Introduction daylight within buildings. Therefore, how moreIntroduction daylight within buildings. Therefore, how more

Introduction
and history of daylighting system

 

Introduction

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Daylighting
systems receive natural
light from the sun and deliver it deep into the heart of buildings to provide
the visual comfort and reduce the energy consumption as well as the energy
saving. The energy saving can be achieved by reducing the use of artificial
lighting and convert the solar energy to electricity by using the solar panel.
Daylighting system can be categorized into two main types. One is daylighting
systems with shading. These types that rely primarily on diffuse skylight and reject direct sunlight. Another
one is daylighting systems without shading. Daylighting systems without shading
are designed primarily to redirect daylight to areas away from a window or
skylight opening. They may or may not block direct sunlight.

 

History

For obtaining efficient daylight, glass was first
developed by the Egyptians as early as 3000 BCE. However it was not applied in
a building during a long time. At the first century BCE in Imperial Rome, panes
of glass with small size were used to simultaneously receive the heat of
sunlight indoors to get the human comfort. It was not until the seventeenth century
AD in England that large panes of glass were designed and installed in
buildings. During England’s industrial
revolution, glass walls and wrap-around windows at the corners of buildings
were used to achieve higher levels of daylight in workplaces. Nevertheless,
eventually there was a strong demand for economical use of space led to the reduction
of roof heights and the reduced penetration of daylight within buildings.
Therefore, how more efficiently to get the natural light is one important
principle of today’s
daylighting system.

 

Types of
daylighting system

 

1.Clerestory windows

Clerestory
windows are normally placed higher compared to other windows and they are very
close to roof. Sunlight can be delivered far deeper into a living space than
normal windows throughout the clerestory windows. Therefore, they take main
responsibility to deliver efficient daylight to the house and they also can
provide the heat in wall mass which would normally be in shade to meet the
human demand.

 

 

 

 

 

 

 

 

 

 

 

 

 

Benefits of clerestory windows.

 

They provide
efficient daylight into the building
Reduce glare
and provide privacy.
They increase
solar heat gain to save energy.
They provide a
wide view range if the bottom-storey windows are obstructed by trees,
neighboring homes or other structures.
This window is a magnificent
architectural element and add to the overall aesthetic of the home.

 

 

Drawbacks of clerestory windows.

They may
receive unnecessary light such light from neighbors and even moonlight.
This will bring negative influence in sleeping areas.
Since they’re
high up, they are very close to the warmest air causing excessive heat
storage.
They require
very high ceilings compared to most homes.

 

 

 

 

2.Light pipes

The basic principle of light pipes
is that the outdoor natural light is efficiently collected by a rooftop dome
and re-distributed into the system. After that, natural light will be
transmitted through a light pipe and irradiate them efficiently to any place
requiring light from the diffusing device at the bottom. Even overcast days,
light pipes still can provide enough light. This device is mainly composed by
three parts: light collection device, light guide device, diffuser device.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Benefits of light pipes.

l  
Light Tubes are energy-efficient
to provide more light since less energy escapes from the interior due to less
surface area.

l  
Light Tubes produce more Light
than traditional skylights

l  
Light pipes are more thermally
Insulated

l  
Light pipes bring light to lower floors

l  
Light pipes offer affordability
due to their compact size and modular design

 

 

 

Drawbacks of light pipes.

l  
They are always designed to small sizes. This
small size renders tubular daylighting devices a less ideal solution for
large-scale commercial applications.

l  
High roof occupancy demand. In order to provide adequate light, many light pipes must
be installed

 

 

 

 

 

3.Skylight System

A skylight is like a window in the roof, but its frame is
designed and flashed to withstand the rigors of rainfall that a roof receives.
Since the position of the window is on the top of the building, daylight can be
directly transported to the deep space of the room to decrease the use of
artificial light.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Benefits of skylights

l  
Reduce energy consumption as they
use more daylight instead of artificial light. Therefore, electricity usage is
lower as well as the reduction of the bill.

l  
Reduction of mildew or mold
buildup. Natural lighting can naturally
lessen the production of harmful organisms. Sunlight is considered to be one of
the best natural disinfectants.

l  
Increase human comfort as
daylight provides excellent aesthetics, excellent color, excellent range of
view, and highlights architectural details

 

Drawbacks of skylights

l  
It is difficult to control the
direct beam solar radiation from the sun when it is directly overhead.

l  
Give too much light when the sun
shines directly on the top of the window. It will cause the room becoming too
bright and people will feel uncomfortable.

l  
Increase the heat gain. When the
daylight is being transported from the sun to building, heat will also be
conducted through the window at the same time. Therefore, heat transfer is
increased when sufficient sun lights go into the building.

 

 

 

 

4.Light
shelves

An overhang, usually horizontal, with a highly reflective
upper surface, that reflects daylight onto the ceiling and deep into a space. Light
shelves have two types. One is exterior light shelf. Exterior light shelves are
always robust enough to withstand wind, rain and snow. Therefore, they are able
to protect windows and reduce wall moisture problems. The upper surface of
exterior light shelves is to reflect the light from the sun and they are
normally very flat. Another one type is interior light shelf. This type of
light shelves also can provide a same function to increase penetration and
reduce glare. But they are lightweight and easier to maintain.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Benefits of light shelves

l  
Light shelves improve daylighting
quality and quantity

 

l  
They increase light penetration and
reduce glare

l

l  
They reduce cooling costs. It is
because when they reflect lights from the sun, the heat can be rejected.
Therefore, reduction in cooling demand.

 

 

Drawbacks of light shelves

l  
Their design must be suitable with
windows

 

l  
Maintenance for light shelves is
difficult

 

l  
They require a higher floor-to-ceiling
height.

 

 

 

Real-life
examples of existing buildings making use of these systems

 

Example: BCA
Academy(Singapore)

 

1.Using Light Shelves

Location: Library, L3 offices, experimental office

 

 

 

 

 

 

 

 

 

 

2.Using Light Pipes

Location: Experimental office

 

 

 

 

 

 

 

 

 

 

3.Using shading device

Location: Visitor centre, library, L3 office

 

 

 

 

 

 

 

 

Shading devices minimize direct sunshine and they also reduce
solar gain on the facade.

 

Example: Malaysia’s Diamond Building(Malaysia)

This building wins the latest Asia awards. It includes many
daylighting systems such as light pipes, skylight and PV panels. It contain
self-shading and dynamic shading system to increase daylight and decrease solar
heat gain. It also has daylight sensors in all workplace. Therefore, this
building reduces a huge amount of energy consumption for lighting part.