smart_lighting_noor

1. Smart Lighting for a Smart House

Noor Atari
March 23, 2004

2. SmartHouse Mission Statement

“The DELTA Project seeks to create an interconnected living
environment that will contribute to an increased standard of safety,
technological awareness, and comfort intrinsically linked to conservation
of resources and minimal impact on an already fragile environment.
Engineering students will tailor their research within the three E’s:
Energy & Efficiency,
Environment & Health, and
Entertainment & Communications
Simultaneously, the fourth E: Education, will be evident in all aspects of
the project as we seek to educate both the engineer and the consumer
through the project.”

3. Daylighting Advantages and…

Artificial lighting accounts for as much as 40% to 50% of the energy
consumption in many commercial and institutional buildings.
Daylighting can significantly reduce the lighting power density without
reducing measured lighting levels.
Helps reduce a building owner’s electricity consumption during the
utility’s peak demand periods.
Can help reduce heating and cooling costs
May also reduce the loss of worker productivity during power failures
Although difficult to quantify, daylighting generally increases occupant
satisfaction by providing a healthier, more pleasant environment.

4. The Disadvantages

Direct sunlight causes glare and fades interior furnishings
Daylighting may also contribute to heat losses in the winter and
undesirable heat gain in the summer.
Challenging to provide illumination in areas such as the northern
exposures, internal cavities, and ground levels of buildings.
The major disadvantage is unpredictability. Affected by factors such as:
Position and intensity of the sun
Cloud cover
Nearby shading from hills, vegetation, or buildings
Conclusion: Large quantities of data must be collected so that after
installation, controls and sensors can be calibrated for proper operation.

5. Transmitting Daylight

One way to get daylight into a building is to increase the number and
size of glazed areas in the sides or top of a building. Various
architectural elements:
Conventional windows
Atriums and dome structures
Skylights and roof monitors
Recent development of new films has led to “smart windows” that
change tint in response to light intensity/heat
One technique known as “beam” daylighting redirects light from one
portion of the building to another.
Finally, light-colored walls and angled window openings reduce glare by
providing surfaces that reflect light.

6. Enhancement Devices

A heliostat can be used. Usually located on the roof, the heliostat uses
light sensors, pulse motors, and computers to track the sun. A second
mirror directs the concentrated beam of sunlight to light pipes or down
through an atrium or skylight.
Light pipes are tubes that direct and transmit light to areas where it is
needed.
An adaptation of light pipes are fiber optic cables, which transmit light
by total internal reflection. Can be coupled with a light dispersing cable
to light portions of a building.
The Fresnel lens is an adaptation of the heliostat but it can filter out UV
and IR light and keep visible light.

7. The last step: Artificial Lighting Controls

Important: daylighting will not reduce energy consumption unless users
turn off or reduce the use of unnecessary artificial levels
Lighting control options include on/off switching, dimmers, and multilevel cut-off systems that make use of timers or occupancy snesors.
The SmartHouse can probably use HAL and the built-in sensors to
control light usage.
However, a conscious, conservative life style is crucial to effective
daylighting schemes.

8. Case Study 1 - Overview

London’s Great Hall, completed on July of
2002
Chosen because of great tilted egg design,
an intriguing concept which was both costefficient and aesthetically pleasing.
Energy efficient design minimizes the total
surface area of the building
Building tilts to the south, effectively
promoting self-shading
Creative response of a building to its
environment. Coined as a highperformance façade.

9. Case Study 1 - Details

The structure has 17 degree tilt to
the south and a curved geometry,
which negated the use of vertical
columns. Instead inclined and
faceted columns were used.
A close collaboration between the
architect and the structural
engineers was needed in studying
the variations on the spherical
shape to provide for the best use
of interior space and energy
efficiency.

10. Daylighting Focus: Retractable Roof

Continues the overlying theme of integrating the indoors with the
outdoors. Creates an transitional interface to the environment.
The ability to retract the roof and sidewalls provides the ability to
control temperatures, humidity, wind and light conditions. Possible for
the chimney effect of hot air.
A return to archaic methods of ventilation—an open courtyard—but
with improved control.
Makes the central courtyard manageable for any vegetation present.
Once opened can provide an unobstructed view of the outdoors.

11. Potential Designs – Conventional

Designs by Bentech of Sweden
Capable of spanning over
swimming pools
Rainproof to an angle of two
degrees. Electronic control.
Glassfiber composites provides
load carrying capacity almost
double that of steel
Architecturally simple and elegant

12. Potential Designs - DSL technology

Designs for planar or spherical
retractable roofs
Individual elements are rigid but
designed so that their relative
motion does not cause
interference
Open to a nearly circular
opening
Rigid and gap-free in both the
open and closed states
Works well with the symbolism
of opening to the environment

13. Case Study 2 - Overview

Oita Main Stadium completed in 2001 for the World Cup in Japan
Steel and reinforced concrete
A slit allowing ventilation is set between the roof and the spectator
seating permitting both a view of the mountains and comfort for
the summer spectator. The slit also is designed to not create a
feeling of being closed inside the stadium.
The idea emerged to install a moving camera on the main beam,
the world's first, to deliver dynamic images to the rest or the world.

14. Case Study 2 - Details

Through the gentle curves of the
spherical design, the stadium matches
well with the surroundings in the
background.
The choice of a sphere is naturally an
expression of abstract symbolism, but
the shape actually enables the
retractable portion to move along its
surface.
The use of ultra-modern teflon
membrane panels with 25% lightpermeablity removes the need for
artificial lighting during daylight hours.

15. Contact Info

Noor Atari, nna@duke.edu
Additional readings at
http://www.retractableroof.com/technical/literatur
e.html