provide light-coloured interior walls and finishing.

• Checklist of designing with daylight - If minimization of

energy consumption is a moderately important
parameter
1. Revise the size of the windows with the help of an
Daylighting in Passive energy calculations expert.
2. If expert advice is not available, explore alternative
Design envelope designs that can incorporate shading
devices or light shelves.

Daylighting Design : Window Design And Visual 3. By means of a simple model (physical or virtual, by
computer) check the quality of light and control glare.
Comfort
 • The light shelf is generally made of a horizontal or
nearly horizontal shelf arranged on the outside and/or
inside of the window, in its upper part..
Daylighting in Passive • Light shelves have a considerable impact on the
Design architectural design of the building and must be taken
into account at the early stages of the design process..
• They are especially suitable for climates with high
Systems To Enhance Natural Lighting: sunshine levels on windows facing south or north in
Light Shelves.. near equatorial latitudes.
Daylighting in Passive
Design
Systems To Enhance Natural Lighting:
Light Shelves.. Basic type of light shelves and depth of a light shelf is always a compromise
between the needs for natural light and sun protection.
 Sizing the light shelf

• The minimum depth of an external light shelf is

determined by the shading requirements; the deeper
the shelf, the better it shades the window below,
Daylighting in Passive preventing the penetration of direct radiation, which
causes glare and solar gains.
Design • For the interior light shelf, the limiting factor is still the
glare; i.e. it is necessary to prevent the penetration of
direct radiation.
Systems To Enhance Natural Lighting:
• The depth required is greater in the case of east and
Light Shelves.. west-facing façades, and it varies with the orientation.
Daylighting in Passive Light shelf with recessed window

Design
Systems To Enhance Natural Lighting: • If the optimum depth of the external light shelf is
excessive in relation to other needs, the same result
Light Shelves.. can be obtained by recessing the window below
Daylighting in Passive Tilted light shelf

Design • At low latitudes, if the south or north-facing light shelf

is tilted upwards.
Systems To Enhance Natural Lighting: • The contribution of natural light increases, but the
exterior part must be extended to provide satisfactory
Light Shelves.. window shading.
Daylighting in Passive Reducing the depth of the light shelf

Design
• For south-east or south-west (north-west or north-
Systems To Enhance Natural Lighting: east) facing façades, the resulting depth of the inner
shelf may be excessive; in this case a series of smaller
Light Shelves.. shelves, properly spaced, can be used.
Daylighting in Passive Light shelf with profiled surface

Design • The effectiveness of natural lighting with the light shelf

can be increased appropriately by curving the surface
hit by sun’s rays..
Systems To Enhance Natural Lighting:
• The surface must be white or reflective, and periodic
Light Shelves.. maintenance is necessary to avoid losing its features.
Daylighting in Passive Reflecting blades instead of internal light shelf

Design • An alternative solution consists of a Venetian blind

with reflective, fixed or mobile, slats on the inside or
outside of the glass strip.
Systems To Enhance Natural Lighting:
• In this case the outer shelf has the sole function of
Light Shelves.. solar protection for the underlying glass.
 Venetians with reflective blades to redirect the light

Daylighting in Passive • Venetian blinds are a classic system for controlling

Design sunlight, but they can also be used to redirect it.
• In some cases, the slats have sophisticated shapes and
surface finishes..
Systems To Enhance Natural Lighting:
• In any of these positions, they must be reflective in
Venetian Blinds With Reflective Slats order to redirect light..
 Adjustable reflective perforated slats

Daylighting in Passive
Design • There are several types of slats that are able to
redirect light: fixed or mobile, solid or micro
perforated..
Systems To Enhance Natural Lighting: • Slats perforated with small holes, permit a reasonable
level of inside illumination and some view outside,
Venetian Blinds With Reflective Slats even if they are completely shut
 Anidolic system

Daylighting in Passive • Systems with anidolic ceilings are based on non-

imaging optics and take advantage of the optical

Design properties of CPC (Compound Parabolic Concentrator)

to collect the diffuse light from the sky and convey it to
the less illuminated area part of the room.
Systems To Enhance Natural Lighting: • Outside the building an optical anidolic concentrator
captures and focuses the scattered light coming from
Systems With Anidolic Ceilings the highest part of the sky..
 Anidolic system

Daylighting in Passive
Design • Corresponding with the outlet of the pipe in the back
of the room, a parabolic reflector distributes light into
the lower parts of the room.
Systems To Enhance Natural Lighting: • , the penetration of direct sunlight can be controlled
by a roller blind that unfolds above the outer glass of
Systems With Anidolic Ceilings the opening.
 Shadows cast by the context

• The ideal sun-shading device will block solar radiation

Daylighting in Passive while allowing daylight and breeze to enter the
window, and an external view.
Design • Shading is related primarily to the direct component of
radiation, while the diffuse and reflected components..
Systems To Enhance Natural Lighting: • Shading may be unintentional or independent from
the design choices, or it can be especially designed to
Shading.. control the flow of solar energy into a building.
 Shadows cast by by elements of the building

• In the first case, the main cause of shading is the

Daylighting in Passive profile of the orographic context and the presence of
shading elements such as trees, buildings, etc. In the

Design second case, specific elements and components are

used, such as overhangs, shading, etc.
• There are many methods for evaluating the shadows
Systems To Enhance Natural Lighting: cast on a surface by projecting elements or by
surrounding obstructions, based on the use of
Shading – Diagrams / Tools diagrams or on analytical tools.
Daylighting in Passive Solar angles

Design • Sun path diagrams show the apparent path of the sun
across the sky.
Systems To Enhance Natural Lighting: • The position of the sun in sky is defined by two angles:
solar azimuth (φ) and solar altitude (β) as shown in
Shading – Diagrams / Tools Figure.
Daylighting in Passive Sunpath diagram

Design • Figure above is sun path diagram of Kuala Lumpur. The

paths of the sun are represented by elliptical curves..
Systems To Enhance Natural Lighting: • The vertical curves indicate the location of the sun
along the path at a particular time of the day in solar
Shading – Diagrams / Tools time.
 Superimposed shadow angle protractor on sun path diagram

Daylighting in Passive • In determining the best sun-shading design, Shadow

Design Angle Protractor can be superimposed on the sun

path diagram to determine the Vertical Shadow Angle
(VSA) and the Horizontal Shadow Angle (HSA).
Systems To Enhance Natural Lighting: • Figure above shows the superimposed Shadow Angle
Protractor on the sun path diagram for Kuala Lumpur
Shading – Diagrams / Tools to determine VSA and HSA for North-East (NE) façade..
 Solar angles and shadow angles

Daylighting in Passive
Design
Systems To Enhance Natural Lighting: Shadow angle guidelines for Kuala Lumpur

Shading – Diagrams / Tools

 Construction of the shading mask for a horizontal overhang

Daylighting in Passive
Design
Systems To Enhance Natural Lighting: Construction of the shading mask for a vertical overhang

Shading – Diagrams / Tools

 Sample of shading mask for a vertical and horizontal overhang

Daylighting in Passive
Design
Systems To Enhance Natural Lighting:
Shading – Diagrams / Tools
The same shading mask could be used both for a single overhang and for a
series of blades
 • Solar gains are controlled most effectively with
sunshades outside the windows
• As the sun is always high in the sky at the equator,
horizontal shading devices are the optimal choice for
north and south-facing façades.
• Horizontal overhangs located above the windows on
Daylighting in Passive the north and south-facing façades are very effective
and should extend beyond the width of the window to
Design shade it properly..
• East and west-facing façades are harder to protect
than those facing north and south, because of the low
Systems To Enhance Natural Lighting: position of the sun in the morning and afternoon.
Shading - Devices
Daylighting in Passive
Design
Systems To Enhance Natural Lighting:
Shading - Devices Solar protection types
Daylighting in Passive
Design
Systems To Enhance Natural Lighting:
Shading - Devices
Characteristics of different types of horizontal shading devices
Daylighting in Passive
Design
Systems To Enhance Natural Lighting: Characteristics of different types of vertical shading devices

Shading - Devices
Daylighting in Passive
Design
Systems To Enhance Natural Lighting: Characteristics of different types of egg crate shading devices

Shading - Devices
 • Fixed systems:
• fixed systems are generally placed externally, in order to
intercept the incident solar radiation before it strikes the

Daylighting in Passive
glazed surfaces or other openings, dissipating the
absorbed energy into the outside air;
• they include structural elements such as balconies and
Design overhangs, but also non-structural elements such as
awnings, louvres and blinds..
• each façade requires specific treatment: each orientation
Systems To Enhance Natural Lighting: has to be evaluated separately;
• the tilt angle has to take into account the direction of the
Shading – Devices.. solar rays hitting each façade at different times of day.
 • Movable systems;
• movable shading systems “react” in a more suitable way
Daylighting in Passive •
to sun movement, as compared to fixed systems;
they include systems such as deciduous vegetation, roller
Design •
blinds, perforated slats, Venetian blinds, curtains;
each façade requires specific treatment: each orientation
has to be evaluated separately;
Systems To Enhance Natural Lighting: • the tilt angle can be regulated according to the solar rays
hitting each façade at different times of day.
Shading – Devices..
 • Recommendations;
• Use external shading systems whenever possible; they are
much more effective than interior shading systems at
controlling solar gains, especially if the space is artificially
cooled.
• Use horizontal elements for openings facing south and
north.
• Use egg-crate elements on windows facing east and west.
Daylighting in Passive • Prioritize shading of windows facing east and especially –
west.
Design •
•
The colour of the sunshades affects light and heat..
Choose the materials the shading devices are made of and
their surface properties carefully..
Systems To Enhance Natural Lighting: • Use fixed systems if the budget is limited. Using mobile
systems in order to allow a more efficient use of natural
Shading – Devices.. light and natural ventilation..
 [1] G.C. Brainard, et al., Action spectrum for melatonin regulation in human: evidence for a novel circadian
photoreceptor, J. Neurosci 21 (2001) 6405–6412.

[2] P. Tregenza, M. Wilson, Daylighting: architecture and lighting design, Routledge, New York, 2011.

[3] CIE, Commission internationale de l'Eclairage proceedings, Cambridge University Press, Cambridge, 1931.

[4] DIN 50332, CIE standard colorimetric observers. International compliance: ISO/CIE 10527, CIE 527 (1972) 1991.

[5] DIN 5034-2, Daylight in Interiors, Part 2: Principles, Beuth Verlag, Berlin, 1985.

[6] M.S. Rea, Sustainable Lighting: Let’s talk about Value. Proceedings of CISBAT 2011, EPFL, Lausanne, CH, 2011.

[7] P. Boyce, Human Factors in Lighting, second ed., Taylor & Francis, London, 2003, 584.

[8] R.G. Hopkinson, Glare from daylighting in buildings. Applied Ergonomics (3): 206–215. IEA International Energy
Agency, SHC, Task 21, 2000: Daylight in Buildings, A Source Book on Daylighting Systems and Components,
http://www.iea-shc.org/task21.

[9] CIE-117, Discomfort glare in interior lighting, Austria: Bureau Central de la Commission Internationale de L’Éclairage,
Vienna, 1995.

[10] IES, Lighting Handbook: Reference and Application, eighth ed., Illuminating Engineering Society of North America,
New York, New York, 1993a. IES, American National Standard Practice for Of ce Lighting. ANSI/IESNA RP-1–1993,
Illuminating Engineering Society of North America, New York, New York, 1993b.

[11] J. Wienold, J. Christoffersen, Evaluation methods and development of a new glare prediction model for daylight
environments with the use of CCD cameras, Energy and Buildings, 2006. (in press, corrected proof, available online 24
April 2006).

[12] D. Gall, C. Vandahl, W. Jordanowa, S. Jordanowa, Light protection equipments in of ce rooms, The Shutters and

Daylighting in Passive
Blind Expert. Magazine for Building Details, Kleffmannverlag Bochum, 2000.

[13] DIN EN 12464–1, Light and lighting – Lighting of work places – Part 1: Indoor workplaces, Beuth Verlag, Berlin, 2011.

Design
[14] DIN 5034-3, Daylight in Interiors, Part 3: Calculation, Beuth Verlag, Berlin, 2007.

[15] DIN 5034-1, Daylight in Interiors, Part 1: General requirements, Beuth Verlag, Berlin, 2011.

[16] U. Ficher, Tageslichttechnik, Verlagsgesellschaft Rudolf Mueller, Cologne, 1985.

[17] H. Buelow-Huebe, Daylight in glazed of ce buildings, 2008, http://www.ebd.lth.se/

References leadmin/energi_byggnadsdesign/images/Publikationer/Report_EBD_R_08_17_dagsljus.pdf.

(18) Butera, F., Adhikari, R. S., & Aste, N. (2015). Sustainable building design for tropical climates. UN-Habitat-UNON,
Publishing Services Section.

(19) Sayigh, A. (2013). Sustainability, energy and architecture: Case studies in realizing green buildings. Academic Press.
Thank You
Nik ’Shawn’ Syazwan
01-26789127
niksyazwan.wahab@taylors.edu.my